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help with speaker configuration
I am hoping that someone would be able to offer some insight into a
speaker configuration problem I'm having. I have built an mp3 jukebox and have installed 3 full range speakers into the cabinet (full range so I didn't have to bother with cross over networks). My amp delivers 70watts into 4Ohms, my speaker configuration consists of 2 x 50watt 8 Ohms speakers in one parallel leg(giving me 4 Ohms) and 1 80watt 4Ohms speaker in series with the parallel leg. So 2 x 4Ohms in series gives me 8Ohms. This ofcourse should mean my amp will deliver only half its stated output (therefore, should be delivering 35watts). My problem is the lager 4Ohms 80watt speaker that is in series with the parallel leg has burn't out. I have no idea why. ----8Ohms---- (50watts) | | | | ----8Ohms---- (50watts) | | | -------4Ohms------- (80watts) | | I read a similar reply recently that stated maybe its because the wattage is unbalanced or the number of speakers were unbalanced, resulting in the 4Ohms 80watt speaker doing double the work. Please help if you can, any insight into this problem would be greatly appreciated, its driving me nuts.. Thanks in advance Steve |
help with speaker configuration
1. YOu cannot be certain that the speaker ratings are accurate.
2. You cannot state that the 8ohm load will result in your amp supplying only half power. It depends on the current capability of the amp. 3. The so-called 80watt speaker is in series with the now 100watt pair and any power disipated goes through both. Kal On 28 Oct 2003 08:24:46 -0800, (steven robinson) wrote: I am hoping that someone would be able to offer some insight into a speaker configuration problem I'm having. I have built an mp3 jukebox and have installed 3 full range speakers into the cabinet (full range so I didn't have to bother with cross over networks). My amp delivers 70watts into 4Ohms, my speaker configuration consists of 2 x 50watt 8 Ohms speakers in one parallel leg(giving me 4 Ohms) and 1 80watt 4Ohms speaker in series with the parallel leg. So 2 x 4Ohms in series gives me 8Ohms. This ofcourse should mean my amp will deliver only half its stated output (therefore, should be delivering 35watts). My problem is the lager 4Ohms 80watt speaker that is in series with the parallel leg has burn't out. I have no idea why. ----8Ohms---- (50watts) | | | | ----8Ohms---- (50watts) | | | -------4Ohms------- (80watts) | | I read a similar reply recently that stated maybe its because the wattage is unbalanced or the number of speakers were unbalanced, resulting in the 4Ohms 80watt speaker doing double the work. Please help if you can, any insight into this problem would be greatly appreciated, its driving me nuts.. Thanks in advance Steve |
help with speaker configuration
In article , steven
robinson wrote: My problem is the lager 4Ohms 80watt speaker that is in series with the parallel leg has burn't out. I have no idea why. ----8Ohms---- (50watts) | | | | ----8Ohms---- (50watts) | | | -------4Ohms------- (80watts) | | I read a similar reply recently that stated maybe its because the wattage is unbalanced or the number of speakers were unbalanced, resulting in the 4Ohms 80watt speaker doing double the work. The main concern I have is that calling a speaker '4 Ohm' or '8 Ohm' is an entirely nominal value.The *actual* value of the impedance is likely to be very frequency dependent, and at some frequencies it may be a long way from the quoted nominal value. Putting dissimilar speaker units in series is a recipy for potential pun disaster for this reason... At some frequencies the impedance of one unit may be much higher than the nominal value, and the other(s) much lower. This mean mean the power is far from being distributed as you might assume from the 'nominal' values. Also: Since you are not using any crossover networks it may be that at - for example - low frequencies *all* your speakers have low impedances (thus drawing more current/power than you assume), and their values are such that most of the power ends up in one unit - which can then fail. To say more, I'd need to see impedance/frequency plots for each of the units. Another reason putting dissimilar units in series is often a bad idea is that each one (for the reason given above) will experience a drive voltage that is frequency dependent. Thus the resulting overall output sound power/frequency response is likely to be changed. Each unit *used and driven individually* might be acceptable as a broadband speaker, but combined, the results may be very different. There are also some other variables involved, so in general, I would not expect what you produced to sound particularly good, even if it survived! However this depends upon the units, and how they were fitted to the cabinets, etc, etc. Personally, I'd also use some kind of added network, just to define the impedance values. For example, some amplifiers may not like the load they see at LF or HF from a speaker of the kind you describe. This can also lead to trouble if the amp is not unconditionally stable. Also occurs to me to point out that when putting reactive components in series, the magnitudes of the voltages on each, if added, can actually add up to *more* than the total applied across them all. ( ;- ) So, again, this can be a recipy for problems... (The voltages add up as vector/complex values, and may be out of phase with each other, hence leading to this effect.) Please help if you can, any insight into this problem would be greatly appreciated, its driving me nuts.. Do you have impedance/frequency plots of the individual units? Any idea how these values were altered by the cabinets and/or combined useage? What amplifier did you use, and is it unconditionally stable? Slainte, Jim -- Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html |
help with speaker configuration
In article , steven
robinson wrote: My problem is the lager 4Ohms 80watt speaker that is in series with the parallel leg has burn't out. I have no idea why. ----8Ohms---- (50watts) | | | | ----8Ohms---- (50watts) | | | -------4Ohms------- (80watts) | | I read a similar reply recently that stated maybe its because the wattage is unbalanced or the number of speakers were unbalanced, resulting in the 4Ohms 80watt speaker doing double the work. The main concern I have is that calling a speaker '4 Ohm' or '8 Ohm' is an entirely nominal value.The *actual* value of the impedance is likely to be very frequency dependent, and at some frequencies it may be a long way from the quoted nominal value. Putting dissimilar speaker units in series is a recipy for potential pun disaster for this reason... At some frequencies the impedance of one unit may be much higher than the nominal value, and the other(s) much lower. This mean mean the power is far from being distributed as you might assume from the 'nominal' values. Also: Since you are not using any crossover networks it may be that at - for example - low frequencies *all* your speakers have low impedances (thus drawing more current/power than you assume), and their values are such that most of the power ends up in one unit - which can then fail. To say more, I'd need to see impedance/frequency plots for each of the units. Another reason putting dissimilar units in series is often a bad idea is that each one (for the reason given above) will experience a drive voltage that is frequency dependent. Thus the resulting overall output sound power/frequency response is likely to be changed. Each unit *used and driven individually* might be acceptable as a broadband speaker, but combined, the results may be very different. There are also some other variables involved, so in general, I would not expect what you produced to sound particularly good, even if it survived! However this depends upon the units, and how they were fitted to the cabinets, etc, etc. Personally, I'd also use some kind of added network, just to define the impedance values. For example, some amplifiers may not like the load they see at LF or HF from a speaker of the kind you describe. This can also lead to trouble if the amp is not unconditionally stable. Also occurs to me to point out that when putting reactive components in series, the magnitudes of the voltages on each, if added, can actually add up to *more* than the total applied across them all. ( ;- ) So, again, this can be a recipy for problems... (The voltages add up as vector/complex values, and may be out of phase with each other, hence leading to this effect.) Please help if you can, any insight into this problem would be greatly appreciated, its driving me nuts.. Do you have impedance/frequency plots of the individual units? Any idea how these values were altered by the cabinets and/or combined useage? What amplifier did you use, and is it unconditionally stable? Slainte, Jim -- Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html |
help with speaker configuration
In article , Kalman Rubinson
wrote: 3. The so-called 80watt speaker is in series with the now 100watt pair and any power disipated goes through both. Not sure what you mean by the above. Can you clarify? Slainte, Jim -- Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html |
help with speaker configuration
In article , Kalman Rubinson
wrote: 3. The so-called 80watt speaker is in series with the now 100watt pair and any power disipated goes through both. Not sure what you mean by the above. Can you clarify? Slainte, Jim -- Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html |
help with speaker configuration
In article ,
steven robinson wrote: I read a similar reply recently that stated maybe its because the wattage is unbalanced or the number of speakers were unbalanced, resulting in the 4Ohms 80watt speaker doing double the work. Please help if you can, any insight into this problem would be greatly appreciated, its driving me nuts.. Speaker impedances are nominal and will vary with frequency and also from one to another of different types. So it's perfectly possible that the 4 ohm one is being asked to handle much more power at some frequencies than the other two than the simple resistance calculation suggests. Wiring speakers in series is not a good idea, anyway. Far better to use one amp per speaker. -- *It is wrong to ever split an infinitive * Dave Plowman London SW 12 RIP Acorn |
help with speaker configuration
In article ,
steven robinson wrote: I read a similar reply recently that stated maybe its because the wattage is unbalanced or the number of speakers were unbalanced, resulting in the 4Ohms 80watt speaker doing double the work. Please help if you can, any insight into this problem would be greatly appreciated, its driving me nuts.. Speaker impedances are nominal and will vary with frequency and also from one to another of different types. So it's perfectly possible that the 4 ohm one is being asked to handle much more power at some frequencies than the other two than the simple resistance calculation suggests. Wiring speakers in series is not a good idea, anyway. Far better to use one amp per speaker. -- *It is wrong to ever split an infinitive * Dave Plowman London SW 12 RIP Acorn |
help with speaker configuration
Jim Lesurf wrote in message ...
In article , steven robinson wrote: My problem is the lager 4Ohms 80watt speaker that is in series with the parallel leg has burn't out. I have no idea why. ----8Ohms---- (50watts) | | | | ----8Ohms---- (50watts) | | | -------4Ohms------- (80watts) | | I read a similar reply recently that stated maybe its because the wattage is unbalanced or the number of speakers were unbalanced, resulting in the 4Ohms 80watt speaker doing double the work. The main concern I have is that calling a speaker '4 Ohm' or '8 Ohm' is an entirely nominal value.The *actual* value of the impedance is likely to be very frequency dependent, and at some frequencies it may be a long way from the quoted nominal value. Putting dissimilar speaker units in series is a recipy for potential pun disaster for this reason... At some frequencies the impedance of one unit may be much higher than the nominal value, and the other(s) much lower. This mean mean the power is far from being distributed as you might assume from the 'nominal' values. Also: Since you are not using any crossover networks it may be that at - for example - low frequencies *all* your speakers have low impedances (thus drawing more current/power than you assume), and their values are such that most of the power ends up in one unit - which can then fail. To say more, I'd need to see impedance/frequency plots for each of the units. Another reason putting dissimilar units in series is often a bad idea is that each one (for the reason given above) will experience a drive voltage that is frequency dependent. Thus the resulting overall output sound power/frequency response is likely to be changed. Each unit *used and driven individually* might be acceptable as a broadband speaker, but combined, the results may be very different. There are also some other variables involved, so in general, I would not expect what you produced to sound particularly good, even if it survived! However this depends upon the units, and how they were fitted to the cabinets, etc, etc. Personally, I'd also use some kind of added network, just to define the impedance values. For example, some amplifiers may not like the load they see at LF or HF from a speaker of the kind you describe. This can also lead to trouble if the amp is not unconditionally stable. Also occurs to me to point out that when putting reactive components in series, the magnitudes of the voltages on each, if added, can actually add up to *more* than the total applied across them all. ( ;- ) So, again, this can be a recipy for problems... (The voltages add up as vector/complex values, and may be out of phase with each other, hence leading to this effect.) Please help if you can, any insight into this problem would be greatly appreciated, its driving me nuts.. Do you have impedance/frequency plots of the individual units? Any idea how these values were altered by the cabinets and/or combined useage? What amplifier did you use, and is it unconditionally stable? Slainte, Jim Hi Jim Thanks for the reply, a lot of what you are saying is foreign to me, but this is what I know: The spec of the 8Ohms 50watt speakers in the parallel leg a Nominal power 30watts Peak power 50watts SPL @ 1W/1m 82db Frequency range 100Hz to 20kHz Resonant Frequency 130Hz Max cone displacement 5mm Voice coil diameter 20mm Magnetic inductance 0.8 Tesla Magnetic flux 200u Weber Withount using cross overs how can I block damaging frequencies lower than 100Hz and higher than 20kHz from the drivers? or isn't that a concern? Unfortunately I don't know anything about the 4Ohms speaker, except its Peak power is 80watts. Likewise the amp is a bit of a mistery, it is an amp called a v-series manufactured by an amusement company in leeds. Its output is supposed to be 70watts into 4Ohms. I'm getting the impresion that putting dis-similat drivers in series is a bad idea. What if I put two 8Ohms in series twice and parallel them together, would this be a better idea? I could then use the same speakers with the same properties. In this configuration you would expect the output to be spread evenly across the four speakers, wouldn't you? What do you think? Thanks Steve |
help with speaker configuration
Jim Lesurf wrote in message ...
In article , steven robinson wrote: My problem is the lager 4Ohms 80watt speaker that is in series with the parallel leg has burn't out. I have no idea why. ----8Ohms---- (50watts) | | | | ----8Ohms---- (50watts) | | | -------4Ohms------- (80watts) | | I read a similar reply recently that stated maybe its because the wattage is unbalanced or the number of speakers were unbalanced, resulting in the 4Ohms 80watt speaker doing double the work. The main concern I have is that calling a speaker '4 Ohm' or '8 Ohm' is an entirely nominal value.The *actual* value of the impedance is likely to be very frequency dependent, and at some frequencies it may be a long way from the quoted nominal value. Putting dissimilar speaker units in series is a recipy for potential pun disaster for this reason... At some frequencies the impedance of one unit may be much higher than the nominal value, and the other(s) much lower. This mean mean the power is far from being distributed as you might assume from the 'nominal' values. Also: Since you are not using any crossover networks it may be that at - for example - low frequencies *all* your speakers have low impedances (thus drawing more current/power than you assume), and their values are such that most of the power ends up in one unit - which can then fail. To say more, I'd need to see impedance/frequency plots for each of the units. Another reason putting dissimilar units in series is often a bad idea is that each one (for the reason given above) will experience a drive voltage that is frequency dependent. Thus the resulting overall output sound power/frequency response is likely to be changed. Each unit *used and driven individually* might be acceptable as a broadband speaker, but combined, the results may be very different. There are also some other variables involved, so in general, I would not expect what you produced to sound particularly good, even if it survived! However this depends upon the units, and how they were fitted to the cabinets, etc, etc. Personally, I'd also use some kind of added network, just to define the impedance values. For example, some amplifiers may not like the load they see at LF or HF from a speaker of the kind you describe. This can also lead to trouble if the amp is not unconditionally stable. Also occurs to me to point out that when putting reactive components in series, the magnitudes of the voltages on each, if added, can actually add up to *more* than the total applied across them all. ( ;- ) So, again, this can be a recipy for problems... (The voltages add up as vector/complex values, and may be out of phase with each other, hence leading to this effect.) Please help if you can, any insight into this problem would be greatly appreciated, its driving me nuts.. Do you have impedance/frequency plots of the individual units? Any idea how these values were altered by the cabinets and/or combined useage? What amplifier did you use, and is it unconditionally stable? Slainte, Jim Hi Jim Thanks for the reply, a lot of what you are saying is foreign to me, but this is what I know: The spec of the 8Ohms 50watt speakers in the parallel leg a Nominal power 30watts Peak power 50watts SPL @ 1W/1m 82db Frequency range 100Hz to 20kHz Resonant Frequency 130Hz Max cone displacement 5mm Voice coil diameter 20mm Magnetic inductance 0.8 Tesla Magnetic flux 200u Weber Withount using cross overs how can I block damaging frequencies lower than 100Hz and higher than 20kHz from the drivers? or isn't that a concern? Unfortunately I don't know anything about the 4Ohms speaker, except its Peak power is 80watts. Likewise the amp is a bit of a mistery, it is an amp called a v-series manufactured by an amusement company in leeds. Its output is supposed to be 70watts into 4Ohms. I'm getting the impresion that putting dis-similat drivers in series is a bad idea. What if I put two 8Ohms in series twice and parallel them together, would this be a better idea? I could then use the same speakers with the same properties. In this configuration you would expect the output to be spread evenly across the four speakers, wouldn't you? What do you think? Thanks Steve |
help with speaker configuration
In article , steven
robinson wrote: Jim Lesurf wrote in message ... [snip loads] Do you have impedance/frequency plots of the individual units? Any idea how these values were altered by the cabinets and/or combined useage? What amplifier did you use, and is it unconditionally stable? Hi Jim Thanks for the reply, a lot of what you are saying is foreign to me, but this is what I know: The spec of the 8Ohms 50watt speakers in the parallel leg a Nominal power 30watts Peak power 50watts SPL @ 1W/1m 82db Frequency range 100Hz to 20kHz Resonant Frequency 130Hz Max cone displacement 5mm Voice coil diameter 20mm Magnetic inductance 0.8 Tesla Magnetic flux 200u Weber Alas, the above does not tell you what you'd need to know to be able to start the process of trying to design an 'in series' design. TBH such designs, using dissimilar speakers, would be a nightmare to get right without a lot of test gear, etc. Best avoided in my view as trying this (as you have found) can be more grief that you'd expect. Withount using cross overs how can I block damaging frequencies lower than 100Hz and higher than 20kHz from the drivers? or isn't that a concern? I can't tell what may or may not be the real cause of the problem you had. The problem is that there is too much we don't know that might have an effect. However the resonance frequency (which I assume is 'free air') of 130 Hz seems quite high for a 'full range' speaker. I may well be wrong as I lack data. Someone who knows more about speaker building may well be able to give a better comment on this. However I'd suspect that below 100 Hz the cone movements might become too great unless you use the unit in a cabinet that acts as a closed box to limit this. Otherwise, to control movements, you will need a cross-over - although this could be an 'active' type applied before using distinct power-amps to drive the individual units. This may all be to complicated for you to wish to do, though. For the above reasons it is possible that the speaker was damaged by being forced to move too far to provide LF output. i.e. by exceeding its mechanical limits, not by overheating by excessive power. It is unlikely that signals above 20kHz will do any damage. Chances are that there is only a little power at such frequencies, and the units will essentially ignore it. :-) (This assumption may not be correct if the amplifier went into oscillations and was producing very high powers at an ultrasonic frequency. However normal music and speech does not usually have much in the way of sustained high powers above 20kHz.) Unfortunately I don't know anything about the 4Ohms speaker, except its Peak power is 80watts. Likewise the amp is a bit of a mistery, it is an amp called a v-series manufactured by an amusement company in leeds. Its output is supposed to be 70watts into 4Ohms. Unless you can establish that it is an unconditionally stable design, then it is possible that it went into oscillation and this caused problems. This is probably less likely than other causes, but I can't rule it out at this point. I'm getting the impresion that putting dis-similat drivers in series is a bad idea. It is, unless you know a great deal about the units, and can carry out the relevant design/measurement process. Afraid it isn't as simple as assuming the power is divided up as if the units were plain resistors. In general, 'hi fi' designs avoid speakers in series without any cross-over or adjustment networks. What if I put two 8Ohms in series twice and parallel them together, would this be a better idea? I could then use the same speakers with the same properties. This is more likely to work as the inherent properties of the units are the same. However it may still not work as you expect for various reasons. For example: Putting the units into the same cabinet mean they couple acoustically. This alters their properties, so even though you have connected them in 'series/parallel' the resulting impedances, etc may not be the same as for a single driver in the same cabinet. In this configuration you would expect the output to be spread evenly across the four speakers, wouldn't you? What do you think? The output would probably be distributed reasonably evenly, but it is hard to be certain about this as the cabinet has an effect. It would be better than using dissimilar units, but it is not something I'd normally recommend as the results may still not be what you anticipate. For example: there will be acoustic interference between the units that will alter the resulting total response, etc. To be honest, trying to do anything like this is risky without having a fair amount of data, and/or doing the right measurements, or proceeding with care and taking a long time experimenting. FWIW I've happily designed and build various amplifiers, and tuners, and other 'electronic' items over the years. I also cheerfully modify commercial electronics to alter the performance to suit. However I have always avoided trying to self-design speakers. Simply too difficult and time-consuming to get right. :-) That said, many people do develop their own designs, and produce good results. However this can involve a lot of effort and patience and understanding. Some of the 'kits' and published designs can work well if made with care, but these are obviously based upon someone else having already put in the time and effort to sort out the necessary details! Slainte, Jim -- Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html |
help with speaker configuration
In article , steven
robinson wrote: Jim Lesurf wrote in message ... [snip loads] Do you have impedance/frequency plots of the individual units? Any idea how these values were altered by the cabinets and/or combined useage? What amplifier did you use, and is it unconditionally stable? Hi Jim Thanks for the reply, a lot of what you are saying is foreign to me, but this is what I know: The spec of the 8Ohms 50watt speakers in the parallel leg a Nominal power 30watts Peak power 50watts SPL @ 1W/1m 82db Frequency range 100Hz to 20kHz Resonant Frequency 130Hz Max cone displacement 5mm Voice coil diameter 20mm Magnetic inductance 0.8 Tesla Magnetic flux 200u Weber Alas, the above does not tell you what you'd need to know to be able to start the process of trying to design an 'in series' design. TBH such designs, using dissimilar speakers, would be a nightmare to get right without a lot of test gear, etc. Best avoided in my view as trying this (as you have found) can be more grief that you'd expect. Withount using cross overs how can I block damaging frequencies lower than 100Hz and higher than 20kHz from the drivers? or isn't that a concern? I can't tell what may or may not be the real cause of the problem you had. The problem is that there is too much we don't know that might have an effect. However the resonance frequency (which I assume is 'free air') of 130 Hz seems quite high for a 'full range' speaker. I may well be wrong as I lack data. Someone who knows more about speaker building may well be able to give a better comment on this. However I'd suspect that below 100 Hz the cone movements might become too great unless you use the unit in a cabinet that acts as a closed box to limit this. Otherwise, to control movements, you will need a cross-over - although this could be an 'active' type applied before using distinct power-amps to drive the individual units. This may all be to complicated for you to wish to do, though. For the above reasons it is possible that the speaker was damaged by being forced to move too far to provide LF output. i.e. by exceeding its mechanical limits, not by overheating by excessive power. It is unlikely that signals above 20kHz will do any damage. Chances are that there is only a little power at such frequencies, and the units will essentially ignore it. :-) (This assumption may not be correct if the amplifier went into oscillations and was producing very high powers at an ultrasonic frequency. However normal music and speech does not usually have much in the way of sustained high powers above 20kHz.) Unfortunately I don't know anything about the 4Ohms speaker, except its Peak power is 80watts. Likewise the amp is a bit of a mistery, it is an amp called a v-series manufactured by an amusement company in leeds. Its output is supposed to be 70watts into 4Ohms. Unless you can establish that it is an unconditionally stable design, then it is possible that it went into oscillation and this caused problems. This is probably less likely than other causes, but I can't rule it out at this point. I'm getting the impresion that putting dis-similat drivers in series is a bad idea. It is, unless you know a great deal about the units, and can carry out the relevant design/measurement process. Afraid it isn't as simple as assuming the power is divided up as if the units were plain resistors. In general, 'hi fi' designs avoid speakers in series without any cross-over or adjustment networks. What if I put two 8Ohms in series twice and parallel them together, would this be a better idea? I could then use the same speakers with the same properties. This is more likely to work as the inherent properties of the units are the same. However it may still not work as you expect for various reasons. For example: Putting the units into the same cabinet mean they couple acoustically. This alters their properties, so even though you have connected them in 'series/parallel' the resulting impedances, etc may not be the same as for a single driver in the same cabinet. In this configuration you would expect the output to be spread evenly across the four speakers, wouldn't you? What do you think? The output would probably be distributed reasonably evenly, but it is hard to be certain about this as the cabinet has an effect. It would be better than using dissimilar units, but it is not something I'd normally recommend as the results may still not be what you anticipate. For example: there will be acoustic interference between the units that will alter the resulting total response, etc. To be honest, trying to do anything like this is risky without having a fair amount of data, and/or doing the right measurements, or proceeding with care and taking a long time experimenting. FWIW I've happily designed and build various amplifiers, and tuners, and other 'electronic' items over the years. I also cheerfully modify commercial electronics to alter the performance to suit. However I have always avoided trying to self-design speakers. Simply too difficult and time-consuming to get right. :-) That said, many people do develop their own designs, and produce good results. However this can involve a lot of effort and patience and understanding. Some of the 'kits' and published designs can work well if made with care, but these are obviously based upon someone else having already put in the time and effort to sort out the necessary details! Slainte, Jim -- Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html |
help with speaker configuration
On Tue, 28 Oct 2003 17:41:53 +0000 (GMT), Jim Lesurf
wrote: In article , Kalman Rubinson wrote: 3. The so-called 80watt speaker is in series with the now 100watt pair and any power disipated goes through both. Not sure what you mean by the above. Can you clarify? Just from your wiring. All current must go through the 80watt speaker which is in series with the paralleled others. Thus, it now becomes the limiting power factor, further stressed by the non-linear drive imposed on it by the others. I wish I could suggest a solution but I do not know your goals. Kal |
help with speaker configuration
On Tue, 28 Oct 2003 17:41:53 +0000 (GMT), Jim Lesurf
wrote: In article , Kalman Rubinson wrote: 3. The so-called 80watt speaker is in series with the now 100watt pair and any power disipated goes through both. Not sure what you mean by the above. Can you clarify? Just from your wiring. All current must go through the 80watt speaker which is in series with the paralleled others. Thus, it now becomes the limiting power factor, further stressed by the non-linear drive imposed on it by the others. I wish I could suggest a solution but I do not know your goals. Kal |
help with speaker configuration
In article , Kalman Rubinson
wrote: On Tue, 28 Oct 2003 17:41:53 +0000 (GMT), Jim Lesurf wrote: In article , Kalman Rubinson wrote: 3. The so-called 80watt speaker is in series with the now 100watt pair and any power disipated goes through both. Not sure what you mean by the above. Can you clarify? Just from your wiring. The wiring was, I think, Steven's, not mine. All current must go through the 80watt speaker which is in series with the paralleled others. Erm... Current is not power. They are quite distinct physical quantities, albeit ones which have a specific relationship for a specific component. The current will pass through the '80 watt' speaker, but this does not necessarily mean that the 'power' passes though the speaker on its way to the others. This is because the actual power is conveyed by the EM fields, and the 80 Watt speaker has no way to know what electric potential ('voltage') is across any *other* loads in series with it. Hence it does not actually experience the power being dissipated by the other units. Thus, it now becomes the limiting power factor, Afraid that, again, I'm not quite sure why you are saying this. Each individual speaker unit has no awareness as such of what voltages or currents or powers any *other* units experience. It only knows about the potential between its own terminals, and the current that it then passes. further stressed by the non-linear drive imposed on it by the others. Are you talking about non-linear impedance here? if so, I'm unsure why. My own comments on what Steven said were based upon things like frequency dependence, and linear acoustic effects, not signal-level dependence. I wish I could suggest a solution but I do not know your goals. I assume that you mean Steven's goals. :-) My own recommendation to him would be to avoid using dissimilar speakers in series. Slainte, Jim -- Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html |
help with speaker configuration
In article , Kalman Rubinson
wrote: On Tue, 28 Oct 2003 17:41:53 +0000 (GMT), Jim Lesurf wrote: In article , Kalman Rubinson wrote: 3. The so-called 80watt speaker is in series with the now 100watt pair and any power disipated goes through both. Not sure what you mean by the above. Can you clarify? Just from your wiring. The wiring was, I think, Steven's, not mine. All current must go through the 80watt speaker which is in series with the paralleled others. Erm... Current is not power. They are quite distinct physical quantities, albeit ones which have a specific relationship for a specific component. The current will pass through the '80 watt' speaker, but this does not necessarily mean that the 'power' passes though the speaker on its way to the others. This is because the actual power is conveyed by the EM fields, and the 80 Watt speaker has no way to know what electric potential ('voltage') is across any *other* loads in series with it. Hence it does not actually experience the power being dissipated by the other units. Thus, it now becomes the limiting power factor, Afraid that, again, I'm not quite sure why you are saying this. Each individual speaker unit has no awareness as such of what voltages or currents or powers any *other* units experience. It only knows about the potential between its own terminals, and the current that it then passes. further stressed by the non-linear drive imposed on it by the others. Are you talking about non-linear impedance here? if so, I'm unsure why. My own comments on what Steven said were based upon things like frequency dependence, and linear acoustic effects, not signal-level dependence. I wish I could suggest a solution but I do not know your goals. I assume that you mean Steven's goals. :-) My own recommendation to him would be to avoid using dissimilar speakers in series. Slainte, Jim -- Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html |
help with speaker configuration
On Wed, 29 Oct 2003 16:59:50 +0000 (GMT), Jim Lesurf
wrote: The current will pass through the '80 watt' speaker, but this does not necessarily mean that the 'power' passes though the speaker on its way to the others. This is because the actual power is conveyed by the EM fields, and the 80 Watt speaker has no way to know what electric potential ('voltage') is across any *other* loads in series with it. Hence it does not actually experience the power being dissipated by the other units. Thus, it now becomes the limiting power factor, Afraid that, again, I'm not quite sure why you are saying this. Each individual speaker unit has no awareness as such of what voltages or currents or powers any *other* units experience. It only knows about the potential between its own terminals, and the current that it then passes. Current is measured in amps. If two units are connected in series, the same amperage will flow through both. If not, where would it go? The resistance of each unit will determine how much power is drawn by it. "Power is conveyed by the EM fields" is meaningless gobbledygook. |
help with speaker configuration
On Wed, 29 Oct 2003 16:59:50 +0000 (GMT), Jim Lesurf
wrote: The current will pass through the '80 watt' speaker, but this does not necessarily mean that the 'power' passes though the speaker on its way to the others. This is because the actual power is conveyed by the EM fields, and the 80 Watt speaker has no way to know what electric potential ('voltage') is across any *other* loads in series with it. Hence it does not actually experience the power being dissipated by the other units. Thus, it now becomes the limiting power factor, Afraid that, again, I'm not quite sure why you are saying this. Each individual speaker unit has no awareness as such of what voltages or currents or powers any *other* units experience. It only knows about the potential between its own terminals, and the current that it then passes. Current is measured in amps. If two units are connected in series, the same amperage will flow through both. If not, where would it go? The resistance of each unit will determine how much power is drawn by it. "Power is conveyed by the EM fields" is meaningless gobbledygook. |
help with speaker configuration
On Thu, 30 Oct 2003 13:36:51 +0000
Laurence Payne wrote: Current is measured in amps. If two units are connected in series, the same amperage will flow through both. If not, where would it go? The resistance of each unit will determine how much power is drawn by it. "Power is conveyed by the EM fields" is meaningless gobbledygook. Power is not the same as current. -- Spyros lair: http://www.mnementh.co.uk/ |||| Maintainer: arm26 linux Do not meddle in the affairs of Dragons, for you are tasty and good with ketchup. |
help with speaker configuration
On Thu, 30 Oct 2003 13:36:51 +0000
Laurence Payne wrote: Current is measured in amps. If two units are connected in series, the same amperage will flow through both. If not, where would it go? The resistance of each unit will determine how much power is drawn by it. "Power is conveyed by the EM fields" is meaningless gobbledygook. Power is not the same as current. -- Spyros lair: http://www.mnementh.co.uk/ |||| Maintainer: arm26 linux Do not meddle in the affairs of Dragons, for you are tasty and good with ketchup. |
help with speaker configuration
In article ,
Laurence Payne wrote: Current is measured in amps. If two units are connected in series, the same amperage will flow through both. If not, where would it go? The resistance of each unit will determine how much power is drawn by it. Exactly. And it's the heating effect of the watts that does the damage. Think of how a fuse works. -- *Real women don't have hot flashes, they have power surges. Dave Plowman London SW 12 RIP Acorn |
help with speaker configuration
In article ,
Laurence Payne wrote: Current is measured in amps. If two units are connected in series, the same amperage will flow through both. If not, where would it go? The resistance of each unit will determine how much power is drawn by it. Exactly. And it's the heating effect of the watts that does the damage. Think of how a fuse works. -- *Real women don't have hot flashes, they have power surges. Dave Plowman London SW 12 RIP Acorn |
help with speaker configuration
On Wed, 29 Oct 2003 16:59:50 +0000 (GMT), Jim Lesurf
wrote: All current must go through the 80watt speaker which is in series with the paralleled others. Erm... Current is not power. They are quite distinct physical quantities, albeit ones which have a specific relationship for a specific component. If the 80watter is in series with the others (my interpretation of the wiring) then all the current passes through it. What power it dissipates, of course, depends on its own construction. Thus, it now becomes the limiting power factor, Afraid that, again, I'm not quite sure why you are saying this. Each individual speaker unit has no awareness as such of what voltages or currents or powers any *other* units experience. It only knows about the potential between its own terminals, and the current that it then passes. Sure but if the user is trying to pump a lot of power out of the set, whatever current that is used by the higher-wattage parallel-pair must pass through the 80watter which is in series with it. Assuming identical power dissipation for the moment, the 80watter will blow before the parallel-pair. further stressed by the non-linear drive imposed on it by the others. Are you talking about non-linear impedance here? if so, I'm unsure why. My own comments on what Steven said were based upon things like frequency dependence, and linear acoustic effects, not signal-level dependence. Yes, non-linear impedance (non-linear wrt frequency primarily) whose effects can be exacerbated at higher levels. I wish I could suggest a solution but I do not know your goals. I assume that you mean Steven's goals. :-) My own recommendation to him would be to avoid using dissimilar speakers in series. Sorry. I didn't see your name at the top. I agree with your recommendation. Kal |
help with speaker configuration
On Wed, 29 Oct 2003 16:59:50 +0000 (GMT), Jim Lesurf
wrote: All current must go through the 80watt speaker which is in series with the paralleled others. Erm... Current is not power. They are quite distinct physical quantities, albeit ones which have a specific relationship for a specific component. If the 80watter is in series with the others (my interpretation of the wiring) then all the current passes through it. What power it dissipates, of course, depends on its own construction. Thus, it now becomes the limiting power factor, Afraid that, again, I'm not quite sure why you are saying this. Each individual speaker unit has no awareness as such of what voltages or currents or powers any *other* units experience. It only knows about the potential between its own terminals, and the current that it then passes. Sure but if the user is trying to pump a lot of power out of the set, whatever current that is used by the higher-wattage parallel-pair must pass through the 80watter which is in series with it. Assuming identical power dissipation for the moment, the 80watter will blow before the parallel-pair. further stressed by the non-linear drive imposed on it by the others. Are you talking about non-linear impedance here? if so, I'm unsure why. My own comments on what Steven said were based upon things like frequency dependence, and linear acoustic effects, not signal-level dependence. Yes, non-linear impedance (non-linear wrt frequency primarily) whose effects can be exacerbated at higher levels. I wish I could suggest a solution but I do not know your goals. I assume that you mean Steven's goals. :-) My own recommendation to him would be to avoid using dissimilar speakers in series. Sorry. I didn't see your name at the top. I agree with your recommendation. Kal |
help with speaker configuration
In article , Laurence
Payne wrote: On Wed, 29 Oct 2003 16:59:50 +0000 (GMT), Jim Lesurf wrote: Current is measured in amps. More precisely: The standard *unit* for current is the Amp. Hence values are quoted in amps. If two units are connected in series, the same amperage will flow through both. If not, where would it go? Yes, I think I agreed before that the current will pass through both. However this is not the same as the initial comment which prompted my response. This was that: Quote starts ---- On 28 Oct in uk.rec.audio, Kalman Rubinson wrote: 3. The so-called 80watt speaker is in series with the now 100watt pair and any power disipated goes through both. Quote ends ---- My initial point was that this is not really the case. The *power* does not 'go through both'. This remains the case even if the current does go through both, for the reasons I outlined. The resistance of each unit will determine how much power is drawn by it. Yes. However let's consider that we can choose almost any value we like for the value of an impedance to place in series with our load. Provided we then choose an appropriate potential to apply across both in series, we can get the same 'I' value in our load. Hence our load isn't directly concerned by the choice of what it in series with it. Just with the value of the current that then happens to flow through the load. "Power is conveyed by the EM fields" is meaningless gobbledygook. Sorry if what I wrote was not clear to you. If you examine the energy of the EM fields in and around components you will find that what I said is formally correct. For example, look at the Poynting vector values around conducting wires and resistors. You then find that the actual power is conveyed 'along' wires by the EM fields external to the wires. The levels of the internal field powers are relatively tiny. Similarly, the Poynting vector on the surface of a resistor points inwards, and its integral over the surface equals the power dissipation. Thus the field is 'guided' to the resistive component by the fields outside the conductors, and for all practical purposes only that portion which is dissipated in a component actually enters it. If my explanations are not clear, I'd recommend the texts by people like Kraus (Electromagnetics) or Ramo et al as they cover this sort of thing in much more detail that I can explain here. Some estimates (based upon the standard EM texts) of the kinds of values for the power levels in the external fields and in wires are on some of the pages in the 'Scots Guide' in my sig if you are interested. Similar calculations are probably findable in some of the standard texts. Slainte, Jim -- Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html |
help with speaker configuration
In article , Laurence
Payne wrote: On Wed, 29 Oct 2003 16:59:50 +0000 (GMT), Jim Lesurf wrote: Current is measured in amps. More precisely: The standard *unit* for current is the Amp. Hence values are quoted in amps. If two units are connected in series, the same amperage will flow through both. If not, where would it go? Yes, I think I agreed before that the current will pass through both. However this is not the same as the initial comment which prompted my response. This was that: Quote starts ---- On 28 Oct in uk.rec.audio, Kalman Rubinson wrote: 3. The so-called 80watt speaker is in series with the now 100watt pair and any power disipated goes through both. Quote ends ---- My initial point was that this is not really the case. The *power* does not 'go through both'. This remains the case even if the current does go through both, for the reasons I outlined. The resistance of each unit will determine how much power is drawn by it. Yes. However let's consider that we can choose almost any value we like for the value of an impedance to place in series with our load. Provided we then choose an appropriate potential to apply across both in series, we can get the same 'I' value in our load. Hence our load isn't directly concerned by the choice of what it in series with it. Just with the value of the current that then happens to flow through the load. "Power is conveyed by the EM fields" is meaningless gobbledygook. Sorry if what I wrote was not clear to you. If you examine the energy of the EM fields in and around components you will find that what I said is formally correct. For example, look at the Poynting vector values around conducting wires and resistors. You then find that the actual power is conveyed 'along' wires by the EM fields external to the wires. The levels of the internal field powers are relatively tiny. Similarly, the Poynting vector on the surface of a resistor points inwards, and its integral over the surface equals the power dissipation. Thus the field is 'guided' to the resistive component by the fields outside the conductors, and for all practical purposes only that portion which is dissipated in a component actually enters it. If my explanations are not clear, I'd recommend the texts by people like Kraus (Electromagnetics) or Ramo et al as they cover this sort of thing in much more detail that I can explain here. Some estimates (based upon the standard EM texts) of the kinds of values for the power levels in the external fields and in wires are on some of the pages in the 'Scots Guide' in my sig if you are interested. Similar calculations are probably findable in some of the standard texts. Slainte, Jim -- Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html |
help with speaker configuration
In article , Kalman
Rubinson wrote: On Wed, 29 Oct 2003 16:59:50 +0000 (GMT), Jim Lesurf wrote: All current must go through the 80watt speaker which is in series with the paralleled others. Erm... Current is not power. They are quite distinct physical quantities, albeit ones which have a specific relationship for a specific component. If the 80watter is in series with the others (my interpretation of the wiring) then all the current passes through it. What power it dissipates, of course, depends on its own construction. Agreed. :-) However I was above really referring back to the previous posting that described the *power* as if flowing through each component. This is not strictly correct, although the comment about current normally is correct. My later comments were then just to clarify that power and current are distinct quantities even though they have a specific individual relationship for a specific individual component. Sure but if the user is trying to pump a lot of power out of the set, whatever current that is used by the higher-wattage parallel-pair must pass through the 80watter which is in series with it. Assuming identical power dissipation for the moment, the 80watter will blow before the parallel-pair. Yes, I'd agree. (If we take steven's initial values as being a faithful repesentation.) IIRC the original diagram that steven drew showed two '8 Ohm 50 W' speakers in parallel combination - thus (if we take this literally) making a composite load of 4 Ohms with a total dissipation capability of 100 W. Putting this combination in series with a 4 Ohm 80 load, then I'd agree that if we wound up the input we could expect the 4 Ohm 80 W speaker to fail first. further stressed by the non-linear drive imposed on it by the others. Are you talking about non-linear impedance here? if so, I'm unsure why. My own comments on what Steven said were based upon things like frequency dependence, and linear acoustic effects, not signal-level dependence. Yes, non-linear impedance (non-linear wrt frequency primarily) whose effects can be exacerbated at higher levels. OK. Can you explain a bit more on how you were expecting this to lead to the '4 Ohm 80W' speaker to fail first? Curious about this. I am aware that speakers show non-linearity, but do not know much more than that about conventional speakers... Slainte, Jim -- Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html |
help with speaker configuration
In article , Kalman
Rubinson wrote: On Wed, 29 Oct 2003 16:59:50 +0000 (GMT), Jim Lesurf wrote: All current must go through the 80watt speaker which is in series with the paralleled others. Erm... Current is not power. They are quite distinct physical quantities, albeit ones which have a specific relationship for a specific component. If the 80watter is in series with the others (my interpretation of the wiring) then all the current passes through it. What power it dissipates, of course, depends on its own construction. Agreed. :-) However I was above really referring back to the previous posting that described the *power* as if flowing through each component. This is not strictly correct, although the comment about current normally is correct. My later comments were then just to clarify that power and current are distinct quantities even though they have a specific individual relationship for a specific individual component. Sure but if the user is trying to pump a lot of power out of the set, whatever current that is used by the higher-wattage parallel-pair must pass through the 80watter which is in series with it. Assuming identical power dissipation for the moment, the 80watter will blow before the parallel-pair. Yes, I'd agree. (If we take steven's initial values as being a faithful repesentation.) IIRC the original diagram that steven drew showed two '8 Ohm 50 W' speakers in parallel combination - thus (if we take this literally) making a composite load of 4 Ohms with a total dissipation capability of 100 W. Putting this combination in series with a 4 Ohm 80 load, then I'd agree that if we wound up the input we could expect the 4 Ohm 80 W speaker to fail first. further stressed by the non-linear drive imposed on it by the others. Are you talking about non-linear impedance here? if so, I'm unsure why. My own comments on what Steven said were based upon things like frequency dependence, and linear acoustic effects, not signal-level dependence. Yes, non-linear impedance (non-linear wrt frequency primarily) whose effects can be exacerbated at higher levels. OK. Can you explain a bit more on how you were expecting this to lead to the '4 Ohm 80W' speaker to fail first? Curious about this. I am aware that speakers show non-linearity, but do not know much more than that about conventional speakers... Slainte, Jim -- Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html |
help with speaker configuration
On Thu, 30 Oct 2003 17:09:03 +0000 (GMT), Jim Lesurf
wrote: In article , Kalman Rubinson Yes, non-linear impedance (non-linear wrt frequency primarily) whose effects can be exacerbated at higher levels. OK. Can you explain a bit more on how you were expecting this to lead to the '4 Ohm 80W' speaker to fail first? Curious about this. I am aware that speakers show non-linearity, but do not know much more than that about conventional speakers... Only that the non-linearity of the parallel-pair will effect the 80watter (and vice versa) and that pulling more current through the whole network at certain frequencies is likely to stress the weaker link. OTOH, without knowing the impedance plots of the various drivers wrt frequency and power, one cannot be certain. Kal |
help with speaker configuration
On Thu, 30 Oct 2003 17:09:03 +0000 (GMT), Jim Lesurf
wrote: In article , Kalman Rubinson Yes, non-linear impedance (non-linear wrt frequency primarily) whose effects can be exacerbated at higher levels. OK. Can you explain a bit more on how you were expecting this to lead to the '4 Ohm 80W' speaker to fail first? Curious about this. I am aware that speakers show non-linearity, but do not know much more than that about conventional speakers... Only that the non-linearity of the parallel-pair will effect the 80watter (and vice versa) and that pulling more current through the whole network at certain frequencies is likely to stress the weaker link. OTOH, without knowing the impedance plots of the various drivers wrt frequency and power, one cannot be certain. Kal |
help with speaker configuration
Jim Lesurf wrote in message ...
In article , steven robinson wrote: Jim Lesurf wrote in message ... [snip loads] Do you have impedance/frequency plots of the individual units? Any idea how these values were altered by the cabinets and/or combined useage? What amplifier did you use, and is it unconditionally stable? Hi Jim Thanks for the reply, a lot of what you are saying is foreign to me, but this is what I know: The spec of the 8Ohms 50watt speakers in the parallel leg a Nominal power 30watts Peak power 50watts SPL @ 1W/1m 82db Frequency range 100Hz to 20kHz Resonant Frequency 130Hz Max cone displacement 5mm Voice coil diameter 20mm Magnetic inductance 0.8 Tesla Magnetic flux 200u Weber Alas, the above does not tell you what you'd need to know to be able to start the process of trying to design an 'in series' design. TBH such designs, using dissimilar speakers, would be a nightmare to get right without a lot of test gear, etc. Best avoided in my view as trying this (as you have found) can be more grief that you'd expect. Withount using cross overs how can I block damaging frequencies lower than 100Hz and higher than 20kHz from the drivers? or isn't that a concern? I can't tell what may or may not be the real cause of the problem you had. The problem is that there is too much we don't know that might have an effect. However the resonance frequency (which I assume is 'free air') of 130 Hz seems quite high for a 'full range' speaker. I may well be wrong as I lack data. Someone who knows more about speaker building may well be able to give a better comment on this. However I'd suspect that below 100 Hz the cone movements might become too great unless you use the unit in a cabinet that acts as a closed box to limit this. Otherwise, to control movements, you will need a cross-over - although this could be an 'active' type applied before using distinct power-amps to drive the individual units. This may all be to complicated for you to wish to do, though. For the above reasons it is possible that the speaker was damaged by being forced to move too far to provide LF output. i.e. by exceeding its mechanical limits, not by overheating by excessive power. It is unlikely that signals above 20kHz will do any damage. Chances are that there is only a little power at such frequencies, and the units will essentially ignore it. :-) (This assumption may not be correct if the amplifier went into oscillations and was producing very high powers at an ultrasonic frequency. However normal music and speech does not usually have much in the way of sustained high powers above 20kHz.) Unfortunately I don't know anything about the 4Ohms speaker, except its Peak power is 80watts. Likewise the amp is a bit of a mistery, it is an amp called a v-series manufactured by an amusement company in leeds. Its output is supposed to be 70watts into 4Ohms. Unless you can establish that it is an unconditionally stable design, then it is possible that it went into oscillation and this caused problems. This is probably less likely than other causes, but I can't rule it out at this point. I'm getting the impresion that putting dis-similat drivers in series is a bad idea. It is, unless you know a great deal about the units, and can carry out the relevant design/measurement process. Afraid it isn't as simple as assuming the power is divided up as if the units were plain resistors. In general, 'hi fi' designs avoid speakers in series without any cross-over or adjustment networks. What if I put two 8Ohms in series twice and parallel them together, would this be a better idea? I could then use the same speakers with the same properties. This is more likely to work as the inherent properties of the units are the same. However it may still not work as you expect for various reasons. For example: Putting the units into the same cabinet mean they couple acoustically. This alters their properties, so even though you have connected them in 'series/parallel' the resulting impedances, etc may not be the same as for a single driver in the same cabinet. In this configuration you would expect the output to be spread evenly across the four speakers, wouldn't you? What do you think? The output would probably be distributed reasonably evenly, but it is hard to be certain about this as the cabinet has an effect. It would be better than using dissimilar units, but it is not something I'd normally recommend as the results may still not be what you anticipate. For example: there will be acoustic interference between the units that will alter the resulting total response, etc. To be honest, trying to do anything like this is risky without having a fair amount of data, and/or doing the right measurements, or proceeding with care and taking a long time experimenting. FWIW I've happily designed and build various amplifiers, and tuners, and other 'electronic' items over the years. I also cheerfully modify commercial electronics to alter the performance to suit. However I have always avoided trying to self-design speakers. Simply too difficult and time-consuming to get right. :-) That said, many people do develop their own designs, and produce good results. However this can involve a lot of effort and patience and understanding. Some of the 'kits' and published designs can work well if made with care, but these are obviously based upon someone else having already put in the time and effort to sort out the necessary details! Slainte, Jim Hi Jim I seem to be going round in circles with this one. I am starting to understand the phrase "lot of effort and patience and understanding" you quoted. I am considerring having to use a crossover in my design, do you think this would solve some of my power distribytion issues? I would still use the two paralleled 50W 8Ohms for mid to high fq and the 80W 4Ohms for low fq, providing the frequency range of the speakers are suitable. I'm either going this way or the two paralled/series setup with the same drivers, but without crossovers, what do you think? Thanks and regards Steve |
help with speaker configuration
Jim Lesurf wrote in message ...
In article , steven robinson wrote: Jim Lesurf wrote in message ... [snip loads] Do you have impedance/frequency plots of the individual units? Any idea how these values were altered by the cabinets and/or combined useage? What amplifier did you use, and is it unconditionally stable? Hi Jim Thanks for the reply, a lot of what you are saying is foreign to me, but this is what I know: The spec of the 8Ohms 50watt speakers in the parallel leg a Nominal power 30watts Peak power 50watts SPL @ 1W/1m 82db Frequency range 100Hz to 20kHz Resonant Frequency 130Hz Max cone displacement 5mm Voice coil diameter 20mm Magnetic inductance 0.8 Tesla Magnetic flux 200u Weber Alas, the above does not tell you what you'd need to know to be able to start the process of trying to design an 'in series' design. TBH such designs, using dissimilar speakers, would be a nightmare to get right without a lot of test gear, etc. Best avoided in my view as trying this (as you have found) can be more grief that you'd expect. Withount using cross overs how can I block damaging frequencies lower than 100Hz and higher than 20kHz from the drivers? or isn't that a concern? I can't tell what may or may not be the real cause of the problem you had. The problem is that there is too much we don't know that might have an effect. However the resonance frequency (which I assume is 'free air') of 130 Hz seems quite high for a 'full range' speaker. I may well be wrong as I lack data. Someone who knows more about speaker building may well be able to give a better comment on this. However I'd suspect that below 100 Hz the cone movements might become too great unless you use the unit in a cabinet that acts as a closed box to limit this. Otherwise, to control movements, you will need a cross-over - although this could be an 'active' type applied before using distinct power-amps to drive the individual units. This may all be to complicated for you to wish to do, though. For the above reasons it is possible that the speaker was damaged by being forced to move too far to provide LF output. i.e. by exceeding its mechanical limits, not by overheating by excessive power. It is unlikely that signals above 20kHz will do any damage. Chances are that there is only a little power at such frequencies, and the units will essentially ignore it. :-) (This assumption may not be correct if the amplifier went into oscillations and was producing very high powers at an ultrasonic frequency. However normal music and speech does not usually have much in the way of sustained high powers above 20kHz.) Unfortunately I don't know anything about the 4Ohms speaker, except its Peak power is 80watts. Likewise the amp is a bit of a mistery, it is an amp called a v-series manufactured by an amusement company in leeds. Its output is supposed to be 70watts into 4Ohms. Unless you can establish that it is an unconditionally stable design, then it is possible that it went into oscillation and this caused problems. This is probably less likely than other causes, but I can't rule it out at this point. I'm getting the impresion that putting dis-similat drivers in series is a bad idea. It is, unless you know a great deal about the units, and can carry out the relevant design/measurement process. Afraid it isn't as simple as assuming the power is divided up as if the units were plain resistors. In general, 'hi fi' designs avoid speakers in series without any cross-over or adjustment networks. What if I put two 8Ohms in series twice and parallel them together, would this be a better idea? I could then use the same speakers with the same properties. This is more likely to work as the inherent properties of the units are the same. However it may still not work as you expect for various reasons. For example: Putting the units into the same cabinet mean they couple acoustically. This alters their properties, so even though you have connected them in 'series/parallel' the resulting impedances, etc may not be the same as for a single driver in the same cabinet. In this configuration you would expect the output to be spread evenly across the four speakers, wouldn't you? What do you think? The output would probably be distributed reasonably evenly, but it is hard to be certain about this as the cabinet has an effect. It would be better than using dissimilar units, but it is not something I'd normally recommend as the results may still not be what you anticipate. For example: there will be acoustic interference between the units that will alter the resulting total response, etc. To be honest, trying to do anything like this is risky without having a fair amount of data, and/or doing the right measurements, or proceeding with care and taking a long time experimenting. FWIW I've happily designed and build various amplifiers, and tuners, and other 'electronic' items over the years. I also cheerfully modify commercial electronics to alter the performance to suit. However I have always avoided trying to self-design speakers. Simply too difficult and time-consuming to get right. :-) That said, many people do develop their own designs, and produce good results. However this can involve a lot of effort and patience and understanding. Some of the 'kits' and published designs can work well if made with care, but these are obviously based upon someone else having already put in the time and effort to sort out the necessary details! Slainte, Jim Hi Jim I seem to be going round in circles with this one. I am starting to understand the phrase "lot of effort and patience and understanding" you quoted. I am considerring having to use a crossover in my design, do you think this would solve some of my power distribytion issues? I would still use the two paralleled 50W 8Ohms for mid to high fq and the 80W 4Ohms for low fq, providing the frequency range of the speakers are suitable. I'm either going this way or the two paralled/series setup with the same drivers, but without crossovers, what do you think? Thanks and regards Steve |
help with speaker configuration
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help with speaker configuration
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help with speaker configuration
On Sun, 02 Nov 2003 11:19:35 -0500
Kalman Rubinson wrote: (2) this post is a good argument for top-posting. Bull****. its a good example of how NOT to do bottom/interspersed posting (ie. no snipping) -- Spyros lair: http://www.mnementh.co.uk/ |||| Maintainer: arm26 linux Do not meddle in the affairs of Dragons, for you are tasty and good with ketchup. |
help with speaker configuration
On Sun, 02 Nov 2003 11:19:35 -0500
Kalman Rubinson wrote: (2) this post is a good argument for top-posting. Bull****. its a good example of how NOT to do bottom/interspersed posting (ie. no snipping) -- Spyros lair: http://www.mnementh.co.uk/ |||| Maintainer: arm26 linux Do not meddle in the affairs of Dragons, for you are tasty and good with ketchup. |
help with speaker configuration
In article , steven
robinson wrote: [snip] Hi Jim I seem to be going round in circles with this one. I am starting to understand the phrase "lot of effort and patience and understanding" you quoted. :-) You have my sympathy with this. I've been banging my head up against these things for decades and I still struggle. Loudspeakers is an area where things tend to look simpler than they really are. I am considerring having to use a crossover in my design, do you think this would solve some of my power distribytion issues? I would still use the two paralleled 50W 8Ohms for mid to high fq and the 80W 4Ohms for low fq, providing the frequency range of the speakers are suitable. I'm either going this way or the two paralled/series setup with the same drivers, but without crossovers, what do you think? The short answer is: dunno! :-) (Or, "pass", if you prefer.) The longer answer is as follows... ;- The problem is that I don't really know enough of the details of your speakers, the cabinets you would make, your amp, etc, etc. Nor am I really much of an expert on the practical side of speaker building. Above said, my *guesses* are as follows: Simply using two 'identical' units connected in parallel might work OK. However the impedance may well not just be half that of a single unit for various reasons, and having the two units beside each other in a box will alter the response. This option is therefore the 'easy' one for getting a working speaker, but it is hard to predict the actual performance. Using a more complicated arrangement with some sort of cross-over gives you more variables to play with and try and get decent results. However designing a good cross-over can be quite a complex task if you want the results to work well. It isn't necessarily just a case of lifting a standard network out of a book. That said, this approach might work fine. Just that it is hard to predict. One of the unknowns here is your amplifier. Assuming this is happy, either of the above could be approached by experimentation whilst keeping down the power level. However I'm afraid can't really say which of the two options you suggest would end up being 'better'. You'd have to give them a try and then decide on the basis of experience. Someone with more experience in self-developing speakers may well be able to give you more pointed advice on this, I'm afraid. I was always wary of getting into this area. Decided it was simpler to just buy good commercial speakers. :-) Speakers are a nightmare in design terms, as they require good electrical and mechanical engineering, dealing with some very complex topics. Slainte, Jim -- Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html |
help with speaker configuration
In article , steven
robinson wrote: [snip] Hi Jim I seem to be going round in circles with this one. I am starting to understand the phrase "lot of effort and patience and understanding" you quoted. :-) You have my sympathy with this. I've been banging my head up against these things for decades and I still struggle. Loudspeakers is an area where things tend to look simpler than they really are. I am considerring having to use a crossover in my design, do you think this would solve some of my power distribytion issues? I would still use the two paralleled 50W 8Ohms for mid to high fq and the 80W 4Ohms for low fq, providing the frequency range of the speakers are suitable. I'm either going this way or the two paralled/series setup with the same drivers, but without crossovers, what do you think? The short answer is: dunno! :-) (Or, "pass", if you prefer.) The longer answer is as follows... ;- The problem is that I don't really know enough of the details of your speakers, the cabinets you would make, your amp, etc, etc. Nor am I really much of an expert on the practical side of speaker building. Above said, my *guesses* are as follows: Simply using two 'identical' units connected in parallel might work OK. However the impedance may well not just be half that of a single unit for various reasons, and having the two units beside each other in a box will alter the response. This option is therefore the 'easy' one for getting a working speaker, but it is hard to predict the actual performance. Using a more complicated arrangement with some sort of cross-over gives you more variables to play with and try and get decent results. However designing a good cross-over can be quite a complex task if you want the results to work well. It isn't necessarily just a case of lifting a standard network out of a book. That said, this approach might work fine. Just that it is hard to predict. One of the unknowns here is your amplifier. Assuming this is happy, either of the above could be approached by experimentation whilst keeping down the power level. However I'm afraid can't really say which of the two options you suggest would end up being 'better'. You'd have to give them a try and then decide on the basis of experience. Someone with more experience in self-developing speakers may well be able to give you more pointed advice on this, I'm afraid. I was always wary of getting into this area. Decided it was simpler to just buy good commercial speakers. :-) Speakers are a nightmare in design terms, as they require good electrical and mechanical engineering, dealing with some very complex topics. Slainte, Jim -- Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html |
help with speaker configuration
On Sun, 02 Nov 2003 11:19:35 -0500, Kalman Rubinson wrote:
After reading this again and again, all I can say is (1) the OP should tell us what his application is and why he is using such non-descript components and (2) this post is a good argument for top-posting. There is no good argument for top posting, just as there is no good argument for urinating in public on the floor in dance halls, failing to wash one's hands after defecating then shaking hands with one's visitors or any other item of behaviour which might save oneself a few seconds, but is ultimately to the detriment of the society in which one exists. It is especially unwelcome in uk.*, please see: http://www.usenet.org.uk/ukpost.html -- Anthony Edwards |
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