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bi-wire config question
I have a Musical Fidelity A5 cd player and A5 intergrated amp, I have it
bi-wired to a pair of Acoustic Energy AE120 speakers (tri-wireable), my question is this:- My speakers are three way, so at the moment I have the MF and HF bridged together & the LF is seperate, is this correct? Or I should I have the MF AND LF bridged together & the HF seperate? I'm using Chord Chorus interconnects and Chord Oddessy bi-wire speaker cable. I like a mellow Jazz/soul/funk & detail etc not a lot of gutsy rock/bass & I was just wondering if I had the config correct. Thanks. AD |
bi-wire config question
In article , aid
wrote: I have a Musical Fidelity A5 cd player and A5 intergrated amp, I have it bi-wired to a pair of Acoustic Energy AE120 speakers (tri-wireable), my question is this:- My speakers are three way, so at the moment I have the MF and HF bridged together & the LF is seperate, is this correct? TBH I'm not sure what meaning "correct" would have in this context. :-) Or I should I have the MF AND LF bridged together & the HF seperate? Or simply link the MF + LF + HF together. You can approach this in three ways: 1) Try different arrangements and if you think they sound different, choose the one you prefer. If there are audible differences, it will be your preference that determines what is "correct" for you, not the opinions of others who may use different systems in a different room acoustic, etc. 2) Note that controlled listening tests have never (so far as I know) shown any reliably audible differences due to bi-wiring, and engineering analysis implies that any differences will be in the range from slight to imaginary. [1] Thus simply use what you have and save bother. 3) Check with the speaker manufacturers to see if they have any engineering reason for specifying a particular arrangement. If they do, consider that. My vote would be for (2), but its your money and your ears... ;- Slainte, Jim [1] If you use unusually inappropriate cable/equipment this might not be the case. But in such cases the way to deal with the problem would be to use more appropriate cables, etc. This isn't a matter of expensive or fancy, just things like ensuring the cables don't have excessive resistance, etc. -- 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 |
bi-wire config question
Jim Lesurf wrote:
In article , aid wrote: I have a Musical Fidelity A5 cd player and A5 intergrated amp, I have it bi-wired to a pair of Acoustic Energy AE120 speakers (tri-wireable), my question is this:- My speakers are three way, so at the moment I have the MF and HF bridged together & the LF is seperate, is this correct? TBH I'm not sure what meaning "correct" would have in this context. :-) Or I should I have the MF AND LF bridged together & the HF seperate? Or simply link the MF + LF + HF together. You can approach this in three ways: 1) Try different arrangements and if you think they sound different, choose the one you prefer. If there are audible differences, it will be your preference that determines what is "correct" for you, not the opinions of others who may use different systems in a different room acoustic, etc. 2) Note that controlled listening tests have never (so far as I know) shown any reliably audible differences due to bi-wiring, and engineering analysis implies that any differences will be in the range from slight to imaginary. [1] Thus simply use what you have and save bother. Totally agree. I think Jim is being kind, I would put the differences as somewhere between imaginary and non-existent, once you do the sums. S. |
bi-wire config question
"Serge Auckland" wrote in message ... Jim Lesurf wrote: In article , aid wrote: I have a Musical Fidelity A5 cd player and A5 intergrated amp, I have it bi-wired to a pair of Acoustic Energy AE120 speakers (tri-wireable), my question is this:- My speakers are three way, so at the moment I have the MF and HF bridged together & the LF is seperate, is this correct? TBH I'm not sure what meaning "correct" would have in this context. :-) Or I should I have the MF AND LF bridged together & the HF seperate? Or simply link the MF + LF + HF together. You can approach this in three ways: 1) Try different arrangements and if you think they sound different, choose the one you prefer. If there are audible differences, it will be your preference that determines what is "correct" for you, not the opinions of others who may use different systems in a different room acoustic, etc. 2) Note that controlled listening tests have never (so far as I know) shown any reliably audible differences due to bi-wiring, and engineering analysis implies that any differences will be in the range from slight to imaginary. [1] Thus simply use what you have and save bother. Totally agree. I think Jim is being kind, I would put the differences as somewhere between imaginary and non-existent, once you do the sums. Agreed. But still the OP might like to do the experiment, and decide for himself. The subject is covered in an objective way in the book: AUDIO REALITY by Bruce Rozenblit. pp 42-43. Iain |
bi-wire config question
"Serge Auckland" wrote in message ... Jim Lesurf wrote: In article , aid wrote: I have a Musical Fidelity A5 cd player and A5 intergrated amp, I have it bi-wired to a pair of Acoustic Energy AE120 speakers (tri-wireable), my question is this:- My speakers are three way, so at the moment I have the MF and HF bridged together & the LF is seperate, is this correct? TBH I'm not sure what meaning "correct" would have in this context. :-) Or I should I have the MF AND LF bridged together & the HF seperate? Or simply link the MF + LF + HF together. You can approach this in three ways: 1) Try different arrangements and if you think they sound different, choose the one you prefer. If there are audible differences, it will be your preference that determines what is "correct" for you, not the opinions of others who may use different systems in a different room acoustic, etc. 2) Note that controlled listening tests have never (so far as I know) shown any reliably audible differences due to bi-wiring, and engineering analysis implies that any differences will be in the range from slight to imaginary. [1] Thus simply use what you have and save bother. Totally agree. I think Jim is being kind, I would put the differences as somewhere between imaginary and non-existent, once you do the sums. Number 1 is correct, as only you with your equipment, cables, room and furniture can LISTEN to the results. Plenty of sums are done by speaker manufacturers, to make sure their product is technically brilliant, yet get them into a room and they will sound anything from horrible to superb. Same with interconnects and cables - use whatever sounds right to you. Some people prefer the sums, some prefer the sound - it's a personal thing. Cessna172. |
bi-wire config question
Cessna172 wrote:
"Serge Auckland" wrote in message ... Jim Lesurf wrote: In article , aid wrote: I have a Musical Fidelity A5 cd player and A5 intergrated amp, I have it bi-wired to a pair of Acoustic Energy AE120 speakers (tri-wireable), my question is this:- My speakers are three way, so at the moment I have the MF and HF bridged together & the LF is seperate, is this correct? TBH I'm not sure what meaning "correct" would have in this context. :-) Or I should I have the MF AND LF bridged together & the HF seperate? Or simply link the MF + LF + HF together. You can approach this in three ways: 1) Try different arrangements and if you think they sound different, choose the one you prefer. If there are audible differences, it will be your preference that determines what is "correct" for you, not the opinions of others who may use different systems in a different room acoustic, etc. 2) Note that controlled listening tests have never (so far as I know) shown any reliably audible differences due to bi-wiring, and engineering analysis implies that any differences will be in the range from slight to imaginary. [1] Thus simply use what you have and save bother. Totally agree. I think Jim is being kind, I would put the differences as somewhere between imaginary and non-existent, once you do the sums. Number 1 is correct, as only you with your equipment, cables, room and furniture can LISTEN to the results. Plenty of sums are done by speaker manufacturers, to make sure their product is technically brilliant, yet get them into a room and they will sound anything from horrible to superb. I've yet to see a product that didn't work properly when the sums were done correctly, rigorously, and applying the rules. That's not to say that an intuitive designer can't get a good sound without doing the sums, what I'm saying is if you then analyse such a design, you will find that the sums come out right as well. S. |
bi-wire config question
Serge Auckland wrote:
Cessna172 wrote: speaker manufacturers, to make sure their product is technically brilliant, yet get them into a room and they will sound anything from horrible to superb. I've yet to see a product that didn't work properly when the sums were done correctly, rigorously, and applying the rules. That's not to say that an intuitive designer can't get a good sound without doing the sums, what I'm saying is if you then analyse such a design, you will find that the sums come out right as well. What about the perfect speaker - a point source with a flat frequency response? It will sound perfect if your room has no walls or floor. If you design the perfect speaker for your room, it may not work well in mine. -- Eiron No good deed ever goes unpunished. |
bi-wire config question
housetrained wrote:
"aid" wrote in message ... I have a Musical Fidelity A5 cd player and A5 intergrated amp, I have it bi-wired to a pair of Acoustic Energy AE120 speakers (tri-wireable), my question is this:- My speakers are three way, so at the moment I have the MF and HF bridged together & the LF is seperate, is this correct? Or I should I have the MF AND LF bridged together & the HF seperate? I'm using Chord Chorus interconnects and Chord Oddessy bi-wire speaker cable. I like a mellow Jazz/soul/funk & detail etc not a lot of gutsy rock/bass & I was just wondering if I had the config correct. Thanks. AD Years ago I read that one should disconnect everything periodically, clean all the contacts and re-assemble. Did it. Everything sounded better. Now, many years later I'm convinced that its psychological. Do it now. Play a couple of tracks. Unplug your speakers and CD player. Re-connect and I bet you think it sounds better. Works every time. Re-wire your speakers any way you like. It will sound better when you have them wired the way YOU think is right. So if you keep unplugging and plugging, does it keep getting better? If it works every time, after 20m in doing this, it must sound wonderful. Have you considered you may just be cleaning the electrical contact the first time? -- Nick |
bi-wire config question
Eiron wrote:
Serge Auckland wrote: Cessna172 wrote: speaker manufacturers, to make sure their product is technically brilliant, yet get them into a room and they will sound anything from horrible to superb. I've yet to see a product that didn't work properly when the sums were done correctly, rigorously, and applying the rules. That's not to say that an intuitive designer can't get a good sound without doing the sums, what I'm saying is if you then analyse such a design, you will find that the sums come out right as well. What about the perfect speaker - a point source with a flat frequency response? It will sound perfect if your room has no walls or floor. If you design the perfect speaker for your room, it may not work well in mine. Two points from the above:- Firstly, there is no practical way of producing a point source with a flat frequency response and sufficient audio output for music reproduction. Quad has come the closest, I suppose, with a sound-field synthesis for a point source, but this is a long way from a real point source. Consequently, there are no "sums" to be done with this example, as it is not realisable. Secondly, if you were to design the "perfect" 'speaker for my room, that is exactly what it would be, the "perfect" 'speaker for *my* room, not yours or anyone else's. You would have to design a different "perfect" 'speaker for every different room. This is clearly not a practical commercial proposition, but theoretically of course, it could be done. Incidentally, you would need to define carefully what "perfect" meant, but let's accept, for the sake of this argument that we both understand what we mean by "perfect". In pursuit of the above "perfect" for every room, several manufacturers are now including DSP control with measuring microphones so that their 'speakers can be better matched to the room. Whilst an improvement, you cannot DSP away the floor and walls which cause echoes, nasty resonances, frequency response anomalies caused by frequency-variable absorptions in furniture, (although this last is probably the easiest for DSP to make a difference) and a whole host of other stuff that we all live with. Many years ago, I did some 'speaker measurements in an anechoic chamber, and as a working environment it wasn't very pleasant. I suspect this was because the acoustic space ( effectively no walls, floor or ceiling) didn't match one's visual space, which was that of a small room. However, listening with eyes closed and the room darkened, did actually sound very good. More recently, I visited a Scandinavian Broadcaster who had a number of IEC standard listening rooms of different sizes in their centre. They were using B&W 807s, and the sound was quite extraordinarily good. If you ever get a chance to visit any UK commercial radio station that still has studios made during the old IBA Code of Practice days, you will again hear what a really good room can sounds like. S. |
bi-wire config question
On Tue, 13 Jun 2006 13:08:21 +0100, Serge Auckland
wrote: Secondly, if you were to design the "perfect" 'speaker for my room, that is exactly what it would be, the "perfect" 'speaker for *my* room, not yours or anyone else's. You would have to design a different "perfect" 'speaker for every different room. Can a good violin (and player) sound good (though different) in different acoustics? Why not a speaker? |
bi-wire config question
On Tue, 13 Jun 2006 13:51:28 +0100, Laurence Payne
lpayne1NOSPAM@dslDOTpipexDOTcom wrote: On Tue, 13 Jun 2006 13:08:21 +0100, Serge Auckland wrote: Secondly, if you were to design the "perfect" 'speaker for my room, that is exactly what it would be, the "perfect" 'speaker for *my* room, not yours or anyone else's. You would have to design a different "perfect" 'speaker for every different room. Can a good violin (and player) sound good (though different) in different acoustics? Why not a speaker? Yes, but for totally different reasons. The violinist will actually change the way he performs in response to the different acoustics. The speaker won't do that - the combination will simply sound different. In some circumstances it will sound good, in others it won't. There are plenty of acoustic spaces in which no speaker will ever sound good. d -- Pearce Consulting http://www.pearce.uk.com |
bi-wire config question
Laurence Payne wrote:
On Tue, 13 Jun 2006 13:08:21 +0100, Serge Auckland wrote: Secondly, if you were to design the "perfect" 'speaker for my room, that is exactly what it would be, the "perfect" 'speaker for *my* room, not yours or anyone else's. You would have to design a different "perfect" 'speaker for every different room. Can a good violin (and player) sound good (though different) in different acoustics? Why not a speaker? Because the purpose of the speaker is to give the illusion that you are in the concert hall, not that the orchestra is in your lounge (Bose excepted). -- Eiron No good deed ever goes unpunished. |
bi-wire config question
"Eiron" wrote in message ... Laurence Payne wrote: On Tue, 13 Jun 2006 13:08:21 +0100, Serge Auckland wrote: Secondly, if you were to design the "perfect" 'speaker for my room, that is exactly what it would be, the "perfect" 'speaker for *my* room, not yours or anyone else's. You would have to design a different "perfect" 'speaker for every different room. Can a good violin (and player) sound good (though different) in different acoustics? Why not a speaker? Because the purpose of the speaker is to give the illusion that you are in the concert hall, not that the orchestra is in your lounge (Bose excepted). Nicely put. You will be pleased to know I'm having serious trouble choosing between the Pinkies and the 609s!! (Different in minor ways, but *sooo* similar overall....!!) |
bi-wire config question
In article ,
Cessna172 wrote: Totally agree. I think Jim is being kind, I would put the differences as somewhere between imaginary and non-existent, once you do the sums. Number 1 is correct, as only you with your equipment, cables, room and furniture can LISTEN to the results. Plenty of sums are done by speaker manufacturers, to make sure their product is technically brilliant, yet get them into a room and they will sound anything from horrible to superb. I doubt you'll find anyone who would argue with that. Room/speaker interface is very important and easily demonstrated. Same with interconnects and cables - use whatever sounds right to you. Some people prefer the sums, some prefer the sound - it's a personal thing. I doubt you'll find anyone who can demonstrate this effect. ;-) -- *There's two theories to arguing with a woman. Neither one works * Dave Plowman London SW To e-mail, change noise into sound. |
bi-wire config question
In article , Dave Plowman (News)
wrote: In article , Cessna172 wrote: Totally agree. I think Jim is being kind, I would put the differences as somewhere between imaginary and non-existent, once you do the sums. Number 1 is correct, as only you with your equipment, cables, room and furniture can LISTEN to the results. Plenty of sums are done by speaker manufacturers, to make sure their product is technically brilliant, yet get them into a room and they will sound anything from horrible to superb. I doubt you'll find anyone who would argue with that. Room/speaker interface is very important and easily demonstrated. Alas, the snag in this context is that if there is a problem with the room acoustics and its interaction with the speaker radiation patterns, then the sensible way to deal with this is to alter the room acoustics, and/or speaker radiation pattern - or the speaker/listening positions. Changing the cabling is unlikely to have any effect - unless some of the cable involved have extraordinarily inappropriate characteristics. Same with interconnects and cables - use whatever sounds right to you. Some people prefer the sums, some prefer the sound - it's a personal thing. I doubt you'll find anyone who can demonstrate this effect. ;-) For me the situation here is, alas, as in so many other areas of audio. That people say things in reviews, etc, but none of them seem to have ever been able to show any reliable basis for what they say. I know of no test on 'bi wiring' that: 1) Ensured those listening had only the sounds produced to go on. 2) Repeated the test enough times, and with a protocol, that allows anyone to assess the reliability of the reported results. 3) Used a protocol to exclude obvious uncontrolled factors like differences in volume level. ...and which then gave results that supported the idea that anyone could tell bi wiring from just using single wiring. 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 |
bi-wire config question
aid wrote:
My speakers are three way, so at the moment I have the MF and HF bridged together & the LF is seperate, is this correct? Or I should I have the MF AND LF bridged together & the HF seperate? I'm using Chord Chorus interconnects and Chord Oddessy bi-wire speaker cable. My gut instinct would be to bridge the HF and MF, with the LF fed separately. But try both ways and use whichever one you think sounds better. That's some pretty nice speaker cable too, I'm using Chord Rumour 4 which does sound excellent. What it might be worth doing, depending on how over the top you want to go, is to tri-wire the speakers. For this I'd suggest using the Odyssey 4 for LF and MF and Rumour 2 for HF (HF needs less current so a thinner cable will suffice). But the bottom line is to do what you think sounds best. You've got to live with the system, there's no "right" and "wrong" way with some of these things, it's just what sounds "right" to you. HTH. -- Glenn Richards Tel: (01453) 845735 Squirrel Solutions http://www.squirrelsolutions.co.uk/ IT consultancy, hardware and software support, broadband installation |
bi-wire config question
Glenn Richards wrote:
aid wrote: My speakers are three way, so at the moment I have the MF and HF bridged together & the LF is seperate, is this correct? Or I should I have the MF AND LF bridged together & the HF seperate? I'm using Chord Chorus interconnects and Chord Oddessy bi-wire speaker cable. My gut instinct would be to bridge the HF and MF, with the LF fed separately. But try both ways and use whichever one you think sounds better. That's some pretty nice speaker cable too, I'm using Chord Rumour 4 which does sound excellent. What it might be worth doing, depending on how over the top you want to go, is to tri-wire the speakers. For this I'd suggest using the Odyssey 4 for LF and MF and Rumour 2 for HF (HF needs less current so a thinner cable will suffice). But the bottom line is to do what you think sounds best. You've got to live with the system, there's no "right" and "wrong" way with some of these things, it's just what sounds "right" to you. HTH. Are you seriously trying to tell us that tri or bi-wiring makes (or even can make) a difference? Have you done the sums to see what effect bi or tri wiring makes? All you are doing with bi or tri wiring is reducing the resistance from already low values, increasing the capacitance from normally low values to still low values, and reducing inductance. Any amplifier/'speaker combination for which this makes ANY difference is only fit to be used as a boat anchor. S. |
bi-wire config question
In article , Serge Auckland
wrote: All you are doing with bi or tri wiring is reducing the resistance from already low values, increasing the capacitance from normally low values to still low values, and reducing inductance. If you use the same type/length of cable for 'bi wiring' to each speaker unit as you did for 'normal wiring' and don't link the cables together at the speaker end, then the cable resistance, etc, will so far as the individual speaker units are concerned, be the same as for 'normal wiring'. If the amp has a minimal source impedance, then each unit will be unaware of the existence of the 'other cables' and so see the same cable as if it were connected in the 'normal' manner. You *will* no longer by shunting this with the impedance of the 'other speaker units'. But since this is likely to have an impedance which is much larger than that of the cable and amp, it is questionable if this is of any significance. However if the cable series resistance and/or amp output resistance are high, the frequency response may alter in a way that depends on the input impedances of the sections of the speaker system. FWIW I did do an analysis of these effects. People can read this and decide for themselves if they are likely to have any relevance. To see the analysis, go to the 'Scots Guide' (URL in my sig), use the link to the 'Analog and Audio' section, scroll down that page, and use the links to the pages on "An explanation of bi-wiring", etc, to see the analysis and results. These show that bi wiring can change the frequency response - but by only a small amount even when using cables of exceptionally high series resistance. Hence changes in measured behaviour are possible. But are they audible in any sensible arrangement?... My reaction tends to be that if I wanted a change in frequency response of a few tenths of a dB I'd move my head slightly whilst listening. :-) Above analysis notwithstanding, I've never seen a single report of a series of listening tests that showed any signs that such effects were audible, and which were done in a way that gave the results any assessable reliability. Any amplifier/'speaker combination for which this makes ANY difference is only fit to be used as a boat anchor. Given the series resistances required, the cables involved might be too light to be a decent anchor. :-) However very long thin cables, and an amp with loads of metalwork might fit the bill. You might therefore wish to use a poor valve amp and some bell wire for this application. Odd how heavy 'vacuum' is... ;- 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 |
bi-wire config question
In article ,
Bob Latham wrote: The amplifier will see the capacitance of two speaker cables and in this sense they are in parallel which will add the capacitance of each. The cables are not connected together at the speaker end and don't cover the same frequency spectrum so in no sense are they in parallel for current flow to the speaker. Unless the cables have significant capacitance inductance resistance etc they are effectively in parallel at the speaker end. And are carrying exactly the same signal since they are paralleled at the source of that signal. -- *He who dies with the most toys is, nonetheless, dead. Dave Plowman London SW To e-mail, change noise into sound. |
bi-wire config question
Bob Latham wrote:
In article , Serge Auckland wrote: [Snip] All you are doing with bi or tri wiring is reducing the resistance from already low values, increasing the capacitance from normally low values to still low values, and reducing inductance. Any amplifier/'speaker combination for which this makes ANY difference is only fit to be used as a boat anchor. I've seen these sort of comments before and simply don't understand, I would be grateful for some clarification. The amplifier will see the capacitance of two speaker cables and in this sense they are in parallel which will add the capacitance of each. The cables are not connected together at the speaker end and don't cover the same frequency spectrum so in no sense are they in parallel for current flow to the speaker. Therefore, to my mind, resistance is not changed anywhere. Where could I connect my fictitious superbly accurate meter to measure this change in resistance? The change in "total" resistance comes from the doubling of the 'speaker cables, and therefore a halving of the total resistance. As each 'speaker cable now carries a lower current, the already small loss down each 'speaker cable becomes smaller still. If bi-wiring is used with two identical speaker cables then I can see no possibility that this will make any difference what so ever. Correct for all normal lengths of normal 'speaker cable. Current personal theory coming up. It maybe utter **** but makes sense to me and matches my experience. Bi-wiring opens up the possibility of using two different cables and that, in my experience can make a difference even if it would require one of the cables to be less than perfect in an engineering sense. In addition if there is a small level change for a whole loudspeaker that is just less than audible it has no effect. Take that change and apply it to just part of the spectrum and now you change the balance of the speaker with the other (frequency) part acting as a reference making the difference more obvious. This may well tip the speaker away from the flat response it was designed for but if this gives the owner more pleasure I don't have a problem with it. Again correct. If you change one 'speaker cable for something with a high resistance, for example, this can modify the frequency response audibly. If you change one cable for one with a very high capacitance, and your amplifier is less than stable, then that too could affect the sound you hear. Your comment above, that it is less than perfect in engineering terms is apposite. At best bi-wiring makes no difference, at worse, it makes differences that are perhaps better not made, or that can be achieved more usually by tone control. Any room you place the loudspeaker in will modify its frequency response. Make that perceived frequency response, and you are right again. There's no mystery to any of this, it's another example of the hi-fi fraternity accepting what some mags and shops tell them as truth, without any engineering rigour being applied. S. |
bi-wire config question
In article , Bob Latham
wrote: In article , Serge Auckland wrote: [Snip] All you are doing with bi or tri wiring is reducing the resistance from already low values, increasing the capacitance from normally low values to still low values, and reducing inductance. Any amplifier/'speaker combination for which this makes ANY difference is only fit to be used as a boat anchor. I've seen these sort of comments before and simply don't understand, I would be grateful for some clarification. The amplifier will see the capacitance of two speaker cables and in this sense they are in parallel which will add the capacitance of each. Yes. The cables are not connected together at the speaker end and don't cover the same frequency spectrum so in no sense are they in parallel for current flow to the speaker. In essence, correct. When bi-wired, the individual speaker unit won't have any way of sensing what currents flow in the 'other cable' - i.e. the one not connect to it. Therefore, to my mind, resistance is not changed anywhere. Where could I connect my fictitious superbly accurate meter to measure this change in resistance? The problem is that what Serge wrote only really explains the behaviour if the cables are connected in parallel at both ends (and we ignore intercable field interactions). My understanding is that is *not* what people normally do when 'bi-wiring' loudspeakers. Hence your puzzlement is quite understandable. :-) The webpages which I referred to in an earlier posting outline the situation in more detail. Briefly: The network when bi-wired has a topologically different arrangement of nodes/paths to when conventionally wired. This means the affects of the impedances have to be modelled in a suitably different manner. However unless the bi-wires are connected together at *both* ends (amp and speakers) the bi-wiring isn't simply described just by saying that the series resistance halves and the shunt capacitance doubles. (Assuming two nominal lengths of cable.) If bi-wiring is used with two identical speaker cables then I can see no possibility that this will make any difference what so ever. See the analysis I refer to above. In principle, it can alter the frequency response by an amount that would be quite measurable. What is unclear is if, in practice, this happens to a degree that would be audible. On that point I have my doubts as I've never seen a single reliable test whose results showed this. Bi-wiring opens up the possibility of using two different cables and that, in my experience can make a difference even if it would require one of the cables to be less than perfect in an engineering sense. Yes. If you wished to deliberately use cables with wildly different series resistances, etc, then they could then interact with the load impedances of the speaker units and alter the overall response accordingly. However the levels of resistance required for this would probably more cheaply and controllably be obtained by deliberately adding low-value series resistors and shunt capacitors, etc, at the speakers. This is usually called "modifying the crossover networks"... ;- 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 |
bi-wire config question
In article , Dave Plowman (News)
wrote: In article , Bob Latham wrote: The amplifier will see the capacitance of two speaker cables and in this sense they are in parallel which will add the capacitance of each. The cables are not connected together at the speaker end and don't cover the same frequency spectrum so in no sense are they in parallel for current flow to the speaker. Unless the cables have significant capacitance inductance resistance etc they are effectively in parallel at the speaker end. And are carrying exactly the same signal since they are paralleled at the source of that signal. I am trying to recall how a Flag Officer is supposed to comment when his Admiral says something that perhaps isn't quite correct... :-) If the amplifier has an o/p impedance that is essentially 'nil' then the speakers won't be affected by cable capacitance. The individual units will be affected by the individual series resistance and inductance of the cable connected to that unit - but not that connected to the other unit. If the amp has a non-zero o/p impedance then there will be a resulting interaction. The 'signals' involve both current and voltage. The amp may be asserting the same voltage pattern at the (common) amp end of the bi wired cables. But the currents in the cables may differ, and the individual cable-speaker impedance interactions are in different paths. Please see the webpages I've referred to previously as they should clarify this topic. 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 |
bi-wire config question
In article , Serge Auckland
wrote: Bob Latham wrote: The change in "total" resistance comes from the doubling of the 'speaker cables, and therefore a halving of the total resistance. As each 'speaker cable now carries a lower current, the already small loss down each 'speaker cable becomes smaller still. Serge: Are you assuming the two cables are being connected together at *both* ends? If so, I'd agree with what you say. But if not, the statement that the "total" resistance halves leads to the question - which device in the system experiences a current that passes through this "total" resistance? I can see that the amp would be such a device. But not the individual speaker units. [snip] There's no mystery to any of this, it's another example of the hi-fi fraternity accepting what some mags and shops tell them as truth, without any engineering rigour being applied. With this I am inclined to agree. The curious thing is that I did the webpages I've referred to back in 2002. Perhaps I should try writing a magazine article on this sometime as it continues to be a 'mystery' in the magazines... :-) 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 |
bi-wire config question
Jim Lesurf wrote:
In article , Serge Auckland wrote: Bob Latham wrote: The change in "total" resistance comes from the doubling of the 'speaker cables, and therefore a halving of the total resistance. As each 'speaker cable now carries a lower current, the already small loss down each 'speaker cable becomes smaller still. Serge: Are you assuming the two cables are being connected together at *both* ends? If so, I'd agree with what you say. But if not, the statement that the "total" resistance halves leads to the question - which device in the system experiences a current that passes through this "total" resistance? I just re-read what I wrote earlier, and it's complete tosh! Crossover distortion of the brain.... The amp would still see each individual drive unit and its crossover components, and each part of the cable would still carry the same individual current to each drive unit. Consequently, there would be no change in "total" resistance. S. I can see that the amp would be such a device. But not the individual speaker units. [snip] There's no mystery to any of this, it's another example of the hi-fi fraternity accepting what some mags and shops tell them as truth, without any engineering rigour being applied. With this I am inclined to agree. The curious thing is that I did the webpages I've referred to back in 2002. Perhaps I should try writing a magazine article on this sometime as it continues to be a 'mystery' in the magazines... :-) Slainte, Jim |
Some difficult questions regarding bi-wiring
What would happen when you have bi-wiring if some of the electrons went down
the wrong wire and didn't realise it until they got to the speaker. They would have to come back and go down the right wire. The ones coming back would have to crash into some going down. If the wire was hard and brittle couldn't these crashes cause cracks in the wire because of the impact. The cracks would have to affect sound quality because of the reduction in cross sectional area of the wire at the crack. When these electron crashes occur, wouldn't this disrupt the "electron traffic flow" and result in a noticible degradation of the sound quality. Also, the electrons that went down the wrong wire and have to go back would actually arrive at their speaker later then they should. Wouldn't this muddy the sound. |
Some difficult questions regarding bi-wiring
Dopey wrote: What would happen when you have bi-wiring if some of the electrons went down the wrong wire and didn't realise it until they got to the speaker. They would have to come back and go down the right wire. The ones coming back would have to crash into some going down. If the wire was hard and brittle couldn't these crashes cause cracks in the wire because of the impact. The cracks would have to affect sound quality because of the reduction in cross sectional area of the wire at the crack. When these electron crashes occur, wouldn't this disrupt the "electron traffic flow" and result in a noticible degradation of the sound quality. Also, the electrons that went down the wrong wire and have to go back would actually arrive at their speaker later then they should. Wouldn't this muddy the sound. I'm sure the lunatics at Audio Asylum would be very concerned about this ! ;~) Graham |
bi-wire config question
Serge Auckland wrote:
Are you seriously trying to tell us that tri or bi-wiring makes (or even can make) a difference? Have you done the sums to see what effect bi or tri wiring makes? I've done several comparisons, using one then two runs of identical cable (originally tested it with Gale XL-105). When I switched to bi-wiring the sound was clearer, switching back to single wiring made it sound muddy. Interestingly a few years back I went with a friend to dem some new speakers at Richer Sounds, the guy who'd wired the system up had bi-wired them but hadn't taken the bridging straps off (so the speakers were in fact single-wired) [1]. After commenting that I thought the sound was "a bit muddy" I had a quick look behind the speakers and noticed this. I didn't tell my friend the way it was set up, just said to him "pause the CD for a moment", removed the straps (making sure he couldn't see what I was doing!) and said "ok, carry on". His reaction was something along the lines of "bloody hell, that sounds way better, what did you do?" I showed him the bridging straps that I'd removed... More recently I did some tests using my own setup, single-wiring using two of the four cores of Chord Rumour 4, then bi-wiring, then bi-amping. Could hear a significant difference in clarity between single and bi-wired, but couldn't hear any difference between bi-wired and bi-amped [2]. So the cables were identical on both tests, just with bi-wiring two runs of the same type of cable (or in this case a 4-core bi-wire cable) were in use. "Doing the maths" only tells half the story. A few years back at the Bristol Sound & Vision show I heard a classic example of this, how a particular manufacturer (TAG McLaren if memory serves correctly) had done all these calculations to make sure this CD player, amplifier and speaker combo was "the best in the world". The guy then put on a CD. It sounded horrible. Thinking it was just a badly mastered CD, I got him to play one of the test CDs I'd brought with me. It still sounded horrible. So much for the maths... [1] I didn't realise the speakers were single-wired when I commented that it sounded a bit muddy. Just to avoid any confusion, misinterpretation etc that usually happens on here. [2] Bi-amping implies bi-wiring, just to state the bleeding obvious - as someone previously asked how I managed to bi-amp without bi-wiring... duh! -- Glenn Richards Tel: (01453) 845735 Squirrel Solutions http://www.squirrelsolutions.co.uk/ IT consultancy, hardware and software support, broadband installation |
bi-wire config question
"Jim Lesurf" wrote in message ... In article , Serge Auckland wrote: snip To see the analysis, go to the 'Scots Guide' (URL in my sig), use the link to the 'Analog and Audio' section, scroll down that page, and use the links to the pages on "An explanation of bi-wiring", etc, to see the analysis and results. These show that bi wiring can change the frequency response - but by only a small amount even when using cables of exceptionally high series resistance. Hence changes in measured behaviour are possible. But are they audible in any sensible arrangement?... My reaction tends to be that if I wanted a change in frequency response of a few tenths of a dB I'd move my head slightly whilst listening. :-) Ah yes - the issue of listening position! Something I've noticed is that when listening to music if I happen to tilt my head so that I'm either looking upwards or downwards then there is a discernable change in the sound - I hear more or less treble. I suspect that the actual shape of my ears influences how well certain frequencies are heard. So (assuming that I'm not the only one that this affects) unless we're going to restrain our heads in some sort of clamp then any comparitive test of speaker connectivity is more likely than not going to have to deal with 'is my head in exactly the right position to make it a fair trial' and indeed if moving one's head slightly can affect the sound heard then is there any point in worrying about minor changes that might be imparted via the speaker cable arrangement? Unfortunately in my case I also know that my ears are not equal with regard to how well they 'hear' various frequencies - I have had both eardrums repaired because infections created perforations and minor auditory nerve damage so I have had my hearing tested a few times! I imagine others hear differently with left and right ears just as our vision isn't always perfectly matched left to right. Why seek perfection when more than likely the most imperfect part of the system is ourselves?! Howard |
bi-wire config question
Glenn Richards wrote:
Serge Auckland wrote: Are you seriously trying to tell us that tri or bi-wiring makes (or even can make) a difference? Have you done the sums to see what effect bi or tri wiring makes? I've done several comparisons, using one then two runs of identical cable (originally tested it with Gale XL-105). When I switched to bi-wiring the sound was clearer, switching back to single wiring made it sound muddy. Interestingly a few years back I went with a friend to dem some new speakers at Richer Sounds, the guy who'd wired the system up had bi-wired them but hadn't taken the bridging straps off (so the speakers were in fact single-wired) [1]. After commenting that I thought the sound was "a bit muddy" I had a quick look behind the speakers and noticed this. I didn't tell my friend the way it was set up, just said to him "pause the CD for a moment", removed the straps (making sure he couldn't see what I was doing!) and said "ok, carry on". His reaction was something along the lines of "bloody hell, that sounds way better, what did you do?" I showed him the bridging straps that I'd removed... More recently I did some tests using my own setup, single-wiring using two of the four cores of Chord Rumour 4, then bi-wiring, then bi-amping. Could hear a significant difference in clarity between single and bi-wired, but couldn't hear any difference between bi-wired and bi-amped [2]. So the cables were identical on both tests, just with bi-wiring two runs of the same type of cable (or in this case a 4-core bi-wire cable) were in use. "Doing the maths" only tells half the story. A few years back at the Bristol Sound & Vision show I heard a classic example of this, how a particular manufacturer (TAG McLaren if memory serves correctly) had done all these calculations to make sure this CD player, amplifier and speaker combo was "the best in the world". The guy then put on a CD. It sounded horrible. Thinking it was just a badly mastered CD, I got him to play one of the test CDs I'd brought with me. It still sounded horrible. So much for the maths... [1] I didn't realise the speakers were single-wired when I commented that it sounded a bit muddy. Just to avoid any confusion, misinterpretation etc that usually happens on here. [2] Bi-amping implies bi-wiring, just to state the bleeding obvious - as someone previously asked how I managed to bi-amp without bi-wiring... duh! You've obviously convinced yourself that it makes a difference. I've never managed to hear any myself, and when I do the sums, I'm not a bit surprised. By the way, if you are indeed sure it does make a difference, have you tried to analyse why and how? What mechanism can be acting to make the sound better (or even different)? S. |
bi-wire config question
Serge Auckland wrote:
You've obviously convinced yourself that it makes a difference. I've never managed to hear any myself, and when I do the sums, I'm not a bit surprised. By the way, if you are indeed sure it does make a difference, have you tried to analyse why and how? What mechanism can be acting to make the sound better (or even different)? Not going to start drawing too many ASCII art diagrams at 1am, but a lot of people think that "bi-wiring" just consists of running two lengths of cable between amp and speakers. But if you don't remove the bridging straps at the speaker end, all you're doing is halving the series resistance of the cable (which should be negligible anyway). Or if you prefer it as "doing the sums": C = R / 2 where C is the resistance of the cable run(s) and R is the series resistance of one run of cable. Once you take the bridging straps off however, something else is occurring. And what happens makes an audible difference. Too tired to do the maths atm, but I'm sure a few ASCII art diagrams will help. (For those people using brain-dead newsreader software, switch to a monospaced font at this point.) The HF driver is drawing a much lower current from the amp than the LF driver (it doesn't need to move in and out so much, this should be obvious). If you imagine the cable as a resistor and the driver voice coil as an inductor, what you've basically got is this (note highly simplified): Single wired speaker ==================== + -----[===]----+-----+ CSR | | {L} {C} | | {D} {D} CSR | | - -----[===]----+-----+ LF HF whe CSR = Cable Series Resistance L = Inductor (low pass filter in x-over) C = Capacitor (high pass filter in x-over) D = Driver voice coil Bi-wired speaker ================ + --+-----[===]----+ | CSR | | {C} | | | {D} HF \ CSR | - ---|-+--[===]----+ / \ +---|-[===]----+ / CSR | | {L} | | | {D} LF | CSR | +--[===]----+ Treat the run of cable between the amp and speaker as if it were a resistor and it makes it easier to understand what's happening. And remember that the LF driver can take a hefty current when you're trying to move a lot of air - and that current is effectively being drawn through a series resistor (ie the run of speaker cable). By bi-wiring, you're no longer drawing that high current required by the LF driver through the same series resistor as the HF driver. The result - much more linearity from the HF driver, as it's no longer suffering from current drain via a series resistor when the LF driver draws current. Therefore no current sag to the HF driver, resulting in a cleaner and more dynamic HF response. Again, apologies if this makes little sense, it is 1am and I'm rather tired... -- Glenn Richards Tel: (01453) 845735 Squirrel Solutions http://www.squirrelsolutions.co.uk/ IT consultancy, hardware and software support, broadband installation |
bi-wire config question
"Glenn Richards" wrote in message . uk... Treat the run of cable between the amp and speaker as if it were a resistor and it makes it easier to understand what's happening. And remember that the LF driver can take a hefty current when you're trying to move a lot of air - and that current is effectively being drawn through a series resistor (ie the run of speaker cable). By bi-wiring, you're no longer drawing that high current required by the LF driver through the same series resistor as the HF driver. The result - much more linearity from the HF driver, as it's no longer suffering from current drain via a series resistor when the LF driver draws current. Therefore no current sag to the HF driver, resulting in a cleaner and more dynamic HF response. Again, apologies if this makes little sense, it is 1am and I'm rather tired... -- Glenn Richards Tel: (01453) 845735 Squirrel Solutions http://www.squirrelsolutions.co.uk/ IT consultancy, hardware and software support, broadband installation But is the wiring between the amp output devices and the speaker terminals to which you attach the bi-wiring to be considered in this equation or do you just ignore it and concentrate totally on the speaker cables. If you run separate wires to the amp output devices (not the amp terminals) are you then to consider the resistance and other effects of the output devices. Do we then consider the diameter of wiring between the power supply and the amplifier circuitry in this equation as it will cause voltage drop at higher currents. Should we require a power supply (transformer/capacitors) that suffer no voltage drop at higher current requirements. Are the power supply capacitor leg wires sufficient to minimise/eliminate voltage drop under high/heavy current requirements All you are doing with bi-wiring is placing the terminal that joins the the LF and HF driver circuit inputs at the amp terminals instead of the speaker terminals. If the speaker wire is so inadequate that you are able to measure any significant changes in HF linearity due to the effect of speaker wire resistance then the wire run is too long or the wire is too light. |
bi-wire config question
APR wrote:
All you are doing with bi-wiring is placing the terminal that joins the the LF and HF driver circuit inputs at the amp terminals instead of the speaker terminals. If the speaker wire is so inadequate that you are able to measure any significant changes in HF linearity due to the effect of speaker wire resistance then the wire run is too long or the wire is too light. Glenn said recently: "(HF needs less current so a thinner cable will suffice)." Which shows that there is no point in discussing technical stuff with him, unless it is to give the rest of us a laugh. -- Eiron No good deed ever goes unpunished. |
bi-wire config question
Eiron wrote:
Glenn said recently: "(HF needs less current so a thinner cable will suffice)." Which shows that there is no point in discussing technical stuff with him, unless it is to give the rest of us a laugh. It's called "speaking in layman's terms". Some people aren't technically minded, and don't really care about the how and the why, just the what. But since you're being pedantic, let's put it another way. A loudspeaker voice coil is basically a linear motor. The LF driver is going to draw more current than the HF driver - which should be blindingly obvious as it has to move in and out much more (a throw of anything up to an inch or so). The HF driver only moves by a few microns, as the frequencies it is reproducing are far higher. Therefore the HF driver is going to draw far less current than the LF driver - and therefore is less likely to be affected by a slightly higher series resistance (eg a thinner cable) than the LF driver. -- Glenn Richards Tel: (01453) 845735 Squirrel Solutions http://www.squirrelsolutions.co.uk/ IT consultancy, hardware and software support, broadband installation |
bi-wire config question
APR wrote:
All you are doing with bi-wiring is placing the terminal that joins the the LF and HF driver circuit inputs at the amp terminals instead of the speaker terminals. If the speaker wire is so inadequate that you are able to measure any significant changes in HF linearity due to the effect of speaker wire resistance then the wire run is too long or the wire is too light. Ok, for those people that still don't "get it", here's an experiment that will demonstrate visually what's going on: Take a 12V DC power supply (one of those bench PSUs capable of supplying several amps will suffice) and a 12V 1W bulb (any type will do, it's easier to perform the experiment using a MES bulb and batten holder with screw terminals though). Connect the bulb to the power supply using 5 metres of 13-strand zip wire and power up. Observe the brightness of the bulb. Now take a second bulb and holder, and attach a few inches of the same wire to the second holder. Connect the second bulb in parallel with the first so that it is "chained" from the first bulb, ie you've got 5m of cable from PSU to first bulb, then a few inches from the first bulb to the second bulb. Make this connection with the power turned on. As you connect the second bulb, you'll see the first bulb's brightness decrease. This is caused by a voltage drop in the cable. Disconnect the second bulb and the brightness of the first will increase again. Now replace the short piece of wire on the second bulb with another 5 metre length, and connect the two bulbs in parallel by attaching two sets of wire to the power supply. This time when you connect the second bulb the first one won't dim, and the second will light up at full brightness. This is exactly what is happening with your speaker cables. The cable run acts like a series resistor, and the load (in this case the driver voice coil) causes a voltage drop across that series resistor. By bi-wiring you are avoiding the load from the LF driver causing a voltage drop to the HF driver. (Again this is a greatly simplified description of what's going on.) I've specified 13-strand zip wire in the experiment above as it makes the results more obvious, but the effect will still stand with thicker cable, it'll just be harder to see. And eventually you'll get to a thickness of cable that will have a low enough series resistance that the effect will no longer occur - but in the case of speakers that cable will either be so expensive or so unwieldy that it makes more sense to use two thinner runs of cable. -- Glenn Richards Tel: (01453) 845735 Squirrel Solutions http://www.squirrelsolutions.co.uk/ IT consultancy, hardware and software support, broadband installation |
bi-wire config question
On Sun, 18 Jun 2006 07:45:45 +0100, Glenn Richards
wrote: Eiron wrote: Glenn said recently: "(HF needs less current so a thinner cable will suffice)." Which shows that there is no point in discussing technical stuff with him, unless it is to give the rest of us a laugh. It's called "speaking in layman's terms". Some people aren't technically minded, and don't really care about the how and the why, just the what. But since you're being pedantic, let's put it another way. A loudspeaker voice coil is basically a linear motor. The LF driver is going to draw more current than the HF driver - which should be blindingly obvious as it has to move in and out much more (a throw of anything up to an inch or so). The HF driver only moves by a few microns, as the frequencies it is reproducing are far higher. Therefore the HF driver is going to draw far less current than the LF driver - and therefore is less likely to be affected by a slightly higher series resistance (eg a thinner cable) than the LF driver. Glenn. Do yourself a favour and stop posting right now. Go read up on Ohms law, apply it to this situation, then come back and say sorry. This was one of the funniest posts that has appeared here in ages. The implication of this post is that cables are nonlinear - they distort. d -- Pearce Consulting http://www.pearce.uk.com |
bi-wire config question
On Sun, 18 Jun 2006 08:00:27 +0100, Glenn Richards
wrote: APR wrote: All you are doing with bi-wiring is placing the terminal that joins the the LF and HF driver circuit inputs at the amp terminals instead of the speaker terminals. If the speaker wire is so inadequate that you are able to measure any significant changes in HF linearity due to the effect of speaker wire resistance then the wire run is too long or the wire is too light. Ok, for those people that still don't "get it", here's an experiment that will demonstrate visually what's going on: Take a 12V DC power supply (one of those bench PSUs capable of supplying several amps will suffice) and a 12V 1W bulb (any type will do, it's easier to perform the experiment using a MES bulb and batten holder with screw terminals though). Connect the bulb to the power supply using 5 metres of 13-strand zip wire and power up. Observe the brightness of the bulb. Now take a second bulb and holder, and attach a few inches of the same wire to the second holder. Connect the second bulb in parallel with the first so that it is "chained" from the first bulb, ie you've got 5m of cable from PSU to first bulb, then a few inches from the first bulb to the second bulb. Make this connection with the power turned on. As you connect the second bulb, you'll see the first bulb's brightness decrease. This is caused by a voltage drop in the cable. Disconnect the second bulb and the brightness of the first will increase again. Now replace the short piece of wire on the second bulb with another 5 metre length, and connect the two bulbs in parallel by attaching two sets of wire to the power supply. This time when you connect the second bulb the first one won't dim, and the second will light up at full brightness. This is exactly what is happening with your speaker cables. The cable run acts like a series resistor, and the load (in this case the driver voice coil) causes a voltage drop across that series resistor. By bi-wiring you are avoiding the load from the LF driver causing a voltage drop to the HF driver. (Again this is a greatly simplified description of what's going on.) I've specified 13-strand zip wire in the experiment above as it makes the results more obvious, but the effect will still stand with thicker cable, it'll just be harder to see. And eventually you'll get to a thickness of cable that will have a low enough series resistance that the effect will no longer occur - but in the case of speakers that cable will either be so expensive or so unwieldy that it makes more sense to use two thinner runs of cable. OK, Glenn - two things. First lets assume that your experiment is applicable. Now complete it. Use you second case - with the two wires run separately right back to the source ( for maximum brightness). Now take your short piece of wire and join the two bulbs together. If biwiring made a difference, there should be a change in brightness as you do this. There is no change. All you have shown is that it is usually better to have thicker wire. The second point is that the tweeter and woofer are not in parallel. Does that surprise you? This because we are dealing with signals in defined frequency bands, and we have a crossover, which presents a high impedance to the cable in the stopband of each driver. This means that low frequency signals - no matter how big - do not suck voltage away from the tweeter. In fact the tweeter doesn't even know there is a woofer there. There are of course electrical devices that have the effect you describe; they are called modulators and rely on controlled non-linearity to achieve a multiplying function. If you can show that cables act as modulators, you will have saved the broadcasting industry a fortune overnight and your fame will be assured. Glenn, as I said in another post, please stop this. You have a minuscule technical knowledge which ends far short of an ability to understand and apply Ohm's law, but you persist in airing your howlers. I know we are all amused when we have nothing better to do, but you really are doing yourself no favours. d -- Pearce Consulting http://www.pearce.uk.com |
bi-wire config question
"Glenn Richards" wrote in message ... But since you're being pedantic, let's put it another way. A loudspeaker voice coil is basically a linear motor. The LF driver is going to draw more current than the HF driver - which should be blindingly obvious as it has to move in and out much more (a throw of anything up to an inch or so). The HF driver only moves by a few microns, as the frequencies it is reproducing are far higher. Glen, a LF driver with 25mm travel at 50 hertz travels the same distance as a HF driver travelling 0.01mm at 12,500 hertz. Admittedly the energy required to accelerate the lower mass of a HF driver will be significantly less, however, depending on the crossover frequency the energy to a HF circuit can be greater then that going to a LF unit, especially in 3 way and up systems where the LF crossover can be well below 300 hertz. |
bi-wire config question
In article , Glenn Richards
wrote: Serge Auckland wrote: Are you seriously trying to tell us that tri or bi-wiring makes (or even can make) a difference? Have you done the sums to see what effect bi or tri wiring makes? I've done several comparisons, using one then two runs of identical cable (originally tested it with Gale XL-105). When I switched to bi-wiring the sound was clearer, switching back to single wiring made it sound muddy. However, IIUC from previous discussions, none of the "comparisions" you have reported here have been carried out in the ways we have discussed and which would then allow the 'results' to reliable as evidence. [snip] More recently I did some tests using my own setup, single-wiring using two of the four cores of Chord Rumour 4, then bi-wiring, then bi-amping. Could hear a significant difference in clarity between single and bi-wired, but couldn't hear any difference between bi-wired and bi-amped [2]. So the cables were identical on both tests, just with bi-wiring two runs of the same type of cable (or in this case a 4-core bi-wire cable) were in use. This prompts the following questions (amongst others)... What test protocols did you use? How many times did you repeat the comparisons? How did you 'randomise' the order of listening? How did you ensure level matching, etc? How did you ensure that you had no knowledge of which arrangement was in use at a given moment *other* than the sounds produced? How did you deal with various other factors - e.g. variations in hearing physiology with time and exposure to sounds? How did you do a statistical analysis, and what (numerical) level of confidence did this return as an estimate? My recollection from previous reports you have made was that you did not deal with the above experimental/protocol/assessment issues. The result being that your conclusions were of little use as 'evidence'. However if what you are reporting here was a more carefully run test I'd be interested in the 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 |
bi-wire config question
Glenn Richards wrote:
Serge Auckland wrote: You've obviously convinced yourself that it makes a difference. I've never managed to hear any myself, and when I do the sums, I'm not a bit surprised. By the way, if you are indeed sure it does make a difference, have you tried to analyse why and how? What mechanism can be acting to make the sound better (or even different)? Not going to start drawing too many ASCII art diagrams at 1am, but a lot of people think that "bi-wiring" just consists of running two lengths of cable between amp and speakers. But if you don't remove the bridging straps at the speaker end, all you're doing is halving the series resistance of the cable (which should be negligible anyway). Or if you prefer it as "doing the sums": C = R / 2 where C is the resistance of the cable run(s) and R is the series resistance of one run of cable. Once you take the bridging straps off however, something else is occurring. And what happens makes an audible difference. Too tired to do the maths atm, but I'm sure a few ASCII art diagrams will help. (For those people using brain-dead newsreader software, switch to a monospaced font at this point.) The HF driver is drawing a much lower current from the amp than the LF driver (it doesn't need to move in and out so much, this should be obvious). If you imagine the cable as a resistor and the driver voice coil as an inductor, what you've basically got is this (note highly simplified): Single wired speaker ==================== + -----[===]----+-----+ CSR | | {L} {C} | | {D} {D} CSR | | - -----[===]----+-----+ LF HF whe CSR = Cable Series Resistance L = Inductor (low pass filter in x-over) C = Capacitor (high pass filter in x-over) D = Driver voice coil Bi-wired speaker ================ + --+-----[===]----+ | CSR | | {C} | | | {D} HF \ CSR | - ---|-+--[===]----+ / \ +---|-[===]----+ / CSR | | {L} | | | {D} LF | CSR | +--[===]----+ Treat the run of cable between the amp and speaker as if it were a resistor and it makes it easier to understand what's happening. And remember that the LF driver can take a hefty current when you're trying to move a lot of air - and that current is effectively being drawn through a series resistor (ie the run of speaker cable). By bi-wiring, you're no longer drawing that high current required by the LF driver through the same series resistor as the HF driver. Yes, but that doesn't matter at all, as the current drawn by the LF driver is isolated from the current drawn by the HF driver by virtue of being at different frequencies, and the current is being drawn through a frequency-sensitive network, the crossover. The only exception is at or close to the cross-over frequency itself. When you substitute real-world values for the cable resistance, you will find that the drop in level at the crossover frequency is so small (fractions of a dB) that it won't affect the sound heard. Outside the crossover frequency, it could matter if the cable were to be non-linear, that is, exhibited intermodulation distortion, but cables are linear to a huge degree, so that can't account for the change in sound from bi-wiring. The result - much more linearity from the HF driver, as it's no longer suffering from current drain via a series resistor when the LF driver draws current. Therefore no current sag to the HF driver, resulting in a cleaner and more dynamic HF response. No, for the reasons mentioned above. Again, apologies if this makes little sense, it is 1am and I'm rather tired.. No apology needed, it was well argued, but I feel it is wrong, unless I've missed something. S. |
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