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Dual 505 update
On 9/03/2015 2:15 AM, Java Jive wrote:
As I said earlier, these days manufacturers take even less care with vinyl than they do with other media sources. CD technology could and should have given us a flat FR from near DC up to 25kHz, easily covering the range of human hearing. **Bull****. With a sampling rate of 44.1kHz, Nyquist tells us that the theoretical maximum of CDs is 22.05kz. Even going up to 22kHz it still covers quite comfortably the range of older listeners such as myself. **It actually covers pretty much everyone over the age of 10. So to all intents and purposes we could and should be getting near perfect audio reproduction. But what do we actually get? While there are some very good quality CDs available, even of those recordings originally released on vinyl, there are also too many examples where the sound has been ruined by over-processing. As has been said many times before, the fault lies not in the technology, but in the people who use it **Duh. -- Trevor Wilson www.rageaudio.com.au --- This email has been checked for viruses by Avast antivirus software. http://www.avast.com |
Dual 505 update
In article ,
Bob Latham wrote: Did you not in the late 70s replace twin flex speaker cables that came with the speakers with QED 79 strand? I did and couldn't believe how much difference it made. I've never had speakers that 'came with twin flex' But adequately rated twin flex is just fine. Or even adequately rated solid core. -- *All men are idiots, and I married their King. Dave Plowman London SW To e-mail, change noise into sound. |
Dual 505 update
In article ,
Bob Latham wrote: If I could arrange for the above test to be done in my room with my kit in particular the speakers and with a range of speaker cables I have some say in, I'm confident I could pass the test. The very fact you have a range of speaker cables suggests you expect to hear a difference. And when you expect such a thing, you often think you do. -- *Go the extra mile. It makes your boss look like an incompetent slacker * Dave Plowman London SW To e-mail, change noise into sound. |
Dual 505 update
In article , Bob Latham
wrote: In article , Dave Plowman (News) wrote: In article , Jim Lesurf wrote: I'm quite happy to accept others can hear things that pass me by. But where's the beef? I'm happy to accept others may hear things differently too. But then you get comments like 'you must be deaf if you can't hear the difference I can'. In which case it should be easy to identify the 'better' cable without seeing what is in use. Of course having spent a lot of money on new cables - obviously expecting them to be better otherwise why bother - its easy to convince yourself there is a difference. Seems the cash prize may still be on offer:- http://gizmodo.com/305549/james-rand...les-are-better Did you not in the late 70s replace twin flex speaker cables that came with the speakers with QED 79 strand? I did and couldn't believe how much difference it made. I assume you're asking Dave that. FWIW I tried various cables many years ago and then settled on the one with the lowest series resistance and modest series inductance. Not really because of any difference I could hear but simply because it made sense in principle to minimise any change in frequency response given that I could. If I could arrange for the above test to be done in my room with my kit in particular the speakers and with a range of speaker cables I have some say in, I'm confident I could pass the test. I will admit I've not heard cables sound different on other speakers or in others rooms but to be honest I can't recall ever trying. I'm only qualifying the cables choice to prevent the examiner providing 3 pretty identical cables. I've never thought I could hear differences in all cables. Oh and I can't prove one cable is better than another. I can under the right circumstances characterise them and pick my personal preference. The test referred to was never about showing which was 'best'. Just to find out if someone could actually *show* they could hear the differences they claimed when they only had the sound to decide with. As I'm sure you know full well already (but others reading this may not) the basic problems here are that; 1) Its easy to show that people hear 'differences' even when faced with the same source material played on exactly the same setup (inc cables). Reason being that human perceptions change with time, and with having previously heard sounds. 2) That people are affected by expectations and other cues. So knowing what change has or had not been made can affect the results even when the person believes it hasn't. Hence it is good practice to do tests in ways that deal with those factors and see if someone could tell when a change had been made when they *only* have the sounds to go on. Jim -- Please use the address on the audiomisc page if you wish to email me. Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html Audio Misc http://www.audiomisc.co.uk/index.html |
Dual 505 update
On Mon, 09 Mar 2015 12:58:54 +1100, Trevor Wilson
wrote: On 9/03/2015 2:15 AM, Java Jive wrote: As I said earlier, these days manufacturers take even less care with vinyl than they do with other media sources. CD technology could and should have given us a flat FR from near DC up to 25kHz, easily covering the range of human hearing. **Bull****. With a sampling rate of 44.1kHz, Nyquist tells us that the theoretical maximum of CDs is 22.05kz. As it was actually implemented it was something of a compromise, sacrificing FR to give greater playing time, but the space available on the prototype technology "COULD AND SHOULD" (note what I actually wrote) have been allocated differently to give us a shorter playback time at a higher sampling rate that would have covered the range of human hearing. Even going up to 22kHz it still covers quite comfortably the range of older listeners such as myself. **It actually covers pretty much everyone over the age of 10. I and several others tested the range of our hearing in the Physics Lab at college when I was about 17 or 18, and I wasn't the only one in the group who could hear above 23KHz at that age. So to all intents and purposes we could and should be getting near perfect audio reproduction. But what do we actually get? While there are some very good quality CDs available, even of those recordings originally released on vinyl, there are also too many examples where the sound has been ruined by over-processing. As has been said many times before, the fault lies not in the technology, but in the people who use it **Duh. Duh indeed! -- ================================================== ======= UK Residents: If you feel can possibly support it please sign the following ePetition before closing time of 30/03/2015 23:59: http://epetitions.direct.gov.uk/petitions/71556 ================================================== ======= Please always reply to ng as the email in this post's header does not exist. Or use a contact address at: http://www.macfh.co.uk/JavaJive/JavaJive.html http://www.macfh.co.uk/Macfarlane/Macfarlane.html |
Dual 505 update
On Mon, 09 Mar 2015 14:27:49 +0000 (GMT), Jim Lesurf
wrote: http://www.st-andrews.ac.uk/~www_pa/...eshift/cp.html The authors claimed they'd found an 'effect' where the cable delayed signals by an amount that varied with the current level. But when I looked at the details I noticed that they'd changed something in their test rig without realising the consequences. I think the authors were honest. But people make mistakes. I wrote to the author about this. He had changed the current in part by changing the load resistor. This, naturally enough, interacted with the cable reactances to give a different group delay. I'm not sure he really understood (a background in microwaves really helps), and I never saw a retraction. d |
Dual 505 update
In article ,
Java Jive wrote: As it was actually implemented it was something of a compromise, sacrificing FR to give greater playing time, but the space available on the prototype technology "COULD AND SHOULD" (note what I actually wrote) have been allocated differently to give us a shorter playback time at a higher sampling rate that would have covered the range of human hearing. The reasons for the original CD spec are all based around the limits of the PCM recorders of the day - basically a semi-pro video recorder (U-matic). As we know from later, CD itself is capable of a longer playing time. I doubt there's much in the way of musical information above about 15 kHz anyway. Excepting some electronic stuff. -- *I stayed up all night to see where the sun went. Then it dawned on me.* Dave Plowman London SW To e-mail, change noise into sound. |
Dual 505 update
In article , Don Pearce
wrote: On Mon, 09 Mar 2015 14:27:49 +0000 (GMT), Jim Lesurf wrote: http://www.st-andrews.ac.uk/~www_pa/...eshift/cp.html The authors claimed they'd found an 'effect' where the cable delayed signals by an amount that varied with the current level. But when I looked at the details I noticed that they'd changed something in their test rig without realising the consequences. I think the authors were honest. But people make mistakes. I wrote to the author about this. He had changed the current in part by changing the load resistor. This, naturally enough, interacted with the cable reactances to give a different group delay. Indeed. I'm not sure he really understood (a background in microwaves really helps), and I never saw a retraction. FWIW I did know one of the authors (Harrison, or 'Harry') enough to exchange some emails with him at one point. This was because he was one of the editors of HFN at the time I started writing for them. [1] I'd guess his main involvment was in writing and being interested in the topic. So the 'technical' side was, I guess, done by Ben Duncan. Alas, I am less then entirely 'whelmed' by some other things Ben Duncan has written. e.g the reports he wrote for Uncle Russ about RFI and fancy mains cables. So I'm curious to know which one you wrote to, and what reply he made if any. My guess is you tried Ben Duncan. Jim [1] He beat me to buying a collection of back issues of HFN that reached back to issue one! Damn! I still lack a few issues from the first few volumes. :-/ -- Please use the address on the audiomisc page if you wish to email me. Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html Audio Misc http://www.audiomisc.co.uk/index.html |
Dual 505 update
On Mon, 09 Mar 2015 18:38:18 +0000 (GMT), Jim Lesurf
wrote: In article , Don Pearce wrote: On Mon, 09 Mar 2015 14:27:49 +0000 (GMT), Jim Lesurf wrote: http://www.st-andrews.ac.uk/~www_pa/...eshift/cp.html The authors claimed they'd found an 'effect' where the cable delayed signals by an amount that varied with the current level. But when I looked at the details I noticed that they'd changed something in their test rig without realising the consequences. I think the authors were honest. But people make mistakes. I wrote to the author about this. He had changed the current in part by changing the load resistor. This, naturally enough, interacted with the cable reactances to give a different group delay. Indeed. I'm not sure he really understood (a background in microwaves really helps), and I never saw a retraction. FWIW I did know one of the authors (Harrison, or 'Harry') enough to exchange some emails with him at one point. This was because he was one of the editors of HFN at the time I started writing for them. [1] I'd guess his main involvment was in writing and being interested in the topic. So the 'technical' side was, I guess, done by Ben Duncan. Alas, I am less then entirely 'whelmed' by some other things Ben Duncan has written. e.g the reports he wrote for Uncle Russ about RFI and fancy mains cables. So I'm curious to know which one you wrote to, and what reply he made if any. My guess is you tried Ben Duncan. Jim [1] He beat me to buying a collection of back issues of HFN that reached back to issue one! Damn! I still lack a few issues from the first few volumes. :-/ Yes it was Ben Duncan. The article was so detailed - and so wrong. It was the first time I had thought to set a published record straight. d |
Dual 505 update
On Mon, 09 Mar 2015 17:37:01 +0000 (GMT), "Dave Plowman (News)"
wrote: The reasons for the original CD spec are all based around the limits of the PCM recorders of the day - basically a semi-pro video recorder (U-matic). As we know from later, CD itself is capable of a longer playing time. Well that rather goes to show that it would have been better to have chosen from the start a spec that completely encompassed the range of human hearing, rather than one that almost does. I doubt there's much in the way of musical information above about 15 kHz anyway. Excepting some electronic stuff. Are you claiming that there is no difference between Audio-Cassette, which rolls off about there, and open-reel, vinyl, and CD, all of which had higher roll-offs?. I suspect that most people would be able to tell the difference immediately between the frequency response of AC and those other types - I certainly could and still can with no problem at all. After some searching I've just found some AC recordings of tracks from an album that I now have on CD, it's Barbara Dickson's seminal folk album "From The Beggar's Banquet", 1970. The AC recordings were originally made from a library copy of the LP, while the CD is a re-issue of 5 or 6 years ago that I feel most fortunate to have obtained. The difference between the two is utterly unmistakable. -- ================================================== ======= UK Residents: If you feel can possibly support it please sign the following ePetition before closing time of 30/03/2015 23:59: http://epetitions.direct.gov.uk/petitions/71556 ================================================== ======= Please always reply to ng as the email in this post's header does not exist. Or use a contact address at: http://www.macfh.co.uk/JavaJive/JavaJive.html http://www.macfh.co.uk/Macfarlane/Macfarlane.html |
Dual 505 update
On 10/03/2015 2:29 AM, Java Jive wrote:
On Mon, 09 Mar 2015 12:58:54 +1100, Trevor Wilson wrote: On 9/03/2015 2:15 AM, Java Jive wrote: As I said earlier, these days manufacturers take even less care with vinyl than they do with other media sources. CD technology could and should have given us a flat FR from near DC up to 25kHz, easily covering the range of human hearing. **Bull****. With a sampling rate of 44.1kHz, Nyquist tells us that the theoretical maximum of CDs is 22.05kz. As it was actually implemented it was something of a compromise, sacrificing FR to give greater playing time, but the space available on the prototype technology "COULD AND SHOULD" (note what I actually wrote) have been allocated differently to give us a shorter playback time at a higher sampling rate that would have covered the range of human hearing. Even going up to 22kHz it still covers quite comfortably the range of older listeners such as myself. **It actually covers pretty much everyone over the age of 10. I and several others tested the range of our hearing in the Physics Lab at college when I was about 17 or 18, and I wasn't the only one in the group who could hear above 23KHz at that age. **AT WHAT LEVEL? The human ear does not have a 'brickwall filter' at 20kHz. No one ever suggested it did. I recall visiting a warehouse owned by the company I worked for when I was around 25 years old. I was assaulted by the most appalling 'feeling' and I had to immediately leave. Curious, I decided to work out what was going on. Turns out I was reacting to the ultrasonic burglar alarm system. A microphone, preamp, oscilloscope and frequency counter showed me that the space in the warehouse was constantly flooded with a high intensity acoustic signal of approximately 26kHz. OTOH, using conventional hearing tests, my hearing extended to around 19kHz at the time. MORAL: With sufficient intensity, human hearing can extend way past 20kHz. That intensity is NEVER achieved with any commercial recordings. -- Trevor Wilson www.rageaudio.com.au --- This email has been checked for viruses by Avast antivirus software. http://www.avast.com |
Dual 505 update
Java Jive wrote:
I and several others tested the range of our hearing in the Physics Lab at college when I was about 17 or 18, and I wasn't the only one in the group who could hear above 23KHz at that age. ** Fraid that has been thoroughly proven to have nothing to do with music reproduction. No matter how many naïve audiophools think it does. ..... Phil |
Dual 505 update
Dave Plowman ( Raving Nutcase) wrote:
The reasons for the original CD spec are all based around the limits of the PCM recorders of the day - basically a semi-pro video recorder (U-matic). ** The CD spec was *tweaked* to be compatible with those recorders - hence sampling at 44.1kHz instead of some other very similar number. It is NOT a quality limitation. As we know from later, CD itself is capable of a longer playing time. ** The original CD was smaller than the final 12cm dia version, chosen to increase the playing time to well over 1 hour. 44.1kHz and 16 bit gives audibly perfect reproduction plus a comfortable margin beyond. 100dB s/n and 0.005% THD are well beyond what is necessary. .... Phil |
Dual 505 update
Trevor Wilson wrote:
**AT WHAT LEVEL? ** Certainly over 100dB SPL. Easily achieved with headphones or a tweeter held close to one's ear while being fed from a sine wave generator and amplifier. .... Phil |
Dual 505 update
In article ,
Phil Allison wrote: The reasons for the original CD spec are all based around the limits of the PCM recorders of the day - basically a semi-pro video recorder (U-matic). ** The CD spec was *tweaked* to be compatible with those recorders - hence sampling at 44.1kHz instead of some other very similar number. It is NOT a quality limitation. Never said it was. I was absolutely blown away when I attended the first UK demonstration of CD - as were all of my colleagues. As we know from later, CD itself is capable of a longer playing time. ** The original CD was smaller than the final 12cm dia version, chosen to increase the playing time to well over 1 hour. The limit of an NTSC U matic tape was also 74 minutes of programme material. Allowing for line-up. PAL was 90 minutes. 44.1kHz and 16 bit gives audibly perfect reproduction plus a comfortable margin beyond. 100dB s/n and 0.005% THD are well beyond what is necessary. Absolutely. I've never said different. -- *I used up all my sick days so I called in dead Dave Plowman London SW To e-mail, change noise into sound. |
Dual 505 update
Dave Plowman (Rabid Nutcase) wrote:
The reasons for the original CD spec are all based around the limits of the PCM recorders of the day - basically a semi-pro video recorder (U-matic). ** The CD spec was *tweaked* to be compatible with those recorders - hence sampling at 44.1kHz instead of some other very similar number. It is NOT a quality limitation. Never said it was. ** Yes you did. As we know from later, CD itself is capable of a longer playing time. ** The original CD was smaller than the final 12cm dia version, chosen to increase the playing time to well over 1 hour. The limit of an NTSC U matic tape was also 74 minutes of programme material. Allowing for line-up. PAL was 90 minutes. ** Yawnnnnn.... 44.1kHz and 16 bit gives audibly perfect reproduction plus a comfortable margin beyond. 100dB s/n and 0.005% THD are well beyond what is necessary. Absolutely. I've never said different. ** But you snidely implied differently. ..... Phil |
Dual 505 update
In article , Java Jive
wrote: After some searching I've just found some AC recordings of tracks from an album that I now have on CD, it's Barbara Dickson's seminal folk album "From The Beggar's Banquet", 1970. The AC recordings were originally made from a library copy of the LP, while the CD is a re-issue of 5 or 6 years ago that I feel most fortunate to have obtained. The difference between the two is utterly unmistakable. Alas the LP and CD come into that if you're trying to assess AC. Particularly if you've not heard the LP for a long time and become habituated to the AC. FWIW I also routinely find that an LP sounds different to a CD of the 'same' material. The problem being that this may be down to the two versions being 'mastered' sic quite differently. Can tell you more about the people cutting the LP or 'improving' sic again what they put on LP than it does about the frequency response capabilities of either system. All comes down to how much care and skill were applied when producing the LP or CD, and to the replay systems. A couple of days ago I made a digital copy of a 1960 LP of Schubert symphonies conducted by Beecham. Early EMI stereo LP. The sound is lovely. And with far fewer ticks and clicks than from later EMI LPs. On-center and flat disc, too! Just a tragedy that as time passed EMI ceased to take care when making either LPs *or* CDs and the results sounded worse as a result. Bean counters were more interested in "Who cares about manufacturing quality if we can sell them and they don't come back. How quickly and cheaply can me make them?" From the LPs I have I'd say that during the early 'stereo' years EMI did make some great LPs with real care. But by the mid 1970s they simply turned out 'product' and it was a matter of luck what you got. They relied on you wanting to hear those artists and bits of music. The hifi mag pages routinely carried letters bewailing the poor pressings, etc. Yet it remained clear that a well-made LP could sound very good. Sadly, they got harder to find! Jim -- Please use the address on the audiomisc page if you wish to email me. Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html Audio Misc http://www.audiomisc.co.uk/index.html |
Dual 505 update
On 09/03/2015 20:49, Trevor Wilson wrote:
MORAL: With sufficient intensity, human hearing can extend way past 20kHz. I wouldn't exactly call the sensation of a high level 20 kHz tone 'hearing' more like 'detection'. My normal hearing barely extends to 9-10 kHz these days but I was aware of an odd clicking sensation (best way I can describe it) in an a relatives garden. Turned out to be a cat repellent gadget. Sensation vanished when it was switched off. I've also been aware of a vaguely uncomfortable feeling standing close to a shop window that had some sort of 'anti-teen' sound device installed. Couldn't hear anything at all...just an awareness of something unpleasant. And I'm no teen. |
Dual 505 update
In article ,
Phil Allison wrote: The reasons for the original CD spec are all based around the limits of the PCM recorders of the day - basically a semi-pro video recorder (U-matic). ** The CD spec was *tweaked* to be compatible with those recorders - hence sampling at 44.1kHz instead of some other very similar number. It is NOT a quality limitation. Never said it was. ** Yes you did. Should have realised you'd put your own spin on 'limits'. Should also have known there is absolutely no point in trying to have a discussion with you. -- *I never drink anything stronger than gin before breakfast * Dave Plowman London SW To e-mail, change noise into sound. |
Dual 505 update
In article , Sumatriptan
wrote: On 09/03/2015 20:49, Trevor Wilson wrote: MORAL: With sufficient intensity, human hearing can extend way past 20kHz. I wouldn't exactly call the sensation of a high level 20 kHz tone 'hearing' more like 'detection'. My normal hearing barely extends to 9-10 kHz these days but I was aware of an odd clicking sensation (best way I can describe it) in an a relatives garden. Turned out to be a cat repellent gadget. Sensation vanished when it was switched off. I've also been aware of a vaguely uncomfortable feeling standing close to a shop window that had some sort of 'anti-teen' sound device installed. Couldn't hear anything at all...just an awareness of something unpleasant. And I'm no teen. FWIW Oohashi and others published research papers some years ago which reported doing things like brain scans whilst people listened to sound with/without and 'ultrasonic' portion. Played by itself, people couldn't hear the 'ultrasound'. But their brainscans were different with/without it when the main music was played. So it seems possible that high frequency tones which are - in isolation - 'inaudible' may affect our perception when they accompany clearly audible lower frequency sounds. This isn't particularly surprising if true since human hearing physiology is known to be highly nonlinear. What it means for listening to music is harder to say. But it does make it plausible that there *might* be some advantage in having bandwidths above 20kHz even when you can't hear isolated tones at that frequency, at least in some cases. Jim -- Please use the address on the audiomisc page if you wish to email me. Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html Audio Misc http://www.audiomisc.co.uk/index.html |
Dual 505 update
On Tue, 10 Mar 2015 13:15:43 +0000 (GMT), Jim Lesurf
wrote: In article , Sumatriptan wrote: On 09/03/2015 20:49, Trevor Wilson wrote: MORAL: With sufficient intensity, human hearing can extend way past 20kHz. I wouldn't exactly call the sensation of a high level 20 kHz tone 'hearing' more like 'detection'. My normal hearing barely extends to 9-10 kHz these days but I was aware of an odd clicking sensation (best way I can describe it) in an a relatives garden. Turned out to be a cat repellent gadget. Sensation vanished when it was switched off. I've also been aware of a vaguely uncomfortable feeling standing close to a shop window that had some sort of 'anti-teen' sound device installed. Couldn't hear anything at all...just an awareness of something unpleasant. And I'm no teen. FWIW Oohashi and others published research papers some years ago which reported doing things like brain scans whilst people listened to sound with/without and 'ultrasonic' portion. Played by itself, people couldn't hear the 'ultrasound'. But their brainscans were different with/without it when the main music was played. So it seems possible that high frequency tones which are - in isolation - 'inaudible' may affect our perception when they accompany clearly audible lower frequency sounds. This isn't particularly surprising if true since human hearing physiology is known to be highly nonlinear. What it means for listening to music is harder to say. But it does make it plausible that there *might* be some advantage in having bandwidths above 20kHz even when you can't hear isolated tones at that frequency, at least in some cases. Jim I think a likely explanation is the simple non-linearity of the ear causing audible intermod products when the ultrasonics were on. d |
Dual 505 update
In article , Don Pearce
wrote: Played by itself, people couldn't hear the 'ultrasound'. But their brainscans were different with/without it when the main music was played. So it seems possible that high frequency tones which are - in isolation - 'inaudible' may affect our perception when they accompany clearly audible lower frequency sounds. I think a likely explanation is the simple non-linearity of the ear causing audible intermod products when the ultrasonics were on. Agreed. Which in turn implies that the sound *level* may matter. i.e. Any such impact on the 'perceived sound quality' may only occur when the sound level at the ears is loud enough. Which may indicate why some people notice and care whilst others don't - even if using the same kit and having 'similar ears' in conventional hearing tests. But to me this all illustrates the problem I found so regrettable wrt many claims of 'cable sound'. Since none of those making the claim would take the test, we couldn't find out if/when they were right or mistaken. No way to sort wheat from chaff. I'd have been facinated to get assessable evidence for the possibility of some genuine new factor here. Partly to learn something new and interesting. Partly to then be able to systematically engineer better audio systems *without* having to suffer the many 'enthusiastic' claims made by manufacturers for their very, very expensive cables - when something cheaper and easier might do just fine without all the promotional blarny or product cost. Jim -- Please use the address on the audiomisc page if you wish to email me. Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html Audio Misc http://www.audiomisc.co.uk/index.html |
Dual 505 update
On 10/03/2015 15:10, Jim Lesurf wrote:
In article , Don Pearce wrote: Played by itself, people couldn't hear the 'ultrasound'. But their brainscans were different with/without it when the main music was played. So it seems possible that high frequency tones which are - in isolation - 'inaudible' may affect our perception when they accompany clearly audible lower frequency sounds. I think a likely explanation is the simple non-linearity of the ear causing audible intermod products when the ultrasonics were on. Agreed. Which in turn implies that the sound *level* may matter. i.e. Any such impact on the 'perceived sound quality' may only occur when the sound level at the ears is loud enough. Which may indicate why some people notice and care whilst others don't - even if using the same kit and having 'similar ears' in conventional hearing tests. These threads feel like some kind of altered reality. Sound is experienced in all manner of ways - not just through ears. Honestly, you boffins. Surprised we get anything done with you lot pushing the buttons :-) -- Cheers, Rob |
Dual 505 update
On 10/03/2015 14:38, Don Pearce wrote:
I think a likely explanation is the simple non-linearity of the ear causing audible intermod products when the ultrasonics were on. There's a simple test that could confirm that idea. Two (or more) high level ultrasonic tones a few hundred Hz apart should result in audible tones. Surely this has been tried. I know that this sort of two-tone intermod test is used in audio systems: http://www.whathifi.com/forum/comput...ms-performance There is a download file for this test at the above location. For testing human ear linearity, the levels would have to be high and the tones generated separately in independent systems to eliminate audio system intermod from the test results. I would think the required equipment would be available in many audiophile premises. Any takers? ;-) |
Dual 505 update
On Tue, 10 Mar 2015 18:29:28 +0000, Sumatriptan
wrote: On 10/03/2015 14:38, Don Pearce wrote: I think a likely explanation is the simple non-linearity of the ear causing audible intermod products when the ultrasonics were on. There's a simple test that could confirm that idea. Two (or more) high level ultrasonic tones a few hundred Hz apart should result in audible tones. Surely this has been tried. I know that this sort of two-tone intermod test is used in audio systems: http://www.whathifi.com/forum/comput...ms-performance There is a download file for this test at the above location. For testing human ear linearity, the levels would have to be high and the tones generated separately in independent systems to eliminate audio system intermod from the test results. I would think the required equipment would be available in many audiophile premises. Any takers? ;-) I'm pretty sure my speakers can't do anything much with 30 and 33kHz. I'll try with 20 and 23. d |
Dual 505 update
On Tue, 10 Mar 2015 18:29:28 +0000, Sumatriptan
wrote: On 10/03/2015 14:38, Don Pearce wrote: I think a likely explanation is the simple non-linearity of the ear causing audible intermod products when the ultrasonics were on. There's a simple test that could confirm that idea. Two (or more) high level ultrasonic tones a few hundred Hz apart should result in audible tones. Surely this has been tried. I know that this sort of two-tone intermod test is used in audio systems: http://www.whathifi.com/forum/comput...ms-performance There is a download file for this test at the above location. For testing human ear linearity, the levels would have to be high and the tones generated separately in independent systems to eliminate audio system intermod from the test results. I would think the required equipment would be available in many audiophile premises. Any takers? ;-) Actually, 30 and 33kHz are going to generate products at 27 and 36kHZ - not much help. I made a file with 20kHz and 38kHz. The 2kHz product was clearly audible, and very level dependent. There was actually some kind of threshold effect. I prevented distortion in the amplifier being a confounding factor by recording them on separate channels. d |
Dual 505 update
On Tue, 10 Mar 2015 09:39:00 +0000 (GMT), Jim Lesurf
wrote: In article , Java Jive wrote: After some searching I've just found some AC recordings of tracks from an album that I now have on CD, it's Barbara Dickson's seminal folk album "From The Beggar's Banquet", 1970. The AC recordings were originally made from a library copy of the LP, while the CD is a re-issue of 5 or 6 years ago that I feel most fortunate to have obtained. The difference between the two is utterly unmistakable. Alas the LP and CD come into that if you're trying to assess AC. Particularly if you've not heard the LP for a long time and become habituated to the AC. Of course, but equally, I have several digitisations of vinyls of similar material and sound, digitised on the same deck with the same cartridge, and they too are way better than these AC recordings. Also, I have both a commercial AC and a rather worn vinyl of Eddie Walker's "Red Shoes On My Feet", and, even though worn with a great deal of needle-in-the-groove noise, the vinyl is otherwise still way better quality than the AC. From this and many other historical AC recordings now replaced from better sources, I know that the big problem with AC is the slow tape-speed, leading to the poor FR, and the narrowness of the tape which contributes to a generally poor SNR. FWIW I also routinely find that an LP sounds different to a CD of the 'same' material. The problem being that this may be down to the two versions being 'mastered' sic quite differently. Can tell you more about the people cutting the LP or 'improving' sic again what they put on LP than it does about the frequency response capabilities of either system. Yes, yes, we've been here several times before, and generally tend to agree on the topic. All comes down to how much care and skill were applied when producing the LP or CD, and to the replay systems. As I said at the top of this sub-thread, but care can not make up for the low FR of AC, a constraint arising out of its slow tape-speed. -- ================================================== ======= UK Residents: If you feel can possibly support it please sign the following ePetition before closing time of 30/03/2015 23:59: http://epetitions.direct.gov.uk/petitions/71556 ================================================== ======= Please always reply to ng as the email in this post's header does not exist. Or use a contact address at: http://www.macfh.co.uk/JavaJive/JavaJive.html http://www.macfh.co.uk/Macfarlane/Macfarlane.html |
Dual 505 update
On 08/03/2015 11:34, Sumatriptan wrote:
it's a pigs ear. Just for closure on the hum issue... I corrected the wiring errors causing the L-R reversal and phasing error. I also fitted the Behringer phono--USB into the turntable as per suggestions in this thread. The (good quality) screened cables from tonearm wire connectors to the Behringer phono inputs are now about 3 cm long. Hum is now completely gone. At maximum volume with tt motor running the only sound is a small amount of noise, presumably from the preamp front end. |
Dual 505 update
In article ,
Java Jive wrote: As I said at the top of this sub-thread, but care can not make up for the low FR of AC, a constraint arising out of its slow tape-speed. Commercial cassettes were usually duplicated at high speed. So never going to be at the top end of even that lowly format. Cassettes made on a good home deck using top quality tape could be remarkably good, considering. -- *Ever stop to think and forget to start again? Dave Plowman London SW To e-mail, change noise into sound. |
Dual 505 update
On Wed, 11 Mar 2015 01:19:07 +0000 (GMT), "Dave Plowman (News)"
wrote: In article , Java Jive wrote: As I said at the top of this sub-thread, but care can not make up for the low FR of AC, a constraint arising out of its slow tape-speed. Commercial cassettes were usually duplicated at high speed. So never going to be at the top end of even that lowly format. Cassettes made on a good home deck using top quality tape could be remarkably good, considering. Not too difficult to achieve considerably higher quality than commercially recorded music cassettes given a reasonable quality cassette deck and chrome/SA tape formulations (let alone metal tapes with Dolby noise reduction with the better decks) when you consider that the duplication process was often run at 8 times speed and even as high as 16 speed in some cases. I'm not sure what the maximum duplication speed was, possibly as high as 32 speed for audio book recordings were the lower demands for good quality speech allowed the duplicating equipment to be pushed to its limits[1] without any obvious degradation becoming evident in the playback. As the saying goes, "Time is Money" and there was every temptation to run the duplication plant as fast as possible, often a choice of 8 speed over quad speed on older kit and probably 16 speed in place of the 8 speed option on the newer and improved duplicators (where the 16, and possibly 32, speed was intended for audiobook quality alone). [1] The real limits were down to heating effects and saturation of the magnetic cores and pole pieces of the special 4 track recording tape heads used by the slave drives to transfer the master in a single pass. Notably the nominal 60KHz bias current being scaled up to 960KHz for a 16 speed transfer rate. In this case, it was the limits of the heads that defined the maximum peak limits of the recordings rather than the limits of the tape formulation itself which would normally be the limiting factor on a cheap deck's performance at real time speeds. -- J B Good |
Dual 505 update
In article , Sumatriptan
wrote: On 10/03/2015 14:38, Don Pearce wrote: I think a likely explanation is the simple non-linearity of the ear causing audible intermod products when the ultrasonics were on. There's a simple test that could confirm that idea. Two (or more) high level ultrasonic tones a few hundred Hz apart should result in audible tones. Surely this has been tried. Yes, it has. See what others have now said, for example. Also IIRC it is touted by at least one company as a way to 'throw' audio so that it can be heard in one area but not others. The trick is to send one set of ultrasonic tones from one speaker and another from a different speaker. You then are said to only hear the intended intermod in the area where the beams cross. No idea how well it works. Only recall hearing reports about it. Must admit my concern was the exposure to high levels of ultrasound and I wonder if it would eventually damage hearing or cause some other problem. Jim -- Please use the address on the audiomisc page if you wish to email me. Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html Audio Misc http://www.audiomisc.co.uk/index.html |
Dual 505 update
In article , Trevor Wilson trevor@SPA
MBLOCKrageaudio.com.au scribeth thus On 10/03/2015 2:29 AM, Java Jive wrote: On Mon, 09 Mar 2015 12:58:54 +1100, Trevor Wilson wrote: On 9/03/2015 2:15 AM, Java Jive wrote: As I said earlier, these days manufacturers take even less care with vinyl than they do with other media sources. CD technology could and should have given us a flat FR from near DC up to 25kHz, easily covering the range of human hearing. **Bull****. With a sampling rate of 44.1kHz, Nyquist tells us that the theoretical maximum of CDs is 22.05kz. As it was actually implemented it was something of a compromise, sacrificing FR to give greater playing time, but the space available on the prototype technology "COULD AND SHOULD" (note what I actually wrote) have been allocated differently to give us a shorter playback time at a higher sampling rate that would have covered the range of human hearing. Even going up to 22kHz it still covers quite comfortably the range of older listeners such as myself. **It actually covers pretty much everyone over the age of 10. I and several others tested the range of our hearing in the Physics Lab at college when I was about 17 or 18, and I wasn't the only one in the group who could hear above 23KHz at that age. **AT WHAT LEVEL? The human ear does not have a 'brickwall filter' at 20kHz. No one ever suggested it did. I recall visiting a warehouse owned by the company I worked for when I was around 25 years old. I was assaulted by the most appalling 'feeling' and I had to immediately leave. Curious, I decided to work out what was going on. Turns out I was reacting to the ultrasonic burglar alarm system. A microphone, preamp, oscilloscope and frequency counter showed me that the space in the warehouse was constantly flooded with a high intensity acoustic signal of approximately 26kHz. OTOH, using conventional hearing tests, my hearing extended to around 19kHz at the time. MORAL: With sufficient intensity, human hearing can extend way past 20kHz. That intensity is NEVER achieved with any commercial recordings. Didn't Eckersley of the BBC prove the effects of filters operating above the usual 15 kHz limit did cause audible differences?.. -- Tony Sayer |
Dual 505 update
In article , Don Pearce
wrote: Actually, 30 and 33kHz are going to generate products at 27 and 36kHZ - not much help. Why are you assuming their'd be no f1 - f2 result? I made a file with 20kHz and 38kHz. The 2kHz product was clearly audible, and very level dependent. There was actually some kind of threshold effect. I prevented distortion in the amplifier being a confounding factor by recording them on separate channels. 2*f1 - f2 ? Jim -- Please use the address on the audiomisc page if you wish to email me. Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html Audio Misc http://www.audiomisc.co.uk/index.html |
Dual 505 update
On 11/03/2015 09:12, Jim Lesurf wrote:
Yes, it has. See what others have now said, for example. Also IIRC it is touted by at least one company as a way to 'throw' audio so that it can be heard in one area but not others. The trick is to send one set of ultrasonic tones from one speaker and another from a different speaker. You then are said to only hear the intended intermod in the area where the beams cross. No idea how well it works. Only recall hearing reports about it. Must admit my concern was the exposure to high levels of ultrasound and I wonder if it would eventually damage hearing or cause some other problem. Interesting result from Don in this thread. I didn't try it myself because of worries about screaming high ultrasonics affecting my hearing. So, the verdict seems to be that they can't be heard in isolation but may impact perception of sound within the audible range. Just wondering, does material outside the usual hearing range contribute or detract from perceived 'realism' of recordings? Quite relevant because we have a whole niche industry selling products offering performance at at 20 kHz and above that may/may not be relevant to the sound we can hear. Of course, subsonics are an example of sounds that may not be heard but are widely known to be perceived. I'm interested in Don's report of sudden onset of IM products. I wonder where in the ear they are being generated...drum, stapes, cochlea, brain? Plenty of scope for non linearity in that soft squidgy stuff we are made from. |
Dual 505 update
On Wed, 11 Mar 2015 10:42:43 +0000 (GMT), Jim Lesurf
wrote: In article , Don Pearce wrote: Actually, 30 and 33kHz are going to generate products at 27 and 36kHZ - not much help. Why are you assuming their'd be no f1 - f2 result? I made a file with 20kHz and 38kHz. The 2kHz product was clearly audible, and very level dependent. There was actually some kind of threshold effect. I prevented distortion in the amplifier being a confounding factor by recording them on separate channels. 2*f1 - f2 ? Jim I was assuming a third order product as we're dealing with intermods (2*f1 - f2, as you say). There may be some second order effect, but it isn't guaranteed. d |
Dual 505 update
In article , Sumatriptan
wrote: Just wondering, does material outside the usual hearing range contribute or detract from perceived 'realism' of recordings? Its certainly possible. Hard to say more as things stand. I'm interested in Don's report of sudden onset of IM products. I wonder where in the ear they are being generated...drum, stapes, cochlea, brain? Plenty of scope for non linearity in that soft squidgy stuff we are made from. This may help http://www.audiomisc.co.uk/HFN/hearing/index.html Jim -- Please use the address on the audiomisc page if you wish to email me. Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html Audio Misc http://www.audiomisc.co.uk/index.html |
Dual 505 update
On Wed, 11 Mar 2015 10:57:34 +0000, Sumatriptan
wrote: On 11/03/2015 09:12, Jim Lesurf wrote: Yes, it has. See what others have now said, for example. Also IIRC it is touted by at least one company as a way to 'throw' audio so that it can be heard in one area but not others. The trick is to send one set of ultrasonic tones from one speaker and another from a different speaker. You then are said to only hear the intended intermod in the area where the beams cross. No idea how well it works. Only recall hearing reports about it. Must admit my concern was the exposure to high levels of ultrasound and I wonder if it would eventually damage hearing or cause some other problem. Interesting result from Don in this thread. I didn't try it myself because of worries about screaming high ultrasonics affecting my hearing. So, the verdict seems to be that they can't be heard in isolation but may impact perception of sound within the audible range. Just wondering, does material outside the usual hearing range contribute or detract from perceived 'realism' of recordings? Quite relevant because we have a whole niche industry selling products offering performance at at 20 kHz and above that may/may not be relevant to the sound we can hear. Of course, subsonics are an example of sounds that may not be heard but are widely known to be perceived. Yes, this all rather begs the question of _just_ how far we should go in pursuit of 'perfect reproduction' of the original 'sonic experience'. Do we (or even _should_ we) go so far as to risk hearing damage by reproducing the full range of frequencies and SPLs or do we make some reasonable compromise in this regard? One excellent example of using a compromise to successfully emulate a sonic experience is demonstrated in the "Wolfenstein 3D" 'demo' games in regard of the pistol shots. Firing a hand gun without ear defenders causes the ear's own AGC to kick in in response to the initial high level transient after clipping the 'crack' of the shot so that the ensuing reverberations and other incidental noises become very muted, initially swiftly returning back to more normal sensitivity levels in an exponential return to full sensitivity. Obviously, in a computer game, no sane game designer is going to ask or even expect the serious gamer to invest in a KW rated PC speaker system or use 10 watts per channel into efficient closed back headphones to provide the 40 or 50 dB extra dynamic range to permit the game player the 'full experience' of firing such a weapon under combat conditions. However, what the clever game designer has done here, is to impose a simulation of the ear's own dynamic sensitivity response on the sound track's volume level curve so that what the listener experiences (in a reasonably quiet environment free of other sonic distractions that would otherwise 'give the game away') is very close to the perception of the real experience but without imposing any damaging stresses on the gameplayer's hearing. I've no doubt the experience of fire arms enthusiasts were enlisted to fine tune the simulation of the 'pistol shots' at least to the point of eliminating unsoliicited criticism from those game players who've actually fired such weaponery. It certainly met my expectations of just how one would percieve such sounds, ignoring the physical pain and damaging effects of the 'real thing'. I have to say, it was this attention to detail that left a lasting impression even though, by today's standards, the screen resolution was ludicrously low (however, it was, at the time, the best resolution in a "First Person '3D' Point and Shoot 'em up" game, mainly, it has to be said, on account it was the _only_ "First Person '3D' Point and Shoot 'em up" game available at that time :-) The point I was making is that we don't necessarily want to reproduce the whole of the audio spectrum of an original performance with such extreme accuracy when very often all we really require is verisimilitude. Admittedly such processing to 'simulate' the dynamic effects of the human ear can only be optimised for a small range of 'ideal' SPLs but this hasn't stopped us fitting and using volume controls in the past and to this day. Even extreme audiophiles will accept such compromises as a necessary evil to accommodate the needs of others and also to trade off reality against the need to preserve one's sense of hearing for other novelties. IOW, the volume control is a tacit admission that we're never going to achieve the Nirvana of sonic perfection (at least not in this 'Plane of Existence'. :-) I'm interested in Don's report of sudden onset of IM products. I wonder where in the ear they are being generated...drum, stapes, cochlea, brain? Plenty of scope for non linearity in that soft squidgy stuff we are made from. A lot of the 'overload' distortion arises in the the modified jaw bones (stapes, hammer and anvil) when, just like a mistracking stylus, they part company at their points of contact on sound pressure peaks. It's actually possible to observe this type of 'in the ear' distortion' when stood too close to the speakers at a rock music performance by making the 'overload' distortion go away by the simple expedient of plugging your ears with your fingers. The disappearance of such 'clipping distortion' products has nothing to do with the LPF effect associated with shoving a finger in each ear and more to do with reducing the SPL at the ear drum. The other sources of distortion in the cochlea and the central nervous system become less quantifiable (in that order) but undoubtedly exist. It's the very last part of the chain that's the least quantifiable and hardest to understand (the cochlea is merely a more subtle example of the mechanical problems demonstrated by the three smallest bones in the human body). Here we get ourselves into the realm of 'Psycho-acoustics' where a dichotomy exists between our processing of sounds to allow us to overcome interference effects in the environment in order to extract the important 'information' that assisted our survival against other threats as well as more recently, understand messages from fellow members of our immediate tribe once our species had evolved into co-operative hunter gatherer groups, a skill that finally evolved into the one that lets us speak to each other, even under extremes of interference. That same skill that allows us to appreciate the 'message' contained in 'musical works of art' ( that is, the ability to enjoy a modern pop record despite the less than ideal listening conditions :-). The thing is, such 'signal processing' powers of the brain, can be 'reprogramed' by the mind contained within that brain. Indeed, such 'reprograming' is an ever continuing process during each individuals' lifetime. It's a consequence of the 'adaptability through learning' that gave our otherwise ill armoured, under-weaponised bodies the edge over other 'better equipped' prey and predator species. The consequence, of course being that we can choose to ignore deficiencies in the whole audio system in order to concentrate on the message in the music (including MP3 encoding/decoding errors) or else, in looking for 'more detail' in the playing of more complex orchestrations, find ourselves picking out the deficiencies of the whole audio system. Dedicated audio engineers, being engineers, like to define 'The Problem' as simply as possible (hence the basic definition of working over a range of frequencies limited to between 20 and 20000Hz with a dynamic range of 90dB and almost zero distortion within that well defined audio spectrum). Such 'limits' are wide enough to satisfy all but a very few dedicated Hi-Fi enthusiasts so dedicated in their pusuit of sonic Nirvana as to be willing to take the risks involved in reproducing the more extreme musical performances (the cannonade in Tchaikovsky's 1812 Overture, anyone? see the comments for this you youtube example https://www.youtube.com/watch?v=VbxgYlcNxE8 ) I'm currently listening to it as I type. I started with the volume set at "Easy Listening Level" and it's at the 4 minute mark. I'll let you know whether I agree with the comments in another eleven minutes or so. :-) The point is, I feel any such such 'Ultra Hi-Fi' system will need to incorporate a mode switch marked "SOAR"[1] and "Ultra (risk of some hearing loss)". I've just finished auditioning that youtube rendition. Sadly, it was a lttle disappointing since either the recording itself failed to capture the dynamic range or the the streaming wasn't up to handling the job. The cannon shots were obviously clipped with no sign of psycho-acoustic processing as per the Wolfenstein 3D example of pistol shots which so excellently dealt with the problem. However, I have to admit I was only using a pair of PC speakers, admittedly of above average quality and box volume, rather than through my 50+50W RMS per channel (200W PMPO) mini power amp and large speakers capable of rattling the otherwise unrattleable windows of the downstairs lounge. I suspect I'd have still heard the same shortcoming. There are so many places in the transmission chain for such clipping effects to manifest themselves, including the recording itself for which there was no information as to its origin. Too many unknowns to fathom out the cause for my sense of disappointment. :-( [1] SOAR = "Safe Operating Area Restrictions applied" -- J B Good |
Dual 505 update
On 11/03/2015 9:23 PM, tony sayer wrote:
In article , Trevor Wilson trevor@SPA MBLOCKrageaudio.com.au scribeth thus On 10/03/2015 2:29 AM, Java Jive wrote: On Mon, 09 Mar 2015 12:58:54 +1100, Trevor Wilson wrote: On 9/03/2015 2:15 AM, Java Jive wrote: As I said earlier, these days manufacturers take even less care with vinyl than they do with other media sources. CD technology could and should have given us a flat FR from near DC up to 25kHz, easily covering the range of human hearing. **Bull****. With a sampling rate of 44.1kHz, Nyquist tells us that the theoretical maximum of CDs is 22.05kz. As it was actually implemented it was something of a compromise, sacrificing FR to give greater playing time, but the space available on the prototype technology "COULD AND SHOULD" (note what I actually wrote) have been allocated differently to give us a shorter playback time at a higher sampling rate that would have covered the range of human hearing. Even going up to 22kHz it still covers quite comfortably the range of older listeners such as myself. **It actually covers pretty much everyone over the age of 10. I and several others tested the range of our hearing in the Physics Lab at college when I was about 17 or 18, and I wasn't the only one in the group who could hear above 23KHz at that age. **AT WHAT LEVEL? The human ear does not have a 'brickwall filter' at 20kHz. No one ever suggested it did. I recall visiting a warehouse owned by the company I worked for when I was around 25 years old. I was assaulted by the most appalling 'feeling' and I had to immediately leave. Curious, I decided to work out what was going on. Turns out I was reacting to the ultrasonic burglar alarm system. A microphone, preamp, oscilloscope and frequency counter showed me that the space in the warehouse was constantly flooded with a high intensity acoustic signal of approximately 26kHz. OTOH, using conventional hearing tests, my hearing extended to around 19kHz at the time. MORAL: With sufficient intensity, human hearing can extend way past 20kHz. That intensity is NEVER achieved with any commercial recordings. Didn't Eckersley of the BBC prove the effects of filters operating above the usual 15 kHz limit did cause audible differences?.. **Well, it would, wouldn't it? Phase shift and all that.... The human hearing system is exquisitely sensitive to phase shift. -- Trevor Wilson www.rageaudio.com.au --- This email has been checked for viruses by Avast antivirus software. http://www.avast.com |
Dual 505 update
On Thu, 12 Mar 2015 06:40:05 +1100, Trevor Wilson
wrote: **Well, it would, wouldn't it? Phase shift and all that.... The human hearing system is exquisitely sensitive to phase shift. The human hearing system is essentially totally deaf to phase shift. I've seen an experiment in which the phase of the harmonics of a square wave was cyclically shifted. You could see the waveform changing shape on a scope. Even with the picture in view, it was impossible to hear any change in the resulting sound. Deafness to phase shift is the reason why Orban's Optimod system is able to operate inaudibly. d |
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