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CD transports and resonance
Following on from previous posts where I found that various damping materials
affected the sound of my Pioneer CDP used as transport only (I have an outboard DAC), I've found the same with the CD-Rom I'm now using. I went over to the CD-Rom because the build was more sturdy and there seemed to be a better sound in it, which started to happen when I swapped the switch-mode power supply for a normal toroid PSU. That's the story so far Latest step was to bolt the CD-Rom down to a 10mm slab of aluminium 9.5" by 6.5". This after seeing the Flatfish which is exactly that. It's sitting on the carpet as I write - haven't tried any fancy feet yet! Well, the sound is very noticeably clearer. A CD-Rom vibrates quite a bit in your hand, so I guess this is dampening it usefully. The most noticeable thing is that louder passages are less congested and shouty - they have soothed out audibly. Now I have no idea why resonances affect CD transports, but this is without any doubt what I'm hearing - change the damping, change the sound. I suppose this is back to the debate whether 'bits are bits' or whether the signal is complex and affected by other factors. Since it isn't hard to try, maybe somebody else would like to replicate bolting a CD-rom down to a 10mm slab of alu? I wonder if the measurements would be different on any parameters. Andy === Andy Evans === Visit our Website:- http://www.artsandmedia.com Audio, music and health pages and interesting links. |
CD transports and resonance
Andy Evans wrote:
Following on from previous posts where I found that various damping materials affected the sound of my Pioneer CDP used as transport only (I have an outboard DAC), I've found the same with the CD-Rom I'm now using. I went over to the CD-Rom because the build was more sturdy and there seemed to be a better sound in it, which started to happen when I swapped the switch-mode power supply for a normal toroid PSU. That's the story so far Latest step was to bolt the CD-Rom down to a 10mm slab of aluminium 9.5" by 6.5". This after seeing the Flatfish which is exactly that. It's sitting on the carpet as I write - haven't tried any fancy feet yet! Well, the sound is very noticeably clearer. A CD-Rom vibrates quite a bit in your hand, so I guess this is dampening it usefully. The most noticeable thing is that louder passages are less congested and shouty - they have soothed out audibly. Now I have no idea why resonances affect CD transports, but this is without any doubt what I'm hearing - change the damping, change the sound. I suppose this is back to the debate whether 'bits are bits' or whether the signal is complex and affected by other factors. Since it isn't hard to try, maybe somebody else would like to replicate bolting a CD-rom down to a 10mm slab of alu? I wonder if the measurements would be different on any parameters. Andy No doubt these will be available soon from all good snake oil outlets. IAn -- Ian Bell |
CD transports and resonance
No doubt these will be available soon from all good snake oil outlets.
We're talking engineering here - Fays metals, Chiswick. The difference is quite audible, as I said, so I'm interested in knowing how resonance dampening affects CD transports. Andy. === Andy Evans === Visit our Website:- http://www.artsandmedia.com Audio, music and health pages and interesting links. |
CD transports and resonance
Andy Evans wrote:
Since it isn't hard to try, maybe somebody else would like to replicate bolting a CD-rom down to a 10mm slab of alu? I wonder if the measurements would be different on any parameters. Andy I'll try it if you can *measure* any difference in the output of your own setup. |
CD transports and resonance
|
CD transports and resonance
Since it isn't hard to try, maybe somebody else would like to replicate
bolting a CD-rom down to a 10mm slab of alu? I wonder if the measurements would be different on any parameters. Andy I'll try it if you can *measure* any difference in the output of your own setup.(IanM) I don't have the gear or the knowledge when it comes to digital electronics - it's an area I know very little about. Andy === Andy Evans === Visit our Website:- http://www.artsandmedia.com Audio, music and health pages and interesting links. |
CD transports and resonance
On Fri, 05 Nov 2004 21:40:23 +0000, Andy Evans wrote:
Following on from previous posts where I found that various damping materials affected the sound of my Pioneer CDP used as transport only (I have an outboard DAC), I've found the same with the CD-Rom I'm now using. I went over to the CD-Rom because the build was more sturdy and there seemed to be a better sound in it, which started to happen when I swapped Surely, the whole point of a *digital* media like CD is that there can be *no* change at all to the sound, no matter what turns the disk or how it is supported. All you get back from the laser assembly is digital data. Now, after that you can change things. An outboard DAC with its own PSU is *probably* going to give better results than the built-in one running off the motor PSU - it depends on a lot of things. You really need to do *measurements* of both the raw data and the DAC output signal from the same drive mounted on the plate & off it before you can start along these lines. Yes, the error correction system will cause differences and you *may* reduce errors by bolting the transport down solidly. That won't necessarily make any audible or measurable difference at all to the output from the DAC though. You may reduce "skipping" on faulty disks too, as the drive mechanics may operate more precisely with a better support and, possibly, more inertia in the mounting. I read somewhere (sorry, can't give a ref) that the error correction on transports intended for audio is more lax than on those intended for data, as your ears are incapable of detecting low error rates but are more sensitive to the gaps caused by error correction. If that is so, then using a data drive for audio may give a different sound, but not one that is necessarily "better" as it will contain a different sort of inaccuracy! I'm sure someone will be able to correct me on this if I'm wrong. OTOH, if it sounds better to you, then do it! There is only you to be satisfied at the end of the day. They are *your* ears after all! Don't try to quantify the results as "better" to those of a more scientific bent though. They tend to like to see proof of "better"... ;-) -- Mick (no M$ software on here... :-) ) Web: http://www.nascom.info |
CD transports and resonance
"Andy Evans" wrote in message
Following on from previous posts where I found that various damping materials affected the sound of my Pioneer CDP used as transport only (I have an outboard DAC), Oh, your memos from placebo-land? I've found the same with the CD-Rom I'm now using. ....because your preconceived notions haven't changed. I went over to the CD-Rom because the build was more sturdy and there seemed to be a better sound in it, which started to happen when I swapped the switch-mode power supply for a normal toroid PSU. Constructor's ear. That's the story so far Latest step was to bolt the CD-Rom down to a 10mm slab of aluminium 9.5" by 6.5". You'd have a lot to think about if you did any reasonble testing, subjective or technical. This after seeing the Flatfish which is exactly that. Monkey see, monkey do. It's sitting on the carpet as I write - haven't tried any fancy feet yet! Audio jewelry. Well, the sound is very noticeably clearer. In your dreams, but whatever. A CD-Rom vibrates quite a bit in your hand, so I guess this is dampening it usefully. You'd have a lot to think about if you did any reasonble testing, subjective or technical. The most noticeable thing is that louder passages are less congested and shouty - they have soothed out audibly. You'd have a lot to think about if you did any reasonble testing, subjective or technical. Now I have no idea why resonances affect CD transports, but this is without any doubt what I'm hearing - change the damping, change the sound. I suppose this is back to the debate whether 'bits are bits' or whether the signal is complex and affected by other factors. No, you're hearing your preconceived notions which are BTW, faulty. Since it isn't hard to try, maybe somebody else would like to replicate bolting a CD-rom down to a 10mm slab of alu? Anybody with the time to waste... I wonder if the measurements would be different on any parameters. I could tell you how to easily do a representative set of measurements, but it would be a cosmic waste of my time because you're so far gone on your radical subjectivism that you'd never stop mentally masturbating long enough to do them. |
CD transports and resonance
In article , Andy Evans
wrote: Following on from previous posts where I found that various damping materials affected the sound of my Pioneer CDP used as transport only (I have an outboard DAC), I've found the same with the CD-Rom I'm now using. I have also recently added damping material into my Meridian 200 transport and feel this improves the results. However this seems to be due to a reduction in the low level mechanical 'buzz' that was previously *just* audible now being utterly inaudible. Doubt it had any effect on the actual S/PDIF stream emerging from the transport. Hence I suppose it is possible you have encountered something similar. [snip] . A CD-Rom vibrates quite a bit in your hand, Indeed. However when spinning at speeds above x1 it can re-read the disc to ensure consistent and reliable data recovery before sending out the resulting bitstream. so I guess this is dampening it usefully. No idea. The most noticeable thing is that louder passages are less congested and shouty - they have soothed out audibly. Now I have no idea why resonances affect CD transports, but this is without any doubt what I'm hearing - change the damping, change the sound. You may have no doubts, but I in turn doubt this guarantees your perceptions are reliable guides as to any 'cause' of what you beleive may be occurring. :-) I suppose this is back to the debate whether 'bits are bits' or whether the signal is complex and affected by other factors. Since it isn't hard to try, maybe somebody else would like to replicate bolting a CD-rom down to a 10mm slab of alu? I wonder if the measurements would be different on any parameters. To find out: Try making some relevant measurements! Then tell us the results. In principle, vibrations can make it harder for a transport to recover the data from the disc, and there will always be a finite error rate. In practice the actual recovery with a decent transport should be highly reliable in normal use. Can't say much more without some relevant *measurements*. So in principle. Some bit errors may be emerging. Some jitter may be affecting the result. But in practice this seems questionable. To resolve, employ suitable measurements. Otherwise we (including you) have no real idea if the effects you describe have anything to do with the 'causes' you assume. 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 |
CD transports and resonance
mick wrote:
I read somewhere (sorry, can't give a ref) that the error correction on transports intended for audio is more lax than on those intended for data, as your ears are incapable of detecting low error rates but are more sensitive to the gaps caused by error correction. If that is so, then using a data drive for audio may give a different sound, but not one that is necessarily "better" as it will contain a different sort of inaccuracy! I'm sure someone will be able to correct me on this if I'm wrong. Thats wrong, however IIRC there is less error correction *data* on the CDs themselves for redbook audio than an ISO9660 disc. |
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