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Old November 7th 04, 08:08 AM posted to uk.rec.audio
Pooh Bear
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Posts: 203
Default 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


Unless you are using the analogue outs, there is no possible reason why the sound (
digital data ) should be remotely in the least interested in your choice of power
supply, chassis or whatever. If there is gross damage to / contamination of the
media ( or maybe excessive vibration ) the error-correction will kick in ( CDs have
a *lot* of inbuilt error correction bits of data ).


You might as well suggest that in a PC - you can write better prose by using these
techniques - the 'interference' of the switching PSU etc - interfering with your
writing skills !


Graham