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.

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

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.

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.

On 05 Nov 2004 22:27:54 GMT, ohawker (Andy
Evans) wrote:

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.

Perhaps you need two transports, two identical CD-Rs, and a bit of
time to try a DBT, before rushing off on what's likely a wild goose
chse.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

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.

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

"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.

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

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.