I have no idea why, btw, but I'd be
curious if I could be bothered.

Hello Rob - you summed up the situation quite neatly. Like you I have no idea
why, and as you can see I have had no explanation. I put some time into this
because, like you, I was curious and in my case I had some mechs lying about.
New CD transports aren't exactly chump change, so it makes sense to start with
what one has. Andy

=== Andy Evans ===
Visit our Website:- http://www.artsandmedia.com
Audio, music and health pages and interesting links.

In article ,
Rob wrote:
The assumption - and I think it's not unreasonable - is that
stabilising a cd mechanism brings audible benefits.

It would do if a record player. They can suffer from all sorts of
vibration influenced effects.

But a CD player is surprisingly digital. Assuming that digital signal can
still be read it will work normally. If it is subjected to severe
vibration it will stop - or at least produce some alarming noises. Nothing
really in between.

--
*How much deeper would the oceans be without sponges? *

Dave Plowman London SW
To e-mail, change noise into sound.

On Sat, 6 Nov 2004 19:49:08 -0000, "Rob"
wrote:


"Stewart Pinkerton" wrote in message
.. .
On 06 Nov 2004 15:15:40 GMT, ohawker (Andy
Evans) wrote:

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.

Hello Jim - I'm open minded - my assumption is that it's to do with
resonance,
I suppose, but I've been very clear in saying I don't understand how this
happens. I'm not in a position to measure, so my next step is to find
others
who have observed similar things and others who can offer some kind of
explanation based on their own empirical knowledge. Andy

Actually, your assumption is that there *is* a real effect.
--

No, I read that as a finding. The assumption - and I think it's not
unreasonable - is that stabilising a cd mechanism brings audible benefits. I
would find that assumption reasonable, in the sense that it's worthy of
test, because of the massive engineering you see in some CDPs and stated
preferences for particular mechanisms. I have no idea why, btw, but I'd be
curious if I could be bothered.

Basic scientific research - first, you have to establish that there
actually *is* an effect, before looking for a cause. Easiest way has
already been suggested, just rip a file with audio off, one with audio
on, and another pair with the transport bonded to a large mass. If all
four files are identical, forget the 'problem', and do something
useful, like improve your room.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

In article , Rob
wrote:

"Stewart Pinkerton" wrote in message
...
On 06 Nov 2004 15:15:40 GMT, ohawker (Andy
Evans) wrote:

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.

Hello Jim - I'm open minded - my assumption is that it's to do with
resonance, I suppose, but I've been very clear in saying I don't
understand how this happens. I'm not in a position to measure, so my
next step is to find others who have observed similar things and
others who can offer some kind of explanation based on their own
empirical knowledge. Andy

Actually, your assumption is that there *is* a real effect. --

No, I read that as a finding.

No, the 'finding' is that Andy thinks he hears a difference. This does not
mean that we have 'found' either that the effect is produced by
'resonance' or to the actual CD player. To establish that, more tests of a
systematic and controlled nature would be required.

The assumption - and I think it's not unreasonable - is that stabilising
a cd mechanism brings audible benefits.

As a vague and unspecific generalisation that is fine. However it does not
establish that this *is* the case in this specific instance. For that we
require suitable tests to obtain relevant evidence.

I would find that assumption reasonable, in the sense that it's worthy
of test, because of the massive engineering you see in some CDPs and
stated preferences for particular mechanisms. I have no idea why, btw,
but I'd be curious if I could be bothered.

Agreed.

FWIW as I've already pointed out earlier in this thread, I have also had
reason to find that applying samping to quite a decent transport caused
what I feel was a slight but audible improvement. However this was for
reasons quite different to those being assumed here! I also think it
possible that I was mistaken, being human.

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

In article , Andy Evans
wrote:
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.

Hello Jim - I'm open minded - my assumption is that it's to do with
resonance, I suppose,

I see no reason from what you say to assume it is "resonance" rather than,
for example, simple vibration effects, or a fault of some kind.

but I've been very clear in saying I don't understand how this happens.
I'm not in a position to measure, so my next step is to find others who
have observed similar things and others who can offer some kind of
explanation based on their own empirical knowledge. Andy

The difficulty is that you are hampered in your desire to find others "who
have observed similar things" by only having an unspecific impression of a
possible symptom. Without relevant measurements or tests you can't assume
that someone who thinks they have heard something similar is actually
experinencing the same causal mechanism at work.

The bottom line, I'm afraid, is that if you do development work without the
relevant measurement kit and being able to study/understand the
implications of the measured results, then you can expect to be 'at sea' at
such times. Finding someone else who is also 'at sea' may be comforting,
but may not help much.

Slainte,

Jim


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

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