optical out sound card for linux?

[D. Hugh Redelmeier]

| From: tleslie <tleslie-RBVUpeUoHUc at public.gmane.org>

The HiFi field is populated with magic thinkers.  It is really hard to
sort the facts from the fantasy.

Many of the fantasies have the side-effect (or perhaps intent) of
sucking much money out of your wallet.

Peter, for example, clarified the impedance issue (he should know --
he was a prof in the EE department at Ryerson).

I can only use common sense.  You can add to that testing.

Charles mentioned an issue that I think may matter: the fact that
certain Sound Blaster models (whole generations, I think) resample
everything to 48K.  In theory, this could be done well but maybe it is
not.

In the good old days, the aim of HiFi designers was flat frequency
response.  That may not be the goal for sound card designers since
playing with equalization may make the card more attractive to more
buyers.

I don't really trust analogue signals coming out of a computer.  Lots
of electrical noise in those boxes.  So digital out should be better.
Of course I have no idea how much better and whether a normal human
could notice.

Digital signals can come out as
- USB (not usually suitable for an amplifier)
- TOSLINK (optical)
- S/PDIF (coax with RCA connector or TOSLINK optical)
- some soundcards have an external pod for analogue connections where
  the pod is connected via a digital bus to the soundcard.
Of course, switching to digital may imply resampling anyway.  I don't
actually understand the protocols involved: perhaps more than two
channels are implied by S/PDIF.

Slew rate?  I don't see how that could be an issue.  The slew rate is
a function of the output, not the input.  If it was a problem, it
would be a problem of the headphones, which does not seem likely.

MP3 is a lossy representation.  And it is digital.  And it is highly
processed.  And each different encoder has its own artifacts.  A
certain amount of purity is lost there.  Even CDs, which have less
monkey-business, impose artifacts.  As do music production processes.

All-in-all, problems could come from many places and my first move
would not be to spend lots of money on an amplifier just for
headphones.

Your one explicit complaint was:
| the high energy song mixed with huge bass cause the
| headphones to make that bass sound like someone 
| hitting a shoe box with a hammer, its bad.
Perhaps the base is being boosted by equalization.
Perhaps this music drove the MP3 encoder into bad behaviour.

Consider trying to play a .wav file of the same track, BEFORE MP3
encoding, through your system (I assume that you have the original
track on a CD, not just as an MP3).

To battle magic thinkers, use science.  Analytical/diagnostic
techniques one must already have developed to be an effective computer
user.
--
The Toronto Linux Users Group.      Meetings: http://gtalug.org/
TLUG requests: Linux topics, No HTML, wrap text below 80 columns
How to UNSUBSCRIBE: http://gtalug.org/wiki/Mailing_lists