Re: Quiet general purpose + music laptops?

In article <h6uaal$s1k$1@xxxxxxxxxxxxxxxxxxxxx>, Martin Gregorie
<martin@xxxxxxxxxxxxxxxxxxxxxx> wrote:
On Mon, 24 Aug 2009 14:05:53 +0100, Jim Lesurf wrote:

BTW if it is of interest, the results I've obtained thus far with the
machines I have are detailed on


http://www.audiomisc.co.uk/Linux/Sound1/SoundComputing.html

and

http://www.audiomisc.co.uk/Linux/Sound2/ListenAgain.html

That is interesting stuff. I've also wondered for a long time how the
average PC sound card gets the results it apparently does

When I started thinking about using Linux based machines to work with audio
replay I assumed the above kind of data would already be easily available.
I also assumed that by default internal soundcards would preserve sampling
rates of 44.1 or 48. Was surprised in both cases to find my initial
assumptions were wrong!

My impression is that when it comes to sound you most usually get some sort
of "it works" comment from a vendor or 'tester', but with no checks on
questions like real signal/crap ratio, pointless resampling, etc, etc. Alas
from a serious audio POV if "it works" just means "you can hear something"
then that doesn't help much.


- with all the digital hash flying round inside the case and on the
system buss I'm surprised that there isn't more noise and distortion in
the analogue output from the average internal sound card - or maybe
there is and I've got cloth ears from too many rock concerts and
exposure to model engines.

The old laptop I have been using certainly makes 'background noises' from
its 'heaphones' output whenever the HD heads move. That plus the fan noises
make it useless for any serious listening as I couldn't tell if any editing
or manipulation had slightly upset the sound data over all the 'unwanted
noises' as the laptop stumbles and wheezes! Hence looking for something
newer and better. Doesn't need to be perfect. Just decent. However I do
tend to focus on 'classical' and 'jazz' which is a bit more demanding on
keeping unwanted noises low-level than if my interest were some sort of
heavy metal. 8-]

Maybe this has something to do with the DACmagic's good performance?

Maybe, yes, But at present I can't say for sure as I've not yet tested
other DACs or USB to spdif convertors. So have no real outboard
comparisons.

Aim to examine some other units in due course, and when I do I'll put up
results a la the above pages. I'd started hoping someone had already done
this, but I've only seen some limited results for <mode=circumlocution>
"other choices of OS than linux"</mode> which doesn't help me much.[1]

I am quite pleased with the DACmagic, though. But something simpler and
cheaper may well do for general uses. The snag is finding out data to
decide...

Alas, many vendors of USB DACs/convertors don't even say if their unit
works with linux distributions. Or say what chip, etc, they use so you
could even predict. Fortunately Cambridge Audio were helpful in this
respect and told me they'd had their DAC working with Ubuntu so I could
start using it expecting to get somewhere!

I do have at least one other unit lined up. But at one other maker (who I
won't name unless I give up on them) seems reluctant to help.

But I digress... How much of this stuff needs to be portable as opposed
to being part of a fixed wired installation?

In my case here I just want a system I can setup and put away, used on my
dining table. So a laptop or similar makes sense as I can avoid the extra
fuss of having another monitor, etc, etc. It may well mostly be used with
its PSU running unless the batteries give some practical advantage like
being quieter or reducting jitter. I prefer wired net as I can easily
connect it to a spare lead on my existing network.

So the need isn't portable as such, but convenient to setup and put away.
That said, I may well also use it for uses elsewhere at a later stage so
being portable makes sense. But the idea at present is just to make it 'one
box' for most uses.

The system won't normally be connected to the main audio system which is in
another room. But I may wish to listen to things I am working on with it to
check on various aspects of what I am working on. For that I can link it to
a more modest audio system in the dining room where I'd be using the
laptop. That said, much of the time I'll probably be using it to analyse
and manipulate audio data without listening.

It occurs to me that another way out is to leave the bits with fans and
disks in another room and use an SPDIF link to your audio kit plus thin
client technology to handle screen/mouse/keyboards in your listening
area. The thin client kit is very small and lacks any fans, disks, etc -
its effectively a CAT5 connected X-term terminal for your Linux box.

Well, I already have the Shuttle in the room with the main audio system, so
can use that from there for serious music replay, etc. With the DACMagic it
does that very nicely. The laptop is for more general uses, but these
include things like analysing or editing recordings.

Slainte,

Jim

[1] e.g the June 2009 issue of 'Stereophile' (USA audio magazine) does have
some similar spectra and jitter measurements using the DACMagic via USB.
But not using *nix as the OS.

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scots_Guide/intro/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

.

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