[Linux-users] USB audio

[Roger Oberholtzer]

On Fri, 2007-08-24 at 20:23 -0400, Jerry McBride wrote:
> On Friday 24 August 2007 02:26:03 am Roger Oberholtzer wrote:
> > On Thu, 2007-08-23 at 17:55 -0400, Kurt Wall wrote:
> > > On Wed, Aug 22, 2007 at 01:49:20PM -0400, Kurt Wall wrote:
> > > > On Tue, Aug 21, 2007 at 04:25:30PM +0200, Roger Oberholtzer wrote:
> > > > > Hello
> > > > >
> > > > > Is anyone using a USB audio device with Linux? It seems that there is
> > > > > some sort of a standard for these. But there is no requirement that
> > > > > all devices follow that standard. Nothing new here. Just looking for
> > > > > pointers to possible devices.
> > > >
> > > > Roger,
> > > >
> > > > I have one at home. Some little TurtleBeach thing I bought from NewEgg.
> > > > The sound isn't great, but that might have reflected the Linux driver's
> > > > quality more than the underlying hardware. When I get home tonight,
> > > > I'll see if I can dig it up and get the specifics.
> > >
> > > As promised, here's what I bought:
> > >
> > > http://www.newegg.com/Product/Product.aspx?Item=N82E16829118107
> > >
> > > It wasn't this card precisely, but an earlier version.
> >
> > Thanks for that. It is generally what I was looking for. As always, the
> > wish list has more...
> >
> > I will put this in measurement systems in US-type vans, where the
> > computer is in the back and the operator, up front, has a display with
> > USB connectivity. Putting USB sound up there eliminates cables. Ummm no
> > more canbles ... uummm no more cables ... (chanted from a comfy lotus
> > position). So, I have been looking at things like
> > http://www.usbgear.com/USB-Speakers.html
> >
> > I see in the Linux USB sound drivers a reference to a USB sound
> > standard. I just never see a USB device claiming to follow it. I bet the
> > Turtle Beach one does, as it worked for you.
> >
> > Time to experiment.
> 
> If you don't mind a kind suggestion on your project... but keep it simple... 
> If you're going to be  running one wire, then there's very little additional 
> work and cost in adding in a dozen more... Personally, I'd rather rely on 
> good old fashioned wire and speakers than an additional layer of hardware and 
> drivers.
> 
> Just my humble opinion. Cheers and have yourself a nice weekend.

I value all advice. Yours is what one first considers. We used to drag a
wire from the speaker out to the world. These days, such speakers are a
single component mounted om the MB. No more simple access. Hence the new
solution.

The vehicle is, as expected, not grounded. When running 220V in such an
environment (DC-AC inverters, non-switching clean sine wave UPS), every
wire is suspect. Any unconnected wire becomes an antenna - a source of
noise. And what do wires have as their reason for existing? To become
unconnected. I guess wires are essentially male.

A UPS connection is electrically more sound than a plain old wire. If
one end becomes unattached, it seems no noise gets past the hub.

Also, we would have to add a PCI sound card. One more thing to break /
jiggle loose / anoy.

The current situation is that we have a single power cable and a single
USB cable course through the vehicle to the operator's station. The
display has built-in USB connectors to which we attach mouse and
keyboard (back of display, very secure and out of the way). The operator
can easily plug in USB storage into another USB connector built into the
side of the display. We do now worry about the operator's exercise
level. But at least they are not tempted to move around in the vehicle
when it is in motion.

Finally, as a 'hi-tech' company, we pride ourselves on making things
work. Our pride may be misplaced, but this is a challenge. Simple, I
admit. But a challenge none the less. I think USB is fast becoming 'good
old fashioned wire'. At least, PCs are being built that way.

-- 
Roger Oberholtzer

OPQ Systems / Ramb?ll RST

Ramb?ll Sverige AB
Kapellgr?nd 7
P.O. Box 4205
SE-102 65 Stockholm, Sweden

Tel: Int +46 8-615 60 20
Fax: Int +46 8-31 42 23