using gem+linux for gigs (was Re: Gem segfault)

[Joseph A. Sarlo]

I've been using the Swissonic Studio D USB audio interface under Linux
with my laptop and after some initial difficulties it seems to work fine.
The latency is nominal. I haven't done any hard-core testing, but the
total latency (including audio buffer) is definately under 50 ms. It seems
all the horror stories about usb are not true (well, most of them anyway).
I can even use a usb joystick on the same port (with a hub) at the same
time, which makes sense since full duplex 44.1k 16 bit stereo should only
require about 350KByte/s of bandwidth and USB (ideally) offers 1.5MByte/s.

The trick with linux is that the drivers only work with devices that are
100% usb audio class compliant.  I've only found two devices that can
claim that, the Swissonic Studio D and Sound Technology's SoundBuster.
The prolem is they're both kind of expensive and the Soundbuster is more
of a data aquisition device for acoustic measurements.  You also are going
to want to get the latest usb kernel modules.  I had some problems using a
2.2 backport that all went away when I moved to 2.4.1.  Also, I have an
OHCI controller which everybody seems to say doesn't wor well, but it's
been working fine for me. Some things are a little weird but nothing
unworkable.

-- 
 __________________________
|
| Joseph A. Sarlo
| Computer Music Dept.
| Peabody Conservatory
| Johns Hopkins University
|
| jsarlo at peabody.jhu.edu
|__________________________



On Fri, 30 Mar 2001 pix at test.at wrote:

> I'm really interested in the 'remote gui' option rather than the
> netsend/receive option, as it doesnt really require any functional changes
> to existing patches. but at the moment im not in a oaition to test it,
> only having the one pc. but real soon now i'll be getting a laptop
> (curently in the 10-14 business days tease-zone), so i'll probably give it
> a whirl then.
>
> another thing i hadn't thought about until today was looking into the
> possibility of using multiple gfx cards under x4. it might not be
> possible, but if it were possible to do multi-head using two different
> kinds of cards (i know its possible with expensive cards that support
> multihead) than you could just have the gem window appearing on whichever
> one has video out. maybe i'm ascribing mythical superpowers to x4 here :)
>
> also, a friend forwarded me some mailing list exceprts about huge
> latencies using usb-audio solutions on laptops under windows (using
> audiomulch). has anyone on this list played with usb-audio (especially
> under linux), and what kind of latencies have they got? i'm hoping the
> latency isnt inherent in usbaudio, but i wouldnt be surprised if it was...
>
> (then again, my current patch has so much inherent latency, that this
> wouldnt really be a problem for me anyhow, but i'm just curious).
>
> On Wed, 28 Mar 2001, Timmy B wrote:
>
> > HI Pix, Miller and others
> >
> > the way I have this running is to seperate the
> > control to a laptop and the rendering to a linux box with a
> > good graphics card. i use netsend/netreceive to send info from the
> > laptop to
> > a patch i have written on the box which opens the gem window
> > at maximum size. i use pd -nogui on the box to get rid of the gui. i use
> > twm as the window manager as it should be the simplest and fastest. i
> > have
> > added my own .twmrc to remove title bars and boundaries from
> > the window, but i cannot get the positioning requests to be
> > honoured, so i have to drag the top left corner of the gem window
> > to the top left corner of the screen manually. suggestions
> > welcome
> >
> > i chose netsend as the control mech because i believe it would
> > be the simplest and fastest rather than using some remote
> > control / X-window confusion.
> >
> > this is planned also to be very portable - for a workshop
> > i need only take the video card and linux install CDs, all
> > the extra code is on the laptop, so i can de-Bill a PC
> > at the venue and make it do clever (well, half-clever)
> > things [hopefully] quite quickly....
> >
> > haha
> >
> > tm
> >
> >
> >
> >
> >
> > Miller Puckette wrote:
> > >
> > > This should work... you can feed Pd a command line option "-guicmd" to
> > > set how Pd will start the GUI up, which could use rsh to start up on another
> > > machine, or even set the DISPLAY variable.  In either case Gem's window
> > > should start up on the machine Pd is running on.
> > >
> > > I got this working once but I have another problem, which is that I don;t have
> > > a good way of sizing and positioning the Gem window to cover all of the
> > > display.  Should be easy, but it didn't just work instantly when I tried it.
> > >
> > > cheers
> > > Miller
> > >
> > > >
> > > > my current thought is to have the pd interface on another machine using
> > > > the new gui options... i dont know if this is a possibility tho (i havent
> > > > tried it yet)... also if it did work, would the gem window open up on the
> > > > machine running pd or on the machine running pd-gui (i'm hoping it would
> > > > open on the machine running pd).
> > > >
> > > > pix.
> >
> > --
> > -------- ------------------------------------
> >  \    /  Tim Boykett   mailto:tim at timesup.org
> >   \  /   TIME'S UP
> >    \/    Industriezeile 33 B
> >    /\    A-4020 Linz
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> >
>
>