In fact I don't think you can achieve lower latency with an USB card.
Anyway if you play a softsynth (like the great ZynAddSubFx, or Om) with
a midi keyboard, the sum of the latency of the softsynth (that you can
adjust by setting the buffer size) plus the interface ->out latency
(~3ms with the UA-25), you'll have the same or even less delay (from
pressing the key to hearing the sound) that you'll get on an hardware
digital synth (6-8ms, AFAIK).
When you need to record an external source you can also use the direct
monitor (available on the UA-25).
cezar@xxxxxxxxxxx wrote:
I have 8ms on M-Audio FW 410 on windows, and It's ok ! for playin keys
So the Ediroll board sounds ok (I guess) being portable also
Florian Paul Schmidt <mista.tapas@xxxxxxx> writes:
On Fri, 05 May 2006 00:51:49 +0000
Cesare Marilungo <cesare@xxxxxxxxxxxxxxxxx> wrote:
6. MIDI is necessary and also lowest latency possible. (which I don't know
what it is on linux)
I'm really happy with my Edirol UA-25.
http://www.roland.com/products/en/_support/dld.cfm?ln=en&dsp=0&iCncd=526
Latency could be set as low as 5.8ms (2.9ms in +2.9ms out) if the CPU
load of the session your're working on is not too heavy.
Just as a sidenote: On a -rt system, which is properly setup (irq and
app priorities) and a delta 44/66/1010 you can use periodsizes down to 8
frames. 8 frames at a samplerate of 48000 corresponds to a (roundtrip)
latency of
2 * (8/48000) = 0.0003333. sec = 0.3333... ms
While context switching overhead gets really huge it is in principle
possible to get ridicously low latency (you really don't want to use a
periodsize of 8 frames though. Even jack idle load is around 20-30% with
that setting -> ugh).
Operation with 32 or 64 frames per period is possible without problems
at all.
I don't think this is possible with USB hardware, and i have no idea
whether it's possible with firewire hardware.
The delta card i use is a PCI card and i suppose in principle the same
should be possible with a pcmcia card (which is afaik just a pci bus in
disguise).
Have fun,
Flo
--
Palimm Palimm!
http://tapas.affenbande.org
c.
--
www.cesaremarilungo.com
