27 May
2003
27 May
'03
4:42 p.m.
Another thing about the quattro is that even the windows drivers will
not allow you to record and playback on all 4 channels at one time.
You can use
4 in, 2 out 48khz 24 bit
2 in, 4 out
2 in, 2 out 94 khz 24 bit
I think I am running up against this with my latest attempts. It may be
that the quattro cannot do all 8 channels because of a hardware switch
maybe for power consumption or something. They do run awfully hot and I
can imagine that it would be possible to melt something if their is too
much power running through them.
USB 1.0/1.1 is built on a 12Mb/Sec physical layer.
96000 * 24-bits * 4-channels = 9.216Mb/S if I did the calculations
correctly.
I think that's probably more than USB can really handle. When I worked for a
company that did USB hardware, we found in many PCs (at that time -
1996-1999) that most USB implementations would really do much more than
about 2Mb/Sec reliably. The newer implementations are much better, but these
numbers bring you up to 75% bus efficiency. Even 1394 doesn't get much
beyond that and it uses much larger packet sizes to get some of that.