[linux-audio-user] USB Quattro and Jack questions

[Patrick Shirkey]

Patrick Shirkey wrote:
> Mark Knecht wrote:
> 
>>> 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.
> 
> 
> that should be divided by three to get bytes as there are 8 bits in 
> every byte the quattro uses 24 with 3 periods (not packed in four like 
> other cards).
> 
> 24 * 3 bytes * 48000 =  3072000 bytes
> => 3072 Kb
> => 3.072 Mb/S
> 


Doh,

96000 * 3 * 24 = what Tobiah said. Better to read his explanation than 
mine as mine was still a bit confused.


-- 
Patrick Shirkey - Boost Hardware Ltd.
Http://www.boosthardware.com
Http://www.djcj.org - The Linux Audio Users guide
========================================

Being on stage with the band in front of crowds shouting, "Get off! No! 
We want normal music!", I think that was more like acting than anything 
I've ever done.

Goldie, 8 Nov, 2002
The Scotsman