In my experience, the limitations have to do with hardware and bus speeds not the software. For example, take your USB hub and divide it's bandwidth by 12, do you now have enough bandwidth per USB card for Audio? If you are only operating with a 400MHz bus, then a USB hub at or below this bandwidth, you only have 33.3MHz of the bus available per card at best. The fact that the software is capable of operating up to 96 audio channels does not mean the hardware you have purchased is capable of this.
However, a couple of things you can try to maximize the bandwidth you do have is:
- Minimize the number of filters/compression/features that you are using that adds to bandwidth and CPU cycles.
- Choose a lower bit rate for the recording of audio streams.
- The more audio cards you can place directly on the buss the better.
- A 64 bit buss will be better than a 32 bit bus.
To me, it sounds like you will need to spend more money in hardware or sacrifice audio quality.
-GW