We haven't really had a chance to debug the sub out board. There was something not right with the ground. But after switching to digital power and ground on the digital out board this weekend, (the sub board depends on it for buffering) it seems to work. The sound has a bit of hiss in it, but I attribute that to the ceramic caps and low grade resistors used. As it is now, it should be fine for bass. We'll try another iteration with better components.

If you do ever decide you want a sub out board from us, you will have to also buy a digital out board. The sub out board is designed to plug right in to all I2S models.

We still need suitable software to enable the sub filtering. We currently have none. We have been running the sub board full range to test it.

Stu