So who would be interested in a receiver with only HDMI inputs, no analog, no S/PDIF; PCM only, no Dolby or DTS, but up to 24-bit/192kHz; 16 channels of balanced, XLR outputs, no RCA?
It'll use a home-brew algorithms to turn up to a 7.1 channels into, rear, heights, wides, etc., along with multiple independent sub outs. In any combination you want. Say Charles wants to run 16 EP800s and nothing else, fine. Want Left, Right, Center, Left Surround, Right Surround, Left Rear, Right Rear, Left Wide, Right Wide, Left Height, Right Height, 4 Subs, and a ButtKicker, it'll do that too.
I've just about finished the DAC board schematic, it looks good. Picked top quality parts. You know the stereo output on the Oppo Special Edition? I'm using one of those DACs in mono, differential mode for each channel. Along with a pair of opamps designed to handle ultrasound imaging, or even radar. Giving it a dynamic range of 135 dB, with -120 dB of THD, virtually noise-free (especially into a balanced input). The problem is the DAC board itself already has a $500 bill of materials. That's not really bad for 16 channels, but that doesn't include the DSP board (I'm not sure how much horsepower I'll need yet for all these channels @192kHz), the power supply(ies), or the HDMI interface.
I'm trying to avoid having to license code from the big boys, because for a small run of electronics that'll be a huge percentage of the cost. I am afraid I'll run afoul of patents, even if I figure out the channel processing on my own.
Anyway, that's an update. I'll probably have all the DAC parts narrowed down soon (need to find an I2C repeater which will allow me to address multiple slaves which would normally all answer on the same address). I probably won't do much of the PCB layout myself. I found a company who will look over designs, give implementation ideas, design the PCB, and send it to manufacture. I have to pay them for the work, but that's the same as hiring someone at a company to do this job, but I only have to pay them once.
EDIT: Found the solution to the I2C problem: http://ics.nxp.com/products/i2chubs/
"Addressing selected devices if there are multiple devices in the system with the same I2C address"