I’m looking at a DAC (Denafrips Pontus) that has I2S as an input and I’m trying to figure out a way to take advantage of that in Roon.
I’ve been searching around for this, but I’m still confused.
If I select the Audio Hat option as “Raspberry Pi DAC I2S” where is this signal output?
Is it the GPIO lines? If so is, do I need some kind of a HAT to get that output via a HMDI port?
As I2S is intended as in internal bus for audio data, basically all HAT’s use I2S. The ‘Rasbberry PI DAC i2S’ enables the default overlay which works with most HAT’s.
What you’re looking for is a way to provide the I2S externally (like on a HDMI connector) to be able to connect an external DAC. In most cases this means that the I2S is made differential, because the I2S signal itself is not designed for long(er) connections.
So, as @cwichura pointed out, the Pi2AES device might be an option.
i2s over HDMI has a few options. Sonore, PS Audio, and Wyred4Sound all have various equipment that use that. I have two i2s streamer rigs which are Roon compatible: Two sets of Sonore microrendu>Sonore Ultradigital. One feeds a W4S DAC, the other feeds a PS Audio Stellar Gain Cell Preamp/DAC. TBH, current USB tends to be pretty close performance wise IMO. Five years ago it wasn’t, but USB has gotten much better. I’m sure i2s is stiil better on paper, but I try not to worry about stuff I can’t hear.
I am very successfully using a Matrix X-SPDIF 2 interface, a usb format converter. USB in, with femto reclocking and format conversion to I2S on HDMI output (also outputs toslink optical, coax, and AES/ EBU simultaneously.) Output up to 32 bit / 768kHz, DSD 512, price $379.