Topic: Understanding the importance and function of clock over ADAT / SPDIF
Hey there,
essentially I have a Digiface with a few extra ADAT / SPDIF connections not in use, so I thought that rather than connecting an HDMI audio extractor to my Fireface UC via the analog input connections and then sending it to the Digiface over ADAT, I would just plug the HDMI audio extractor directly into my Digiface via an optical cable. However, I can't seem to get the extractor to output over optical with a 44.1kHz sample rate (seems to be locked at 48kHz). Because of this, I can see in the MADIface Series Settings panel that the input is constantly alternating between "Lock" and "Sync".
I mean just based on the documentation for the extractor, stating "Audio sample rates up to 192kHZ" in regards to the optical output, I would think that I could get it to output at a 44.1kHz sample rate. But I guess it may also depend on what's providing it with the signal? I've got a PS4 Pro and a Nintendo Switch connected to it, so maybe they're the cause of the 48kHz signal? I don't really expect anyone to have definitive answers to those questions as these are products that aren't made by RME, and I've already messaged the company directly asking if there is some way to force 44.1kHz output. Though at the same time, I wouldn't be at all surprised if someone here knew the answer to these questions as they may be common knowledge. This is the HDMI audio extractor I'm using:
https://jtechdigital.com/product/18g-4k … extractor/
Unfortunately, I can't permanently set the internal clock of the Digiface to 48kHz because I have other devices connected that are locked at 44.1kHz. But even ignoring that, I always assumed that that there would be some sort of blaringly obvious issue when connecting multiple digital sources with varying sample rates to one interface. However, I can't seem to perceive any changes when I alternate the internal sample rate of the Digiface between 48kHz (to match the HDMI audio extractor) and 44.1kHz (to match everything else). I would think that I'd hear some sort of difference whether that be a degradation in quality, or some weird speed up / slow down in time when monitoring a source connected via SPDIF that has different sample rate than the internal one / other connected devices.
Clearly I don't fully understand what's going on here and would appreciate any information that can help me get a better grip on the situation.