On Mon, Jan 25, 2021 at 9:27 PM Matt Feifarek <matt.feifa...@gmail.com> wrote: > My guess is that it's likely in the amp; did you try hooking up the Topping > to the new pi? Or, the converse; hook the amp up to the workstation and see > if you see a delay?
I have a bad feeling that might indeed be the problem, but wanted to eliminate any possible problem with my software config first. Swapping the RPI 3 and 4 is indeed a perfectly valid suggestion. Admittedly, I haven't done that because it's a lot of hardware reworking, was hoping to deduce the program with only config changes and such (ok, ok, I'm lazy!). > Does the Pi have a USB soundcard, or a "hat" sort of thing? Some of the hats > have buffers in them to reclock the audio signal; this can add a delay too. > I'm not familiar with the MA12070P, but as it's I2S, maybe it is adding a > buffer. The ma12070p is a newish digital input (I2S) class D amplifier (essentially, a "power DAC" or a DAC and amplifier in one chip). Between the RPI and amp is an Allo Kali I2S reclocker. I don't think the Kali adds any meaningful latency, as I've used it extensively with other I2S DACs, and never before noticed lag. I do know that the various controls of the ma12070p (volume, I2S format, etc etc) are done via the I2C serial bus, which I don't believe is a high-speed/low-latency bus. > You can login to the pi over ssh and turn up logging to a very verbose degree > and watch it, you'll see messages about measured latency, probably both on > the "server" (the Pi) and on the client (your workstation). Good idea, I will do that and report back. > Regarding your last question, you could certainly login to the Pi, put a wav > file over there, and do "paplay file.wav" and see if the delay after hitting > enter "feels" the same as over the network. My guess is that it will. I did that both directly on the RPI server, and the workstation client as well. It does seem like there is a lag doing paplay directly on the server. The lag might be slightly greater on the client, but I wouldn't swear to it. (It's one of those things that's so simple and trivial, yet when I do it multiple times in a row, I start second-guessing myself, kind of like when you say the same word over and over again, it starts to sound foreign after enough repetitions.) > If the delay can't be worked around, there might be ways to tell the pulse > audio stack to account for it in playback to get for example your YouTube to > sync up right. I know that VLC can do this. It might come to that. I'll continue to investigate, see if I can conclusively determine if that's the fundamental issue. Thanks! _______________________________________________ pulseaudio-discuss mailing list pulseaudio-discuss@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/pulseaudio-discuss
