Raspberry Pi AirPlay delay

[ian2000t]

Hi, I've got 3 devices which I would like to use AirPlay concurrently on, streaming from my Windows laptop running AirFoil.

- 1 Raspberry Pi B using USB Logitech V20 speaker components (inside a Roberts radio) and USB Wifi.
- 1 Raspberry Pi B using USB "7.1 soundcard" (like this https://www.amazon.com/Channel-External ... QMZN0CFP7Z) and USB Wifi.
- 1 Raspberry Pi 2 using HDMI audio out, and either ethernet or USB wifi.

I'm really struggling to "sync" the devices. I can Sync the 2 "B" Pi's almost exactly using the delay (+/- 1 second) control in AirFoil (a slight echo is noticeable if you stand between the 2 rooms.

But, the Pi2 is NOT playing ball - about 2-3 seconds in front of the other 2. It was running OSMC and on Ethernet before, and I thought this was causing it, so I'm now running RuneAudio on it aswell. I've also tried using the USB wifi from one of the Pi B's, thinking Wifi latency was causing the issue. Same problem.

Thinking about it now, the only thing I haven't tried is running the USB Sound card from the "Pi B" on the "Pi 2", but I'd be suprised if that causes 2-3 seconds of lag.

Or, is this simply that the "Pi 2" is faster than the "Pi B" models, so is processing seconds earlier? Are there any "delay" settings in the AirPlay service, or the ALSA programs in RuneAudio I can adjust?

[ian2000t]

Just for future reference, I've sorted this.

Appears to be nothing to do with the difference in OS (i.e. OSMC or RuneAudio), or anything to do with Pi B vs Pi 2.. It was actually USB vs HDMI!

HDMI appears to be a couple of seconds ahead of USB audio. I bought a cheap USB sound card and used this on the Raspberry Pi 2, and it is now within a few milliseconds of the other 2 "Pi B's". The few milliseconds are tune-able through Airfoil.

I have even tried both Optical and 3.5mm analog outputs of the soundcard and they are both about the same.

Haven't tried a "HAT" sound card, but I have one I can try, to see if this is ahead of the USB or not.