Hi all. I have successfully configured both Roonbridge and PiCorePlayer on my RPi 2 with Hifiberry DAC+ Pro. Amazing stuff!
With Roonbridge, I have volume control options in Roon of a) Use Device Controls b) DSP Volume, and c) Fixed Volume. By running amixer on the Pi, I can see that Device Controls manipulates the “Digital” Simple Mixer control. Is this a digital volume control of the DAC+ board? Would it be better to use Device Controls or DSP Volume?
With PiCorePlayer, amixer only shows one device, which is named PCM. The output of amixer doesn’t seem to change when I change the volume in Roon. Note that for this audio device, there are no volume control options in Roon. What’s controlling volume in this setup?
I’m interested in the PiCorePlayer image because it includes Airplay. I will only be using Pi’s with this image for ceiling speakers, so any perceived quality improvements with Roonbridge aren’t that important to me, but the flexibility of having Airplay is. Be nice to have an image that included Shairport!
Your Hifiberry DAC+ Pro offers hardware volume control. In current kernel/Alsa versions, this is indeed exposed as the ‘Digital’ mixer in alsamixer. PiCorePlayer appears to map it all to a single ‘PCM’ mixer channel – I’d guess that is why the volume control from Roon (Use Device Controls) is not working. Perhaps @brian can share some wisdom here, but be advised that any squeezelite-based solution is not officially supported (Squeezeboxes are).
For now, you can either try to install a shairport-based solution on your Pi running Roon Brigde (although I don’t know if they would exist together peacefully) – or use PiCorePlayer with DSP volume controls set in Roon. In the latter case Roon will resample all audio to 24-bit in order to create headroom for the volume control, so technically your signal will not be bit perfect any longer (Roon’s signal path will show this). Given your use case, I don’t think this will be audible while it gives you the convenience of software volume control. In any case – let your ears decide!
We manipulate the “Digital” control for pcm512x devices like the HiFiBerry/IQaudIO devices because we’ve been made to understand that this is the highest quality volume control on the device (I am not totally sure if it is a digital control or not. Many of the best DAC-integrated volume controls available today are digital–so digital volume control is not as much of a dirty word as it used to be).
As for Device Controls vs DSP Volume…I agree with @RBM. Both should sound very good. It’s really about personal preference and/or what works in your setup.
Thanks very much for that information, gentlemen. The Hifiberry people tell me the hardware volume control is digital, so it comes down to whether Roon’s DSP volume control is better than that. I’ll have a play.
My volume problem with PiCorePlayer is that there are no volume options in Roon for it at all. The gear icon in Audio Setup only has Disable, and no other settings. So does that mean all volume control is being done at the RPi end, and if so it would be back to using the DAC+ hardware (digital) volume control?
Much as I’d love to have it, don’t think I’ll embark on getting Shaiport running alongside Roonbridge. My Linux skills don’t really run to that!
I installed shairport-sync on one of my Pi’s running Roon Bridge just for fun. So far, they appear to be working harmoniously in tandem: they both release their grip on Alsa when they’re done playing, so the other can take over. Volume control works with both as well. Be sure to use the more recent shairport-sync instead of plain ole shairport though.
It may look slightly daunting at first and requires a little compiling, but it is really not much more complicated than prepping a Pi and installing Roon Bridge.
Anyway – this could give you the best of both worlds, it seems.
