Quality of Raspberry Pi4 USB For Streaming

[aagstn]

This is a persistent misunderstanding of what was going on in issue #2215. The USB network adapter was a minor factor in whether or how often the pops and clicks might occur. What software was running was a much bigger factor - brutefir was a reliable trigger on both volumio and raspbian unless it was pinned to a single cpu core. With the same hardware running piCorePlayer I never managed to make it pop/click despite streaming the highest rate PCM and DSD files I could find on 2L's free samples, so it certainly could be suitable for audio.

With modern versions of Moode and Volumio I have never had an SMSL DAC pop or click with a 3B. Maybe the issues got worked out.

 

[JakeK]

This is a persistent misunderstanding of what was going on in issue #2215. The USB network adapter was a minor factor in whether or how often the pops and clicks might occur. What software was running was a much bigger factor - brutefir was a reliable trigger on both volumio and raspbian unless it was pinned to a single cpu core. With the same hardware running piCorePlayer I never managed to make it pop/click despite streaming the highest rate PCM and DSD files I could find on 2L's free samples, so it certainly could be suitable for audio.

That's interesting. I had a read of that issue page you linked to.

An unexpected side bonus is that the 5 volt output of the Pi 4 seems to be infinitely cleaner than that of the Pi 2.

My Pi 2 was using the official (at the time) Pi 2 power adaptor and yet the USB 5 volt output was so noisy that "CPU chirping" and other digital noise was readily apparent on the analogue output of the DAC with music paused even at normal amplifier volume settings. Connecting a TV to the HMDI output (normally disconnected with Volumio) made the noise even worse, almost intolerable.

On the Pi 4 (also with the official USB-C power adaptor) there is no CPU chirping or digital noise audible at all. I can turn the amplifier way up to 2 o'clock (well beyond even loud playback) while paused and only hear a small amount of smooth analogue hiss from the amplifier itself that is present with the DAC unplugged.

Basically no power noise of any kind is passing from the Pi through the DAC at all. I'm stunned.

It seems the USB implementation in the RPi 4 is better in other ways as well. Probably nothing audible in most cases but with the low cost of a Pi I think it's worth upgrading to a 4 for audio over USB. For my upgrade I'm planning to get a new screen case as well so I'm pretty much completely rebuilding the streamer anyway. Why spend time building something that might have a tiny issue when the upgrade is pretty cheap. The only downside of the 4 is the extra heat but that doesn't seem to be an issue if you stick on a little passive heatsink.

 

[phofman]

IIUC the previous RPi models had only dwc2 USB-OTG core, while RPi4 has also VL805 hooked to one PCI-e line. While both solutions use DMA, the dwc2 core likely requires more CPU attention during data transfer. That would explain why some softwares experience issues and some don't - brutefir DSP probably takes more CPU than the bare-bone piCorePlayer.

 

[DrCWO]

With modern versions of Moode and Volumio I have never had an SMSL DAC pop or click with a 3B. Maybe the issues got worked out.

Roon Bridle runs flawlessly on a Pi3B also with high resolution.

 

[DrCWO]

That would explain why some softwares experience issues and some don't - brutefir DSP probably takes more CPU than the bare-bone piCorePlayer.

You need a pre-emptive Realtime Kernel on the Pi to make Brutefir run nicely.

 

[somebodyelse]

You need a pre-emptive Realtime Kernel on the Pi to make Brutefir run nicely.

Pinning it to a single core worked for me.

 

[somebodyelse]

With modern versions of Moode and Volumio I have never had an SMSL DAC pop or click with a 3B. Maybe the issues got worked out.

That issue was closed as WONTFIX. It's possible some other change to the USB subsystem has fixed it though - I haven't checked recently whether my old reliable way of provoking it still works.

 

[somebodyelse]

IIUC the previous RPi models had only dwc2 USB-OTG core, while RPi4 has also VL805 hooked to one PCI-e line. While both solutions use DMA, the dwc2 core likely requires more CPU attention during data transfer.

That sounds right on the hardware side - the USB-OTG is on the Type C port on the RPi4. I don't remember whether I managed to reproduce the issue using the Type C in host mode. IIRC the best guess was that something that was done in software for the OTG but in hardware for the pure host mode hit a scheduling issue under some conditions, increasing the latency between request for more data and the response being sent.

That would explain why some softwares experience issues and some don't - brutefir DSP probably takes more CPU than the bare-bone piCorePlayer.

Oddly pure cpu load wasn't the cause. Someone found that artificially adding load using something like cpuburn fixed the issue rather than making it worse as they were expecting. That's what prompted me to try pinning brutefir to a single core which also fixed it. I have vague memories of someone identifying a database as another thing that could provoke it, and that was used by some of the streamer images to store the music metadata, but I may be misremembering.

 

[phofman]

IIRC RPi (I think it was the older SoC) experienced long latency when switching cpu frequencies, several milliseconds at worst case (people reported fixing audio dropouts when setting cpufreq to single fixed value, even the minimum one). That could have caused issues with time-critical handling of the inefficient USB core. Maybe the described scenarios just avoided frequency changes on the core which handles the USB hardware. Just 2 cents...

 

[Phorize]

On the software side, I install rooextend on my pi4 today and set up the rooadi extension so I now have control of the gain my adi 2 from the roon app. It's very good.

 

[laudio]

Nice Pi streamer, I've built many over the year and would never pay the price though.

These days give me a Wiim with auto eq room correction as an endpoint. Hands down better than any Pi streamer IMO.

 

[watchnerd]

Nice Pi streamer, I've built many over the year and would never pay the price though.

These days give me a Wiim with auto eq room correction as an endpoint. Hands down better than any Pi streamer IMO.

Well, if I want a Roon endpoint, why pay $149 for a Wiim Pro when I can build a Pi endpoint for <$100?

 

[BeeKay]

when I can build a Pi endpoint for <$100?

Even the $50 ballpark is easily possible, assuming everyone has no longer used phone chargers in the cupboard.

 

[watchnerd]

Even the $50 ballpark is easily possible, assuming everyone has no longer used phone chargers in the cupboard.

Or, heck, you don't really need a case, either, if you're really being super cheapie

 

[aagstn]

Nice Pi streamer, I've built many over the year and would never pay the price though.

These days give me a Wiim with auto eq room correction as an endpoint. Hands down better than any Pi streamer IMO.

I have tried the Wiim on a few occasions. If I was only using streaming services I would love it, but it is not that great for accessing and sorting your own music on a server. Volumio, Moode and a few others are just better at accessing local large libraries. There are probably other programs you can use with Wiim to improve this experience, but I see no reason when a Pi does so well and at such a low cost.

 

[amper42]

I have tried the Wiim on a few occasions. If I was only using streaming services I would love it, but it is not that great for accessing and sorting your own music on a server. Volumio, Moode and a few others are just better at accessing local large libraries. There are probably other programs you can use with Wiim to improve this experience, but I see no reason when a Pi does so well and at such a low cost.

$55 RPi4 with a $11 amour case and a $13 SanDisk 128GB Ultra microSDXC UHS-I Memory Card gives you a dynamite Streamer supporting UPnP with a broad list of devices. That $79 offers the best quality and value of any streamer. Moode is amazingly versatile with support for UPnP, Roon, Airplay/Bluetooth (if you want it) and much more. Plus, you can easily network with the SDCARD and copy your local high res files to it. That gives you an instant Music server you can hold in the palm of your hand plus external storage options from NVM to SSD or a USB drive. What I really like about Moode, is I can turn off any feature I don't want. I leave off Airplay, Bluetooth so only Hi Res UPnP is possible in playback. No wondering if Airplay is engaged.

Personally, I usually leave my music on a MacBook Pro and Audirvana software plays all my Qobuz and local files directly to the RPi4/Moode over Wifi. The RPi4 feeds the RME ADI-2 DAC FS via USB. It's so easy to setup. I could teach a 1st grader to do it. And the quality beats Wiim by a landslide as it supports UPnP without issues where Wiim is limited to using its app for stabile UPnP playback. Plus, having the option to play all my local music and Qobus streaming from a single screen on Audirvana is heavenly. You won't get that from Wiim.

I've looked for other options but nothing offers a better set of features, stability or the same quality even at prices hundreds more. It's funny how RPi4/Moode is one of the best kept secrets in Audio. It gets little press coverage for such a standout winner.

 

[laudio]

I have tried the Wiim on a few occasions. If I was only using streaming services I would love it, but it is not that great for accessing and sorting your own music on a server. Volumio, Moode and a few others are just better at accessing local large libraries. There are probably other programs you can use with Wiim to improve this experience, but I see no reason when a Pi does so well and at such a low cost.

I have always used Lyrion (formerly Logitech) on the server side. The Wiim can be an endpoint just like any Pi running squeeze, and works better albeit without a display I suppose. For accessing local libs - sure maybe a Pi is better than Wiim. And running any kind of PEQ on a Pi never worked for me. Wiim makes it easy.

 

[aagstn]

I have always used Lyrion (formerly Logitech) on the server side. The Wiim can be an endpoint just like any Pi running squeeze, and works better albeit without a display I suppose. For accessing local libs - sure maybe a Pi is better than Wiim. And running any kind of PEQ on a Pi never worked for me. Wiim makes it easy.

I have sold both of my Wiims so unfortunately I can't try this right now. I may get another one at some point to try out Lyrion. That seems like the piece of the puzzle I was missing for using a Wiim with my local media.

 

[watchnerd]

I have always used Lyrion (formerly Logitech) on the server side. The Wiim can be an endpoint just like any Pi running squeeze, and works better albeit without a display I suppose. For accessing local libs - sure maybe a Pi is better than Wiim. And running any kind of PEQ on a Pi never worked for me. Wiim makes it easy.

If you use Roon and a Pi as an endpoint, you run the PEQ on the Roon server.

No need to run it on the Pi itself.

 

[somebodyelse]

If you use Roon and a Pi as an endpoint, you run the PEQ on the Roon server.

No need to run it on the Pi itself.

Similarly there are server side EQ plugins for LMS so the endpoint doesn't need to do the EQ. Having said that, Moode's EQ is meant to work with its squeezelite endpoint out of the box.