[PROBLEM] Brief 'buzz' when skipping to next track

[dr.diem]

Hi all,

I'm using Moode 7.6.1 on an Allo USBridge Signature feeding a Schiit Bifrost 2 DAC over USB. Whenever i click the track skip buttons there is a brief but audibly unpleasant 'buzz', as if playback is looping over a few samples extremely quickly for about one tenth of a second, before the next track starts. This was present on my initial install (7.1.0) and has remained as I've upgraded.

I should also note that I am using the parametric EQ feature to perform room correction, meaning I think I am limited to using the plughw ALSA output (i.e. I cannot us the direct hw output).

My feeling is that it is some sort of artifact between the USBridge and Bifrost USB, but I wonder if anyone else has experienced similar behaviour and could suggest a configuration change that would stop it happening? MPD settings? ALSA special settings? Would an upgrade to v8 be my best bet?

Thanks in advance for any suggestions folks,

Ian

[Nutul]

Hi all,

I'm using Moode 7.6.1 on an Allo USBridge Signature feeding a Schiit Bifrost 2 DAC over USB. Whenever i click the track skip buttons there is a brief but audibly unpleasant 'buzz', as if playback is looping over a few samples extremely quickly for about one tenth of a second, before the next track starts. This was present on my initial install (7.1.0) and has remained as I've upgraded.

I should also note that I am using the parametric EQ feature to perform room correction, meaning I think I am limited to using the plughw ALSA output (i.e. I cannot us the direct hw output).

My feeling is that it is some sort of artifact between the USBridge and Bifrost USB, but I wonder if anyone else has experienced similar behaviour and could suggest a configuration change that would stop it happening? MPD settings? ALSA special settings? Would an upgrade to v8 be my best bet?

Thanks in advance for any suggestions folks,

Ian

I am reading the small help about "Silence before stop", in the MPD configuration... it is said to prevent noise upon "stopping" audio on some devices...
Though you say you are noticing it upon skipping; could you just try it out, and see if for some reason the two issues are related?
It would be good if that helped you out.

Just my 2c.
Cheers, Al.

[Tim Curtis]

Hi all,

I'm using Moode 7.6.1 on an Allo USBridge Signature feeding a Schiit Bifrost 2 DAC over USB. Whenever i click the track skip buttons there is a brief but audibly unpleasant 'buzz', as if playback is looping over a few samples extremely quickly for about one tenth of a second, before the next track starts. This was present on my initial install (7.1.0) and has remained as I've upgraded.

I should also note that I am using the parametric EQ feature to perform room correction, meaning I think I am limited to using the plughw ALSA output (i.e. I cannot us the direct hw output).

My feeling is that it is some sort of artifact between the USBridge and Bifrost USB, but I wonder if anyone else has experienced similar behaviour and could suggest a configuration change that would stop it happening? MPD settings? ALSA special settings? Would an upgrade to v8 be my best bet?

Thanks in advance for any suggestions folks,

Ian

I am reading the small help about "Silence before stop", in the MPD configuration... it is said to prevent noise upon "stopping" audio on some devices...
Though you say you are noticing it upon skipping; could you just try it out, and see if for some reason the two issues are related?
It would be good if that helped you out.

Just my 2c.
Cheers, Al.

Also try without the EQ and see if the audio glitch occurs and then if no improvement try latest 8.1.2 fresh image.

[dr.diem]

Thanks both,

Unfortunately neither enabling DSD silence before stop nor disabling the parametric EQ curve solved the issue (I additionally tried switching to 'hw' output in ALSA settings having disabled the EQ).

What is the approved method to upgrade to an 8.x release? Can I take a complete settings backup, install the fresh 8.1.2 image, then restore the settings?

Cheers,

Ian

[Tim Curtis]

Your best bet is to start with a fresh 812 image and your USB DAC. If the issue still occurs there may be some sort of incompatibility between the particular USB chipset used in the DAC and the Linux USB audio driver.

[dr.diem]

Thanks Tim, I'll try that next.

What is the correct process to retain my settings following an upgrade? Can I back them up from 7.6.1 then restore them to 8.1.2? Or are you suggesting that I don't do that, and instead rebuild my settings manually?

Separately, I'm pretty certain there is no fundamental incompatibility between the Linux USB audio driver and the Schiit Bifrost, since I previously used it with my Lenovo laptop running Gentoo Linux on a 4.19 kernel and that did not exhibit this issue.

Cheers,

Ian

[Tim Curtis]

Give the fresh moOde image approach a try and see how that goes.

[Geojanitor]

I have a similar problem with a Schiit Modius, although mine manifested itself when I switched between radio stations. I changed the pi output from usb to SPDIF and the problem went away. I surmised that issue has to do with the Schiit implementation of the usb interface. Hope this helps.

[dr.diem]

Many thanks for the input Geojanitor - that's what I feared, knowing that Schiit have their own in-house USB receiver design

I don't want to use an alternate interface precisely because Schiit say that USB input sounds the best of all options they offer. I will double-check by trying it direct from my Linux laptop rather than from the Allo USBridge to see if the behaviour is reproduced and report back.

Cheers,

Ian

[dr.diem]

I performed some tests with the Schiit DAC plugged into a USB port on my Lenovo Thinkpad running Gentoo Linux. tl;dr is that I could not reproduce the issue.

The audio chain was Strawberry as the transport, which uses the GStreamer engine, fed direct to ALSA (i.e. no PulseAudio). I tried using both the hw or plughw interface, and at no time could I reproduce the issue. I did notice that there was a slight pause as the next track buffered - the same length of pause filled with the 'short sample buzz loop' I experience using Moode on the USBridge; it is as if the last few samples continue to play in a tight loop until the next track comes down the pipe.

In my (probably incomplete) understanding this points towards an issue between MPD and the Schiit DAC - as if MPD is still directing the DAC to perform playback without providing new samples to play. I am at a loss to explain how the physical interface (USB versus SP/DIF) plays a part in the equation.

Next, with the DAC connected to Moode/USBridge once again, I experimented with altering each of the MPD Resource Allocation configuration options, none of which affected the issue. I tried raising and lowering Audio Buffer Size, Output Buffer Size and Input Cache.

Next I will try a 'vanilla' install of Moode 8.1.2 on the USBridge in order to factor out any unexpected configuration tweaks or cruft.