Occasional dropouts when streaming, particularly at 192/24

Support
1

I have Roon core running on a late model Mac mini. I have a single audio out which is a Raspberry Pi 2 running Roon Bridge which is connected to a Trinnov Amethyst. Both the Mac mini and the Raspberry Pi are connected via ethernet to a netgear gigabit switch.

I have noticed that I get brief dropouts in a couple of situations:

  • Any time I’m playing high bitrate files there are random dropouts
  • Sometimes when I’m actually using the UI on the mac mini, I get very brief dropouts even when just streaming TIDAL.

I have checked the cpu utilization on the mac mini. It is low. Under 10% total, Roon tends to use about 6%. I also checked network utilization and it’s sitting under 2 MB/second. I also watched ping times and they are pretty steady at 300-400 microseconds.

I also tried increasing the hardware buffer size to 500ms for Roon Bridge.

I’m running the latest Roon.

Any further recommendations for things to try?

Thanks!
Matt

2

which Netgear switch?

if it’s a smart one try disabling flow control
had the same issue with files above 176.4 and the above fixed it
still having random, light, hiccups with DSD but… Roon team is investigating

3

Is this straight USB audio from the Pi to DAC? If so, it could be you are bumping up against the rate limitations of the shared usb / ethernet bus on the rPi 2. Can you try another endpoint?

4

Thanks for the suggestions. I am using the i2s interface on the raspberry pi to a hifiberry digi+ board. No usb is involved.

Here is the specific netgear switch I’m using. Is it possible that this switch is causing issues? Can you even disable flow control on this thing?

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Another question: Is there any diagnostic information I can get from roon bridge on the rpi? Logs maybe?

6

A post was split to a new topic: Dropouts when streaming 196/24

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Hi @MattT ---- Thank you for the report here and the continued feedback!

Moving forward, the switch you are using should be ok as it is unmanaged, which is what we suggest using :thumbsup: In the interest of trying to isolate some variables, I would recommend (temporarily) bypassing the RPi2 + Trinnov Amethyst zone and confirm if you get the same dropouts when playing directly out of the Mac Mini via the headphone jack.

-Eric

8

Hi @Eric ,

No dropouts if I tell Roon to use the System Output. Is the RPi2 just underpowered for this bitrate? I do notice the cpu usage going from approximately 5% to 20% on the RPi2 when I change the bitrate from 16/44 to 24/192.

Thanks,
Matt

9

Hi @MattT ----- Thank you for your patience and my apologies for the slow response. Appreciate you sharing the results of the proposed test with me.

Moving forward, as I am sure you’re aware, dropouts are the result of the audio stream being sent to it’s destination and not making it there in time. We usually see this as a result of some sort of environmental issue (networking related, etc) or hardware performance troubles.

In the interest of isolating some more variables here, I would recommend the following:

  1. If you are using any sort of network based storage, I would recommend moving a few of your 192/24 files to local storage on the MacMini and confirming how they behave under these conditions.

  2. If you have another DAC available to you, I would consider:

  • a) testing with it mounted to the RPi2 to see how it functions, do you have dropouts while playing 192?

  • b) if the DAC is USB capable, I would also see how it functions directly mounted to the MacMini.

  1. While I am not sure which model of MacMini you are implementing, I would be curious to see how the Trinnov Amethyst DAC functions via a Toslink connection to the MacMini (depending on which model you have of course).

-Eric