Roon freezes up using Blackhole

Core Machine (Operating system/System info/Roon build number)
MacPro running Catalina 10.15.6.

Network Details (Including networking gear model/manufacturer and if on WiFi/Ethernet)
Century Link Modem (60mps Internet), Apple WiFi.
Roon is hardwired to modem.

Audio Devices (Specify what device you’re using and its connection type - USB/HDMI/etc.)
Content streams via PS Audio DirectStream DAC in main music room/theater and office zones, as well as to Sonos Connect to various speakers throughout main house.

Description Of Issue
Here’s perhaps a new one for you. I do a weekly radio show and during the pandemic we’ve been able to broadcast from home. To do this, we use an app called Mixlr and another app called Blackhole which allows whatever I’m playing on my mac to be transmitted by Mixlr back to the main studio and broadcast from there.

Roon lets me select Blackhole as a zone. I like using Roon because I can mix together my own file as well as Tidal/Qobuz selections into a single playlist. The problem is, Roon freezes up at times, which as you can imagine is a problem when in the middle of a radio broadcast your player decides to have a breakdown.

Any thoughts about why this could be happening and how I could fix it. I have, btw, cleaned out my computer, rebooted it and looked for anything that might be causing issues and so far nothing seems to work. I have not problems whatsoever playing to any other of my zones.


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Hi David,

Thanks for reaching out, you are indeed the first user I have seen mention using Roon with live broadcasting, so it is very awesome that you are able to do so! (Except the issues, which we can take a look into).

Can you be a bit more exact as to the symptoms you’re seeing? By “freezing up”, does the track timer stop? Do you get any error messages? Does it look like Roon is still playing but you only hear silence?

Can you please share a screenshot of your Roon Settings -> Audio tab and the Device Setup info for this zone?

One of two things happen,

The slider bar at the bottom of the screen does not advance. although the blue indicator next to the track shows a volume level, as if it is actually being played, even though the slider bar is not advancing


It skips to the next track in the playlist, doesn’t play it, then skips to the next track, and doesn’t play it, and so on.

Here’s the screenshot:

Thanks for you help with this

Here’s the Device Setup

Is Blackhole presenting itself as a 16 channel device? What does the channel layout say under Show Advanced.

I know that under Procedural EQ, Mix, Roon only displays 8 potential channels (7.1) so I wonder if that might be causing an issue.

Yes I believe it is 16 channels. The channel layout is currently set to 2.0.

I’ll try it at the higher layout and see what happens.

So if Roon can’t do any higher than 7.1, then I guess I’ll have to figure out an alternative.

Actually, found something. Searching the forums is your friend. Under Procedural EQ, add Mix, and select “Show All Channels”, that might enable all 16.

for the life of me I can’t find this setting. Where is it exactly? Although, preliminary results setting it to 7.1 are promising, no problems yet.

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@soyka0120 - Do let us know if the change in channel settings resolved the issue!

If you do however experience another hiccup, please note the time + date + track it occurs on in case we need to look into diagnostics.

Yeah, alas it did eventually stall. I’ll run it again and get specific details if/when it repeats.

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Hi David,

I found another post that had a picture of it

Under Procedural EQ, you need to ADD Mix. And then under mix you will see at the top a slider switch that says “Show All Channels”. ( I do think this pic is old and the slider is more towards the left)

Well, for anyone else who might be using Roon to broadcast a radio show using Mixlr, here is what seems to work. It’s not completely foolproof, as occasionally a track is distorted, but I think this has something to do with the interaction with Mixlr (I think) which can be a bit dodgy. Overall it’s not flawless, but close.

  1. Go to settings, select Blackhole (or Mixlr Audio Link, which for some reason doesn’t like, your mileage may vary; of course this assumes that you’ve established one or the other already as an audio zone), click on the cogs (wheels) for the Device Settings and up the Channel Layout from 2 to 7.1 (the highest you can select).

  2. Select Blackhole (or Mixlr Audio Link, which for some reason doesn’t like, your mileage may vary) as your audio zone.

  3. Click on the audio icon and click DSP.

  4. Select/enable Procedural EQ.

  5. Add the Mix filter.

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Hi @soyka0120,

Glad you were able to make improvements with those setting! If you want, you can also try to output Roon to System Output and then setting Mac OS audio output and then sen that to Blackhole. It might provide a bit more reliable output.

I tried the System Output option you suggested, seems to work about the same. New fun fact I just discovered. The occasional distortion of a track is caused by “Master” tracks in Tidal. For whatever reason, a Master Tidal track through Blackhole/System Output is distorted, No issue with regular" non-Master tracks. Using the Tidal app, I can play Master tracks via Blackhole with no problem. Here’s another wrinkle–I have the same problem with Quobuz tracks. Playing via Roon/Blackhole I get distortion. No distortion using the Quobuz app set to Blackhole. And, needless to say, no distortion using Roon for Tidal Masters or Quobuz using any of my regular audio zones.

Any thoughts about what might be going on? Thanks.

I wonder if bandwidth has something to do with it. Tidal sends flac to the device and the unpack happens in he device. Roon unpacks to PCM in the server, and to first unfold if master MQA, then sends that.

I don’t have the same issue using Audrivana. So what might it be doing different, bandwidth or otherwise, in playing Master and high rez Quobuz?

Hi @soyka0120,

A though here - does this happen even if you set the same sample rate and down-sample Masters/Qobuz? Perhaps the higher sample rates are causing the issue, you can set the down-sampling via Roon’s DSP engine:

Well, it half works. I entered the settings as you suggested and while Quobuz tracks not play correctly, Tidal/Masters do not. I get the message “Unexpected error communicating with audio device.” And then I lose control of other zones and I have to reboot not only Roon, but restart my Mac.

After I rebooted, all zones are restored. Qubouz plays correctly in Blackhole zone using recommended DSD settings of 48 for all. Playing Tidal tracks, both Masters and non-Masters, gets “Unexpected error communicating with audio device” message and needless to say, no sound.

Tried it again with the new update, again Tidal Masters is unplayable. Okay with other sources, though. So, that’s a step in the right direction. Must be something with the MQA unfolding (duh).