Unable to output via DisplayPort

Audacity Help Forum macOS
1

I have a 2018 Mac Mini with three monitors attached. All three are DisplayPort and support audio. One of them has my audio system attached to it. The system and all other apps present no issues outputting audio in this setup, however Audacity doesn’t output any sound when this method is selected. If I choose my headset or the internal Mac Mini speakers I get audio without issue. I have tried all three instances of DisplayPort in the output drop down.

Diagnostics follows:

==============================
Default recording device number: 3
Default playback device number: 1
==============================
Device ID: 0
Device name: DisplayPort
Host name: Core Audio
Recording channels: 0
Playback channels: 2
Low Recording Latency: 0.01
Low Playback Latency: 0.0024375
High Recording Latency: 0.1
High Playback Latency: 0.0117708
Supported Rates:
    8000
    9600
    11025
    12000
    15000
    16000
    22050
    24000
    32000
    44100
    48000
    88200
    96000
    176400
    192000
    352800
    384000
==============================
Device ID: 1
Device name: DisplayPort
Host name: Core Audio
Recording channels: 0
Playback channels: 2
Low Recording Latency: 0.01
Low Playback Latency: 0.0024375
High Recording Latency: 0.1
High Playback Latency: 0.0117708
Supported Rates:
    8000
    9600
    11025
    12000
    15000
    16000
    22050
    24000
    32000
    44100
    48000
    88200
    96000
    176400
    192000
    352800
    384000
==============================
Device ID: 2
Device name: DisplayPort
Host name: Core Audio
Recording channels: 0
Playback channels: 2
Low Recording Latency: 0.01
Low Playback Latency: 0.0024375
High Recording Latency: 0.1
High Playback Latency: 0.0117708
Supported Rates:
    8000
    9600
    11025
    12000
    15000
    16000
    22050
    24000
    32000
    44100
    48000
    88200
    96000
    176400
    192000
    352800
    384000
==============================
Device ID: 3
Device name: Jabra Engage 75
Host name: Core Audio
Recording channels: 1
Playback channels: 0
Low Recording Latency: 0.008375
Low Playback Latency: 0.01
High Recording Latency: 0.036375
High Playback Latency: 0.1
Supported Rates:
==============================
Device ID: 4
Device name: Jabra Engage 75
Host name: Core Audio
Recording channels: 0
Playback channels: 2
Low Recording Latency: 0.01
Low Playback Latency: 0.00335417
High Recording Latency: 0.1
High Playback Latency: 0.0126875
Supported Rates:
    8000
    9600
    11025
    12000
    15000
    16000
    22050
    24000
    32000
    44100
    48000
    88200
    96000
    176400
    192000
    352800
    384000
==============================
Device ID: 5
Device name: HD Pro Webcam C920
Host name: Core Audio
Recording channels: 2
Playback channels: 0
Low Recording Latency: 0.26125
Low Playback Latency: 0.01
High Recording Latency: 0.28925
High Playback Latency: 0.1
Supported Rates:
==============================
Device ID: 6
Device name: Mac mini Speakers
Host name: Core Audio
Recording channels: 0
Playback channels: 2
Low Recording Latency: 0.01
Low Playback Latency: 0.0125
High Recording Latency: 0.1
High Playback Latency: 0.0218333
Supported Rates:
    8000
    9600
    11025
    12000
    15000
    16000
    22050
    24000
    32000
    44100
    48000
    88200
    96000
    176400
    192000
    352800
    384000
==============================
Selected recording device: 3 - Jabra Engage 75
Selected playback device: 2 - DisplayPort
Supported Rates:
    8000
    9600
    11025
    12000
    15000
    16000
    22050
    24000
    32000
    44100
    48000
    88200
    96000
    176400
    192000
    352800
    384000
==============================
Available mixers:
==============================
Available recording sources:
==============================
Available playback volumes:
0 - PCM
==============================
Recording volume is native
Playback volume is emulated

Any suggestions to try something else? I’ve never had issues getting Audacity to output on any system, Windows or Mac, simple audio or complex interfaces. This is a first. :slight_smile:

Thanks!
Chris

2

From the audio device info, you can see that Audacity recognises 3 display port stereo outputs (ID 0, 1 and 2). What happens when you select each of those as the playback device in the device toolbar?

3

I’ve flipped between all three in the bar with no change. Interestingly, no matter which is picked in that chooser the one in preferences is always the third one. Wondering if I’ve found a bug?

4

Imagine that we can’t see your machine, and that we only know what you tell us.
What happens when you select each of the “display port” options as the playback device in the device toolbar?

5

Image attached. There is no errors or popups when selecting them. The checkmark moves to the one I’ve selected. Playing the audio shows playback in the meters but no sound exits the system.
Screen shot.png
screen shot 2.png
I can do a screen recording if you’d like to see it in action… Definitely no errors or anything informational.

6

It looks like Audacity is sending the audio correctly. Perhaps it is muted somewhere else on your system (?)
I don’t have a DisplayPort device, so I’m not able to make further suggestions. Perhaps someone else on this forum has experience of DisplayPort devices.

7

The same audio device is used by the system for all sounds. There is no further routing in Core Audio to be muted. All other application including system sounds, youtube in Chrome, etc. are playing audio properly even if I do them at the same time this is being attempted. That’s why I’m here. Audacity appears to be generating audio but failing to get it to the output if I use DisplayPort audio. I’m at a loss.

8

So what happens if you go to Audacity Preferences and choose different display port options there?
– Bill

9

Took this all the way down to the basics…

  • Clean boot, nothing else running, same issue…
  • unplugged all three displays and just plugged in a single display (the one I’m using audio out on) and audio worked.
  • Brought the other two up and it continued to work.
  • Rebooted and restarted app multiple times and can no longer reproduce.

Going to have to write this one off as a non reproducible issue. :frowning: I suspect that Audacity wasn’t actually selecting the output I wanted, but it is definitely working now.

Thanks for the

10

OK, but what happens if you go to Devices Preferences and change the output, then change it back, or do the same in the Device Toolbar? Which of the three “Display Port” options is shown as selected when it is working?

What happens if you go through the above procedure but first plug in one monitor that is not being used for audio? Then plug in the monitor that is being used for audio and try to switch to it?

This may, in fact, be an issue where having three devices with the same name causes a problem.

Or, if you’re happy it’s working and don’t want to mess with it, that’s fine. This does seem to be a very rare problem.

– Bill

11

Give me a bit and I’ll gladly try it. Would love to help if this is in fact a bug.

Chris