TBT3-UDZ doesn't output audio through Monitor's speaker when connected via DisplayPort

Thunderbolt TBT3-UDZ
1

Hi, I’m running MacOS BigSur 11.6.1 on my 2019 Macbook Pro 16-inch. I have two 4k monitors, Acer ET322QK, with built-in speaker connected to this TBT3-UDZ dock via DisplayPort. However, I get no audio played out of my Monitor’s speakers. This wasn’t the case when I was on MacOS Catalina, but it’s been like this since I upgraded to BigSur couple months ago.

Interestingly, If I directly connect my monitor to my macbook via DisplayPort to usb-c adapter like j5create USB-C to 4K DisplayPort Adapter, then I can get audio out of my monitor’s speaker. Do you know how to fix this?

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2

Hello Jasper,

Thank you for contacting Plugable support! Sorry to hear about this issue. I’d be more than happy to assist you.

Looking at the diagnostics I see that macOS does see the monitors and has one set as the default audio device:

Audio:

_ Devices:_

_ Acer ET322QK:_

** Default Output Device: Yes**

** Default System Output Device: Yes**​

_ Manufacturer: Apple Inc._

_ Output Channels: 2_

_ Current SampleRate: 48000_

_ Transport: DisplayPort_

_ Output Source: Acer ET322QK_

_ Acer ET322QK:_

_ Manufacturer: Apple Inc._

_ Output Channels: 2_

_ Current SampleRate: 48000_

_ Transport: DisplayPort_

_ Output Source: Acer ET322QK_

It’s interesting that despite this the audio is not working through the monitor. Since you have two monitors connected to the dock, what happens if you try to select the other monitor as the playback device? (I’m unsure if both of your monitors have their speakers enabled and the volume turned up.) It’s possible that macOS after the upgrade the system is trying to playback via the other monitor than what you’d been using for sound originally.

If you’d tried both monitors and have checked the speakers in them are on and turned up then I am uncertain why this is happening. I can confirm I am able to use macOS Big Sur (11.6.1) + our TBT3-UDZ and get sound from a few different monitors here through either HDMI/DP ports.

Since you have an Intel based MacBook Pro, it may be beneficial to try the following steps and see if there’s any improvement:

  1. Unplug the dock from the Mac and unplug power from the dock. Please leave the dock disconnected until the final step.
  2. Perform an SMC reset: https://support.apple.com/en-us/HT201295
  3. Perform an NVRAM/PRAM reset: https://support.apple.com/en-us/HT204063
  4. After logging back in, wait about 30-60 seconds, then plug power in to the dock and plug the dock in to the Mac and see if the behavior has improved.

If this has not helped please let me know. And please don’t hesitate to let me know of other questions.

Thanks again for contacting Plugable support and best wishes!

Joshua Henry
Senior Engineer | Product Owner
Plugable Technologies

3

Hi Joshua,

I tried to just use the dock itself to connect to the 2 monitors, but I get no sound. Therefore, when I did the test, I only have one monitor connected to the dock and the other one was directly connected to my macbook through a DisplayPort to USB-C adapter. And when I ran the test, I chose to output audio through the speaker of the monitor that’s connected to the dock and I didn’t get any sound. If I, however, chose to output audio through the monitor that’s connected to the DisplayPort to USB-C adapter, then I get audio played via the monitor’s speaker.

Also, those 4 steps I did them a couple times in the past, but they didn’t help at all.

4

Hi Joshua,
I just tried the suggested 4 steps again and the issue still persists. May company macbook pro is a 2017 13 inch model which is running Catalina and I get audio out from both of my monitors’ speakers when connected the dock to that device instead of my personal BigSur 16 inch macbook pro.

5

Thank you for trying those steps, I am sorry none of the suggestions have helped.

As a next step we do have a firmware update for this dock which may help. However, the update cannot be installed via macOS, it would require access to a Windows computer with Thunderbolt 3. I understand that this may not be something you have access to, so we may need to send you a pre-updated replacement dock under warranty to see if that helps.

-If you do have access to a Windows computer with Thunderbolt 3 to try updating the firmware please let me know and I will send you the instructions for how to do so.

-If you do not have access let me know and I will then email you directly and ask for some information so we can send you the replacement dock under warranty.

Thank you and best wishes,
Josh

6

Hi Joshua,

Thanks for offering the two solutions to this problem. Unfortunately, I don’t have Windows computer and my company laptop is also a macbook. I’m an Apple guy, so if the firmware can’t be installed via macbook, I guess that only leaves us with one solution then. :persevere:

7

No problem, I’ve just sent you an email directly with a request for some information so we can send you the replacement with the newest firmware under warranty to see if that helps.

Thank you!
Josh

8

Hi Joshua,

I didn’t receive any email from you. :open_mouth:

9

Hmm, be sure to double check your spam folder, sometimes we’ll see they get caught there. It should be from “support@plugable.com”.

I’ll also try sending it again!

Best,
Josh

10

Aha, I got it this time. Thanks!

1 Like
11

Great! I’ll reply to the email again once the replacement has been shipped out and provide tracking information.

Best,
Josh

12

OK. Thank you so much Joshua! :grinning:

13

Hi Joshua,

I got the replacement dock, but unfortunately the issue is still there. I also tried reset SMC and NVRAM a couple times, but that also didn’t help. I do notice the new AC adapter no longer makes buzzing noise that the old AC adapter makes when connected to power and the laptop.

14

Hi Joshua,

I thought I should let you know this other new problem I discovered with the new replacement dock. The monitor that connects to the dock via DisplayPort will turn to black screen momentarily for about 1-3s, then back to normal, once in a while.

15

Hello Jasper,

I am terribly sorry to hear the same issues are present, and that you’re encountering more problems with one of the DP attached monitors blacking out.

I suppose it’s possible that the new dock firmware has somehow made the compatibility with the monitor worse, though that is a bit unexpected.

We can as the next step attempt to ensure the monitor has FreeSync disabled as this is not supported by the dock and it appears it is on by default per the user manual for the monitor:

In addition, since the monitor supports HDMI as well, perhaps it may work better that way (we have seen where some monitors may work better over HDMI rather than DP or vice versa).

If these additional suggestions do not help, and because of the outstanding audio issue we may ultimately need to offer you a return for a full refund since the pretested/updated replacement has not helped.

Best wishes,
Josh

16

Hi Joshua,

My monitors did have FreeSync on, but I don’t see any display issue. Now, I turned it off and the issue is still there. No difference comparing to before. I don’t have any HDMI cable that can handle 60HZ 4k resolution. All my HDMI cables can only do 4k at 30HZ. Initially, why I went with DisplayPort is because I noticed its connector is much less hot than the HDMI connector.

17

Hi Joshua,

By the way, where does it say that TBT3-UDZ doesn’t support FreeSync?

18

Thanks for trying disabling Freesync, sorry that did not help!

Understood that your monitors need to use DP to get the best refresh rate with the cables you have.

For Freesync not being supported, it is mentioned here: https://kb.plugable.com/question/815695 (in our experience most Thunderbolt/USB-C docks cannot support adaptive sync technologies like Freesync/G-Sync)

Another option to try, see if setting the monitor to DisplayPort 1.1 instead of 1.2 makes any difference. This setting may lower DP performance so it’s likely not a true solution to the problem, but it may confirm if there’s some kind of incompatibility causing the blacking out. (If the blacking out stops set to DP 1.1 vs 1.2 there’s likely a low level chipset incompatibility between the monitor and dock.)

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Best,
Josh

19

Hi Joshua,

I tried to switch from DP 1.2 to DP 1.1 on one of the connected monitors and unfortunately that made the monitor completely black out when connected to my personal macbook. I had to temporarily connect to my company macbook in order to access the monitor setting again. I will try to get HDMI cables to test out whether that approach fixes the sound issue for me. I see the page you shared says the dock only supports HDMI 2.0, so what happens if I connect the monitor with the dock using a HDMI 2.1 cable?

20

Hi Jasper,

Thanks for trying that at least, I’m sorry that didn’t work at all!

I would be curious to hear if newer HDMI cables that support 4K/60Hz will help and work better with these monitors than the DisplayPort connection is currently.

For the HDMI cable question, an HDMI 2.1 cable is supported with the dock as newer standard HDMI cables retain backwards compatibility with older standard devices (these newer standard cables are essentially just rated for greater bandwidth). The same is true for DP cables.

For example: an HDMI 2.1 cable will work with an HDMI 2.0 or 1.4 device and a DP 1.4 cable will work with a DP 1.2 or 1.1 device.

Best wishes,
Josh