1 Topic by WaihekeSoundie (edited by WaihekeSoundie 2020-07-16 00:12:42)

  • Registered: 2020-07-15
  • Posts: 15

Topic: Preamp Gain on Fireface UC drifting / re-set without user input

I am running OSX 10.13.6 on a Macbook Pro

I am using my Fireface as an audio interface for video conferencing at work -I use Google Meet.
I have a single mic channel in use (Mic 1).

I set the gain of Mic 1 at a comfortable level - say 40db.. and Mic 2 at 0db.

Everything is sweet.. I'm talking away then suddenly my mic setting changes.. I open CueMix and sure enough, both mic pre are now set at (say) 49 db or full gain. I notice that the line channels AN3 and AN4 are set to 9.0 also

Are 49db and 9db standard settings?

If I change the setting back but then then, say 2 mins later, it happens again.

It doesn't seem to matter whether Cuemix is open or closed on the desktop.


It is very frustrating.  Anyone else experienced this?
Would really appreciate any help on this.
Thank you

  • Registered: 2019-10-01
  • Posts: 675

Re: Preamp Gain on Fireface UC drifting / re-set without user input

Hello!

I have no experience with this, but I remember some posts here with the same symptoms as yours, but with different applications.

The problem was with an "Autoset gain" or similar option, in each software's settings.
Can you search your application's settings for something similar?
Some option involving the words "Gain" or "Reference level" and "Auto"?

If you find any, turn it off, and I think you 'll be set!

RME Gear: Digiface USB, HDSP 9632

3 Reply by WaihekeSoundie (edited by WaihekeSoundie 2020-07-16 05:49:13)

  • Registered: 2020-07-15
  • Posts: 15

Re: Preamp Gain on Fireface UC drifting / re-set without user input

Thank you MetalHeadKeys..
I'm not really using an app though.. it is Chrome Hangouts and that just seems to use the internal OS X sound interface.
(Reaper does not seem to exhibit the same behaviour.

It seems that Hangouts or something  is deciding that the channels mic 1 and mic 2 (and AN3 and AN4) need to be gain matched as pairs..  what happens is that Mic 1 and Mic ch2  get set to the lowest of the pair's level with 3db added.. so the levels creep up. If you turn one down but not to 0 then they match down at the lower level in which case  you suddenly lose your mic signal.

It is unworkable and I can't find any auto-gain or similar setting anywhere that may be causing this sad

4 Reply by WaihekeSoundie (edited by WaihekeSoundie 2020-07-16 21:48:12)

  • Registered: 2020-07-15
  • Posts: 15

Re: Preamp Gain on Fireface UC drifting / re-set without user input

So I upgraded Chrome to latest version, my RME drivers for the Fireface UX to latest  v3.19 and I upgraded OSX Catalina 10.15.6 and now it's worse than ever sad

  • Registered: 2020-07-15
  • Posts: 15

Re: Preamp Gain on Fireface UC drifting / re-set without user input

Anybody?

  • Registered: 2019-10-01
  • Posts: 675

Re: Preamp Gain on Fireface UC drifting / re-set without user input

Hello, again!

Can you have a look at the video in this thread?

https://forum.rme-audio.de/viewtopic.php?id=29757

It regards Drivers Installation on Catalina!

RME Gear: Digiface USB, HDSP 9632

7 Reply by WaihekeSoundie (edited by WaihekeSoundie 2020-07-21 04:26:34)

  • Registered: 2020-07-15
  • Posts: 15

Re: Preamp Gain on Fireface UC drifting / re-set without user input

Thank you. 
Good to know-- I went back and re-installed everything.. my drivers installed just fine I think. Thanks for that.
I think they were installed ok before but worth checking.

I now think that the Fireface is working just fine. I think it always was even though I can easily reproduce the issue of gain getting re-set randomly if I make the Fireface the primary input device for the OS / apps.

I think that the "problem" is that the USB drivers for the Fireface offer a public interface that the hardware uses to receive instructions that control the Fireface (channel gain, channel levels switch on 48v, set pan etc etc.). Total Mix needs this and perhaps all the features that are controllable in TotalMix are exposed to other apps as well?

That would be ok but the problem is that some apps- Google Meet being one of them,  don't play well with this exposed interface and send control instructions that set gain etc randomly and indiscriminately. This is my theory (at a logical level) anyway.

Assuming above what I did to control this issue is to insert a virtual software device (loopback) as a facade / proxy bewteen the offending app and the Fireface.  I create a virtual device that maps the Fireface inputs then use that virtual device as the default input option in the os x / app's Sound settings instead of the Fireface.  The virtual device may well receive the control instructions but it ignores them / doesn't pass them through to the Fireface so gain etc is not reset by them them

This works just fine.  Though it is a bit fiddly to set up, probably introduces latency (though I can't hear it because I monitor directly from the Fireface) and is money I did not want to spend.

Can't find any other way round it though.
Is there another way?

  • Registered: 2020-09-23
  • Posts: 3

Re: Preamp Gain on Fireface UC drifting / re-set without user input

Hello.

I'm probably encountering the same situation.
With Babyface Pro Fs introduced yesterday, Gain is controlled by itself regardless of the settings of Analog Channel 1/2 only when using Google Meet.

Initially, I suspected a problem with Totalmix Fx or a problem with Babyface Pro.
However, I found the following article and said that this is probably due to Google Meet's update of specifications changed at least after 2020/5, which has a protocol that tries to directly operate the microphone volume of the OS. Is my current hypothesis.
(Because the same thing didn't happen with Zoom or MS Teams.)
https://answers.microsoft.com/en-us/win … f7a1444078

I'm also a Mac User, the OS is 10.15.6, and the drivers are up to date.

From now on, I will investigate various measures such as prohibiting Google Chrome from operating the microphone with parameters such as privacy settings.

Up to urgent sharing.

  • Registered: 2020-09-23
  • Posts: 3

Re: Preamp Gain on Fireface UC drifting / re-set without user input

FYI
Google already knows the problem and seems willing to solve it.
https://support.google.com/meet/thread/62667977?hl=en

I couldn't find any settings in Mac OS other than allowing / disallowing access to the microphone, so it seemed difficult to prohibit this operation from the OS side.

  • Registered: 2020-09-18
  • Posts: 8

Re: Preamp Gain on Fireface UC drifting / re-set without user input

One thing you can do is use the Audio Midi Setup to create a new aggregate device. The only thing inside the aggregate device should be your babyface. Catalina will stop offering to control the input gain for the aggregate device, so the auto gain control is defeated. You need to explicitly choose the aggregate device to be your input for meet/hangouts.

  • Registered: 2020-09-23
  • Posts: 3

Re: Preamp Gain on Fireface UC drifting / re-set without user input

Hi cabacon,

You are a genius!
When I tried it immediately, it seems that this workaround works well.

Since this is the first function I use, I don't know what side effects this will cause, but for now it seems that Google Meet's AGC will not work and can be used.

Thank you very much.

12 Reply by MC

  • MC
  • MC
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  • From: Germany/Thailand
  • Registered: 2007-04-06
  • Posts: 25,599

Re: Preamp Gain on Fireface UC drifting / re-set without user input

cabacon wrote:

One thing you can do is use the Audio Midi Setup to create a new aggregate device. The only thing inside the aggregate device should be your babyface. Catalina will stop offering to control the input gain for the aggregate device, so the auto gain control is defeated. You need to explicitly choose the aggregate device to be your input for meet/hangouts.

Nice workaround! Thanks.

Regards
Matthias Carstens
RME

MC's Website