Topic: Weird Gain Crosstalk between Mic Preamps

So I was testing an XY Stereo Setup on my RME Fireface UFX II and wasn't able to match the mics output with the same gain value on both channels (11 and 12 in my case). Channel 11 always puts out a hotter signal than Channel 12. I randomly found ot that the Gain Knob of Channel 10 was controlling the Gain for Channel 12 too. Setting it to maximum Gain gave me the missing 12-13 dB on Channel 12.

https://i.ibb.co/qR49KDh/RME-Gain.jpg

Any Idea what's going on here?!

2 (edited by oli77sch 2024-02-11 21:57:18)

Re: Weird Gain Crosstalk between Mic Preamps

Hi
Have you ruled out all other possibilities that could be causing the issue? Are the mics ok for sure? The cables? How is it on the two other mic inputs of the UFX II? Also, to compare two mic input levels I would suggest not to use an XY array but mounting them together as close as possible in parallel to make sure they pick up the (almost) exact same signal.

UCX - FF 400 - Babyface pro - Digiface USB - ADI-2 (original)
Mac mini M1 - Macbook pro - iPad Air2

3 (edited by waedi 2024-02-11 02:54:49)

Re: Weird Gain Crosstalk between Mic Preamps

What version of Totalmix is this ? Try to update
Also firmware should be checked to be up-to-date.

M1-Sequoia, Madiface Pro, Digiface USB, Babyface silver and blue

4

Re: Weird Gain Crosstalk between Mic Preamps

I am on latest firmware and TM FX and cannot reproduce this issue.

Regards
Matthias Carstens
RME

Re: Weird Gain Crosstalk between Mic Preamps

If you pull up the gain fully on an input with no microphone connected, you'll get a little noise. That is shown on the Mic 10 input of your right picture. That is totally normal, I think.

UFX+, FireFace 802 FS, Digiface USB
12 Mic, M1610 pro, Micstasy
MacBookPro M1
Logic Pro X

6

Re: Weird Gain Crosstalk between Mic Preamps

That's not what the OP described.

Regards
Matthias Carstens
RME

Re: Weird Gain Crosstalk between Mic Preamps

I tested again and the cables and mics are fine. Tested them with my Zoom F6 and it works just how it should. But I noticed that it's not just Channel 10 controlling Ch12 but also Ch9 controlling Ch11 - I just didn't notice because my SMB7 is always connected to Ch9. See picture below.

Im running TotalMix 1.90 beta 1 - I might try going back to the latest official release.

https://i.ibb.co/Bt8J4hJ/RME-Gain2.jpg


oli77sch wrote:

Hi
Have you ruled out all other possibilities that could be causing the issue? Are the mics ok for sure? The cables? How is it on the two other mic inputs of the UFX II? Also, to compare two mic input levels I would suggest not to use an XY array but mounting them together as close as possible in parallel to make sure they pick up the (almost) exact same signal.

8 (edited by oli77sch 2024-02-12 17:14:00)

Re: Weird Gain Crosstalk between Mic Preamps

Is there loopback activated somewhere on the analog outputs corresponding to the mic inputs (so analog out 9 - 12)?
And another question. Is what you see in Totalmix corresponding to what you actually hear when monitoring all this?

UCX - FF 400 - Babyface pro - Digiface USB - ADI-2 (original)
Mac mini M1 - Macbook pro - iPad Air2

9

Re: Weird Gain Crosstalk between Mic Preamps

Perform a Total Reset in TM FX. Also current version is 1.93. Your firmware therefore might be also outdated.

Regards
Matthias Carstens
RME

Re: Weird Gain Crosstalk between Mic Preamps

no loopbacks or anything. everything is clean in the signal chain. And what I see is a direct representation of what I hear. Once I turn up the Gain for my SMB7 on Ch9 the left signal of my XY (Ch11) get's boosted by a lot too.

I did a Total Reset, updated to 1.93 and updated the UFXII Firmware. No changes hmm

Re: Weird Gain Crosstalk between Mic Preamps

touringen wrote:

no loopbacks or anything. everything is clean in the signal chain. And what I see is a direct representation of what I hear. Once I turn up the Gain for my SMB7 on Ch9 the left signal of my XY (Ch11) get's boosted by a lot too.

I did a Total Reset, updated to 1.93 and updated the UFXII Firmware. No changes hmm

Did you swap the microphones already?
Does the issue move with the mics, that you get more output with one?

BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub14

Re: Weird Gain Crosstalk between Mic Preamps

As stated before, mics and cables are not the problem. I can also produce this issue just visually with no mics connected.

13 (edited by ramses 2024-02-13 10:58:55)

Re: Weird Gain Crosstalk between Mic Preamps

touringen wrote:

As stated before, mics and cables are not the problem. I can also produce this issue just visually with no mics connected.

I recommended that to perform tests properly to be on the safe side to get valid test results.
An open analogue input might react other than expected.

I understand your point that you expect all open mic inputs to behave similarly at the same gain, but I would still recommend performing such a test so that the inputs are used according to their specification.
That's why I would re-plug the mics, just to be on the safe side here.

This does not lead to any speculation as to whether it might have something to do with the open analog inputs.

BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub14

14

Re: Weird Gain Crosstalk between Mic Preamps

This thread leads nowhere until touringen starts to use the UFX II for serious testing, and it is not hard to do. Connect the analog outputs to the mic inputs, play back a test tone on all 4 outputs at a very low level (attenuated by TM or the player) so that the mic gain can be fully cranked up without overload. Then compare the levels you get in the input. This is the only way to have valid results for gain mismatches.

An even simple version uses only one output and replugging the inputs to check for differences.

Open inputs suffer from crosstalk at high gains, that is normal and not an issue.

Regards
Matthias Carstens
RME

15 (edited by oli77sch 2024-02-13 13:20:38)

Re: Weird Gain Crosstalk between Mic Preamps

MC wrote:

Open inputs suffer from crosstalk at high gains, that is normal and not an issue.

Nor this statement nor what ramses writes explains this:

touringen wrote:

Once I turn up the Gain for my SMB7 on Ch9 the left signal of my XY (Ch11) get's boosted by a lot too.

UCX - FF 400 - Babyface pro - Digiface USB - ADI-2 (original)
Mac mini M1 - Macbook pro - iPad Air2

Re: Weird Gain Crosstalk between Mic Preamps

I do take this serious - sorry if I did not communicate that clearly. I did test with connected inputs first and then with open inputs because the issue remained unchanged regardless of outside influences.

Now I did another test with a feedback loop as requested. It still remains the same.

440Hz Test Tone at -10dB. Outputs 9-12 (Phones) to Inputs 9-12.

The Threshold for this to happen seems to be around 64dB of Gain. Anything around or under 63dB Gain doesn't influence the other channel.

https://i.ibb.co/W26tGL9/RME-Gain3.jpg

Re: Weird Gain Crosstalk between Mic Preamps

What's the exact firmware and driver version?
Can you reproduce this with the interface connected to another computer?

Regards
Daniel Fuchs
RME

Re: Weird Gain Crosstalk between Mic Preamps

I updated everything to the latest version today. Total Mix 1.93, FW 23 and Driver 0.9833.

I don't have another Computer to test this with.

RME Support wrote:

What's the exact firmware and driver version?
Can you reproduce this with the interface connected to another computer?

19 (edited by oli77sch 2024-02-13 20:43:15)

Re: Weird Gain Crosstalk between Mic Preamps

touringen, in your screenshots from post 16 I can see the input signal strength on channel 10 remains the same regardless of the three gain settings (63,64,75 dB). So as soon it’s over 63dB, not the signal of this channel is increased, but the one of channel 12.
Really weird!
EDIT: you have talkback activated on the phones outputs. What source do you have set for the talkback and what happens when you disable it?

UCX - FF 400 - Babyface pro - Digiface USB - ADI-2 (original)
Mac mini M1 - Macbook pro - iPad Air2

Re: Weird Gain Crosstalk between Mic Preamps

oli77sch wrote:

touringen, in your screenshots from post 16 I can see the input signal strength on channel 10 remains the same regardless of the three gain settings (63,64,75 dB). So as soon it’s over 63dB, not the signal of this channel is increased, but the one of channel 12.
Really weird!

Exactly! Good catch! I was so focused on Ch11/12 that I didn't even notice that. It's the exact same threshold for that behavior. At around 64dB of Gain the gainstaging of Ch9 "takes over" to control Ch 11 and vice versa Ch10 controlling Ch12.

oli77sch wrote:

EDIT: you have talkback activated on the phones outputs. What source do you have set for the talkback and what happens when you disable it?

I have none defined as a talkback input. Disableing it therefore doesn't change anything.

Re: Weird Gain Crosstalk between Mic Preamps

touringen wrote:

I have none defined as a talkback input. Disableing it therefore doesn't change anything.

There normally is a default setting. And also enabling talkback lowers the volume of all channels going to the phones. So I would suggest to disable it while testing.

UCX - FF 400 - Babyface pro - Digiface USB - ADI-2 (original)
Mac mini M1 - Macbook pro - iPad Air2

22

Re: Weird Gain Crosstalk between Mic Preamps

touringen wrote:
oli77sch wrote:

touringen, in your screenshots from post 16 I can see the input signal strength on channel 10 remains the same regardless of the three gain settings (63,64,75 dB). So as soon it’s over 63dB, not the signal of this channel is increased, but the one of channel 12.
Really weird!

Exactly! Good catch! I was so focused on Ch11/12 that I didn't even notice that. It's the exact same threshold for that behavior. At around 64dB of Gain the gainstaging of Ch9 "takes over" to control Ch 11 and vice versa Ch10 controlling Ch12.

That is helpful! Let us check this again. But also tell us which of the three existing UFX II you have. You see it in the FUT: USB 26, 114 or 206.

Regards
Matthias Carstens
RME

Re: Weird Gain Crosstalk between Mic Preamps

oli77sch wrote:
touringen wrote:

I have none defined as a talkback input. Disableing it therefore doesn't change anything.

There normally is a default setting. And also enabling talkback lowers the volume of all channels going to the phones. So I would suggest to disable it while testing.

Yes, I just did that. No changes.

Re: Weird Gain Crosstalk between Mic Preamps

MC wrote:

That is helpful. Let us check this again. But also tell us which of the three existing UFX II you have. You see it in the FUT: USB 26, 114 or 206.

It’s the USB 114 model.

25

Re: Weird Gain Crosstalk between Mic Preamps

Ok, don't waste your time with this anymore. Most probably this is a firmware bug that we try to fix quickly.

Regards
Matthias Carstens
RME

Re: Weird Gain Crosstalk between Mic Preamps

MC wrote:

Ok, don't waste your time with this anymore. Most probably this is a firmware bug that we try to fix quickly.

Sounds promising! Thank you for looking into this!

27

Re: Weird Gain Crosstalk between Mic Preamps

Error found and fixed. New Firmware Update Tools will be available soon.

Regards
Matthias Carstens
RME

Re: Weird Gain Crosstalk between Mic Preamps

Brilliant !

M1-Sequoia, Madiface Pro, Digiface USB, Babyface silver and blue

29

Re: Weird Gain Crosstalk between Mic Preamps

The firmware updates with a fix are now available for download.

Regards
Matthias Carstens
RME