• MMNN
  • New member
  • Offline
  • Registered: 2024-11-28
  • Posts: 4

Topic: Fireface UC - HW inputs phase switch not working?

I recently purchased a set of polarized microphones which - by design - invert the phase of the input signal ('a positive pressure on the diaphragm generates a negative output voltage.')

My assumption was that I would be able to 'invert back' the mic signals (converted to line-level type through a specific external signal conditioner) at RME Fireface inputs by using the Phase button available for the various HW inputs ch. strips in TotalMix.

Running some measurements I realized that the Phase switch in HW inputs has no impact on the acquired signal. The only control in Settings that seems to have an effect is Gain.

On the other hand, Phase switches in SW playback & HW outputs sections do invert the signal, as expected.

I could not find any explicit reference as to why such function should not work for the HW inputs as well.

Am I missing something here?

Thanks in advance for your support!

  • waedi
  • DAW Mastermind
  • Offline
  • From: Swiss Zürich
  • Registered: 2020-12-08
  • Posts: 4,836

Re: Fireface UC - HW inputs phase switch not working?

In the recorded material yes, the gain is the one with obvious effect.
The phase invert has effect on the monitoring not the recording.
Keep in mind Totalmix is mainly a monitoring tool.
The input signals after the gain stage are provided to the DAW directly without manipulation.
Phase invert is no problem to do in the DAW.
From the mic itself it makes no sense to invert the phase, only in the mix it is relevant in some case.
The mic signal alone has no difference to the listener when phase is inverted.

M1-Sequoia, Madiface Pro, Digiface USB, Babyface silver and blue
  • MMNN
  • New member
  • Offline
  • Registered: 2024-11-28
  • Posts: 4

Re: Fireface UC - HW inputs phase switch not working?

Thanks a lot waedi for your input.

The measurements are intended to be the baseline for sound field control processing rather than direct listening - thus the requirement on 'correct' phase alignment.

As we use a proprietary meas. tool that currently does not implement a phase switch for inputs (so not a conventional DAW), we were hoping to 'fix' that aspect directly on the RME.

...looks like we'll need to take care of this in some other way!

4 Reply by waedi (edited by waedi 2024-11-28 16:41:55)

  • waedi
  • DAW Mastermind
  • Offline
  • From: Swiss Zürich
  • Registered: 2020-12-08
  • Posts: 4,836

Re: Fireface UC - HW inputs phase switch not working?

MMNN wrote:

Thanks a lot waedi for your input.

The measurements are intended to be the baseline for sound field control processing rather than direct listening - thus the requirement on 'correct' phase alignment.

As we use a proprietary meas. tool that currently does not implement a phase switch for inputs (so not a conventional DAW), we were hoping to 'fix' that aspect directly on the RME.

...looks like we'll need to take care of this in some other way!

With the Loopback function in Totalmix you can route the mic input signal over an output channel with inverted phase and then via Loopback into an input channel for your use case.

M1-Sequoia, Madiface Pro, Digiface USB, Babyface silver and blue
  • vinark
  • DAW Mastermind
  • Offline
  • Registered: 2009-06-05
  • Posts: 2,834

Re: Fireface UC - HW inputs phase switch not working?

Or buy a phase shift XLR adapter, like this one https://tweedehands-gitaar.nl/dap-xga37 … elaar.html

Vincent, Amsterdam
https://soundcloud.com/thesecretworld
BFpro fs, 2X HDSP9652 ADI-8AE, 2X HDSP9632
  • MMNN
  • New member
  • Offline
  • Registered: 2024-11-28
  • Posts: 4

Re: Fireface UC - HW inputs phase switch not working?

waedi wrote:
MMNN wrote:

Thanks a lot waedi for your input.

The measurements are intended to be the baseline for sound field control processing rather than direct listening - thus the requirement on 'correct' phase alignment.

As we use a proprietary meas. tool that currently does not implement a phase switch for inputs (so not a conventional DAW), we were hoping to 'fix' that aspect directly on the RME.

...looks like we'll need to take care of this in some other way!

With the Loopback function in Totalmix you can route the mic input signal over an output channel with inverted phase and then via Loopback into an input channel for your use case.

Your comment made me dig deeper into the loopback function. I understood that with loopback active the post-TotalMix replaces the direct pre-TotalMix signal, thus allowing the phase switch to work, as you mentioned.

Was not obvious to me, makes sense now. With some proper routing, we should be good.

Thanks again!

  • waedi
  • DAW Mastermind
  • Offline
  • From: Swiss Zürich
  • Registered: 2020-12-08
  • Posts: 4,836

Re: Fireface UC - HW inputs phase switch not working?

You understood correctly. And also the input signal from the mic is still available for routing and monitoring while Loopback uses this input channel.

M1-Sequoia, Madiface Pro, Digiface USB, Babyface silver and blue
  • vinark
  • DAW Mastermind
  • Offline
  • Registered: 2009-06-05
  • Posts: 2,834

Re: Fireface UC - HW inputs phase switch not working?

But the loopback causes a few samples of delay, which might be an issue for your use case or not. Of you loop back all signals you are using they are in sync again.
I just realized that if the mics use phantom power, using a phase inverter plug might not be wise, but I am not 100 sure.

Vincent, Amsterdam
https://soundcloud.com/thesecretworld
BFpro fs, 2X HDSP9652 ADI-8AE, 2X HDSP9632
  • MMNN
  • New member
  • Offline
  • Registered: 2024-11-28
  • Posts: 4

Re: Fireface UC - HW inputs phase switch not working?

vinark wrote:

But the loopback causes a few samples of delay, which might be an issue for your use case or not. Of you loop back all signals you are using they are in sync again.
I just realized that if the mics use phantom power, using a phase inverter plug might not be wise, but I am not 100 sure.

We use arrays of mics of one kind only, all of them would be looped back & phase-inverted in the same way. If we add a consistent delay across all inputs, it shouldn't be a problem.

  • Registered: 2023-03-31
  • Posts: 17

Re: Fireface UC - HW inputs phase switch not working?

It's a mic pre amp... RME really couldn't offer a way to invert the phase on the way in? Hearing, "do it in the DAW," stings after spending three grand on a UFX-III.

11 Reply by Randyman... (edited by Randyman... 2024-12-22 07:43:02)

  • From: Houston, TX
  • Registered: 2007-05-11
  • Posts: 1,192

Re: Fireface UC - HW inputs phase switch not working?

Haven't verified, but have to assume the "DSP EQ+COMP for Record" driver setting also includes the polarity invert portion of TM's input strip.  Can anyone verify?  As long as EQ and Comp are actually disabled on the input, you should not have any other alterations to the signal, and should avoid the need for loopbacks...

MADIface-XT+ARC / 3x HDSP MADI / ADI648
2x SSL Alphalink MADI AX
2x Multiface / 2x Digiface /2x ADI8