• From: Auckland, NZ
  • Registered: 2011-07-14
  • Posts: 5

Topic: Fireface UFX - how matched are the mic preamps?

Hi there,

I apologise if a similar question has been asked already... How closely are the mic preamps matched in terms of gain on the UFX? If they are all set at the same gain, will their actual gains all be within about 0.1 dB of each other?

I'm working with a 4 channel microphone array for room acoustics measurements, which works on the principle of level differences between received signals, hence the need for level matched preamps. There are ways around this (which is how I currently work with my FF800), but its all very clunky and annoying. I already deal with mic sensitivity differences.

Any help be much appreciated,
Daniel

2 Reply by MC

  • MC
  • MC
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  • From: Germany/Thailand
  • Registered: 2007-04-06
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Re: Fireface UFX - how matched are the mic preamps?

The inputs are neither matched nor calibrated. Deviations might happen, caused by the normal gain errors between chips, here the mic preamps and the ADCs. So YMMV. Measuring in real-world gives an astonishing low deviation of about 0.1 dB between units and channels in most cases.

Regards
Matthias Carstens
RME

MC's Website

  • From: Germany
  • Registered: 2007-04-10
  • Posts: 9,778

Re: Fireface UFX - how matched are the mic preamps?

Also, have you got microphones that are matched within 0.1 dB?


Regards
Daniel Fuchs
RME

Regards
Daniel Fuchs
RME

RME Support's Website

  • From: Auckland, NZ
  • Registered: 2011-07-14
  • Posts: 5

Re: Fireface UFX - how matched are the mic preamps?

Cool thanks for the quick responses - sounds promising! Yep, the mics are matched to within that kind of order, and if necessary, any differences in sensitivities can be compensated for pretty easily in post.

  • From: Auckland, NZ
  • Registered: 2011-07-14
  • Posts: 5

Re: Fireface UFX - how matched are the mic preamps?

Even if greater than 0.1 dB, would you agree that the gain relationship between preamps would remain fairly constant, independent of overall gain, temperature, etc? Since the UFX has discrete gain controls, I can measure that relationship once (for a particular UFX) and then compensate for it following any recording (if necessary).

With the FF800 its not so easy. As the gain knobs are continuous, whenever I adjust them I have to measure the gain relationship so I can compensate for the inevitable gain differences between channels in post. hope that makes sense

  • isaac
  • isaac
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  • From: Auckland New Zealand
  • Registered: 2007-05-01
  • Posts: 339

Re: Fireface UFX - how matched are the mic preamps?

danpro wrote:

Even if greater than 0.1 dB, would you agree that the gain relationship between preamps would remain fairly constant, independent of overall gain, temperature, etc? Since the UFX has discrete gain controls, I can measure that relationship once (for a particular UFX) and then compensate for it following any recording (if necessary).

With the FF800 its not so easy. As the gain knobs are continuous, whenever I adjust them I have to measure the gain relationship so I can compensate for the inevitable gain differences between channels in post. hope that makes sense

And you can record the signals straight to a USB stick in the front of the Ufx!

Also welcome to the forum.

Isaac P

  • From: Auckland, NZ
  • Registered: 2011-07-14
  • Posts: 5

Re: Fireface UFX - how matched are the mic preamps?

aw hey isaac, thanks! funny (but not really surprising) to bump into you on here!

8 Reply by MC

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Re: Fireface UFX - how matched are the mic preamps?

danpro wrote:

Even if greater than 0.1 dB, would you agree that the gain relationship between preamps would remain fairly constant, independent of overall gain, temperature, etc?

Yes.

danpro wrote:

Since the UFX has discrete gain controls

???? The mic preamps have digitally controlled gains, which are implemented within the mic preamp chip as analog/discrete solution.

danpro wrote:

With the FF800 its not so easy. As the gain knobs are continuous, whenever I adjust them I have to measure the gain relationship so I can compensate for the inevitable gain differences between channels in post.

Correct, much easier with the FF 400/UC/UFX/Babyface.

Regards
Matthias Carstens
RME

MC's Website

9 Reply by danpro (edited by danpro 2011-07-15 00:17:41)

  • From: Auckland, NZ
  • Registered: 2011-07-14
  • Posts: 5

Re: Fireface UFX - how matched are the mic preamps?

MC wrote:

???? The mic preamps have digitally controlled gains, which are implemented within the mic preamp chip as analog/discrete solution.

In an electrical system the terms discrete and digital mean the same to me... Feel free to nitpick if you want though. Anyway, regardless of how the preamps are implemented, the point is that functionally the gain controls are not continuous and are adjusted at discrete values, so one can recall the gain position exactly.

Thanks for your help, really appreciate it! Can't wait to sell my FF800 and get a UFX :-)