• ayros
  • ayros
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  • From: Vienna
  • Registered: 2013-12-03
  • Posts: 12

Topic: Fireface UCX II - Matching gain levels between lines 1&2 and 3-8

Hi everyone!
I just got my new UCX II and I am testing it.
So far I am impressed by the sound quality, but there is something I cannot really understand.
I am trying to use it as a AD converter, for an external 8ch preamp (DAV BG8).
The output of this preamp is +4dBu.

Therefore, up to my understanding, I have set the input levels of the lines 3-8 to +13dBu and I get a good sound level.
The Line inputs 1+2 are sounding much softer, and the manual says that there is a -6dB attenuation.
If I add the 6dB to the 1&2 channels, I still get a softer sound.
When I tune the levels by ears, I found out that the ideal spot for having a consistent gain level across all the 8 channels (with of course the same gain and same microphones from the DAV!) is to add 11dB to the channels 1 and 2.
I basically "tuned it" connecting one channel to line 1 and the other channel to line 5.
Microphones are the same, both capsules are very close to each other and the gain from the DAV is the same.
Any thought about this? Where this 11dB number comes from?
Am I missing something?

Looking forward to your help!
Cheers,
Marco

2 Reply by ayros (edited by ayros 2024-11-20 14:53:59)

  • ayros
  • ayros
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  • From: Vienna
  • Registered: 2013-12-03
  • Posts: 12

Re: Fireface UCX II - Matching gain levels between lines 1&2 and 3-8

UPDATE, I have been playing around with a slate tone, and that's what I ended up with.
I took as reference inputs 5-8, and I matched inputs 1-2 and 3-4 accordingly.
To reach the unity gain on those inputs, I have to set it like that:

LINE INPUTS 1 and 2: +12dB gain
LINE INPUTS 3 and 4: set them as +13dBu (instr. OFF)
LINE INPUTS 5 to 8: set them as +13dBu

The slate tone was at 0dB.

I hope that makes sense and it can be useful to others.
I am curious to know what the RME engineers think about that.