• cupakm
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Topic: QuadMic II / OctaMic II gain staging

Hi all,

coming from digitally controlled mic preamps only, I wonder how to stage gains on a step-less controlled pres.

The QuadMic II / OctaMic II manuals and front-panels display gain figures from +6 to +60 in 9 marking, the middle one stating +30 dB.
How would I derive approximate amplification levels, if I know I usually start at +45 ro +50 dB for my main mic array?

I kind of compared it to digital preamp and figured out +45 is a slight bit before the 8th mark, leaving me I in some doubt if this analog staging is that useful for stereo pairs... although I usually need to set it up only once for repeated use.

Anyway, the gain range is 60 - 6 = 54 dB, divided by 8 = 6,75 dB one mark, if the scale is linear. Hence:
1. mark: +6 dB
2.: +12,75
3.: +19,5
4.: +26,25
5.: +33
6.: +39,75
7.: +46,5
8.: +53,25
9.: +60

Well, 5th mark calculated +33 dB, front panel says +30 dB... apparently the scale isn't linear, or is it?

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  • waedi
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  • Registered: 2020-12-08
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Re: QuadMic II / OctaMic II gain staging

I used the Quadmic for recordings and was always happy.
Stereo recordings was well enough.
I checked with normalizing both tracks and the difference was neglible.
If you want to have it super accurate then normalizing is the tool.

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  • cyrano
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  • Registered: 2015-04-28
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Re: QuadMic II / OctaMic II gain staging

Analog gain settings never are really precise, because the imprecision on the potentiometers is rather huge. Precision pots do exist, but they are very expensive and would at least double the price of the preamp.

If you're used to digitally controlled preamps, you'll never get to that level of precision with analog controls.

I also don't think the precision is needed for stereo pairs. You can always adjust the level a few dB in the DAW after recording.

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  • cupakm
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  • Registered: 2014-04-03
  • Posts: 101

Re: QuadMic II / OctaMic II gain staging

Thanks guys, I though so... and how do I get an idea of approximate gain in dBs I'm applying with the analog controls? Apart from that 30 vs 33 probably-non-linear scale problem...

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  • cyrano
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Re: QuadMic II / OctaMic II gain staging

You've got the metering in TotalMix to handle that. Or am I missing something?

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6 Reply by cupakm (edited by cupakm 2023-09-07 20:21:05)

  • cupakm
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Re: QuadMic II / OctaMic II gain staging

I could use QuadMic or OctaMic with non-RME interface too, but actually I'm using it under Linux (with a RME interface) - either way, sadly no TM for me. But I have nice metering in Ardour DAW, thats true.

It still does not answer my question from the 1st post.

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  • Registered: 2016-06-14
  • Posts: 1,142

Re: QuadMic II / OctaMic II gain staging

I don’t know how it is on this RME preamps, Quadmic and Octamic. But I do know from own experience input gain rotary knobs are often not linear. I don’t have enough technical knowledge to really understand that.

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