• agolp
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Topic: Quadmic II and a gain hungry mic

Hello!

Sorry if I'm not in the right place. I'm using a Quadmic II to amplify the signal from the Electro-Voice RE20 before plugging it in my ADI-2 Pro FS (I know a real interface would be best, but I'm on Linux and plan on adding an internal PCIe card if latency becomes a problem).

The RE20 is a dynamic mic that's quite gain hungry. While speaking normally into the mic, very close to the mic, my recording is around -30 dB. Would it be a good idea to use a jack cable to boost the signal once more (from instrument out to mic in of another slot of the Quadmic)? or would it be better to boost the signal in post?

Thanks for your help!

2 Reply by waedi (edited by waedi 2021-12-02 20:17:18)

  • waedi
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  • From: Swiss Zürich
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Re: Quadmic II and a gain hungry mic

My recommendation is post processing.
The signal level is good and you have a lot of headroom for changing from normal speaking into screaming like hell.
I would avoid such cable trickery, one mic-preamp stage is enough.

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

3 Reply by KaiS (edited by KaiS 2021-12-04 07:14:32)

  • KaiS
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Re: Quadmic II and a gain hungry mic

agolp wrote:

... I'm using a Quadmic II to amplify the signal from the Electro-Voice RE20 before plugging it in my ADI-2 Pro FS ...

The RE20 is a dynamic mic that's quite gain hungry. While speaking normally into the mic, very close to the mic, my recording is around -30 dB. Would it be a good idea to use a jack cable to boost the signal once more (from instrument out to mic in of another slot of the Quadmic)? or would it be better to boost the signal in post?

More gain than the Quadmic II‘s 60 dB will not improve Signal tp Noise Ratio SNR.
So adding another gain stage won‘t help.

• Set ADI-2 Pro’s analog input’s reference level to lowermost value, +4dB (= highest gain!)

• Use ADI-2 Pro’s Analog Trim Gain to boost another 6 dB.

Both see manual page 21

• If this doesn’t help,
check or let check if the RE-20 is wired for 150 or better, 250 Ohms.
This adds another 5 or 7 dB of level.
Look here for the service manual, green wire stays with green, red goes to yellow:

https://products.electrovoice.com/binar … ervice.pdf

While in this, replace EV RE-20’s internal foam, it’s usually rotten.
If you shake it and something feels loose inside, that’s the case.

Finally:
Remember, the EV RE-20 is built for relatively close miking, about 10 cm mouth to mic distance, or even closer!

KaiS's Website

  • agolp
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Re: Quadmic II and a gain hungry mic

Wow, thanks a lot to both of you!

KaiS, that worked beautifully. With Trim Gain, I reach -18 dB and don't even have to boost in post. I know it's digital gain but that's more than good enough for my use case!