Larsen Feedback Issue at Soundcheck Calibration.

[mmlmusik]

Hello,
I'm a new REW user (Fantastic Tool).
When doing the soundcheck levels in order to make the "in" level same as -18 dBFS ref level
I'm encountering larsen/feedback issue to reach the -18 dBFS.
I'm in a Home Studio and my speakers are 1m far away from the Berhinger ECM8000 I'm using
to make the measurement.
I'm using an UAD 2 Apollo 8 Quad on an iMac M1. (DO I need any cal file for my Apollo 8 ?)
Is there any solution to avoid this feedback in order to reach the -18 dBFS level for soundcheck
calibration please ?
Waiting forward for your help.
All the best,
Antonio

 

[John Mulcahy]

You will need to turn off monitoring, the input signal must not be routed back to the output. You don't need such a high level for mic measurements, anything above about -45 dBFS is plenty, but you must remove the monitoring or the result will not be valid.

 

[mmlmusik]

Thx for your feedback.
If I remove/turn off the monitoring how can I make the measure ?
No sound will go out of my monitors and so not recorded in the microphone in this case ?
I don't understand.
(please be patient I'm a beginner ^^')

 

[John Mulcahy]

Monitoring routes signals from your inputs back to the outputs. Great for hearing your instruments, bad for measuring. REW sends the measurement signal directly to the outputs and captures the mic signal directly from the input.

 

[mmlmusik]

Ok but still confused for me.
Currently I'm sending the REW measurement signal through my main outputs (FOCAL SHAPE 50 plugged in main ouptut of my UAD Apollo 8).
This sound is going out of the 2 Focal speakers (L or R depending on what I want to measure) and then this sound is recorded by a microphone (Berhinger ECM8000) in order to get the results in REW.
That's not the right way to process ? :/

 

[John Mulcahy]

Yes it is, but your interface or it's mixer software is configured to mix the input signal from the mic back to the outputs, that's what causes the feedback and that's what you need to disable.

 

[mmlmusik]

Ok thx a lot for your feedback.
So I must contact uad support to ask how to disable it because I don't know ho w to proceed.
Maybe you know how to do so in this uad soundcard ?

 

[John Mulcahy]

I don't, sorry.

 

[mmlmusik]

Shall I bypass this option (pls see screenshot here attached) to obtain the process for a valid REW measurement ?

 

[John Mulcahy]

No, that is just for levels. In the UAD Console you need to mute the mic input channel.

 

[mmlmusik]

Thx a lot now it works properly, no more feedback/larsen