Empress Compressor, gain reduction led metering not in sync

[boomertech]

The entire email would be good but only if you think there is something that might explain all of this.

Frank,
If you used a 1K sine wave at x level so that the LED's were not coming on, and, if you increased the output 1 dB wouldn't we expect to see 1 dB of compression?

I was thinking that this test could be repeated at 5dB, 10dB, etc. and would be an easy test for the OP with just the output from a computer signal generator straight into the pedal.

The easiest way to test/calibrate is to use a free program like TrueRTA. Load T-RTA on your PC and calibrate the RTA to your sound card per their instructions. Then you could easily monitor the compression and adjust the trimmer to meter the same amounts. I will make a step-by-step using an FFT for the calibration/test.

-Frank

 

[boomertech]

I believe I do have one, I purchased MC Studio MC Studio | TwiddleFactor for that exact purpose. I installed it my iPad. Then I ran a sine wave at 440hz from my iphone to the pedal, then the pedal ouput fed the MC Studio on the iPad but then got stuck there as I couldn’t make sense of the calibration process as described on the Empress site...

Did you calibrate that software to your iPad?

-Frank

 

[charlie monroe]

...
The calibration is not necessary in this case. You could adjust the LED metering with the U2 trim pot and see if they behave more to your liking.
...

I wish I knew a more technical way to do it than solely using my ears...

I trust your ears.

You're a musician right? Your ears are the best asset you have. You should trust them too.

It's just a display meter. Adjust it until you believe it.

 

[geobassix]

Did you calibrate that software to your iPad?

-Frank

Sorry for my ignorance Frank, but I don't even know how what it means to calibrate a software to my iPad.
When I disable internal iPad mic and only use my iRig HD2 as input source, having the calibration reference as -10dB (the default value, the minimum possible value being -25dB and the max 0 dB), nothing being connected to the iRig, the level is fluctuating between -101 and -100 dB.
I guess that I have to adjust the calibration reference to some value but the noobie that I am have no idea...

 

[geobassix]

I trust your ears.

You're a musician right? Your ears are the best asset you have. You should trust them too.

It's just a display meter. Adjust it until you believe it.

Thank you for trusting my ears , I believe I can hear when the compression kicks in and as much as I trust my ears, they are unfortunately not yet able to provide me with an estimate of the actual gain reduction

 

[boomertech]

Sorry for my ignorance Frank, but I don't even know how what it means to calibrate a software to my iPad.
When I disable internal iPad mic and only use my iRig HD2 as input source, having the calibration reference as -10dB (the default value, the minimum possible value being -25dB and the max 0 dB), nothing being connected to the iRig, the level is fluctuating between -101 and -100 dB.
I guess that I have to adjust the calibration reference to some value but the noobie that I am have no idea...

You will need to be familiar with your software. You will need an input and output cable from the FFT audio interface to the comp to make measurements and calibrate the comps LED meter. The FFT software needs to be calibrated to your audio interface so that you can accurately measure and generate tone levels. You need to be able to output a -10dBu at 100Hz signal from the computer/audio interface and be able to measure that -10dBu signal on the FFT plot at 100Hz when the comp is in bypass.

-Frank