# What am I doing wrong?



## rolomoto (Mar 12, 2017)

I have a Classe calibration mic and a focusrite 2i2 interface (2 inputs, one L and one R out). There is a left out going to one speaker and a R out looping back to input 2. The mic is on input 1. I calibrated the soundcard. I check the levels for the sweep and get -14db. I do the sweep and have 11db headroom but nothing shows up on the graph.
Thanks for any help.


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## Wayne A. Pflughaupt (Apr 13, 2006)

Unless the mic uses an XLR connection, it probably will not work with the Focusrite. Does the Focusrite show that it is getting a signal from the mic?

Regards, 
Wayne


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## rolomoto (Mar 12, 2017)

yes, it's getting a signal (if I tap on the mic the little green led lights up). I just tried it with a recording mic that uses XLR and got the same thing.


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## Wayne A. Pflughaupt (Apr 13, 2006)

What is your computer’s operating system?

Regards, 
Wayne


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## rolomoto (Mar 12, 2017)

mac sierra 10.12.3


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## Wayne A. Pflughaupt (Apr 13, 2006)

Copy that. I know nothing about Macs. Hopefully John will weigh in.

Regards, 
Wayne


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## JohnM (Apr 11, 2006)

Looks like you are measuring the loopback input rather than the mic input. From your description of the connections you should make sure the input channel (to the right of the input selector on the REW soundcard preferences) is set to 'Left'.


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## rolomoto (Mar 12, 2017)

JohnM said:


> Looks like you are measuring the loopback input rather than the mic input. From your description of the connections you should make sure the input channel (to the right of the input selector on the REW soundcard preferences) is set to 'Left'.


yes, that helped, thanks!:clap:


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## rolomoto (Mar 12, 2017)

Does this graph look right? I measured the db level from the speakers and it was 75.
thanks


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## JohnM (Apr 11, 2006)

The measurement looks OK, per the other thread you need to run SPL calibration.


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## rolomoto (Mar 12, 2017)

JohnM said:


> The measurement looks OK, per the other thread you need to run SPL calibration.


Thanks for your help.
I used a cell phone app as the SPL meter and entered the info. It said calibration complete but the test shows Mic/Meter: No cal. 
I have it set to Mic or Z Weighted SPL Meter in the prefs.


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## JohnM (Apr 11, 2006)

Level calibration is not the same as response calibration. A mic/meter calibration file is to calibrate out the frequency response of the mic. The SPL calibration sets the level (sensitivity) of the mic.


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## rolomoto (Mar 12, 2017)

I did an spl calibration but now the blue and green graphs to the left don't show up in the main area:


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## JohnM (Apr 11, 2006)

I'm afraid you didn't do it correctly. As the graph legend shows, your SPL is at more than 264 dB so off the top of the graph. You can use the graph controls to add a negative offset to the responses to move them down so they become visible, but you need to get the SPL calibration done correctly. When it has been, the REW SPL meter should read the same as your external SPL meter when both are listening to the same signal in the room.

Edit: note that the SPL calibration will only affect new measurements you make after you have done it, it will not change any measurements you already have.


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## rolomoto (Mar 12, 2017)

Thanks for your patience.
Here is what I am doing for the SPL calibration:
1. the image shows the prefs I'm using. I have the mic going into the L input on the scarlet. The input is at full level. The outputs on the scarlet go to the speakers. 
2. I click the SPL button and hit calibrate. I chose "use REW speaker cal signal". I use a cell phone app as an SPL meter and enter that figure in the "SPL reading calibration" box.
3. The attachments and images show what I get.
Is this right?
thanks


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## JohnM (Apr 11, 2006)

Yes, that looks more like it. Now you can adjust the graph range so that it doesn't make everything look flat, click the Limits button at the top right of the graph and set the top of the SPL scale to 105 dB and the bottom to 45 dB. Make sure the input level doesn't get too high or you will get clipping, making the measurement invalid. When you make a measurement REW shows you how much headroom is left, that figure shouldn't get too small - more than 10 dB is good. Note that if you change the input gain you will shift the calibration, so best to redo the SPL calibration if you have to change the gain.


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## rolomoto (Mar 12, 2017)

Thanks again for your patience and help!


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## rolomoto (Mar 12, 2017)

Sorry to bother you again but I wanted to do another sound card calibration. For some reason I can't get it to work.
I have the 2i2 setup as in the pic: a loopback from input 1 to the L output and the R out going to a speaker.
No matter how I set the prefs I get the error message in the attachment.
Thanks for any help.


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## JohnM (Apr 11, 2006)

There's really no way to tell from those pictures, it would be best if you attached the soundcard calibration measurement file (saved as .mdat).


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## rolomoto (Mar 12, 2017)

Here it is.
Thanks.


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## JohnM (Apr 11, 2006)

That looks fine. I suspect you didn't use the Make Cal button immediately after doing the soundcard calibration and in the meantime selected another measurement, hence the message. Either use Make Cal immediately after running Calibrate or make sure the Soundcard measurement is selected before pressing Make Cal.


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## rolomoto (Mar 12, 2017)

OK, thanks!


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