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TOPIC: High SPL levels using REW pink noise with UMIK 1

High SPL levels using REW pink noise with UMIK 1 3 years 4 weeks ago #27775

  • AVSION
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I setup up my system level match the HT speakers and i'm getting high SPL readings when using REW pink noise.
i was following "Getting Started with REW: A Step-by-Step Guide (Rev 5.2 August 10, 2016)" and setup the system as follows:

1. Prepare the AVR:
a. Using the AVR’s setup menu, adjust each speaker’s trim to zero as a starting point.
b. Set the AVR master volume to zero.
c. Disable output to the sub channel. This can be accomplished by turning off the sub(s), or by setting the speakers to “large”.
d. Set the AVR’s output to stereo.
e. If your AVR has automated room correction, make sure it is turned on (we want the speaker levels set with room correction engaged).
2. Select the calibrated USB microphone and the 90-degree calibration file that contains the sensitivity parameter. (If you don’t have the custom 90-degree calibration file, use the calibration file you have.)
3. Set up the mic at the MLP, pointed towards the ceiling, with the tip of the mic at ear-level.
4. Make sure the Windows audio input and output devices are configured properly as per the instructions earlier in this Guide.
5. Launch REW.
6. Open the REW SPL tool and click the red button so that the SPL is measuring sound levels.
7. In the REW preferences screen, select the HDMI channel for the first speaker you will be measuring (e.g. HDMI1 for the left speaker).
8. Open and configure the REW Signal Generator:
a. Select Pink Noise.
b. While measuring the main speakers, select “Speaker Cal”.
c. Set RMS Level dB FS to -30 (Why -30? See note below)going
9. Click the Play button in the Signal Generator. You should now have a tone playing from the left speaker.
10. Observe the sound level being displayed in the REW SPL. Normally, it should be fairly close to 75dB (within +/- .5db).
11. In the AVR’s setup menu, go to the speaker level-setting screen and adjust the trim for the speaker upwards or downwards until you see a reading of 75dB in the REW SPL. (If the REW SPL meter is fluctuating too rapidly to set the level precisely, you can open the SPL Logger, which might allow a greater degree of precision).

when i get to step 10 it reads 90db SPL not 75db, this is 15db higher, although i followed all steps one by one,

to double check the SPL levels i used another method by generating the build in pink noise in the AVP as the AVP or AVRs uses -20db pink noise, i set the MV down -10 db (from reference) to get 75db SPL and did get 75db SPL readings.
any idea where this 15db in gain coming from? its driving me nuts i would like to use REW manual process that is recommended after running auddyssy.

Also in step 11 they asking me to adjust the levels in the speaker level-setting screen, it is not possible as when you go in to the speaker level-setting screen it automatically run the build in pink noise and disable REW pink noise. i do have in option screen speaker levels settings, for fine tuning, where i can adjust with REW pink noise but the option screen levels solution does not link to auddyssy which is important when making changes. anyone knows how to run pink noise from REW and use speaker level-setting screen to make the changes?

I'm basically stuck at this point, appreciate your help

Thank you
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