New sub REW measurement - Something is very wrong here

ck42

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Just got an SVS SB-1000 Pro and am trying to get measurements and setup everything on my DDRC-24.
The frequency response though is.....just wrong. Looking at the image below

For the measurement, I've:
- Muted the L+R channels on the DDRC-24
- Bypassed all Xover and PEQ settings on the sub OUT connection of the DDRC-24
- Turned off Dirac
- Connected the DDRC-24 sub output channel to the Left input
- Extended the LP Xover on the sub itself all the way out and set it to max volume

To measure, I aimed the UMIK-1 about 1ft in front of the sub driver (centered)
- The UMIK-1 mic has the 0-degree calibration file loaded
- Set REW to Output on L+R
- Set range to 20-120Hz
- Did a level measurement and set output to measure -75dB

The room is 13x15 and untreated. I've tried placing the sub in a few different spots w/o much difference.
The measurement is shown un-smoothed.

Am I not doing something right in REW...or with how I'm measuring?? UMIK-1 has an issue?

40652
 
Last edited:

ck42

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You could take the DDRC-24 out of the signal chain and measure one of your mains to see what happens.

Was thinking about that after having just reset the DDRC back to factory defaults and re-measuring. No difference. Was wondering if MAYBE some previous Dirac measurements I did was somehow played into this. Can rule that out now.
But yeah, I'll try bypassing the DDRC altogether and see what I get. In a way hoping that does NOT fix it....because then I would have to wonder what's wrong with the DDRC?
 

ck42

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Okay...DDRC completely bypassed (physically/electrically).

No difference.
I am absolutely stumped right now.
 

ck42

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So tried using a frequency generator site (https://www.szynalski.com/tone-generator) and did this:
- set freq for 80Hz and adjusted amplitude in REW for 75dB
- set freq down 10Hz at a time all the way to 20Hz and noted the amplitude in REW
- manually plotted out the curve. It looks WAAAY more like what I would expect. Nothing like the graph in my first post.

So...is REW's test signal adjustable somehow, causing it to result in this response curve?
 

ck42

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Apparently, I had the "Enable Audio Enhancements" checkbox checked in Windows for the UMIK-1. Disabled that and things immediately look much more like what I have been expecting!
 

therock01

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Jan 26, 2021
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Yup that's it. Bought a new laptop and this feature was there and enabled. Uncheck that box and everything want back to normal.
 

Ian Eales

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