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First REW test with UMIK-1: weird output

Smidge

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I received my UMIK-1 today and took my very first babysteps with REW. I followed the tutorials from amirm, but when I tested “check levels” it was difficult to get under -20 db SPL headroom. I added max gain to the UMIK (+16 db), and increased the volume to the limit of getting in trouble with my neighbours, and I just reached -20 db SPL. I decided to start my first measurements, but the outcome doesn’t seem right. I doesn’t look like anything I have seen around here. The mic is at listening position on a mic stand, pointed towards the speakers. I’m quite sure I did something wrong but I have no clue where to look at.

Test 1.jpg
 

GDK

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I received my UMIK-1 today and took my very first babysteps with REW. I followed the tutorials from amirm, but when I tested “check levels” it was difficult to get under -20 db SPL headroom. I added max gain to the UMIK (+16 db), and increased the volume to the limit of getting in trouble with my neighbours, and I just reached -20 db SPL. I decided to start my first measurements, but the outcome doesn’t seem right. I doesn’t look like anything I have seen around here. The mic is at listening position on a mic stand, pointed towards the speakers. I’m quite sure I did something wrong but I have no clue where to look at.

View attachment 118559
That’s perfectly normal. You just need to add smoothing. Click on preferences (the gear icon) at the top right and you should see a variety of options there. There are pros and cons of each. 1/24 is common, although it may highlight small changes in SPL that are not truly audible.
 
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Smidge

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That’s perfectly normal. You just need to add smoothing. Click on preferences (the gear icon) at the top right and you should see a variety of options there. There are pros and cons of each. 1/24 is common, although it may highlight small changes in SPL that are not truly audible.

Thanks!
 

pozz

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Shocking, isn't it:)
 

Koeitje

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Room modes and comb filtering, don't you just love it.
 

iann

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Was doing my own first measures with REW today and was actually quite pleased with the response without any EQ.

Average 1.jpg
 
OP
S

Smidge

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This is the same test measurement but now with 1/24 smoothing:
Test 2.jpg


Do I need to be concerned about not getting above -20db SPL headroom? How could I improve this?

it seems my room acoustics could use some help around 36 Hz and 120 Hz.
 

iann

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I don't think you need the SPL to be anything like as much, so I wouldn't worry about the headroom. I did it at 70db and it works fine. The point is to make comparative measurements isn't it?

Is there a subwoofer there or just a room mode at 36Hz?
 
OP
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Smidge

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I don't think you need the SPL to be anything like as much, so I wouldn't worry about the headroom. I did it at 70db and it works fine. The point is to make comparative measurements isn't it?

Is there a subwoofer there or just a room mode at 36Hz?
This is the same test measurement but now with 1/24 smoothing:
View attachment 118637

I guess it’s time for project room treatment :)
 

iann

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Minidsp for me... Subwoofer crossover and room EQ...
 

abdo123

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This is the same test measurement but now with 1/24 smoothing:
View attachment 118637

Do I need to be concerned about not getting above -20db SPL headroom? How could I improve this?

it seems my room acoustics could use some help around 36 Hz and 120 Hz.

Just make sure the lowest point in your graph is 30 dB above your room's noise floor. it's not hard to clip the UMIK-1 so be careful.

Honestly i would just buy Dirac, would be a lot better than anything you would do manually at your knowledge level.
 

abdo123

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I don't think you need the SPL to be anything like as much, so I wouldn't worry about the headroom. I did it at 70db and it works fine. The point is to make comparative measurements isn't it?

Is there a subwoofer there or just a room mode at 36Hz?

do the measurments at the level you typically listen at. If you build filters but end up listening at higher volumes than what you measured, the room modes are further excited, the divide between the tips and dips is increased, and the tonal balance is lost.

same with lower volume.
 

raindance

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Why did you change the mic gain? The cal file is supposed to set that when you load it.
 
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