• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required as is 20 years of participation in forums (not all true). Come here to have fun, be ready to be teased and not take online life too seriously. We now measure and review equipment for free! Click here for details.

Room Measurement Tutorial for Dummies Part 1

DonH56

Major Contributor
Technical Expert
Patreon Donor
Joined
Mar 15, 2016
Messages
2,925
Likes
3,390
Location
Monument, CO
#21
That will not necessarily get you absolute SPL accuracy; not all cal files include the sensitivity parameter (mine did not). But maybe they do now? I have not used it for a while.
 

Sal1950

Major Contributor
The Chicago Crusher
Joined
Mar 1, 2016
Messages
5,592
Likes
3,003
Location
Central Fl
#22
That will not necessarily get you absolute SPL accuracy; not all cal files include the sensitivity parameter (mine did not). But maybe they do now? I have not used it for a while.
Here's the two I got with mine?
Also I tried pushing the Calibrate button in the SPL app and it puts up a dialog box the says the umik doesn't require calibration, it was already included in the file.
 

Attachments

Last edited:

amirm

Founder/Admin
Staff Member
CFO (Chief Fun Officer)
Joined
Feb 13, 2016
Messages
20,088
Likes
23,264
Location
Seattle Area
#23
But maybe they do now?
MiniDSP guys worked with REW author to add level calibration to their USB mic. I tried but don't know how accurate it is.
 

DonH56

Major Contributor
Technical Expert
Patreon Donor
Joined
Mar 15, 2016
Messages
2,925
Likes
3,390
Location
Monument, CO
#24
Thanks guys. I checked my notebook and sure enough I have a cal file from miniDSP with the sensitivity parameter set. Oddly, the cal file from CSL (where I bought the mic) does not.

FWIW I checked the UMIK-1 using the CSL cal file to my Earthworks and they were almost identical in frequency response. There was a little deviation using the miniDSP file, mainly at LF and very HF. Not enough I would worry about it, but being one of those anal engineer types am glad I bought the CSL version. At the time of purchase, miniDSP did not have 90-degree files, which would have led to a much larger error.
 

JohnPM

Active Member
Technical Expert
Joined
Apr 9, 2018
Messages
112
Likes
287
Location
UK
#25
Thanks guys. I checked my notebook and sure enough I have a cal file from miniDSP with the sensitivity parameter set. Oddly, the cal file from CSL (where I bought the mic) does not.
Herb didn't include the sensitivity figure in his cal files as he didn't have a way to verify it, but these days he includes a version with the miniDSP sensitivity figure in an REW folder on the USB stick containing the cal data.
 

amirm

Founder/Admin
Staff Member
CFO (Chief Fun Officer)
Joined
Feb 13, 2016
Messages
20,088
Likes
23,264
Location
Seattle Area
#26
Herb didn't include the sensitivity figure in his cal files as he didn't have a way to verify it, but these days he includes a version with the miniDSP sensitivity figure in an REW folder on the USB stick containing the cal data.
Side question: you are not by chance the JohnPM who is the author of REW, are you?
 

amirm

Founder/Admin
Staff Member
CFO (Chief Fun Officer)
Joined
Feb 13, 2016
Messages
20,088
Likes
23,264
Location
Seattle Area
#28
Oh, wow. You should have told me. You are a heck of a lot more modest than I would be. :D I gave you an appropriate title.

I would love to learn more about the history of REW and motivation for creating it. Do you mind sharing that in a new thread?
 

Donald

New Member
Joined
Apr 19, 2018
Messages
1
Likes
3
#31
Amir:
Despite years of DIY speaker and PC building and somewhat related formal education (PhD in Physiological Acoustics) I've encountered numerous obstacles in my efforts to understand REW. I had just about about given up on the application when I came across your tutorial. Your detailed descriptions, together with helpful information from contributors to this forum, have enabled me to at least begin to make use of this remarkable free software.
Thank you!
Donald
 

amirm

Founder/Admin
Staff Member
CFO (Chief Fun Officer)
Joined
Feb 13, 2016
Messages
20,088
Likes
23,264
Location
Seattle Area
#34
@Amir,
Are you still working on Part 3, or have you just ditched the idea?
Kind regards,
J-J
No, it is on TODO list. Just when I get to it... is not clear. :)
 

amirm

Founder/Admin
Staff Member
CFO (Chief Fun Officer)
Joined
Feb 13, 2016
Messages
20,088
Likes
23,264
Location
Seattle Area
#36
Wow, it works! :)




Am I correct believing that this device (https://www.minidsp.com/products/minidsp-in-a-box/minidsp-2x4-hd) can load the filters generated by REW and correcting the response of my speakers and room?
Yes, REW can generate the filter settings for a number of boxes. Even when it can't, you can get the list and manually put them in there.

In my experience though, the auto-generated ones don't always sound the best. They attempt to get maximum flatness which may not be what sounds best. Good news is that with these type of DSP filters, you can turn them on and off and hear the difference.
 

Krunok

Major Contributor
Joined
Mar 25, 2018
Messages
3,574
Likes
1,838
Location
Zg, Cro
#37
In my experience though, the auto-generated ones don't always sound the best. They attempt to get maximum flatness which may not be what sounds best.
I see, thank you. What do you think is a better alternative to the auto-generated fitler settings? Adjusting the target curve to something other than the flat line, say increase the bass response in 50-100 region and introduce slight roll-off in highs?
 

Krunok

Major Contributor
Joined
Mar 25, 2018
Messages
3,574
Likes
1,838
Location
Zg, Cro
#40
Btw, do you still plan to do a Dirac Live test with miniDSP SHD? Maybe it can serve as some kind of reference point for REW..
 
Top Bottom