Room Measurement Tutorial for Dummies Part 1

[polmuaddib]

Hi,
today i did my first measurement. I didn't do something right, because i get some strange peaks starting at 50hz which is masking everything up to 95 hz, but then there are peaks at 100hz, 150, 250, 350... somehow no peak at 650hz, 950hz...
I am using steinberg ur22 mk2 connected to pc via USB and powered from the same usb. Maybe i should try separate power supply. My mic is samo Stagg cheap microphone. My room is not treated exept for furniture.
I am at the very beginning of measuring and when i learn a bit I plan to treat the room accordingly. I just installed REW today, quickly set it up just to get it working. I know i should read tutorials and all, but i thought i could get some easy help here first, sorry and thanks.
What's this big peak from 20hz to 95hz? Probably some hum from MIC input (I had to switch on HiZ because the level was low), right?
What are those regular peaks every 100hz (skipping only some)?
Why do i have a hi frequency roll of from 10khz to 20 khz? Is this poor mic? Because i doubt that it is speaker or the electronics feeding it...
Thank you very much

 

[QMuse]

Hi,
today i did my first measurement. I didn't do something right, because i get some strange peaks starting at 50hz which is masking everything up to 95 hz, but then there are peaks at 100hz, 150, 250, 350... somehow no peak at 650hz, 950hz...
I am using steinberg ur22 mk2 connected to pc via USB and powered from the same usb. Maybe i should try separate power supply. My mic is samo Stagg cheap microphone. My room is not treated exept for furniture.
I am at the very beginning of measuring and when i learn a bit I plan to treat the room accordingly. I just installed REW today, quickly set it up just to get it working. I know i should read tutorials and all, but i thought i could get some easy help here first, sorry and thanks.
What's this big peak from 20hz to 95hz? Probably some hum from MIC input (I had to switch on HiZ because the level was low), right?
What are those regular peaks every 100hz (skipping only some)?
Why do i have a hi frequency roll of from 10khz to 20 khz? Is this poor mic? Because i doubt that it is speaker or the electronics feeding it...
Thank you very much

For a start you should get proper calibrated measurement mic. UMIK-1 gives pretty good value for the money and decent accuracy.

 

[polmuaddib]

For a start you should get proper calibrated measurement mic. UMIK-1 gives pretty good value for the money and decent accuracy.

Thanks. You don't think i can get away with a different mic? No distributors for UMIK in my country and if i have to import it, shipping and customs will double the price. Because i don't plan to be very exact at this stage. Just to get a feel and maybe make small improvements.
But hey, if UMIK is the way to go, i will order it.
Once again, thanks.

 

[QMuse]

Thanks. You don't think i can get away with a different mic? No distributors for UMIK in my country and if i have to import it, shipping and customs will double the price. Because i don't plan to be very exact at this stage. Just to get a feel and maybe make small improvements.
But hey, if UMIK is the way to go, i will order it.
Once again, thanks.

If you are from EU try here, there will be no custom fees nor additional VAT and shipping will be reasonably priced.

 

[polmuaddib]

Not part of EU, but no problem. Price is not that big of an issue. I just wanted to find use for Steinberg ur22, as i already have it... Thanks for the link.

 

[JustIntonation]

Hi,
today i did my first measurement. I didn't do something right, because i get some strange peaks starting at 50hz which is masking everything up to 95 hz, but then there are peaks at 100hz, 150, 250, 350... somehow no peak at 650hz, 950hz...
I am using steinberg ur22 mk2 connected to pc via USB and powered from the same usb. Maybe i should try separate power supply. My mic is samo Stagg cheap microphone. My room is not treated exept for furniture.
I am at the very beginning of measuring and when i learn a bit I plan to treat the room accordingly. I just installed REW today, quickly set it up just to get it working. I know i should read tutorials and all, but i thought i could get some easy help here first, sorry and thanks.
What's this big peak from 20hz to 95hz? Probably some hum from MIC input (I had to switch on HiZ because the level was low), right?
What are those regular peaks every 100hz (skipping only some)?
Why do i have a hi frequency roll of from 10khz to 20 khz? Is this poor mic? Because i doubt that it is speaker or the electronics feeding it...
Thank you very much

Your measurement shows a peak at 50Hz with very strong odd harmonics. 3rd, 5th, 7th, 9th, etc harmonics of 50Hz.
Hope you find the cause. (of the groundloop)

 

[digitalfrost]

Not part of EU, but no problem. Price is not that big of an issue. I just wanted to find use for Steinberg ur22, as i already have it... Thanks for the link.

Since you already have an interface that supports 48V phantom source, I would advise you buy something like a Behringer ECM8000. But make sure you get it with calibration file (whatever mic you buy).
Dayton Audio EMM-6 would be an alternative.

You'll also need a mic stand. Cheap ones work the beginning, but I broke my cheap one very soon despite not using it much. I then bought a proper musician mic stand, and that thing's been rock solid (König&Meyer).

 

[polmuaddib]

Your measurement shows a peak at 50Hz with very strong odd harmonics. 3rd, 5th, 7th, 9th, etc harmonics of 50Hz.
Hope you find the cause. (of the groundloop)

Thanks. I thank it’s a problem of steinberg. Maybe because it’s powered from the same usb it’s getting a signal. Otherwise it is a balanced Analog connection.

 

[polmuaddib]

But, those peaks are from power issues, right? I can hear them. So, it’s not room issues? I will of course try another mic and try and fix steinberg ground ing. If i find Behringer, great. But, regarding 100hz to 10khz, if you ignore ground loop peaks, not bad, right?

 

[Staffan]

Will the speaker suffer if the measurement starts too low for example 1hz - 20khz. Whether it is protected by a high-pass filter?

 

[MediumRare]

Will the speaker suffer if the measurement starts too low for example 1hz - 20khz. Whether it is protected by a high-pass filter?

No, just like real full range music. But don’t play too loud. Set the volume for about 80 dB, otherwise it will be painful above 5 kHz.

 

[digitalfrost]

The picture you posted looks quite good, however you are zoomed in so far, that we only see 1khz to 22khz in the big screen. If you click the 20 ... 20,000 button it should zoom out. You can see quite a bit of ripple and and huge dip in the thumbnails on the left.

 

[racerxnet]

Sorry,

I moved this to a new thread and did not think this was the correct one to post in. I will click the 20-20k icon. You are seeing the smoothing at 1/24 as well. Do you want me to remove the smoothing or change it?? Can you please reply at the Measurements results thread.

MAK

 

[peterbatah]

Not yet, much good stuff below also if you haven't found it already.
https://www.dropbox.com/s/zdhq72a1puyyxpr/REW 101 HTS Current Version.pdf

Hello. I know that this was posted a while back. Unfortunately, the provided link is no longer valid. Any chance that I can get my hands on the PDF. Thank you. Happy New Year. Peter

 

[Sal1950]

Hello. I know that this was posted a while back. Unfortunately, the provided link is no longer valid. Any chance that I can get my hands on the PDF. Thank you. Happy New Year. Peter

I believe AustinJerry (the author) took that file down from dropbox because it was getting quite old, going on 5 years, and things move very quickly in REW land. Here's a link to a somewhat more current version done by John Mulchay (REW's designer)
https://www.roomeqwizard.com/REWhelp.pdf
If you really want a copy of AustinJerry's original file, PM me your email and I'll send you a dropbox invite.
Happy New Year, Sal

 

[peterbatah]

I believe AustinJerry (the author) took that file down from dropbox because it was getting quite old, going on 5 years, and things move very quickly in REW land. Here's a link to a somewhat more current version done by John Mulchay (REW's designer)
https://www.roomeqwizard.com/REWhelp.pdf
If you really want a copy of AustinJerry's original file, PM me your email and I'll send you a dropbox invite.
Happy New Year, Sal

Good morning @Sal1950 All the best to you and yours in the New Year. Thank you so much for the prompt reply and the PDF link. I wouldn't mind glancing at AustinJerry's original file If it isn't too much trouble. I will send you my email address via PM. Have a safe and wonderful Sunday. Peter

 

[astcal]

I couldn't find "Room Measurement Tutorial for Dummies Part 3". Did I miss something?

Below is my measurement of my study room with Neumann KH 80 and Lewitt LCT 140 microphone at my listening position. I think I need "Part 3" to explain what is going on:

 

[nathan]

You are right that part 3 would be useful for interpreting and acting on your measurements.

However, there is no part 3 yet.

That being said, that measurement looks quite nice!

 

[Sal1950]

Gentleman, I really wouldn't hold my breath for that Part 3 from Amir, Since the first writings of 1 & 2 his time demands have changed drastically. Also the wealth of info available today on the internet would likely make his addition superfluous. Google is your friend but I would recommend you start at the below link. This is the home of REW and author of the software lives there. (John Mulcahy) Numerous links to other REW help sites are also listed here,
https://www.avnirvana.com/threads/some-guides-to-rew-and-acoustic-measurement.121/
Of course I could be wrong and I'm sure Amir will feel free to correct me if warranted.

 

[ArturoKiwi]

Gentleman, I really wouldn't hold my breath for that Part 3 from Amir, Since the first writings of 1 & 2 his time demands have changed drastically. Also the wealth of info available today on the internet would likely make his addition superfluous. Google is your friend but I would recommend you start at the below link. This is the home of REW and author of the software lives there. (John Mulcahy) Numerous links to other REW help sites are also listed here,
https://www.avnirvana.com/threads/some-guides-to-rew-and-acoustic-measurement.121/
Of course I could be wrong and I'm sure Amir will feel free to correct me if warranted.

You are right, Internet are full of guides about Rew and room correction, but it'll be nice to finish our setup with the same point of view.
One more humble user asking for part 3