Help on REW measurement results. - Home Theater Forum and Systems -

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post #1 of 4 Old 01-10-14, 09:13 AM Thread Starter
Join Date: Dec 2013
Posts: 7
Help on REW measurement results.


Yesterday i use the Umik-1 mic and software "Rew" forthe first time and for to measure my present speakers in my room Home Theather.
I have followed the instructions as to use the microphone Umik-1 together with the program.
I use Denon 4311 as avr for my home theather and i use the HDMI connection to my HTPC for make the measurements with umik-1.
I use Asio 4 as you suggest (Input Nvidia HDMI - Output Umik1) and loaded calibration file for Umik-1.
I follow to setting to 75 db my level of speakers following your indication with generator of pink noise (-12db).).
Now i have make sound spl measures and i put them here exhibits.
I am not a technical or engineer and don't know if the result are normal or if there are some my error in the measurement.
Can you help me to indicate some suggestions to the results?
The images are for measure of central speaker (Nr.04 photo -> B&W Lcr600 s3 - 150 watt 8 Ohm), front sx (nr.03 photo -> B&W 803 N - 250watt 8 ohm), and my two connected together Subswoofers (Nr.05 photo -> Nr.02 ASW 1000 - 120watt for everyone).

Now today i have change driver and used Java driver for have same result ad other users of Umik-1.
I attached picture of setup of REW and two photo of a first misure and an average of Spl using java driver and as input Denon Amp throught HDMI 1.4 wire.
Is all correct the setup of REW in preference panel (Nr.05 photo)?
Can you give me an idea on thing there is of wrong in the two measurements (Nr.01 and Nr.02 photos) that I have played?
If I don't mistake can use a minidsp (es.minidsp 10x10), and one time loaded results of Umik-1, it corrects in automatic way my audio room. Or it needs to also do manually in the case of the purchase of a minidsp combined with my microphone Umik-1 however?
Many thanks to want help me.

Attached Thumbnails
Help on REW measurement results.-average-spl.jpg  

Help on REW measurement results.-central-speaker.jpg  

Help on REW measurement results.-front-sx.jpg  

Help on REW measurement results.-misure-java.jpg  

Help on REW measurement results.-setup-rew.jpg  

Help on REW measurement results.-subwoofers.jpg  

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post #2 of 4 Old 01-10-14, 12:06 PM
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Re: Help on REW measurement results.

Welcome to HTS!

Thanks for the information on your measurement setup. It may be working properly.

I use Asio 4 as you suggest (Input Nvidia HDMI - Output Umik1) and loaded calibration file for Umik-1.
I assume you meant, "I use Asio 4 as you suggest (OUTPUT Nvidia HDMI - INPUT Umik1) and loaded calibration file for Umik-1.

In "Preferences" clear the Soundcard calibration file. It should read "None" when using a USB mic.
This may be the only minor issue.

[It looks like you are using the latest REW 5.01 Beta 17 version? Some of the earlier versions were not configured to deal with the new USB mic calibration files.]

After clearing the Soundcard cal file, post another measurement and attach the .mdat file. I suggest you measure the SW very close to the woofer (2 to 3 cm) for this measurement. The close mic position is just to reduce the room influence so it is easier to confirm if the measurement system is setup correctly. Be sure to the reduce the SW volume so the level is still approximately 75 to 85 dB.

A second measurement can be made just after the first with the AVR turned off so no sound is played. This will measure the noise floor in the room.

If these 2 measurements look normal then you are ready to start measuring at the LP.
jtalden is online now  
post #3 of 4 Old 01-10-14, 01:29 PM Thread Starter
Join Date: Dec 2013
Posts: 7
Re: Help on REW measurement results.

Thank you very much for your reply.
Yes...of course i have wrong to write ad i have inverted to write output with input selection.
I use version stable of REW and not beta.
I attached here the misure that you have asked me and i put mic near 3-4 cm to woofer of sub.
I have cancelled the calibration indicate.
And i have take more misure of the subwoofer.
First of all i misure the noise floor you have indicate, setting on mute mode on the Denon and recording noise floor with ambience noise.
After i have make misure setting level of sound to 75db with pink noise and subwoofer with inserted 0 grade selector rear and after setting -180 grade selector for invert the phase of sub.
Here attached also the "ALL SPL"l misure executed.
I wait your answer.
Many thanks again.

Attached Thumbnails
Help on REW measurement results.-mute-noise-floor.jpg  

Help on REW measurement results.-subwoofer-0-grade.jpg  

Help on REW measurement results.-subwoofer-0-grade-all-spl.jpg  

Help on REW measurement results.-subwoofer-near-5-cm-180-grade.jpg  

Help on REW measurement results.-all-spl-180-grade-sub.jpg  

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post #4 of 4 Old 01-10-14, 04:46 PM
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Join Date: Mar 2009
Location: Michigan, USA
Posts: 1,368
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Re: Help on REW measurement results.

It is strongly advised that you update to the latest REW 5.01 Beta 17 version. It can be found HERE (see post #6). It corrects numerous bugs that may (or may not) affect your future work.

The new SW measurements do not look as clean as I would have expected for near field measurements. The SPL response does not fall off in level at the higher frequencies as much as I would expect. They do still look believable however. I suspect that all is okay. You can proceed with you work.

If you like you can use the "Testing" thread to get the 5 posts needed so that you can then attach the .mdat file for the noise floor measurement and one of your near field measurements if you want me to take a little closer look for possible problems. There are several indicators within the saved file that is helpful to review.

Also I want to point out the sticky threads at the top of the forum as they are a great help on several important topics. The REW help screens are also very helpful.

If you have specific REW questions we will try to answer them.
jtalden is online now  


measurement , results , rew

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