# Room mode measurements



## Jason Schultz (Jul 31, 2007)

Hi 
I've attempted to measure my in room system response with a cheap (and probably inaccurate) spl meter with inbuilt mic. I don't trust the readings I've got. what would be the next step, cost being a consideration. Can any one offer any suggestions. 

Thanks Jason


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## brucek (Apr 11, 2006)

The Radio Shack SPL meter is the cheapest option. We have a downloadable correction file on our site.

Use the software REW for taking the measurements. You'll need a few basic cables and the meter to make it all work....

brucek


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## Jason Schultz (Jul 31, 2007)

Thanks brucek
I've been Reading some of the threads on spl meters. I am relieved to find out that my meter is the same (different name) as the Galaxy cm 140 or voltmeter SL 200. In Australia it is called digitech QM 1589. I can also report that it is pretty useless measureing above 8 KHZ. I will have to perform manual measurements (****!). A Question, should i be measureing bass frequencies in 1hz increments or is 2hz - 5hz accurate enough.


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## Otto (May 18, 2006)

Hi Jason,

Yeah, measuring that high in frequency will yield indeterminate results. We mainly measure sub response. It'll also be hard to apply any EQ to high freqeuency issues. It's better to deal with those problems via room treatments. 

You can measure you sub frequencies in 5 Hz increments; I'm sure that'll offer you enough detail for you graph. However, as brucek suggested, you should give REW a try. It'll make things quite a bit easier...


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## Wayne A. Pflughaupt (Apr 13, 2006)

Jason Schultz said:


> Thanks brucek
> A Question, should i be measureing bass frequencies in 1hz increments or is 2hz - 5hz accurate enough.


If you’re using REW, just run the sweep. If you’re measuring manually, I personally prefer frequencies at 1/6- or 1/12-octave spacing. This will make it easier to determine equalizer settings, because the width of EQ filters are set as octaves. 

What you might do is, after finding a peak or depression via the manual method, go back and play individual frequencies above and below that point, to find the exact frequency where it is centered.

Regards,
Wayne


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