# ULF <10hz measuring equipment advice, please



## AndreasMergner (May 13, 2010)

I have plans to make a rotary sub for my home theater. I wanted to get the right measuring equipment. I think down to 5 hz would be adequate even though the rotary would go lower. I also play the bass and guitar, so I will be getting a mixing board with phantom power at some point. 

Would a calibrated Dayton EMM-6 make sense combined with a digital Radio Shack SPL meter? I was thinking of getting the RS SPL meter first to measure my current sub (THT) and then when I have the rotary done buying the EMM-6 and mixing board. 

Can I also use the SPL meter to perform RTA distortion measurements or do I need a mic for that? 

Thanks for any help you can give!


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## JohnM (Apr 11, 2006)

A calibrated EMM-6 should be fine for that, but you will also need to calibrate out the effects of the preamp/soundcard by making a loopback measurement.

You can use the SPL meter for distortion measurements, but make sure the meter range is set appropriately so you do not overload it and generate more distortion in the meter than the source!


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## AndreasMergner (May 13, 2010)

Thanks for the advice! I did a loopback calibration with the sound card already. 

I bought a RS SPL meter yesterday and have had success with getting initial measurements. When I get the rotary built, I can step up to the calibrated microphone.


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## chrapladm (Jun 17, 2009)

Earthworks mic's are the ..........bees knees 
M23 is a good budget minded option but not near as cheap as the calibrated mics (EMM6)

Following your RT sub thread and cant wait see pics when you get the time.


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