# Bryan - Advice needed please on testing Equipment



## kam (Sep 13, 2010)

Hi Bryan

I have been looking into the equipment needed to take sound measurments for the acoustics in my Theatre room. I was proposing to purchase an inexpensive external sound card and RS digital Mic to use with REW on my laptop. I enquired whether this was ok on the other area of this forum and was directed to you. Are you able to let me know if the above setup is ok, or do I need to get the more complex and expensive equipment. I have read the articles that suggest that the behringer ECM8000 is btter than the RS Mic, but then I need a phantom power supply and this all looks a little complex for me! Many thanks, Kam




> Hey kam,
> 
> I’d say subwoofer measurement and EQ is a must-have, and as you’ve found, you can do that with nothing but the Radio Shack SPL meter and the cheapest sound card you can find.
> 
> ...


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## bpape (Sep 14, 2006)

I would agree for the most part. The Radio Shack (or some other SPL meter) will be required anyway to calibrate levels. No reason you can't use it along with the correction plug-in for doing measurements. It will be fine.

As for the sound card, we just need one that is bi-directional (can play and record at the same time). Any non-linear response will be adjusted for during the loopback calibration step.

These measurements will be good enough to allow you to make decisions on proper placement, finding reflections, looking at energy balance and decay times, etc. Is it going to get you within +/-2? Nope. Realistically, if you are willing and able to do proper repositioning and treatment, you can get to within +/-4 to 5 db in room with no EQ required.

Bryan


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## kam (Sep 13, 2010)

Hi Bryan

Thank you for your prompt reply; If I am reading this right, I can use the RS Digital Meter with nothing more than my laptop, the REW software and a suitable soundcard (and need no other equipment other than cables)?

With regard to the 'correction plug-in' do you mean the config file that is available on this forum for the RS meter, or is the correction plug something else?

Also, this is the link to the soundcard I am hoping to purchase, is this ok?

http://www.maplin.co.uk/Module.aspx?ModuleNo=97120

Thank you, Kam


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## kam (Sep 13, 2010)

Bryan

Wayne a Moderator from the SPL meter's area of the forum has just posted this:



> But he may not be aware that we don’t consider the RS meter to have usable (read unpredictable) accuracy above 3 kHz. You might double check with him to clarify if he knows that.
> 
> In addition to the above post, is it therefore still ok to use the RS digital SPL?
> 
> Thank you, Kam


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## kam (Sep 13, 2010)

Bryan, 

I have also ben advised to look at this attachment, does this make any difference to our work if using the digital RS SPL?


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## bpape (Sep 14, 2006)

It just needs to be accounted for when looking at the plots from an absolute response standpoint. WHen doing comparisons for placement, it won't really matter.

Above 3kHz is way too high to worry about in terms of placement and treatment. You're not going to change that. We're more concerned with 20-300Hz for the most part.


Bryan


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## kam (Sep 13, 2010)

Thank you Bryan, can you please help me with the above query on the correction plug? Thanks, Kam


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## bpape (Sep 14, 2006)

Sorry. There is one on this site I believe that should be just fine. I'm not 100% sure if it's for the analog or digital meter though.

Bryan


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## kam (Sep 13, 2010)

Bryan, yes, they have the config file for both meter's. Many thanks for your help, I will be back in touch once i have the equipment and have conducted some tests and hope you will be able to guide me further. I will of course read the guidance notes first! Kam:wave:


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