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pearsall001
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Listening room measurements / How'd you do it?

I presently have a GIK monster bass trap & two Echo busters corner traps. The difference they made was quite noticable. I want to take it further w/ more absorption panels, bass traps, diffusion panels, etc. but first I'd like to measure my room's acoustics. With room measurements I can then decide on a plan of action. Did any of you guys do this & if you did how did you do it? I'm not very savy with this sort of thing. Hopefully the simpler the better.

Kal Rubinson
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Re: Listening room measurements / How'd you do it?


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I presently have a GIK monster bass trap & two Echo busters corner traps. The difference they made was quite noticable. I want to take it further w/ more absorption panels, bass traps, diffusion panels, etc. but first I'd like to measure my room's acoustics. With room measurements I can then decide on a plan of action. Did any of you guys do this & if you did how did you do it? I'm not very savy with this sort of thing. Hopefully the simpler the better.

The cheapest and easiest is with RoomEQ Wizard and an appropriate mic/preamp connected to your PC. I use the M-Audio MobilePre USB and a calibrated mic (but the Behringer ECM8000 will also do the job as will the RS SLM within its limits). See http://www.hometheatershack.com/roomeq/ for the software.

There are simpler FFT spectrum displays but they will not give you information about time decay vs. frequency.

If you develop a more inten$e intere$t and motivation, look at ETF or, even, TEF. More capable, more complex, more expensive.

Kal

cyclebrain
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Re: Listening room measurements / How'd you do it?

Try True Audio's free spectrum analyzer download. You will need a mic and mic amp. Behringer ECM8000 and Rolls MP13.

Jan Vigne
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Re: Listening room measurements / How'd you do it?

You might consider using a professional acoustics firm which will do the calculations and suggest the next appropriate steps. The cost would probably be about what you will pay for the test gear of a DIY job and a few hit and miss attempts at how to proceed. True, you don't get the fun of making all the measurements yourself and you don't get to keep the microphones and other gear afterwards, but you get better results for your money. You can begin with a company such as Rives Audio; http://www.rivesaudio.com/services/servframe.html. Placing "acoustic enginering services" in a search engine will get more possibilities and you might even find someone close to your home to do the work. Most of the companies which manufacture acoustic treatment devices will have services you can employ. Check the classifieds in Stereophile for more suggestions. Possibly others who have gone both routes will weigh in on the subject, but the DIY acoustics jobs often have too many areas of confusion and missteps due to incomplete knowledge of what the measurements suggest should be the next steps. A professional acoustician will have the ability to predict which modifications should be taken in which order and which route will give the most benefit for the dollar spent. I might be misjudging your abilities, but I am assuming you have to this point taken a few basic steps without a complete knowledge of where you were headed. I would liken the job to be done to changing the timing belt on a DOHC engine when all you've done so far is change spark plugs. It all seems to simple until you are faced with what to do once the camshaft is out of the engine. Also, if there are domestic considerations to be taken into account, most professionals can suggest the appropriate route to satisfy those needs as well as improving the sound of the system.

Kal Rubinson
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Re: Listening room measurements / How'd you do it?


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Try True Audio's free spectrum analyzer download. You will need a mic and mic amp. Behringer ECM8000 and Rolls MP13.

The limitation of a spectrum analyzer is that it only shows you the magnitude/frequency domain and not the time domain. It is the latter that is directly influenced by room dimensions/placement while the magnitude/frequency domain only some of the results of that influence.

Kal

cyclebrain
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Re: Listening room measurements / How'd you do it?

My post is a good starting point and is a way for a person new to doing this to get a picture of the effects of room modes and how changes in microphone position interact with modes. Then one can go from there measuring time functions using more advanced programs. In ETF one can quickly become overwhelmed trying to chose all of the correct parameters for your plot.
Yes you could hire someone to do it for you, but what would have learned? I've learned that I'm screwed. No matter what I do, I mess something else up.

imispgh
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Re: Listening room measurements / How'd you do it?

Try a SW product called RAL for your PC. The lite version is cheap. It's an effective RTA. Then you can use an inexpensive DSP to fix this - like the Behringer 2496 (by fix I mean make a big difference that's not the perfect solution. it's a sweet spot fix that doesn't deal with the time variable Kal mentions. But it gets you most of the way there with les than $300 spent in total)

ethanwiner
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Re: Listening room measurements / How'd you do it?


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Try a SW product called RAL for your PC. The lite version is cheap. It's an effective RTA.

I'm not familiar with that program. Does it resolve frequency response to finer than 1/3 or 1/6 octave, and show waterfall plots of ringing too? Both of those are important features in any program meant to analyze smaller rooms like you'll find in most homes.

--Ethan

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