Tools for room measurement

amirm

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What are people using for room measurement? I am using my TacT which obviously is not practical for other people. Are sound cards and microphones used with PCs? If so, what are the recommendations for mic? My TacT comes with a calibrated mic with its profile stored in TacT. How would you get "linear" response otherwise from a mic you buy?
 

RUR

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Amir, despite the fact that I correct the FR curve using TacT, I don't rely upon it for complete, accurate room measurement, generally post-correction. I've used XTZ, for which Kal wrote a nice article in Stereophile and which he continues to use in various gear writeups. I also purchased all the constituent parts for REW, but I've yet to fire it up.

XTZ comes with a calibrated microphone. For REW, simply purchase a mic with a calibration file e.g. http://cross-spectrum.com/measurement/calibrated_behringer.html
 

rblnr

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Just got XTZ and will use it when my new speakers are installed next week. Will report back.
 

amirm

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Thanks guys. Looking at the XTZ specs, its mic is rated for +-3db. Are the variations compensated for in their software or is that the limit of the accuracy of their measurements?
 

Kal Rubinson

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I use an Apple App that makes your iphone an RTA. Pretty slick I might add and a whole lot less than the XTZ (which BTW looks slick but $320 if I read it correctly)
Sure but XTZ is a lot more than just an RTA.
 

RUR

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I use an Apple App that makes your iphone an RTA. Pretty slick I might add and a whole lot less than the XTZ (which BTW looks slick but $320 if I read it correctly)
Steve, cost me $256 all-in about 3 months ago. And the website needs to be updated: the latest SW version works just fine with Vista.
 

Kal Rubinson

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What are people using for room measurement? I am using my TacT which obviously is not practical for other people. Are sound cards and microphones used with PCs? If so, what are the recommendations for mic? My TacT comes with a calibrated mic with its profile stored in TacT. How would you get "linear" response otherwise from a mic you buy?
Most will take a .cal file for the microphone or come with such if the mic is included. What software you choose will depend on the budget, the functions and the resolution you need. I have, and use, REW, TrueRTA and TEF but the easiest (for what it does) is XTZ. There are many others. BTW, I have used TacT, as well , but as with Audyssey and ARC, it is nice to have an independent check on what the s/w is doing.
 

FrantzM

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Apr 20, 2010
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Hi

Quick ... A little measurements plus correction by ear will extract more from your system than a lifetime of swapping components.
This preamble out of the way. The tools are NOT plug and play. You need to read some and be patient. Frustration is around the corner and despair not too far from it .. Pulling hair is optional.. Results can send you to heaven.. So ...

You need a laptop .. OS can be Windows, OSX or Linux, I use it with Windows.
REW Room Eq Wizard. REW , a powerhouse. And it is free. Take a good while to understand and use and a long time to master.Download on this PAGE
Good but not superlative SoundCard M-Audio is your friend , nothing fancy their basic USB Interface.microphone amplifier will do just fine.
Behringer ECM8000 Microphone , the CrossSPectrum Calibrated one at $80
Some Sound signals available free at Burninwave
A tripod
Patience, a willingness to learn and experiment. Persistence, lot of it else ..Hire an acoustician, this is involved and quite a bit so.

Quickly I would not rely on the iPhone for this purpose, results are likely to be unsatisfactory.

Lot of information at that other forum

Results can be very good. You will appreciate your system more and shed a good deal of dogma along the way, or at least understand more.
 

Steve Williams

Site Founder, Site Owner, Administrator
Next time you're here Frantz Ill show you this app On the iPhone. It will surprise even you. After all isn't it you who is always espousing the virtues of a digital world and how much better it is getting. Keep an open mind Frantz. I can show you measurements with the iPhone app and my measurements done by others. They are remarkably similar.
 

FrantzM

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Not against the iPhone per. REW is a much more powerful application and its free. Some of the iPhone application actually supports external microphones because of the inherent difficulty to calibrate the built-in (and not for this purpose) microphone. You would need more than one iPhone app to match REW and even there.

I do not mean that they are useless, simply that a laptop plus REW plus a calibrated microphone is a much more powerful and accurate tool..

I don't think I am alone in embracing digital. We all are, one way or another, We are using this forum after all ;)
 

Johnny Vinyl

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I don't think I am alone in embracing digital. We all are, one way or another, We are using this forum after all ;)

Sneaky! LOL!

John
 

DonH50

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Earthworks measurement mic (M30, I think), m-audio Fast Track Pro for a preamp (very flat, needs more gain), Creative X-Fi external (USB) sound card, RPlusD s/w on a Windows notebook. Also a Radio Shack meter now and then, and various other toys (borrowed from work), but the first line is what I use now most of the time. - Don
 

amirm

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Apr 2, 2010
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Amazing. Everything is on the Internet if you know how to search for it :D. Here is nice test of mics on various iPhones: http://blog.faberacoustical.com/2009/iphone/iphone-microphone-frequency-response-comparison/



"As I have often said, “The built-in microphone of the original iPhone is not recommended for sound level measurements.” Now, you can really see what I mean. Interestingly, the built-in microphone of the iPhone 3GS isn’t recommended, either, unless you don’t care about frequency content below 200 Hz. This behavior is consistent with the headset input frequency response of the iPhone 3GS (I suspect that the built-in microphone signal goes through the same high-pass filter that gets applied to the headset input). The iPhone 3G microphone’s response is clearly the best of the bunch, but its low end rolls off by 15 dB or more at 20 Hz. Not surprisingly, none of the iPhone models rivals a lab-grade sound level meter with its built-in microphone, but either of the 3G models can potentially give you a decent ball-park estimate of the current sound level, although the low frequencies will be de-emphasized."

Still, it is nice to always have an audio meter in your pocket!
 

amirm

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Apr 2, 2010
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Seattle, WA
I would think an RTA program would have some kind of calibration to improve on the above curves but of course, can't make the mic produce sounds it simply can't capture.

I just downloaded an RTA to my Droidx. It seems to work quite well! It has a calibration mode although I am not able to run that yet since I have not downloaded the noise generator. When I get time I will play with it more to see how accurate it is. The free version does 30 bands, the paid one, 120 ($5).
 

vinylphilemag

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I don't think I am alone in embracing digital. We all are, one way or another, We are using this forum after all ;)

Speak for yourself: I'm using this forum from my analogue Babbage Analytical Engine--so there! :p

Edit: Thanks for the pointer to REW, It looks most interesting...
 
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