This is the closest I've done:
Comparison of Ten Measuring Microphones
Note that the Nady and Behringer looked exactly the same, but had different output levels. They did track very closely to each other's response though, within about 1 dB.
--Ethan
Tools for room measurement
- Thread starter amirm
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This is the closest I've done:
Comparison of Ten Measuring Microphones
Note that the Nady and Behringer looked exactly the same, but had different output levels. They did track very closely to each other's response though, within about 1 dB.
--Ethan
From a "what's best" perspective, in my experience the best room measurement system you can get is Bob Hodas running his Sim System II.
A good calibrated mic is pretty much the heart of the system. For quick and dirty stuff I use the cheapo behringer, but when we want to get really technical for stuff like speaker measurements outdoors and away from any interfering objects PJ brings out his calibrated B&K instrumentation mic with the 1/8" capsule. That's the most expensive part of the rig, we use ETF and an old Extigy external card on an old Toshiba laptop for the rest of the rig. We decided to stick with this after comparing the results with Bob Hodas' SIM system and finding the results were very close. Don't get me wrong, the SIM system is far more thorough a measurement system. But our response curves with ETF and the B&K mic were close enough to the SIM that we could compare results and draw similar conclusions. Well, and I must clarify that "we" means PJ. Having an acoustical engineer with 35 years of measurement experience in the company makes analysis of the data a lot more productive. I think that is where a lot of folks run into trouble. Knowing how to read the data is not as simple as it looks on the surface.
A good calibrated mic is pretty much the heart of the system. For quick and dirty stuff I use the cheapo behringer, but when we want to get really technical for stuff like speaker measurements outdoors and away from any interfering objects PJ brings out his calibrated B&K instrumentation mic with the 1/8" capsule. That's the most expensive part of the rig, we use ETF and an old Extigy external card on an old Toshiba laptop for the rest of the rig. We decided to stick with this after comparing the results with Bob Hodas' SIM system and finding the results were very close. Don't get me wrong, the SIM system is far more thorough a measurement system. But our response curves with ETF and the B&K mic were close enough to the SIM that we could compare results and draw similar conclusions. Well, and I must clarify that "we" means PJ. Having an acoustical engineer with 35 years of measurement experience in the company makes analysis of the data a lot more productive. I think that is where a lot of folks run into trouble. Knowing how to read the data is not as simple as it looks on the surface.
The time spent with Bob in our studio was the best investment we could ever have done!
I've been using AudioTools on my iPad recreationally with the iPad's internal microphone. (You can buy a $400 external attachment, which is a bit out of my price range). It works reasonably well, and I assume if I had a good mic, it would work very well. The main problem is that the iPad has what amounts to a lowpass filter, so getting accurate bass measurements with the internal mic is essentially impossible. You can buy various in-app plug-ins, like an fft module. I diagnosed a problematic amp board that came with my DIY amp kit using this thing. I thought I could hear distortion, but the oscilloscope trace of test-tones, combined with the fft, took the guess-work out of it.
Here are a couple of graphs showing the results of moving the speakers a few inches. Done with REW software and a RS SPL meter.
Notice the difference in the peak at 40Hz and the null following.
Notice the difference in the peak at 40Hz and the null following.
I use a Behringer ECM8000 and a M-Audio Fast Track MK2 and it works great (I do wish I had gotten a calibrated ECM8000 though).
to the guys using a laptop and REW, do you use external soundcard as the REW website suggest?
or do you find your laptop's mic input reliable enough. They suggested to use external soundcard because the gain of the mic input of most laptops is generally too high for this purpose.
I have downloaded the REW software, have a Radioshack soundmeter and a calibration mic (came in with my Copland DRC 205) already.. I will probably rig something (a light with adjustable body) to serve as a mic stand.
or do you find your laptop's mic input reliable enough. They suggested to use external soundcard because the gain of the mic input of most laptops is generally too high for this purpose.
I have downloaded the REW software, have a Radioshack soundmeter and a calibration mic (came in with my Copland DRC 205) already.. I will probably rig something (a light with adjustable body) to serve as a mic stand.
Post calibration with REW my laptop has ruler flat response -- certainly far better than the mic and the room
Before it, it had a strong low frequency roll off which the calibration nicely inverted.Yes, it is an issue but I manged to work around it using the gain controls in mine.
It is pretty easy to use the calibration routine to see how far off it is.
Anyone with experience with AudioTools from Studio Six Digital and their new mic?
http://www.studiosixdigital.com/audiotools.html
http://www.studiosixdigital.com/audiotools.html
I have been using REW with an external E-MU's Tracker Pre USB 2.0 and a Behringer ECM8000. I have recently made cross calibration between 5 ECM8000 samples bought along 3 years and 4 of them were flat within +/- 1.5 dB between 30 and 10000 kHz, the black sheep was -4dB at 30 Hz.
The ECM8000 support can be easily fixed to an inexpensive camera stand, that allows much more consistent positioning than the usual microphone stands. The screw standards of microphones and cameras are different, but you can insert an expansion bush in the micro support and use a common screw with a washer to fix it.
Exploring this stuff for the first time. The E-MU device isn't cheap. Is this necessary? How else might one connect the mic? Presumably the software must send test tones through the system - how are people connecting their computers to their audio gear? I was looking at REW. I use a Mac and I note the system requirements for REW:
"Midi communication (used to set filters on Behringer BFD Pro DSP1124P and FBQ2496 equalisers) is supported on Windows platforms. Linux platforms will require Tritonus to support Midi comms. Mac OS X platforms with J2SE V5.0 installed should support Midi but don't appear to, for Midi support use the Mandolane Midi SPI."
If one isn't using these equalisers is this necessary? The link to the Mandolane website doesn't seem to work anymore.
Mics should be omni-directional?
"Midi communication (used to set filters on Behringer BFD Pro DSP1124P and FBQ2496 equalisers) is supported on Windows platforms. Linux platforms will require Tritonus to support Midi comms. Mac OS X platforms with J2SE V5.0 installed should support Midi but don't appear to, for Midi support use the Mandolane Midi SPI."
If one isn't using these equalisers is this necessary? The link to the Mandolane website doesn't seem to work anymore.
Mics should be omni-directional?
I use a $100 m-audio USB interface (though not with REW; I use a different SW program). Most measurement mics are condensers and require phantom power (high DC voltage) that a typical built-in card (and many external cards) do not supply. I use the line out of my built-in soundcard in one PC and a $50 outboard sound card for my old notebook (the built-in card does not have the features needed; virtually every built-in sound card in the past few years will work fine -- my notebook is pretty old!)
Most measurement mics are omnis as it is much easier to get flat frequency response.
The MIDI communication is only if you are using REW to program the filters; you don't need it (or the Behringer units) to take measurements. Just a mic and preamp, plus cables to run from your sound card to the preamp/amp/AVR/whatever.
Most measurement mics are omnis as it is much easier to get flat frequency response.
The MIDI communication is only if you are using REW to program the filters; you don't need it (or the Behringer units) to take measurements. Just a mic and preamp, plus cables to run from your sound card to the preamp/amp/AVR/whatever.
I use my laptop analog input. I did run it through REW calibration which found it to have a low frequency roll off and now compensates for it. With that in there, I measured ruler flat response (I use digital USB out for signal generation). I find that is more than good enough for dialing out low frequency bumps which should be the main use for REW.
Oops. Looks like I had given the same answer on the previous page! Perils of responding to old threads....
Perils of responding to old threads....
The E-MU tracker PRE has several conveniences that IMHO are worth paying for - it has 48V phantom power for the ECM8000, balanced inputs and a potentiometer volume control with a decent scale. Also it has two line inputs and two line outputs - enough to carry tests of your electronics, when you are done with the acoustics.
I am using it with a 2m USB cable, the 5m long XLR microphone cable is not directly connected to the computer, but to the EMU box - something you and your computer will appreciate when someone or you stumbles on it.Also it was tested by Spectraplus:
www.spectrasoft.jp/fft/soundcards/EMUTrackerPre_testreport.pdf
BTW, just found they are now recommending the Roland UA55 Quad Capture USB 2.0
http://www.spectraplus.com/Hardware.htm
thanks gents - does the cheaper cousin work fine? (Perhaps this is what DOn is referring to.) http://www.amazon.co.uk/Avid-Record...SWUG/ref=sr_1_2?ie=UTF8&qid=1349295276&sr=8-2
I've still got to pay for the acoustic treatments, Dirac Live etc etc
I've still got to pay for the acoustic treatments, Dirac Live etc etc
You need phantom power for the measurement mic and that one doesn't seem to have it but the one that Bruce suggested does. You can get an external injector but probably best to get it in the pre-amp if you can.
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