John Sayers' Recording Studio Design Forum Archive

So far I have been measuring with the microphone included with IK multimedia Arc. What I read about that was it is calibrated differently and rolls off in the highs. Up to this point that was decent enough IMO, as I only cared for rough bass treatment. But now, when it comes to the details, I want to buy something better.
According to Radio shack, you can buy an SPL meter with integrated mic or a USB mic where a calibration file exists. But I assume a standard calibration file for a mic brand is not really honest, as calibration would have to be done for each individual mic. Do you agree?
The top of the line in Germany is from NTI, but I actually hope not to spend that much and still get something decent (+/- 1 db precision).
However, I could borough this set for a few days from friend. Maybe it helps for calibration?
http://www.thomann.de/de/nti_audio_exel ... _m4260.htm
Then there is another mic from NTI, which would be more within my price range! But I would need an additional SPL meter and I wouldn't want to spend a lot more than that.
http://www.thomann.de/de/nti_mini_spl.h ... wgodh0ILHw
As I find it attractive to be able to do some measurements without REW, I tend more an SPL meter with some other functions, like this one (Phonic PAA3):
http://www.thomann.de/de/phonic_paa3_pe ... istant.htm
But I am not sure, whether the mic is good enough for usage with REW. It can however send the signal to PC via USB.

What do you guys use and what would you recommend? I will be using this equipment only for my own studio build, which I hope to finally become decent! But it's not going to be perfect, as it is to small for a stellar studio. So, my thought was about +/- 1 db of accuracy, as I aim towards +/- 5 dB linearity in the mixing room. Does that sound good to you? How much would you spend on that? Any other tips for equipment?

Oh, I just found out, the Phonic is 1/3 Octave scale, so not good for measuring small rooms ...

But I assume a standard calibration file for a mic brand is not really honest, as calibration would have to be done for each individual mic. Do you agree?

That is true, yes, but the differences between individual mic's probably won't be huge. Unless you are doing high precision work in high-end rooms, it probably isn't going to be a big problem.

What do you guys use and what would you recommend?

I use three mics and an audio analyzer for acoustic testing. I have a Behringer ECM8000 that I use for rough measurements, low precision measurements, or in places where it might get damaged (construction sites, for example). I have a PreSonus PRM1 for higher precision work in cleaner places. This is the one I use most for room testing and calibration. I have a Dayton iMM6 as well, for use with smart-phones, and I also have a Phonic PAA-3, which I use mostly as a stand-alone tool, not as a reference mic.

As I find it attractive to be able to do some measurements without REW, I tend more an SPL meter with some other functions, like this one (Phonic PAA3)

That's what I use all the time, for all types of measurements, but not as a mic for REW.

But I am not sure, whether the mic is good enough for usage with REW.

As I mentioned, I've never tried using it like that, and as far as I know, there is no way to do that! The XLR output connector on the bottom is a balanced line-out for sending the test tones and test signals to your console or speakers.

It can however send the signal to PC via USB.

No. The PAA3 does not send the mic signal to your computer via USB. It only sends data, such as whatever you have stored in memory and the real-time sounbd level reading and 31-band spectrum information.

Oh, I just found out, the Phonic is 1/3 Octave scale, so not good for measuring small rooms ...

It works fine for most cases, and the overall sound level meter reading is just as accurate as any other meter I have used. More so, in fact. Maybe you didn't understand the adverting: the PAA3 is an excellent sound level meter THAT ALSO can be used as a 31-band spectrum analyzer. If you only look at the sound level, then it works like any other sound level meter, but you also have the huge advantage that you can also look at the individual level of each frequency band, IN ADDITION to just looking at the overall levels. So it is far more useful and far more accurate than an plain sound level meter.

That's why I use both my PAA3 and also my PRM1.

Those are plenty good enough for studio calibration and tuning.

- Stuart -

Thanks, Stuart! That helps a lot!
I am now thinking about getting exactly the same pair. One last thought: when I get a mic without phantom power via battery, I am forced to use one of my recording preamps. I am not sure, how clean they are, as they are prolly tuned to sound good vs. sounding flat, which is not always the same thing.
Now, there is a way to calibrate your DA converter by plugging its output into its input and running the test in REW. Would you do the same including the preamp in the chain? Or is that not as relevant as I think?
Oh, and the SPL would still be necessary to have for good precision, as I would need to compare the SPL level with REW and adjust, right? Or is there another way to do that without SPL meter?
How precise is the Dayton mic with a smartphone vs. buying the phonic meter? And which App(s) are good? I have an old iPhone 4.

calibrate your DA converter by plugging its output into its input and running the test in REW. Would you do the same including the preamp in the chain?

Correct! Always do the calibration in REW using the complete signal chain that you would use for the test itself, as much as possible. So if you are going to use a mic-pre of unknown characteristics, then make sure that is in the chain too....

as I would need to compare the SPL level with REW and adjust, right?

Correct! There's a procedure for calibrating REW to an external meter, and you definitely should do that, to make sure that the graphs are reflecting real levels.

How precise is the Dayton mic with a smartphone vs. buying the phonic meter?

It's much better than using the built-in mic on the smart-phone, but still not as good as the PAA3, which was specifically designed from the ground up as a precision acoustic measurement device. I have compared the PAA3 reading to my Android+iMM6 readings, and mostly they are similar, but every now and then I do see discrepancies.

And which App(s) are good? I have an old iPhone 4.

I use "AudioTool", which is not free: you have to pay for it. It's not expensive though, and well worth it. I'm not sure if it is available for iPhones... I use it on my Samsung Android phones, and it is pretty good.

- Stuart -

Audio tools by Andrew smith? Yes, it's available on the App Store as well. It is 20€ plus 170€ for additional modules and pro upgrades of module (e.g. SPL pro). I guess, I won't need those extras, though. uhhh ....! Choices, choices ... hate them!
But I am way better off deciding thanks to your hints, now!

Why not take a mini computer with a small interface and ARTA?
I use a small Samsung netbook or whatever it's called with an oversized battery. It runs for 8 or 9 hours.
I have a UA 25 interface and a B&K 4007 microphone. I also have a homemade mic (some panasonic capsule) and I have worked with ECM 8000 mics.
As long as the mic is not used for extreme levels (over 120 dB) a calibrated (= talking chique for comparing to the B&K) Behringer is just as good, even for "high end rooms" . You can even do very long LEQ stuff and at the same time recording noise with f.e. Cool edit to see where your measurement is corrupted by external noise.
You have a small setup for € 400,- and can do more than with B&K or RION stuff. I have a calibrated measurement SLM for official measurements, but only to satisfy the requirements of the autorataaz

Soundman2020 wrote:

But I assume a standard calibration file for a mic brand is not really honest, as calibration would have to be done for each individual mic. Do you agree?

That is true, yes, but the differences between individual mic's probably won't be huge. Unless you are doing high precision work in high-end rooms, it probably isn't going to be a big problem.

Hey Stuart! I got the Phonic and the Presonus PRM1 now. I set up everything and the calibration of soundcard and preamp seems to have worked well (I did the test and it was a flat line). However, I did not find any calibration files for the PRM1 in the REW download area ... I found out, you can make your own calibration file with freqency response graphs coming from the manufacturer, but there is also no detailed graph included by presonus, only a rough one, where you cant really read numbers. So, are you using the PRM1 without mic calibration or have you done a professional calibration of the individual mic? Or is there a typical off-self calibration file for the PRM1 I simply didn't find on the internet?

@Bert: Thanks for the hint, but I had already ordered, when I read your message!

So, are you using the PRM1 without mic calibration or have you done a professional calibration of the individual mic?

I don't use a calibration file for my PRM1. For the type of work I use it for, it isn't that critical. One day I will get it calibrated properly, but for now it is quite accurate enough for what I need.

- Stuart -

Hi

Did anyone make a calibration file for the Presonus Mic please?
Im in desperate need.
Thanks

Hi Chris,
in my opinion, in order to get reliable measures a mic requires its own calibration file. Two similar mics (same brand and model) have different frequency responses, even though in the majority of the cases there are not so wide differences for a low-fi use.
However, my suggestion is to calibrate your mic in order to get its own calibration file or buying a calibrated microphone.

Best.
D.