KVR Audio

tarsonis · Post by **tarsonis** » Sun Sep 28, 2014 2:14 am

Hi,

anyone knows a EQ plugin that can read ASCII (text) microphone calibration files and process it in real time?
Maybe its possible to write such plugin?

hope for help. goolge wasnt helpfull

Ivan_C · Post by **Ivan_C** » Sun Sep 28, 2014 11:19 am

What is a ASCII microphone calibration text file ? What does it contain ?

tarsonis · Post by **tarsonis** » Sun Sep 28, 2014 1:37 pm

Its an file which holds the deviation of a mic from flat measuring. Its mostly used in room correction software. Its basiclly a text file with frequency and its amplitude deviation from 0db. Sometimes even more, like Phase...Here an example:
(I shortened it. Actually it goes from 10 to 22000hz and its damn long.)

Code: Select all

Level dBrResolution = 1/1 octave
Numpoints = 720
SamplingRate = 48000 Hz
Frequency(Hz) Magnitude(dB)
10.00	-18.48
10.59	-17.95
11.22	-17.47
11.89	-16.32
12.59	-15.02
13.34	-13.82
14.13	-12.43
14.96	-10.74
15.85	-9.24	
16.79	-7.92	
17.78	-6.51	
18.84	-5.30	
19.95	-4.28	
21.13	-3.29	
22.39	-2.38
23.71	-1.60	
25.12	-0.88	
26.61	-0.41	
28.18	0.04	
29.85	0.39
31.62	0.62
33.50	0.83
35.48	1.01
37.58	1.13
39.81	1.19
42.17	1.22

I'm looking for a EQ vst/dx plugin that can read this for realtime processing. I know it could be emulated with any EQ plugin. But it wouldn't be acurate with shelving filters.

xh3rv · Post by **xh3rv** » Sun Sep 28, 2014 2:43 pm

(This might be a thread for a different subforum, dunno?)

Does any of this software offer conversion to impulse responses? If so that's worth looking in to.

tarsonis · Post by **tarsonis** » Sun Sep 28, 2014 3:00 pm

As this is really specific and one should know how filters mathematical will be caluculated in typical EQ plugins (which I barley know/understand the basics - now trying to learn), It think this is the most agreeing subforum.

You mean the room correction software? Well they calculate ETC, CSD plots through the impulse that your room creates. I think they only work with impulses. Your idea is to use a impulse response that has FR of the calibration file? May work but this would lead to a second problem. How do I convert a calibration info to an impulse.

So I would stay with a EQ solution as this is the most simple solution. Other possibilty. I would have to know how I can calcualte a shelving filter and the frequencey and gain stages it produces in a simple EQ, than I could come close to the calibration. WOuld be an alternative solution not acurate but it would come close

//EDIT:
Here is the resulting FR from the cailbration file for the mic. The room measuring softwares out there take this file, calcute the fr, invert the calibration fr and then substract the calibration FR from the measurement resulting FR of you signal. Obviously to have a neutral representation of your room/signal without the mic flaws.

TB-ProAudio · Post by **TB-ProAudio** » Sun Sep 28, 2014 4:07 pm

well, sounds interesting.

Could you please point us to more examples and probably to the specification of the cal file format?
Thank you.

BTW: what is the use of such compensation. If i use Neumann, i want this sound or?

Regards
TBProAudio

random_id · Post by **random_id** » Sun Sep 28, 2014 4:34 pm

I have used files like this in the past, but it was for measurement purposes. I had a mic with a calibration file that I used with software to measure speaker responses. I was then able to design custom crossovers tailored to the specific response of the woofer, tweeter, etc.

Now that I am thinking about it, if you had the calibration file of your mic and the calibration file of the $$$$$ mic, could you correct your mic to sound like the expensive one?

Of course, there is more to a mic than frequency response (??????)

TB-ProAudio · Post by **TB-ProAudio** » Sun Sep 28, 2014 4:48 pm

well, you know it. Of course there is more

Nebula shows the direction for this kind of stuff, maybe V4 gives us true mic emulation.

regards
TBProAudio

tarsonis · Post by **tarsonis** » Sun Sep 28, 2014 5:04 pm

Well basiclly I want to be able to use a mic calibration in my DAW for realtime analyse and recording. That for I need a Filter/EQ plugin which can interpret this cal/ASCII frequency/gain information in the file.
If this is possible, I can for one thing measure/record flat signal in a daw and for another thing I can emulate mic X with mic Y.

Of course, there is more to a mic than frequency response (??????)

Yes Phase for example. But of course build typ which can't be really compensated but emulated. I don't need this.

Could you please point us to more examples and probably to the specification of the cal file format?
Thank you.

Here a cal file from my calibrated reference mic. The board attachment doesn't allow *.cal & *.txt files lol

You can open it with every text editor. I think its just a txt file renamed to cal anyway
http://www34.zippyshare.com/v/99947572/file.html

xh3rv · Post by **xh3rv** » Mon Sep 29, 2014 3:00 am

tarsonis wrote:How do I convert a calibration info to an impulse.

I thought maybe you had a specific program in use - it'd make sense for a program that's generating these files to also be able to read and generate equivalent IRs (well, more sense than a VST). From IRs it should be much easier to get into plug-ins - (not so familiar with Nebula but I'm sure as noted it's a great option to look at, or anything that does 'convolution'.)

tarsonis · Post by **tarsonis** » Wed Oct 01, 2014 7:15 pm

Thanks for the effort mate. Its of course an idea. But actually seems more complicated and failure intense than just have an EQ that sets gain for that specific frequency that is writen in the text file. Its so basic. Can't understand that no one came to the idea to have a cailbrated mic solution for ones daw.
I mean it isn't a nerdy idea to have his vocals record as best as possible for example. Seems that no one care that mics have fr responses like a cross mountain bike track. Excuse my bashing. I'm frusted that there seems no solution for this after days of research.

EQ that reads ASCII microphone calibration