Audacity Forum

Hi. I want to make an 'audacity EQ curve file' for calibrating audio files for use with my 'Aker MR2700' portable speaker.

I want to do this by playing pink noise through my speaker and tweaking the equalizer until I get a pretty flat spectrum shown on my Spectrum Analyzer. I am using a freeware program called jDFT to do a real-time spectrum analysis from my USB microphone (Samson Go Mic in omnidirectional mode; I know it probably isn't as good as dedicated measuring microphones however I personally find it's response to be pretty flat).

With Adobe Soundbooth CS5 I've successfully done this through a 30-band equalizer and attaching 7 additional parametic equalizer effects to my soundfile. The difference it made on my music files was amazing; it turned the audio from sounding like it came from a tin can to a very solid response above 140hz (every freq below it was tightly cut due to speaker limitations).
Screenshot: http://oi49.tinypic.com/2pyoy0j.jpg

However, now it's time that I create a portable audacity EQ curve file that will give me the same effect. However with the built-in "Equalizer" plugin, I found it to be a real pain to use due to the fact that the previewing cannot be done in real time at the same time as the equalizer drawing graph is not aligned with jDFT's graph (I know there's graphic eq mode, but it didn't seem much easier and I know I'll be also needing a few notch filters on top of equalization like what "draw curves" can do).
Screenshot: http://oi46.tinypic.com/24ky2rs.jpg

How can I do this process more efficiently?

Audacity is a post production editor. Everything happens slowly, later, in unreal time.

We can add your name to the Feature Request List for real time equalization. Koz

But is there any alternative ways for me to do what I want done efficiently for now, even if it involves using a 3rd party program to build/generate the 'audacity eq curve' file?

I posted an experimental plug-in for Audacity that can help you to do this. See this topic: http://forum.audacityteam.org/viewtopic ... 20&t=70531
As it is an "experimental" plug-in, it is not very user friendly (in fact, not at all user friendly). Most of the details should be in that topic, but feel free to ask if you need help with it.

I am not very familiar with this kind of analysis so please excuse my stupid questions.
What exactly do you want the EQ-curve for?
Am I assuming right that you want to post-process Audio in order to get a flat response from your speakers?
Shouldn't that be rather a pre-soundcard Equalizer which is automatically fitted to your speakers response?

I only wanna point out that a lot is possible with Audacity, as long as it doesn't involve real time operations.
We could readily enough write a Nyquist plug-in that suits your needs.
For example:
You could generate Pink noise or a Sweep/chirp tone. You would then record the output from your speakers in a second track.
The power spectra of those tracks can afterwards be compared within a Nyquist plug-in.
The differences should yield the cut/boost factors for your chosen bands. The output could be exported as coefficients for a FFT-/LPC filter or as XML-file for the Equalizer effect. In the later case you might be somewhat restricted by the available bands.
It may be better to store the gained coefficients permanently in a secondary plug-in which filters your audio in future by a single keystroke.

Robert J. H. wrote: What exactly do you want the EQ-curve for?
Am I assuming right that you want to post-process Audio in order to get a flat response from your speakers?
Shouldn't that be rather a pre-soundcard Equalizer which is automatically fitted to your speakers response?

Yes, I want to post-process my MP3 files to be fitted with my speaker's response. As I said above, I've successfully done this manually with Adobe Soundbooth CS5 (and jDFT) using a combination of a 30-band equalizer and 7 different parametric equalizers, and it made an incredible difference to the sound. The processed MP3s will then be stored onto my USB drive, as the portable speaker has a USB port and plays directly from them.

I'm curious, what do you mean by a pre-soundcard equalizer that is automatically fitted to the speaker's response; a hardware 10/20/30-band equalizer that goes between the soundcard output and speaker, an automatically calibrating hardware equalizer, or what? Can you tell me some example model numbers of such hardware?

steve wrote:I posted an experimental plug-in for Audacity that can help you to do this. See this topic: http://forum.audacityteam.org/viewtopic ... 20&t=70531
As it is an "experimental" plug-in, it is not very user friendly.

Looking at the description for the plugin, it looks like it'll be PERFECT one for me. I'll give it a try when I have some time later today, thanks!

I didn't have any special equalizer in mind. In any case, it would have make sense but in connection with a computer and it seems that you have a combi device.
Let us know how you get along with Steve's plug-in.
By the way, are the results from your spectrum analyzer comparable with the spectrum view/plot in Audacity? with