Topic: ISO: 1. EQ analysis and adjustment, 2. RMAA or similar for ASIO devices

[illconditioned]

I'm looking for two pieces of software:

1. EQ analysis and adjustment.  I'm looking for something that can take a calibrated recording (ie., pink noise run through a PA), measure the sound in the room and spit out a set of EQ measurements.  Then I want to apply the inverse of these coefficients to correct a second file recorded from the same room.  Something that would do 30 band (aka 1/3 octave) EQ would be great.  This would also be useful to fix mics with poor/variable frequency response.

2. I'm looking for something like RightMark (RMAA) that works with ASIO devices.  I want to test various cards, and also use this as a (quick) way to test preamps or other gear (by including it in the loopback chain).

Thanks for any pointers.

  Richard

[nickee]

Hi!

1/  Have you heard about Har-bal (http://www.har-bal.com/)? It's been a few years since I used it but it is very easy to correct offending frequencies with it. It is more visual than normal equalizers.

[Church-Audio]

I'm looking for two pieces of software:

1. EQ analysis and adjustment.  I'm looking for something that can take a calibrated recording (ie., pink noise run through a PA), measure the sound in the room and spit out a set of EQ measurements.  Then I want to apply the inverse of these coefficients to correct a second file recorded from the same room.  Something that would do 30 band (aka 1/3 octave) EQ would be great.  This would also be useful to fix mics with poor/variable frequency response.

2. I'm looking for something like RightMark (RMAA) that works with ASIO devices.  I want to test various cards, and also use this as a (quick) way to test preamps or other gear (by including it in the loopback chain).

Thanks for any pointers.

  Richard

There is no software that does that with out hardware. The software that will do it is smaart v6. My Winaudio mls lab version will do it but I need eq plugin's and alot of time to figure it out but it will not do it in real time, Smaart will but only through midi and using external eq processors... In theory your idea sounds interesting but the main problem is time. Location of the test mic must be in the same exact spot where the recording was done. And you must use the same mics That way you get the same transfer function - minus the music. The other main issue is the fact that the "house" eq has most likly changed between now and when you did your recording. So your probably out of luck if you want to be able to get it right. The other main issues is temp and humidity and lets not forget people. All of these things will make your measurements meaningless if your not able to recreate them.


The best way to be able to pull this off is to use a burst of pink noise at the beginning of the performance with the same mics and use the same recorder to capture the pink noise, then analyze the pink noise in the beginning of the performance. But in order for this to work you must be able to have microphones with a calibrated frequency response that can be subtracted from your measurements. That way your getting the room + pink noise + pa system transfer function. Because the room stays the same and the pa for the most part stays the same you should be close to the ball park. But there is one last problem to overcome.. you will not be able to take into consideration the effect of the live performance "stage bleed" from your measurements so you will not be able to recreate the night exactly as it was. But you will be able to recreate the effect of the Pa system from your mics.
Chris

[Gutbucket]

Richard,

You may take a look at some advanced eq plugins targeted at mastering.  The Voxengo Curve EQ may be able to do something like you mention.  It is a linear phase eq that displays both the input and output FFT spectrum.  I believe it has an invert eq curve function, though it's been awhile since I played with the demo (which seemed nicely transparent and worked very well for my recordings BTW, I'll probably purchase a copy).  It has a couple additional features that may apply to what you are trying to achieve which I did not experiment with but sounded interesting.  I just copied the blurb below from the site linked above:

Besides the aforementioned features, Voxengo CurveEQ implements SpectruMatch spectrum matching technology that allows you to perfectly transfer a spectrum's slope from one recording to another.  This allows you to `copy' a frequency balance of existing mixes so that other mixes that are still in the works will sound better.  This technology also greatly helps in music disc mastering, since using it allows you to easily lessen any dramatic differences in the area of frequency balance between various tracks.

GearMatch technology allows you to transfer impulse responses of high-end analog audio gear to your digital audio, while allowing you to adjust frequency response freely.

Sounds similar.  Not sure if it allows for capturing and applying the inverse of the response.  In any case, the developer is quite responsive to questions posed on his message board and was quite helpful when I was looking for a tool to make a constant phase shift across all frequencies.  Worth a look.  If something like that doesn't work you may need to venture into the more arcane world of impulse response capture and manipulation or more involved professional tools like the analysis stuff Chris mentions or dedicated FOH balancing EQ tools with measurement capabilities, all of which are out of my league. 

Though I have no direct experience with this, I'd also stress Chris's points about an strong requirement to use the same mics, absolute mic position and house eq settings to get anything like decent results with this type of manipulation.