At 10.17 09/12/2003 +0100, you wrote:
Hello,
Apostolos Dimitromanolakis wrote:I would be interested in this project too. What I'm looking for is actuallay an anti-reverb that will be able to cancel reverbs in a listening room, well always in conjunction with the listener position.
Then I think DRC (digital room correction) is for you: http://freshmeat.net/projects/drc/ This works with bruteFIR http://www.ludd.luth.se/~torger/brutefir.html But I must confess: I have not understand how to use the result of drc in bruteFIR. For a reverb convolution I think only the first steps of the DRC process are necessary, but I haven't understand what to do there, too.
yep, you are right. To do the convolution between the measured sweep and the inverse filter to get the impulse response you can use brutefir (with a little trickery). I use it to do my own measurements with 45s log sweeps. The inverse filter is almost 2 millions taps, but brutefir eat it without esitation even with just 64 mb of RAM available. A truly wonderful piece of software!
And unfortunately the only DRC tutorial is for windows only :-(( And it doesn't explain the steps, it just shows them ...
Doing it under Linux is a bit more complicated. If you want I have some shell scripts that do all the steps needed to get the impulse response (sweep playing & recording + deconvolution). Anyway they are just a clumsy hack that I use myself for my measurements, don't expect any fancy interface. Despite this, thanks to the brutefir floating point accuracy and the long sweep used the results are state of the art (90+ dB of S/N even in a not so quiet environment with a dirty cheap panasonic WM-60A capsule and a DIY mic preamp).
The other useful thing would be a phase-filter to correct the phases coming out from a two or three way loudspeaker to get clarity in the sound similar to high-end speakers.
As far as I understand what DRC does, this is one of the postprocessing steps.
Exactly, it tries also to compensate for the room acoustic (part of, no miracle can be performed here).
Bye,
--
Denis Sbragion
InfoTecna
Tel: +39 0362 805396, Fax: +39 0362 805404
URL: http://www.infotecna.it