On a different note. Log sine sweeps.. Yes and no.. it's all depending on too many factors to tell you like this. First off.. if you were to check ex 1 2 5 10 20 50 100 200 500 you're leaving too much space in your measurements.. you will loose a lot of the details you need to take a good hard look at. Generally i use a noise source that contains everything and took snapshots of the screen for future reference. Whether for a large sound system in a hall etc.. or for studios we generally do it using a noise generator and a calibrated high performance microphone. Again .. acting in real time and taking action while you're looking at the screen ( setting filters delays etc ) is the conventional way.You're talking studio.. but then again .. depending on what you see. you may not want at all to treat the signal .. but to treat the room in itself. Ex .. Using bass traps .. they can be tubes.. they can be cavities within the walls etc etc Big huge problems with the room have to be corrected for what it is . The room is at fault.. fix the room :) It's a complex mix.. there's tons of opinions out there and they all have ins and outs. You will have to make experimentation and find what's best for your particular application. This being said.. pizza calls :) Ric ( the smiley guy ;) On Fri, 23 Apr 2004 22:19:03 +0200 mrtn <martin(a)nadir.org> wrote: