On Mon, Aug 08, 2005 at 04:39:32PM -0500, Andres Cabrera wrote: > Just tried it, and it looks very cool. Could you explain how a room can > be tuned using japa, or point to some reference for this?
You can use JAPA as the analyser when equalising a sound system. This is not exactly 'tuning a room', it's more making sure that the combination of speakers and room have approximately a flat response. Real room tuning requires more advanced and complicated techniques, and for these you could have a look at the combination of DRC and BruteFIR. To do the equalisation, you need a pink noise source (future version will have this built in), an equaliser (1/3 octave bands or parametric), and a measurement microphone. The setup is like this: pink noise --> equaliser --> speaker system microphone --> preamp --> japa For this application (and for all noise measurements) you need the 'slow' speed setting. The frequency response should be set to 'Prop'ortional, to give a flat trace with pink noise. First make sure levels etc. are OK, then try to obtain a flat response by adjusting the equaliser. In most cases the best results are obtained by setting a response that is not really flat, but drops of gently above 1 kHz, to something between -5 and -10 dB at 10 kHz. Trying to compensate for a deep 'holes' in the response (*) is usually a bad idea - better try to remove the most prominent peaks. (*) a broad response dip near the speaker crossover frequency usually means that the relative phase of the LF and HF speakers is wrong. Most synthesis programs (AMS, SC3, PD, Csound, ...) will provide pink noise. -- FA
