Have you tested the crossovers with sine generator? No other effects than crossover, and the band outputs are mixed together. Whatever the frequency, the sine should come out without modification. The file "crossovers.tar.gz" at ftp://ftp.funet.fi/pub/sci/audio/devel/dsp/ has two papers on crossovers, and I have read a third paper. It looks like the crossovers may easily be implemented wrong. May not be useful but I found these docs on crossovers as well: http://www.linearx.com/files/pdf/FilterShopApp_06.pdf http://www.linearx.com/files/pdf/FilterShopApp_07.pdf Also, if other effect is inserted to a band and if it changes the sign of the signal, then crossover may stop working. The BBE Sound style delays in the bands should be very minimal so that the sign does not invert, I guess. Have you implemented the band delays yet? The original patent 4482866 has been expired, I'm sure. However, the patent deals with defects in the speakers. Mastering application is totally different because the output is stored to audiofile having no similar defects. What we are dealing now seems to be merely the psychoacoustics of the effect when high frequencies starts earlier than low frequencies. BTW, the paper John K. Hilliard, Notes on how phase and delay distortions affect the quality of speech, music and sound effects, IEEE Transaction on Audio, March-April 1964, pp. 23-25. describes the problem. Because they used horn type speakers back at 1920-40, the problem was more severe. I wonder if it makes the solution really that different when now in the solution the air delay is replaced with digital delay. In my opinion, the invention is the introduction of different delays to the bands, and different implementations (digital or not) are just embodiments of the invention. But as said, the system as a psychoacoustics effect is different. Prior the patent at 1982, the psychoacoustics effect was known, but I don't know when it was invented that the correction circuit could be used as an effect circuit (does it matter?). Could be after the 1982 patent. I would like to see the papers on the psychoacoustics itself -- perhaps the authors have written about the possible applications. Our relief is that the crossovers are now used as effects, not as something relating to speakers. It then makes sense to move all circuitry that are related to speakers to the effects genre, not only crossovers. Juhana -- http://music.columbia.edu/mailman/listinfo/linux-graphics-dev for developers of open source graphics software ------------------------------------------------------- The SF.Net email is sponsored by: Beat the post-holiday blues Get a FREE limited edition SourceForge.net t-shirt from ThinkGeek. It's fun and FREE -- well, almost....http://www.thinkgeek.com/sfshirt _______________________________________________ Jamin-devel mailing list Jamin-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/jamin-develReceived on Wed Jan 12 11:27:18 2005
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