Hi, In Broadcast, the downmix from a stereo source to a mono destination was often done with a phase shift of 90 degree in one channel. However, if I understood correctly, your source is already mono but recorded in stereo with the phase inverted in one channel. Then, the way to go would be to extract only one channel as Claus suggested. I do not see a way of inverting the phase without decoding.
Regards, Alexander CB Maillist wrote: > Just adding the channels (even with the phases right) won't necessarily > work. If the stylus has been just slightly turned/twisted adding the > channels will phase out frequencies matching wave length (or harmonics) > of the length of the stylus L/R-track difference. In this case you may > be better of just preserving on channel as the mono signal. > > Just FYI > > mvh > Claus Bruun > > > > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of G. Vincent > Castellano > Sent: 9. januar 2004 18:58 > To: [EMAIL PROTECTED] > Subject: [mp3encoder] Inverting phase in an MP3 file > > > I need to find a way to invert the phase on a single channel of an MP3 > file. I've not seen any utilities that perform this, and I know enough > to do this with sox, except I've been assured that re-encoding MP3s is a > Bad Thing. I'd be willing to > hack the lame source if someone knowledgeable said this was > a feasible approach. > > Any suggestions would be welcome. > > Background for those who might wonder how I came to this turn: I've been > digitizing my album collection, and after about 750 disks, decided to > save a bit of space by downsampling a couple of monaural disks to single > channel. This turned out to be > a great way to remove the signal and leave me with a recording of mostly > surface noise. On headphones or even computer speakers, I could live > with bad phasing, but someday I hope to hook this up to a real stereo > and I'd like to get this right. Flipping the phase on the sound card > output won't cut it either, as I also have a lot of ripped CDs for which > the phasing is of course correct. I think the guys who sold me the > turntable must have wired the cartridge wrong--I would administer a > dope-slap except that I've got several test albums and never applied > them. I've even seen the phase inversion while looking at .WAVs in snd, > but it never occurred to me what was happening. --gvc > -- dipl. ing. alexander lerch zplane.development http://www.zplane.de holsteinische str. 39-42 D-12161 berlin fon: +49.30.854 09 15.0 fax: +49.30.854 09 15.5 _______________________________________________ mp3encoder mailing list [EMAIL PROTECTED] http://minnie.tuhs.org/mailman/listinfo/mp3encoder
