Xref: utzoo rec.audio:8721 sci.electronics:4148 Path: utzoo!yunexus!geac!syntron!jtsv16!uunet!steinmetz!heller From: heller@steinmetz.ge.com (aaron j heller) Newsgroups: rec.audio,sci.electronics Subject: Re: Extracting Mono from Stereo Keywords: mono stereo signal processing Message-ID: <12406@steinmetz.ge.com> Date: 24 Oct 88 21:09:28 GMT Article-I.D.: steinmet.12406 References: <341@ivucsb.UUCP> <343@ivucsb.UUCP> Reply-To: heller@kbsvax.steinmetz.UUCP (aaron j heller) Organization: General Electric CRD, Schenectady, NY Lines: 36 In article <343@ivucsb.UUCP> todd@ivucsb.UUCP (Todd Day ) writes: >In article <341@ivucsb.UUCP> I (Todd Day) write: >_I want to use a DSP chip to extract mono from stereo. Does anybody >_know of any algorithms to accomplish this or can anyone direct me to >_any literature that might describe this? >_ >OK, guys, how about reading past the second paragraph? Since I only >just posted this yesterday and got a couple of smart-aleck responses >already, maybe I should clarify... > >Let's say the stuff in the left channel is L+0.5M (stuff that is not in >the center + half of the stuff that is in the center (mono)). Right >channel is R+0.5M. Now, I want just M. If you add both channels together, >you get R+L+M. I want just M. Subtracting the two channels gives you >R-L. Subtracting the difference from the summation gives 2L+M. I want >just M. > > >Your smart-aleck answers are not appreciated. I won't summarize these. :-) I hope you don't consider this a ``smart-aleck'' answer, but have you taken a linear algebra or information theory course recently? Your problem, in a slightly different form, is that you want to take three channels of information, namely L, R and M; transmit them on two channels as L+M and R+M, and then completely separate them back into L, R and M. This reminds me alot of the SQ matrix system for quad and the DSP stuff you are thinking about whould be very much like the logic steering circuitry that was in these decoders. If you have any success at this, there are many people who would be very interested in it. Aaron Heller (heller@ge-crd.arpa uunet!steinmetz!heller)