tbrown@lehi3b15.csee.Lehigh.EDU (Thomas Brown [901015]) (04/03/91)
What is the best way to obtain a difference output (L-R) from separate L and R outputs (about 12W/channel) without damaging the power amplifier in the radio? If this is a problem, a sum output (L+R) would also be acceptable, but the difference output would enhance the overall stereo effect in the system. Regards, -Tom --=-- Thomas Brown, KA2UGQ BITNET: twb0@lehigh.bitnet Lehigh University UC Box 855 ARPA: tbrown@lehi3b15.csee.Lehigh.EDU Bethlehem, PA 18015 UUCP: ..!uunet!twb0@lehigh.bitnet (215) 758-0093 AX.25: ka2ugq@ka2ugq.nj.usa.na 'You can't have everything...where would you put it?' -S.W.
bks@shiva.Berkeley.EDU (Brian K. Shiratsuki) (04/09/91)
In article <1486@lehi3b15.csee.Lehigh.EDU> tbrown@lehi3b15.csee.Lehigh.EDU (Thomas Brown [901015]) writes: >What is the best way to obtain a difference output (L-R) from separate >L and R outputs (about 12W/channel) without damaging the power amplifier >in the radio? If this is a problem, a sum output (L+R) would also be >acceptable, but the difference output would enhance the overall stereo >effect in the system. the factory stereo in my car came with one center speaker in the front, and two on either side in the rear. i added two speakers on either side in the front, and run them with an outboard power amplifier. the center front speaker is disconnected (none of the factory speakers were Particularly Good), but i run the rear speakers in series and out of phase with the difference signal from the amplifier built into the radio. the way to do this is to disconnect the - sides of the two rear speakers from the radio, and connect them together. if the radio works with a common ground, you hear interesting ambience stuff from the rear. the fader on the radio works as an attenuator, but i like the effect full-blast. the radio has not been damaged at all by this, and i believe it would even be safe to run the rear speakers from the outboard amp. but then the inboard amp wouldn't have anything to do and i wouldn't have a built-in attenuator. i don't think that i would want the ambience stuff coming from the center middle. the idea for the arrangement came from the dyna company, maybe even from hafler. brian
bill@thd.tv.tek.com (William K. McFadden) (04/09/91)
In article <1486@lehi3b15.csee.Lehigh.EDU> tbrown@lehi3b15.csee.Lehigh.EDU (Thomas Brown [901015]) writes: >What is the best way to obtain a difference output (L-R) from separate >L and R outputs (about 12W/channel) without damaging the power amplifier >in the radio? If this is a problem, a sum output (L+R) would also be >acceptable, but the difference output would enhance the overall stereo >effect in the system. First, make sure the amplifier does not have a bridged output. Check with an ohmmeter to make sure the - speaker terminals are connected to ground. Most car radios work this way, but ones labelled "high power" usually have bridged outputs. If your radio does not have bridged outputs, connect the center speaker between the + speaker terminals of the radio. Tune the radio to a mono signal, and adjust the balance control for minimum output from the center speaker. I did this with my mom's car, and it worked great. Disclaimer: If you do this and it causes your radio to and catch fire, burning you and your passengers to death, don't come crying to me! -- Bill McFadden Tektronix, Inc. P.O. Box 500 MS 58-639 Beaverton, OR 97077 bill@videovax.tv.tek.com, {hplabs,uw-beaver,decvax}!tektronix!videovax!bill Phone: (503) 627-6920 "SCUD: Shoots Crooked, Usually Destroyed"