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Old 3rd July 2005, 06:53 PM   #1
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Default Phantom Rear Center ??

Can i connect a speaker to the rear by connecting wires from positives from each speaker to the phantom rear center.

That is one wire from the positive terminal of the left rear to the positive input of the virtual rear;
and one wire from the positive terminal of the right rear to the negative input of the virtual rear.
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Old 3rd July 2005, 09:27 PM   #2
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Daftest thing I've heard in ages.

Connecting two postives together, always ends in tears. Try it for any legnth of time and say goodbye to the amp if it doesn't have decent protection. What your doing here is called a short circuit

A rear center needs a descrete channel assignment/signal and amplifier to be of any use. To do it any otherway would be counterproductive to decent surround and to do it via taking the signal for the stereo rears really doesn't do anything but potentially damage your equipment and listening experience.
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Old 4th July 2005, 04:47 PM   #3
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I've heard of people using an old pro-logic receiver to retrieve the rear channel from ex soundtracks - plug the left and right rear pre-outputs into the receiver, and use the left, centre and right outputs.... - only works on non-discrete stuff though... The good thing is you get amplifiers thrown in with the receiver...

Rob
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Old 17th June 2011, 07:12 PM   #4
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Quote:
Originally Posted by ShinOBIWAN View Post


Daftest thing I've heard in ages.

Connecting two postives together, always ends in tears. Try it for any legnth of time and say goodbye to the amp if it doesn't have decent protection. What your doing here is called a short circuit

A rear center needs a descrete channel assignment/signal and amplifier to be of any use. To do it any otherway would be counterproductive to decent surround and to do it via taking the signal for the stereo rears really doesn't do anything but potentially damage your equipment and listening experience.
Old thread, but wanted to correct this Hogwash post.

What the OP asks is indeed possible with most solid state amps. Just watch that the impedance of the combine 3 speaker load is acceptable (usually is, especially if you use two extra speakers wired in series vs one). This is in fact the basis of Hafler matrix surround when derived from the L & R stereo output instead of the surround channels. The only difference is that in this case you are sending the difference of the surround channels (Ls-Rs) to the back speaker(s) instead of the difference of the 2 channel stereo feed (L-R).
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Old 17th June 2011, 08:59 PM   #5
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Ahhhhh - the original poster suggested connecting the + terminal of one rear speaker through the center speaker to the + terminal of the other rear speaker. I would submit that this particular arraignment would produce no sound in the rear center speaker because at no time would that speaker see a difference in voltage accross it. Gutbucket?
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Old 18th June 2011, 10:57 PM   #6
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That is true only if the signal in the surround channels is identical. In that case there will be no fluxuating voltage difference between the postive terminals of the two surround speakers, so no current will flow across the limited resistance of the extra speaker's voice coil and no electromagnetic force will be produced to interact with the anchored permanent magnet, so no motion will be transfered to the attached cone to compress and rareify air for a human to hear and interperate as sound.

However, if the signals to the two surround channels are not identical*, there will be a varying voltage difference between the two positive terminals, and current will flow.. and not through a short circuit as claimed previously, but through the imedance of the additional speaker, ultimately producing sound.

This is simply a direct way of producing the 'difference' or 'side' signal (in Mid/Side terminology) from a Left/Right stereo signal.. or in this case a LsRs signal.

*BTW, sound will even be produced with mono surround material if the signal level to each side is different. The bigger that balance difference, the louder the sound produced by the extra speaker, which will be the same mono information.
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Old 18th June 2011, 11:57 PM   #7
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Hafler/1970...
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