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"Center Channel" on 2-channel Receiver

Discussion in 'Solid State' started by gggvan, Feb 4, 2014.

  1. gggvan

    gggvan Well-Known Member

    Messages:
    948
    Location:
    Cohasset, MA
    I just hooked up my TV to my sx-1250 via RCA. The 2 speakers are pretty far apart, so certain dialogue can seem a bit faw away. Are there any tricks to adding a third speaker up front? Will it ever be the same or close as a true center?
     

     

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  2. transmaster

    transmaster AK Subscriber Subscriber

    Messages:
    8,170
    Location:
    Cheyenne, Wyoming
    Last edited: Feb 4, 2014
  3. kfalls

    kfalls Super Member

    Messages:
    1,076
    Location:
    Dennison, Illinois
    You could buy an old Dolby Pro-Logic processor and use the three front channels. Or a Dolby Pro-Logic receiver. They should be pretty easy to come by. You may even be able to get a quality piece since the DLP receivers are no longer popular.
     
  4. robgmn

    robgmn Super Member

    Messages:
    4,448
    Location:
    Twin Ports, MN
    An old car audio trick was to wire the positive lead from each channel to a center speaker.
    It provided only the signal that was common to both L/R.

    I did it and it worked, but I don't know if it might have a negative impact on your receiver.

    What speakers are you running?
     
  5. JBL GUY

    JBL GUY Addicted Member

    Messages:
    7,010
    If you connect the additional speaker to the positive terminals on the right and left speakers it will respond the difference between the channels, not what is common between the channels.

    The method in the link provided by transmaster will yield the sum of the right and left channels, although it may have a negative impact on the sound quality, especially if the center speaker contains a crossover network.

    Note that it is recommended that the center speaker be the same as the right and left speakers and this may not necessarily be the best choice for the center channel information.

    I built a simple active circuit to sum the left and right channels and used this signal to drive a monaural amplifier. I incorporated a band pass filter to limit the frequency extremes, since the sum of the right and left channels is full range.
     
  6. jberger

    jberger AK Subscriber Subscriber

    Messages:
    2,066
    Location:
    Long Beach, CA
    Paul Klipsch published a simple splitting circuit that he published in his "Dope from Hope" papers, similar to what you describe (and requiring a mono amp for the center speaker). There were two input jacks, and three output jacks, with 47 k Ohm resistors connecting left in -> left out, left in -> center out, right in -> center out, and right in -> right out. You could probably sub in a stereo audio taper variable resistor for the signal going to the center speaker, so you could adjust the relative level if your power amp didn't have a level adjustment.
     

     

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  7. charles 1973

    charles 1973 Super Member

    Messages:
    3,023
    What you might try is using a 2'nd pair of smaller speakers, Like those $100 Pioneers that get such good reviews or a pair of NHT super zero's and place them beside or under you TV. By running both A and B Speakers it should fill in the hole in the middle, while the main speakers will still provide stereo seperation and full bass response. By installing an L-pad to the new speakers you can blend them in just the right amount.

    I used this idea when I had no 5.1 channel AVR for proper Surround sound, But used the 2'nd pair of speakers to add presence to movies when I placed them in the back of the room. I used the L-pad to reduce their volume.

    I would not be combining in any way the left & right amp outputs into one. Being a big Vintage Pioneer fan I'd hate to see you fry that beautiful SX-1250.

    You could even build a center channel speaker and add two proper full range 4 - 5" speakers with independant speaker connections and a built in Stereo L-Pad, and connect them to the B Speakers.
     
    Last edited: Feb 4, 2014
  8. cademan

    cademan Addicted Member

    Messages:
    8,986
    You could probably turn up your tv volume and hear how the tv speakers would work as a type of center channel. You're not going to get a true center without an actual 5.1 or 7.1 surround receiver. :no:
     
  9. coonmanx

    coonmanx Super Member

    Messages:
    2,186
    Location:
    Colorado Springs
    How about....

    Tape outs to a cheap integrated amplifier (like a Realistic SA-150) in mono mode. Hook that up to a "center channel" speaker. Might work.
     
  10. transmaster

    transmaster AK Subscriber Subscriber

    Messages:
    8,170
    Location:
    Cheyenne, Wyoming
    I guess nobody looked at the old Dynaco 3 Channel setup. :scratch2:

    [​IMG]
     
  11. JBL GUY

    JBL GUY Addicted Member

    Messages:
    7,010
    Actually I did and I posted a comment about it.

    If used for center channel TV, it may not be the best in terms of frequency response, because the center channel speaker will be required to handle the full audio spectrum.
     
    Last edited: Feb 5, 2014

     

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  12. gggvan

    gggvan Well-Known Member

    Messages:
    948
    Location:
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    #1 in signature
     
  13. gggvan

    gggvan Well-Known Member

    Messages:
    948
    Location:
    Cohasset, MA
    The Sony Bravia has the worst speakers eva! They make a horrible rattling sound when turned up even to hearing level. Plus the TV is 6' off the ground.
     
  14. gggvan

    gggvan Well-Known Member

    Messages:
    948
    Location:
    Cohasset, MA
    I found out that when playing a DVD I can have the 2-channel stereo and the AVR on at the same time. The blu-ray player sends HDMI to the TV, the TV send back 2-CH audio to the vintage receiver. I have a seperate coaxial audio cable from the blu-ray player to the Sony AVR, only 1 speaker attached, the center. Did it yesterday, daughter watched Moulan.

    I'm getting 2-CH audio to the vintage receiver for every input to the TV, cable TV, blu-ray, rikomagic. Only the TIVO is remaining, but its a series 2, no HDMI.
     
  15. Kahoona

    Kahoona Super Member

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    Big Pine Key, Conch Republic
  16. transmaster

    transmaster AK Subscriber Subscriber

    Messages:
    8,170
    Location:
    Cheyenne, Wyoming
    The real advantage of the old Dynaco system is except for the center speaker it requires no other equipment so if you don't like the setup you are not out much. The only thing people added to the basic setup was a volume control for the center speaker.
     

     

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  17. gggvan

    gggvan Well-Known Member

    Messages:
    948
    Location:
    Cohasset, MA
    still looking for a solution to the original post, thought there might be an update with more folks using 2-channel setups.
     
  18. robgmn

    robgmn Super Member

    Messages:
    4,448
    Location:
    Twin Ports, MN
    Have you tried any of the solutions?
     
  19. Lavane

    Lavane AK Subscriber Subscriber

    Messages:
    7,201
    Location:
    northern cal.
    Ive used the "Phantom" channel before. If you have a speaker selector on the receiver or amp you can use one speaker center rear. Connect the "+" from both right and left B speaker terminals to the speaker. It will produce just the differences in both channels. IMO how it's sound depends on the recording. Some sounded pretty good. A few even brought out things like toe tapping and such in the background of the recording. With other recordings you may not notice much if anything different at all. If you only have one set of speaker terminals then the Dynaco setup posted above will do. Realistic used "Quadraxox", it was the same as using one center rear channel, but with two speakers, rear right and rear left. I have a Realistic amp with Quadravox I use in my garage. For the rear speakers im using a small set with 5" woofers and a dome tweeter I switch in if I use the Quadravox feature.
     

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