Question on wiring pseudo 7.1

Discussion in 'Archived Threads 2001-2004' started by Frank Carter, Nov 11, 2002.

  1. Frank Carter

    Frank Carter Screenwriter

    Joined:
    Mar 12, 2002
    Messages:
    1,187
    Likes Received:
    0
    I have a pair of Cambridge Soundworks Ensemble IV speakers that aren't being used so I thought I'd use them as rear centers. My parent's have a Yamaha HTR-5250 that's not being used until their basement is finished so I'll use it for now.
    I ran rca cables from the surround preouts on my receiver to the analog DVD input on the HTR-5250. I set it to prologic and if I hook up one speaker to the center channel output I have 6.1. I want to hook up 7.1 instead, is there a way I can do some trickery and use some of the other unused channels to power a second rear center?
    Here is a link for more info on the HTR-5250: http://www.yamaha.com/cgi-win/webcgi...R00010HTR-5250
    Thanks,
    Frank
     
  2. Kevin C Brown

    Kevin C Brown Producer

    Joined:
    Aug 3, 2000
    Messages:
    5,712
    Likes Received:
    0
  3. DanielN

    DanielN Stunt Coordinator

    Joined:
    Sep 4, 2002
    Messages:
    98
    Likes Received:
    0
    Thats my post. I have the same situation and I am going to wire the 2 rear channels in series.
     
  4. Frank Carter

    Frank Carter Screenwriter

    Joined:
    Mar 12, 2002
    Messages:
    1,187
    Likes Received:
    0
    Thanks guys,

    I guess that's what I have to do. I was hoping there was something I could do with splitting the signal from the center channel preout and sending it back to the unit somehow.

    One last question(I think), the main receiver I'm using(Yamaha HTR-5280/RX-V800) does matrix 6.1 w/no output for a 6th channel, when I'm doing my "pseudo 7.1" do I want to turn this feature on or off from my main receiver?

    Frank
     
  5. Wes

    Wes Screenwriter

    Joined:
    Sep 30, 1997
    Messages:
    1,190
    Likes Received:
    1
    Location:
    Utah USA
    Real Name:
    Wes Peterson
    Remember your Prologic receiver needs to do two things:

    -Create and power the new EX channel.

    -Process and power the Surround Left and Right channels to remove the EX info.

    Wes
     
  6. Frank Carter

    Frank Carter Screenwriter

    Joined:
    Mar 12, 2002
    Messages:
    1,187
    Likes Received:
    0
    Wes,

    Are you saying I need to have the second "EX" receiver power my surround left and right as well as the EX channel?
     
  7. Wes

    Wes Screenwriter

    Joined:
    Sep 30, 1997
    Messages:
    1,190
    Likes Received:
    1
    Location:
    Utah USA
    Real Name:
    Wes Peterson
    Frank, What you need is one DD/dts receiver with surround pre-amp outs, and one Dolby Prologic reveiver.

    -The DD/dts receiver will power the "Front Center and Front L/R channels" only.

    -The Surround signal will be fed from the DD/dts receiver's Surround preamp out into the Dolby Prologic receiver input (example: Video 1).

    -The Prologic receiver will now decode and power out of its "FRONT L/R" channels your "Surround L/R" speakers.

    -The new EX channel will be created and powered by the Prologics "Center" channel. Switch the Prologic receiver to Dolby Prologic Normal mode.

    This will create with great results Dolby Digital EX and dts ES Extended Surround on all encoded EX/ES discs and also on most DD/dts 5.1 discs (with varied results on 5.1 discs)!
    Simply switch your Prologic receiver to Stereo to play 5.1 channels.

    Wes
     
  8. Frank Carter

    Frank Carter Screenwriter

    Joined:
    Mar 12, 2002
    Messages:
    1,187
    Likes Received:
    0
    Thanks Wes!

    Now I need to get more speaker wire to move the surround connection from one receiver to the other.

    Frank
     
  9. LanceJ

    LanceJ Producer

    Joined:
    Oct 26, 2002
    Messages:
    3,168
    Likes Received:
    0
    Using two back surrounds (that are being fed the same signal) will result in fuzzy and distorted rear imaging. This will negate the whole reason for the back channel.
    I wouldn't do it.
    LJ
     
  10. Chris Purvis

    Chris Purvis Stunt Coordinator

    Joined:
    Dec 11, 2001
    Messages:
    151
    Likes Received:
    0
    Lance, that's not accurate.

    Dolby labs actually recommends you use more than one speaker for the center surround in certain situations.

    Here's a quote from DolbyLabs.com:

    "If you use a single rear surround speaker, center it behind the listening area at the same height as the side surround speakers, preferably above ear level. If you use two back surround speakers, which give a more diffuse and natural surround effect, they should be at least four feet apart (creating an included angle of about 90 degrees to the listener), also centered behind the listening area and at the same height as the side surround speakers."
     
  11. Frank Carter

    Frank Carter Screenwriter

    Joined:
    Mar 12, 2002
    Messages:
    1,187
    Likes Received:
    0
    Chris,

    Thanks for the reply, I think you'r right on this one.

    Lance,

    Could you please go into more detail on why you think



    I'm not an expert on the subject but I don't agree with you. I would just like to know your reasons.

    Regards,

    Frank
     
  12. LanceJ

    LanceJ Producer

    Joined:
    Oct 26, 2002
    Messages:
    3,168
    Likes Received:
    0
    It's late, but had to answer this one!
    With TWO surrounds (just like with two front mains in a stereo-only system), a "phantom" center image is created.
    When you have a 6.1 system and that back surround (BS [​IMG]) speaker, IT provides that center image. But also it also creates an image between the left surround(LS) and the right surround(RS). O.K., great.
    But when two BS's are utilized (man I wish I could insert a diagram here!!!): between those two BS's there will be a phantom center image, and also: between each of these same speakers and the LS and RS will be two other phantom images consisting of the "side" information (RS + BS#1 and the LS + BS#2 AND RS + BS#2 and the LS + BS#1).
    The result? Instead of pinpoint imaging, you'll have lots of the sound literally smeared across the back wall. Dolby Labs just used a different term for it: "diffused". AND you'll be playing games with your amp's level settings, if the amp can even power two back surrounds properly!
    (How many systems have you seen with two front center channels, if you see what I mean?)
    Now, some people may like this effect. Personally, I don't. Might as well just turn off the 6.1 circuit, and mount two bipolar speakers behind you and get just about the same effect.
    Whatever sounds good to you, is all that matters.
    LJ
     
  13. Wes

    Wes Screenwriter

    Joined:
    Sep 30, 1997
    Messages:
    1,190
    Likes Received:
    1
    Location:
    Utah USA
    Real Name:
    Wes Peterson
    Lance sorry but every EX commercial theater has more than one EX speaker, so I guess the whole smearing thing is not a reality as you state. And in the fact I have two EX speakers and I have clear EX imagine I can testify that two EX speakers works great!
    Sorry but I also disagree!

    Wes
     
  14. Frank Carter

    Frank Carter Screenwriter

    Joined:
    Mar 12, 2002
    Messages:
    1,187
    Likes Received:
    0
    Lance,

    I see your reasoning and it makes sense. I'm gonna try it and see how it works. If I like it I'll keep it, if I don't I'll go back to before. Thanks for your input.

    Frank
     

Share This Page