Bi-Pole or Di-Pole For Rear Wall??

Discussion in 'Archived Threads 2001-2004' started by James_N_H, Apr 30, 2002.

  1. James_N_H

    James_N_H Stunt Coordinator

    Joined:
    Mar 26, 2002
    Messages:
    110
    Likes Received:
    0
    Trophy Points:
    0
    Hello,

    Due to a moving my home theatre into a different room I now would like to use wall mounted rear speakers, however I am confused as to which I need. The speakers are to be wall mounted behind the listening position on the rear wall of a fairly square shaped room, can anyone tell me which I need, bi-pole or di-pole rear speakers? Or have I gone off in the wrong direction and it does not matter which I use?

    Thanks for any advice.
     
  2. Alex Prosak

    Alex Prosak Supporting Actor

    Joined:
    Dec 9, 2001
    Messages:
    773
    Likes Received:
    1
    Trophy Points:
    0
    I recommend using bipolar over dipolar. Dipolar speakers have their drivers on opposite ends so when you mount them on your back wall, they'd be firing in line with the wall. Bipolar speakers will fire into the room. You could also go with monopole speakers on the rear wall, this would save you some money but it also wouldn't fill the room with as much sound.
     
  3. Mikey B

    Mikey B Stunt Coordinator

    Joined:
    Aug 12, 2001
    Messages:
    67
    Likes Received:
    0
    Trophy Points:
    0
    Help HTF help you by providing:

    1. What's your current receiver/amp/other speakers?

    2. Where is the main seating?

    Is the couch, for example, right up against the rear wall or is it several feet into the room?

    From what I know, Bipolar speakers won't fire into the room any different than Dipoles. At least this is true of speakers that are wall mountable. Bipole speakers have all similar drivers "in-phase" with each other, and Dipole speakers are "out of phase" with each other. Some designs that make sense to me use what Paradigm does with there ADP surround speakers: They play in Dipole mode with frequencies above their cross-over point and Bipole with frequencies below. This creates a more spatious or diffuse sound with the upper frequencies, but it provides better bass response with lower frequencies. Kind of a best of both worlds design.

    One surround speaker design I look forward in trying is the Axiom quadpole designs. They are Bipoles that fire up, down, left and right (woofers up and down, and tweeters left and right - more into the room than directly opposite each other). From what I have read, I think these could be the best speaker when doubt is present as to what type of speaker to use. They may even be the way to go in many setups where doubt isn't a concern.
     
  4. Marvin E

    Marvin E Stunt Coordinator

    Joined:
    Mar 1, 2001
    Messages:
    90
    Likes Received:
    0
    Trophy Points:
    0
    Check out the following article:
    http://www.hometheatermag.com/showarchives.cgi?25 I use Atlantic Technology Dipole speakers for the side and rear center surrounds. I tried Def Tech Bipolar speakers for the rear center, but I like the ambient sound of the dipoles. One suggestion from Atlantic Technology customer support was to mount their dipole speakers with the directional arrows facing each other for the rear center. This produces an ambient rear center sound stage with some of the direct radiating properties of bipole speakers. The result is more theater-like. I believe Dolby recommends dipole surround speakers for the side and rear center surround speakers for DD EX applications.
     
  5. James_N_H

    James_N_H Stunt Coordinator

    Joined:
    Mar 26, 2002
    Messages:
    110
    Likes Received:
    0
    Trophy Points:
    0
    Mikey B

    My current receiver is a Marantz SR-4200, obviously to be upgraded in order to provide 7.1 surround. My main speakers are B&W DM605 S2's, Centre B&W LCR60-3, Rears B&W DM601 S3, the further rears that I propose are B&W DS6's.

    The seating position is up against the rear wall which is the main reason for having to wall mount speakers.
     
  6. Jeff Bamberger

    Jeff Bamberger Second Unit

    Joined:
    Sep 15, 1999
    Messages:
    495
    Likes Received:
    0
    Trophy Points:
    0
    Dipoles fire our of phase with each other....so if you mount dipoles on the rear wall behind the seating position, you will have a null with one driver from each speaker cancelling each other out. Dipoles work best, as I have read, on the side wall slightly behind and above the seating position.

    Bipoles fire in phase so there would be no cancellation. I have bipoles (Def Tech BP1X) and love them....
     
  7. Marvin E

    Marvin E Stunt Coordinator

    Joined:
    Mar 1, 2001
    Messages:
    90
    Likes Received:
    0
    Trophy Points:
    0
    James:

    In a previous post, I suggested you try two pairs of dipole speakers for the rear side and read center surround speakers. Well, ah...I was talking to a salesman who does custom HT installations and he said that THX has now changed their recommendation to bipole speakers for the side surrounds and direct radiating for the rear center surrounds for DD EX. So, well, I changed my rear soundstage again. I used the Def Tech BP2X bipole speakers for the side surrounds and a pair of Polk M3II direct radiating speakers that have adjustable brackets. I set the angle for the Polks to about 45 degrees so they fired downward toward the sitting area. The improvement in the rear soundstage was amazing!
     
  8. Eric A

    Eric A Second Unit

    Joined:
    Jan 3, 2001
    Messages:
    336
    Likes Received:
    1
    Trophy Points:
    0
    I use dipoles on the rear wall. My primary listening position is against that same back wall and I am using a Lexicon processor so these dipoles are my rear speakers in a 7.1 system. The reason I chose dipoles is because the direct radiators I was using(NHT Super Zeros) were way too localizable. I am currently using NHT HDP-2s and they bathe the wall with sound in the rear without drawing attention to themselves. I sometimes wonder if they are playing. This is what I was trying to accomplish. I have also previously ran PSB 10s Bipoles and they also drew attention to themselves just as the direct radiators I tried. So to answer your question, it is completely up to you with what you are trying to accomplish. If it is a 7.1 system and you want the speakers to disappear use dipoles (preferable with dipoles as sides as well). If it is a 5.1 system, I would use bipoles or direct radiators. Hope this helps.
     
  9. Bill Lucas

    Bill Lucas Supporting Actor

    Joined:
    Mar 20, 1999
    Messages:
    530
    Likes Received:
    0
    Trophy Points:
    0
    Neither. Direct radiating speakers are preferred for rear wall applications. Good luck.
     
  10. James_N_H

    James_N_H Stunt Coordinator

    Joined:
    Mar 26, 2002
    Messages:
    110
    Likes Received:
    0
    Trophy Points:
    0
    Eric A,

    My set-up is going to be upgraded to 7.1 but I cannot fit Direct speakers on the back wall as their is none from the range I would like that are small enough, so that leave bi-pole or di-pole, also the speakers to match my set-up only come in di-pole form. Idealy I would like it so they are not localiseable if possible, how high have you mounted your di-poles up the wall? My set-up would theirfore be di-poles on the rear wall and then direct radiating speakers firing across the listening position.

    If I have a 7-channel set-up and run a Dolby digital ES dvd on it would I still get dedicated 7.1 surround as I believe ES to be designed for 6.1 use?

    Thanks for your advice.
     
  11. Eric A

    Eric A Second Unit

    Joined:
    Jan 3, 2001
    Messages:
    336
    Likes Received:
    1
    Trophy Points:
    0
    James,

    I have my speakers mounted fairly high (around 7 ft) out of neccessity. Remember I am sitting against the rear wall. They are spaced out evenly with my fronts. Also, if you go with dipoles remember to swap the left and right speakers. Dipoles are oriented to be hung on side walls and have a left/right designation. You should have the in-phase portion of the speaker firing inward towards your ears and the out of phase firing outward towards the walls. This will give you reflected out of phase information.
     

Share This Page