Surround Speaker question

Discussion in 'Speakers & Subwoofers' started by GregBe, Jun 15, 2005.

  1. GregBe

    GregBe Second Unit

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    I am going to be purchasing a set of M&K 850 speakers for my L/C/R. (these each have two 5 1/4" drivers in them). Because of my room arrangement, I am down to two choices/locations for my surrounds in 5.1, but each one has its downsides so I am trying to decide the lesser of two evils.

    My room is relatively large at about 19' x 19' x 8', and I sit about 4' from the back wall.

    1) purchase the 650 bookshelf speaker which is the technical perfect match for the 850 with the exception of 1 driver instead of two. If I go this direction I will have to place it against the wall with an omnimount on the side walls, but they would pretty much need to be up in the corner where the two walls meet the ceiling. I pretty much angle them in any direction, but they would be in the corner all the way up near the ceiling.

    2) purchase the M&K K4 surrounds which is their tripole model that has gotten good reviews. The good is that I can place them in the ideal location which is on the side walls directly to my sides and at any height I choose (because they are smaller, I have more flexibility with the WAF). The bad is that they are smaller. They have a 4" driver and a 1"tweeter facing out, and two 2 1/2" drivers facing front and back in a dipole arrangement.

    Which way would you go?
    Thanks
    Greg
     
  2. LanceJ

    LanceJ Producer

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    I would pick the bookshelf model.

    But I don't understand why you "have" to put them all the way up in the corners. During all the years I've dealt with surround speakers for movies, they are supposed to be behind you by at least a couple feet & about three feet above your listening position.

    The side is the ideal location.......for dipolar speakers but not monopolar ones i.e. "regular" speakers, or bipolars. Can the 4" woofer/tweeter combination be shut off on these speakers? Because having their output firing directly into your ears is going to cancel out part of the surround effect being generated by the 2.5" drivers.

    I'm not sure why I keep seeing regular speakers being placed to the sides of the listening position--that physically cannot provide a surround effect (going by the dictionary definition of that word). As I've said elsewhere, I tried this for a day to see what it was like and it drove me crazy: an irritating & UNsurround-like headphone effect is all it produced.

    >>> And the sides are definitely not the place for the reproduction of surround music from dvd-audios, sacds and DTS-CDs.
     
  3. Victor Ferguson

    Victor Ferguson Stunt Coordinator

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    Lance,

    Please go into a little more detail on this. I have always been told otherwise. That the correct placement is two to three feet behind and above the listener for direct radiating speakers.
     
  4. LanceJ

    LanceJ Producer

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    Victor: Well, that's pretty much it. As far back as the mid 90s when I sold HT I remember reading that advice multiple times from several different sources--manuals, magazine reviews, etc--and that's how we had it set up in our demo room (we used direct-radiating 6.5" JBL bookshelfs in back). And I still see this right now. So when jets flew overhead, they actually flew overhead, i.e. from behind us to the front wall in that room. When the movie scene took place in a submarine, we heard warning klaxons, men shouting, or creaking hull metal all around us.

    But when the rear speakers are at the sides, like in my own experiment or when we stood in between the rears in our demo (this was at the entrance to the room--we weren't supposed to hang out in there unless customers were in there too [​IMG] ) it's like I had my head just inside the open window of a house, watching everything happen in front/to the side of me. Sure, I could sense the 3-D acoustic space being created, but I wasn't part of it, know what I mean?

    Edit: I realized I made a mistake in my post above this one (I fixed it) >>> Only dipoles are supposed to be at the sides so the listener will be in their "null zone". IMO direct radiators and bipolars really shouldn't be placed there.....unless you like that type of sonic effect this produces. Though obivously the bipolar speaker will sound better than the direct radiator because of its particular operating design.

    Until a couple weeks ago when someone mentioned something on Dolby's site about a diagram with speakers placed to the sides, I had never heard of such a thing. Whenever I saw this configuration I thought it was only happening when people couldn't place them where I mentioned because of room/furniture constraints.

    And what really reinforces my opinion is that whenever I see shots of surround mixing studios for music or movies, I don't remember the rear channels ever being placed at the sides of the engineer's listening position at the mixing console.

    Cramming the speaker directly into a corner IMO will also result in a slightly hollow/cheap horn speaker sound or cause bass frequencies to be artificially boosted (especially for music). But placing it near the corner--maybe about 2ft away or so--can help prevent this & help produce a more diffused sound if that's what you want because of the speaker's output reflecting off of the nearby wall/ceiling surfaces.

    Right now my rear channels* are about five feet behind me (being a bachelor helps with this!), toed-in towards the main listening position and about two feet from the side walls/four feet from the back wall. I don't notice any localization of sound effects, unless that is what the movie scene calls for. This finding was actually kind of an accident, since I have my system configured more for surround music playback--I thought this would take away from a movie's effects where supposedly everything is supposed to have a diffused sound. Maybe that is why fewer manufacturers seem to be offering dipole/bipole speaker models lately?

    * Pioneer 8" bookshelfs on stands; Boston Acoustics CR9 8" in front, Infinity SL30 6.5" bookshelf for the center
     
  5. GregBe

    GregBe Second Unit

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    Thanks Lance,

    After reading your input, I think I may go with the bookshelf speakers. Since my couch is 4-5 feet from the back wall, my placement may be ideal based on your experience as they would really be back and to the side. They would need to be on the side wall, and although up near the corner, I could probably get away with 6 inches from the ceiling and 6-12 inches from the rear wall. Because they will be on Omnimounts, I can tilt them in any direction.

    If I go this direction,
    1) would you invert the speaker so the tweeter is on the bottom, placing it a little further away from the corner?
    2) would you angle them right at the listening position, or angle them down, but still facing each other (in effect pointing toward the floor behind the couch), or straight ahead pointing at each other?

    thanks
    Greg
     
  6. LanceJ

    LanceJ Producer

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    Personally speaking, I would point them right at my listening position but you might prefer a less direct/precise surround effect (i.e. point them away). Don't mean to sound wishy-washy but this is definitely a personal preference thing. [​IMG]

    If you can, just try different positions then permanently mount them that way.

    From what I can tell and based on reading instruction manuals from several different manufacturers, dipoles in particular were designed to help the MONO rear channels of the older Dolby Surround system produce a more spacious effect. But Dolby Digital, DTS, DPLII, Logic7, etc use discrete left & right rear channels and in turn can generate whatever type of sound field the mixing engineer desires, so IMO dipoles maybe aren't the best speakers to use nowadays.
     
  7. Victor Ferguson

    Victor Ferguson Stunt Coordinator

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    Thanks for the reply Lance. Last time I redid my room I set the speakers up using the Dolby recommendations for a 6.1/7.1 setup.

    http://www.dolby.com/consumer/home_e...oomlayout.html

    This put my left/right surrounds above and behind to my side. And the rear surrounds above and behind me. If you look at the 5.1 setup diagram it also shows the surronds mounted above and behind to the side and not behind the listener. I am extremely happy with the setup and it works well for me. I am sure every room plays its roll in setup and I'm sure some prefer the sound of different types of speakers. Thanks again for your reply.
     

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