Is your soundfield up to snuff?

Discussion in 'Archived Threads 2001-2004' started by Mike Knapp, Mar 7, 2001.

  1. Mike Knapp

    Mike Knapp Supporting Actor

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    I visit a lot of Home Theaters. Most of them look beautiful even when turned off. But alas, most of them are set up poorly where the audio comes into play. Room configuration is pretty basic where video is concerned but for audio it is much less forgiving. One of the most common mistakes made in the audio systems I see is poor speaker placement.
    Odd how this, the MOST critical element of the soundfield, is almost always glossed over for the sake of room cosmetics. If a room situation degraded the video portion to the same degree that most sound systems are compromised....the room would be changed, I promise you.
    Most (not all) speakers are designed to function as a unit unto themselves. They need room to breathe if they are to work properly. Placing them flat against a wall or on top of your TV or smooshed against the side of the TV will SERIOUSLY hamper their performance. The absolute worst thing you can do is to place them in a cubby-hole on an entertainment furniture piece. Yet, that is the most common thing I see.
    An immersive soundfield is created by the interaction between the speakers. Here is a good test. Play some stereo music in the stereo mode on your equipment. Sit in the sweet spot. If you pinpoint any sound to either speaker....you have a problem. In a properly set up system (stereo or 5.1) all the sound should come from the room, not your speakers.
    [​IMG]
    This is an image of a typical home theater set-up. The red is the listening position, and the black is the display device. The purple boxes represent the 5 directional audio channels. The yellow area indicates the area that you can place sounds within the soundfield that this type set-up will allow.
    Notice the front soundfield does allow a little to the left and right of the speakers and usually the same in the rear. Some forward projection is typical as well but there is little depth to the soundfield. All the audio cues are confined to this yellow area.
    [​IMG]
    Here we have made some changes to the basic speaker set-up. Look at that soundfield! Deep in the front and back and now we even have some imaging on the sides of the room. Notice that we are allowing each speaker to have it's own operating space and that the center speaker is placed in front of the display device. All the speakers are away from the walls and other large surfaces.
    We now have "room sound". Audio cues can be anywhere in the room from directly behind you to directly to your right. This was not possible with the previous arrangement.
    I know that many of you cannot acheive this in your room. But it is something to strive for, Try to get as close as possible to this type of a set-up. You will be immersed in sound rather than surrounded by speakers....major difference.
    Enjoy.
    Mike
     
  2. John Chow

    John Chow Second Unit

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    Nice post, it's funny that you mention this since just this past weekend I spent time re-adjusting my front speakers. They used to be like you had in the front picture, the exception being they were toed it a bit. My rear speakers have always pretty much been as you diagrammed in the second picture. Anyways, I decided to pull out my front floorstanding speakers from the tv stand some since i'd been reading about how speakers need to breathe and all that. I can do this since i'm the master of my castle (i.e. single). Anyways, I do like the difference that it has made. I now get the, hmm...it sounds like my center channel is on even though i'm listening only in 2 channel mode =)
     
  3. Petto

    Petto Auditioning

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    Excellent post, Mike. Very informative!
    I've seen pics of a lot of HT's that do seem to be compromising a bit too much in an effort to keep things neat and tidy. I always cringe when I see a center speaker lodged in a cubbyhole in an entertainment unit.
    Personally, I'd love to pull my speakers out a bit more and further apart, but unfortunately, that would completely block the doorway. I'd also love to hang my center from the ceiling like you, Mike, but I don't think my ceiling is strong enough to hold, and Bob Vila, I am not.
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    cheers,
    Petto
     
  4. Jeremy Anderson

    Jeremy Anderson Screenwriter

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    I had my Polk R10's mounted to the front wall out of necessity, which at first sounded really bland. But after sticking rubber feet on the back of the speaker, it seemed to really make a difference in the sound.
    However, my left main is closer to the side wall than the right, so I get a reflection problem off the left wall. I have an entertainment center where my center sits (again, relatively isolated by pliable rubber feet), so yesterday I tried moving the R10's to the entertainment center instead of the wall to try to eliminate this reflection problem. All I can say is OUCH! Front pans seemed to be a little smoother, but the soundfield was pretty much anchored on the entertainment center. I'll be moving them back to the wall tomorrow, and I guess I'll just have to buy drapes to kill the reflection on the left wall.
     
  5. Kevin Kloet

    Kevin Kloet Agent

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    I have seen many nice systems that have been underutilized or downright degraded by placement.
    I am actually at the point where I make no comment anymore (only advice to good friends who want to learn).
    Fact is... if they think it's good, and they like the way their room looks, they're doing well. Most would not even notice the difference in sound anyway.
    It does wound me deeply to see speaker setups that are far beyond what I could ever afford being destroyed by mis/uninformed users who don't appreciate what they have (and more importantly, what they could have - what they're missing).
    My only refuge is to never again visit their "home theater".
     
  6. Ryan Tsang

    Ryan Tsang Second Unit

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    Thanks Mike,
    I've been lucky to be in situations where I can tailor my room so that optimum placement of all 7 speakers in possible. (5 speakers, 2 subs) Like so many have said, it totally hurts to see a quality system perform like a HT-in-a-box system because they are uninformed, or have other limitations (decor, wives, pets, and/or kids).
    I feel bad when I see others' HT pics and criticize their placement, while other HTF members reply and congratulate them on a nice system. I just can't say "Man, your system really rocks!" when I see a pair of PSB Stratus Silvers shmucked in corners of the room, or flanking a 32" tv. I really hope you reach out and convert a lot of people, like those mattes.
    I've tried to introduce to others the option of raising the RPTV on blocks and placing the center channel in front on a short stand so as to height match the tweeters with floorstanders (assuming they are placed into the room as well). Don't know how many actually cared.
     
  7. Pierre Gagne

    Pierre Gagne Agent

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    Mike,
    Very interesting informations. Now, where would you place the sub in that configuration with the same type of room that you draw where the side walls are closer together (say 11 feet apart) and the front wall (TV) is 20 feet apart of the back wall (surrounds).
    Thanks in advance.
    Pierre
     
  8. Mike Knapp

    Mike Knapp Supporting Actor

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    Sub placement should not effect the directional soundfield at all. If the sub is properly integrated you should not be able to locate it sonically.
    I would try the corners first or.....
    Place the sub in your listening position while playing a thumping bass track. Madonna's "Vouge" works well for this. Walk about the room and get on your knees (sub level) around the outer walls. Wherever the bass sounds best to you.....place the subwoofer there.
    Mike
     
  9. Jay Mitchosky

    Jay Mitchosky Producer

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    That's a great post, Mike. I share the same concern as you when seeing speakers nudged flush up against a big monitor. Bring 'em out and forward! That being said, as much as I agree with your observations it's a reality that few non-dedicated spaces can achieve this. You rightly note this at the end of your post.
    My mains are as forward and out as my room can practically allow. To my ears they pass the blind two channel test. But the center is another matter. I have it leaning forward of the cabinet as much as physics will allow before it falls off (it's also tipped down towards the listening area). There's no way I could rig a bracket such as you did recently in the main area of the house. But I can guarantee that the results would be a vast improvement. If I had a dedicated room all bets are off - every decision would be subject to the criteria of A/V quality.
    I would like to archive this but I don't know how.
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    --Jay
    My Home Theatre Pictures & Pronto CCF...
    "Holy crap! The vultures are eating my head!
     
  10. Brian Mansure

    Brian Mansure Second Unit

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    Mike,
    Thanks for taking the time to write such an informative post! [​IMG]
    This is definitely an issue I have been struggling with the most when setting up my HT equipment. You have answered some of the basic questions that many people, including myself have about speaker placement in one well thought-out post.
    Admins, if it hasn't been brought up yet maybe this could be archived so that we may refer to it in the future?
    Thanks again Mike for sharing your experience and knowledge.
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    BAM
    "If I'm not back in 10 minutes... just wait longer."
     

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