speaker placement and toe-in issues

Discussion in 'Speakers' started by DanielSmi, Aug 17, 2003.

  1. DanielSmi

    DanielSmi Second Unit

    Mar 20, 2002
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    I have Klipsch Rf-5s and I tried this golden ratio speaker placement formula that people raved aboutand now I'm having some trouble. It seems that when I'm in the sweet spot I have a wider soundstage yet not as precise as when I moved them closer together. Also I have my speakers toed-in isn't this supposed to provide a more accurate soundstage? Another problem is that the sweet spot is very small so if I move my head to the left or right I notice the voice move either to the left or right and if scoot over to the next seat the soundstage is gone and i only hear sound from the right speaker even though I only moved about a foot.

    Do you think acoustic paneling at the first reflection and behind the speakers would solve my problem or do you have any other suggestions? BTW, my room is 13x11.

    Daniel Smith
  2. MingL

    MingL Stunt Coordinator

    Mar 26, 2003
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    Oh boy, welcome to the world of acoustics. I might be wrong, but acoustic panels ain't gonna help much for your soundstage problems. I'll dare say it'll be a waste of money getting those panels if one didn't know how to measure even simple frequency/time response.

    To get good imaging, throughout the room is shere fantasy. Within a seat beside the sweet spot, good imaging and soundstaging can still be had if we sat further behind from your sweetspot. Thats just physics and psychoacoustics.

    And if soundstage is a problem to you, bass boom/room modes will be even worse problem.
  3. DavidES

    DavidES Stunt Coordinator

    Jun 23, 2003
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    What you are experiencing is pretty much the way it's supposed to be. That's why stereo is anti-social as far as the sweet spot goes.

    Toe-in does affect image some. You start out with none and then experiment/listen until it sounds right to you. Usually if you aim both speakers to a point about 5" behind your head at the sweet spot, you might find that acceptable. A protractor, T-square, L-square (carpenter's square) on front baffle of each speaker works well here because you can sight down the lines to your seat and aim.
    If you use a protractor, you can find out the area covered within 0 degrees speaker axis +/-30 degrees and arrange room setup so that everyone in your HT can get decent sound.

    The acoustic absorptive paneling will help with early reflections. Early reflections, if not attenuated at least 10-15dB, will smear the image and/or make the sound out of each speaker bloated/fat.

    Treat the floor, ceiling and the wall behind the speakers and then experiment with the reflections on the side walls. Too much attenuation laterally will cut out the spaciousness of the image. Treatment thickness for the sidewalls as thin as a dish towel might be sufficent.

    You will need an assistant and a mirror. You sit in sweet spot and assistant moves mirror parallel along walls, floor, and ceiling until you see the reflection of the midrange and tweeter of speakers. Work with one speaker at a time. Mark the spots and treat. Treatment can be area rugs, tapestries, comforters, heavy drapes, etc...

    Diffusers on the wall behind you can improve spaciousness. Big full bookcases work well if you have them.

    If you can live without it, remove coffeetable if it's in front of you. They are evil for frequency response and comb filtering problems.

    Paraphrased from The Master Handbook of Acoustics 3rd Ed. by F. Alton Everest.
    Check your public library. Definitely a good primer.

    More info on coffeetables here. He put frequency response graphs in the article proving the evilness.

    Hope it helps ya,

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