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Baffel step for on wall, not in wall.

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  • Baffel step for on wall, not in wall.

    For a boxed speaker mounted on a wall, would this be a half step?

  • #2
    Re: Baffel step for on wall, not in wall.

    Originally posted by generic View Post
    For a boxed speaker mounted on a wall, would this be a half step?
    No. Placing a conventional speaker on a wall causes something of a mess because of the strong cancellation by the sound reflecting back off the rear wall. This can be alleviated to some extent by designing for the location if you have the option.

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    • #3
      Re: Baffel step for on wall, not in wall.

      Originally posted by generic View Post
      For a boxed speaker mounted on a wall, would this be a half step?
      Strictly speaking BSC should not be used for an on-wall, as whatever wraps around the cab will reflect off the wall to rejoin the direct wave. The problem with on-wall is Allison Effect, when the baffle is 1/4 wavelength from the wall, so the reflected wave travels 1/2 wavelength when it meets the direct wave, resulting in a cancellation notch. Ideally you want the baffle close enough to the wall so that the 1/4 wavelength distance is above the baffle step frequency.
      www.billfitzmaurice.com
      www.billfitzmaurice.info/forum

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      • #4
        Re: Baffel step for on wall, not in wall.

        Originally posted by billfitzmaurice View Post
        Ideally you want the baffle close enough to the wall so that the 1/4 wavelength distance is above the baffle step frequency.
        IOW a large baffle on a shallow enclosure. Or a large baffle on any enclosure . . . the baffle does not have to be the same size as the face of the box. In some cases the baffle does not even have to be "the baffle". One can often improve the sound of a "bookshelf" speaker in a bookshelf by surrounding it with, um, books . . . which if strategically placed effectively extend the "baffle" surface. But a small box on a bare wall will typically produce some nasty fr ripples.
        "It suggests that there is something that is happening in the real system that is not quite captured in the models."

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        • #5
          Re: Baffel step for on wall, not in wall.

          Originally posted by Deward Hastings View Post
          ...One can often improve the sound of a "bookshelf" speaker in a bookshelf by surrounding it with, um, books....
          That's the way I used to do it.
          Somewhere on Ethan Winer's site is(was) measurements on a front to back cancellation demonstration.
          The Alton Everest book addresses methods of attenuation; which Winer utilizes commercially.
          "Not a Speaker Designer - Not even on the Internet"
          “Pride is your greatest enemy, humility is your greatest friend.”
          "If the freedom of speech is taken away, then dumb and silent we may be led, like sheep to the slaughter."

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          • #6
            Re: Baffel step for on wall, not in wall.

            HT Guide's Completed Speaker Designs is prefaced with an excerpt from Toole's book with data showing all the combinations, albeit for a full BSC design. http://www.htguide.com/forum/showthr...peaker-Designs

            I usually point out that the first pair of FR curves would be the same if the in-wall speaker was designed with no BSC, but the dips are just as Bill described.

            HAve fun,
            Frank

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