Announcement

Collapse
No announcement yet.

On wall response compensation

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • On wall response compensation

    I was reading about an on wall speaker produced by Donald North Audio that is wall mounted and has a crossover circuit that compensates for the frequency response ripple associated with wall mounting. Does anyone know anything about this circuit?

  • #2
    Re: On wall response compensation

    You mean baffle step compensation? In wall or on wall? This makes a.bit of difference in the frequency response. There will be a slight ripple in response due to baffle edge diffraction and there will also be baffle step loss if the box is on wall and not flush with the wall. Both of these issues can be taken Carr of in the crossover. The crossover will be different with different drivers so there is no one single circuit to conquer all.

    Comment


    • #3
      Re: On wall response compensation

      Originally posted by killa View Post
      You mean baffle step compensation? In wall or on wall? This makes a.bit of difference in the frequency response. There will be a slight ripple in response due to baffle edge diffraction and there will also be baffle step loss if the box is on wall and not flush with the wall. Both of these issues can be taken Carr of in the crossover. The crossover will be different with different drivers so there is no one single circuit to conquer all.
      It's not that simple. When a speaker in a box is placed on a wall there will be a deep notch in the response associated with the depth of the cabinet (reflection from the wall and back). I know of no crossover circuit that can compensate for this, even though this is what they appear to be referring too.
      Click here for Jeff Bagby's Loudspeaker Design Software

      Comment


      • #4
        Re: On wall response compensation

        These speakers? The curve looks too good to be true.

        http://www.dnaudio.com/DNA-Sonic-Dec...-Speakers.html
        Bryan K.

        Midwest Audio Club

        Speedster | Sub Attachť | The Wildeman | Sean's NLA Towers | CO‹GAR, COUGAR II and CO‹GAR JR | Triton | Lithium | J-Boom | Trym MLTL | Docere MLTL

        Comment


        • #5
          Re: On wall response compensation

          Originally posted by bkeane1259 View Post
          These speakers? The curve looks too good to be true.

          http://www.dnaudio.com/DNA-Sonic-Dec...-Speakers.html
          That looks like they're using the offset baffle to smooth the response rather than a crossover circuit. The circuit is probably just tuning the step to match the slight baffle step they get from the baffle.
          Click here for Jeff Bagby's Loudspeaker Design Software

          Comment


          • #6
            Re: On wall response compensation

            Here's a pretty good illustration of the effects of various placement


            http://jaysspeakerpage.weebly.com/

            Comment


            • #7
              Re: On wall response compensation

              Originally posted by Jeff B. View Post
              It's not that simple. When a speaker in a box is placed on a wall there will be a deep notch in the response associated with the depth of the cabinet (reflection from the wall and back). I know of no crossover circuit that can compensate for this, even though this is what they appear to be referring too.
              +1. The reflection dip, Allison Effect, is the result of the baffle being 1/4 wavelength from the wall. You can't overcome it with the crossover, but you can overcome it by making the baffle large enough so that the baffle step takes place at or at least close to the Allison Effect frequency. The baffle step being where the baffle is 1 wavelength in dimension you just have to make it 4 times the cabinet depth. In this case the depth is 4.25 inches, so a baffle 17 inches in dimension eliminates Allison Effect, while one at least twice the depth dimension will minimize it. That's the case here, where the baffle dimensions are 10.5 x 16.25. Off-setting the woofer also helps.
              www.billfitzmaurice.com
              www.billfitzmaurice.info/forum

              Comment


              • #8
                Re: On wall response compensation

                Originally posted by Jeff B. View Post
                in the response associated with the depth of the cabinet (reflection from the wall and back). I know of no crossover circuit that can compensate for this, even though this is what they appear to be referring too.
                Ah. Refresher. One of those things I remember reading about but forgot :o :D

                Comment


                • #9
                  Re: On wall response compensation

                  Just curious. Could you use a piece of foam (thinking wedge shape) to absorb the wave before it reflects.

                  Comment


                  • #10
                    Re: On wall response compensation

                    Ok I feel better. I have been working an on wall design and trying to minimize these effects. I read about this product and it was not clear to me how they could filter the effects of wall reflections. The reflected response shape should change the same as the direct wave keeping the notch unchanged.

                    Comment


                    • #11
                      Re: On wall response compensation

                      OK, let me ask one more question. I have attached the measured response for my design mounted on the wall and located 18 inches from the wall. This design is for use with subwoofer only and therefore, is not intended to produce the bottom two octaves. I have the speaker mounted on a stand that I can slide to change the distance from the wall while it is playing. I would say the difference in response is audible, but I would not say the on-wall sound is offensive. If I were not able to listen to the speaker in both locations, I would not say either sounds bad.

                      I am interested in opinions. Would you all keep working to smooth the low-frequency response or continue as is?

                      I also attached a picture of the prototype.

                      Click image for larger version

Name:	speaker 1-14-2015.jpg
Views:	1
Size:	38.9 KB
ID:	1163523 Click image for larger version

Name:	on and 18in off wall 1_6 smooth.jpg
Views:	1
Size:	72.5 KB
ID:	1163524

                      Comment

                      Working...
                      X