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  • Help with In-wall surround design

    Hey guys.......need some help with a pair of in-walls for surround duty in a 5.1 system. I've built a soffit above the listening position that holds the PJ as well as lots of open space for built in enclosures. I have 12" wide by 6.5" available for a baffle size and was thinking a horizontal MTM or TM. My AVR has selectable XO points for the surrounds so flat response to 100hz is fine and preferably sealed. I'd like to keep the budget under $200 for the pair including drivers,XO parts and hardware so if there's any designs out there as ON/IN walls or an TM that could have the BSC adjusted for the application let me know. Buyout drivers are fine as suggestions. There's some Peerless SLS drivers that caught my eye.

  • #2
    Re: Help with In-wall surround design

    http://www.zaphaudio.com/ZA5/

    Scroll down to the in-wall system, would something like this interest you? I think the woofer will fit and the xover is designed specifically for in-wall. Just have to come up with a mounting solution. I am thinking about these myself.

    Comment


    • #3
      Re: Help with In-wall surround design

      I was considering the ZA in wall but i don't think it'll keep up with either my mains or my near reference level usage. Efficiency is a bit low for my liking as well. I've built the TM design for a pair of desktop monitors and was really happy with the sound though. A friend of mine is using them as monitors on his working production desktop.

      Comment


      • #4
        Re: Help with In-wall surround design

        I have built Jon Marsh's Modula MT's in wall version found here (Seas 27TDFC tweeter version): http://www.htguide.com/forum/showthread.php4?t=22625

        The dimensions required may be larger than your space, though.

        I did have some dissatisfaction with the crossover performance, but J Kim helped tremendously with that. Now they sound very good for in walls!

        Another design using the same drivers is available from J Kim.
        http://www.geocities.com/woove99/Spk...RS180_2way.htm

        He used them in a .38 cu ft sealed enclosure so that may work better for your surrounds and size limitations. I have not heard Jay's version, but his help improving my Modula MT response lends me the confidence to expect his own design should perform well.

        Marv
        Last edited by marvin; 02-17-2010, 11:38 PM. Reason: box volume correction

        Comment


        • #5
          Re: Help with In-wall surround design

          Originally posted by marvin View Post
          I have built Jon Marsh's Modula MT's in wall version found here (Seas 27TDFC tweeter version): http://www.htguide.com/forum/showthread.php4?t=22625

          The dimensions required may be larger than your space, though.

          I did have some dissatisfaction with the crossover performance, but J Kim helped tremendously with that. Now they sound very good for in walls!

          Another design using the same drivers is available from J Kim.
          http://www.geocities.com/woove99/Spk...RS180_2way.htm

          He used them in a .38 cu ft sealed enclosure so that may work better for your surrounds and size limitations. I have not heard Jay's version, but his help improving my Modula MT response lends me the confidence to expect his own design should perform well.

          Marv
          Thanx for the tip Marvin, but i think with all the XO components and the drivers they'll bust the budget as well. While the RS drivers have excellent clarity, it takes a lot of parts to bang them into submission!

          Comment


          • #6
            Re: Help with In-wall surround design

            Well, i've been scouring the web for drivers for the in-wall surrounds and i've come up with this. Tell me what you think. I'll need some XO help from the PCD saavy crowd though but i believe a good design starts with the right pairing of drivers so here goes

            For each a pair of the Dalquist buyout WFR-05BV02S

            [http://www.parts-express.com/pe/show...number=299-062

            Zaph tested em and the FR looks pretty nice for $10. Z is pretty nice in a parallel pair with no BSC sensitivity averaging about 91db.



            For the tweeter, in trying to keep the C to C spacing within grasp and orienting the two midwoofers with the flats of the frames facing eachother i think the SEAS 27TFFNC/CG is a good fit . It's on special at Madisound for $23



            http://www.madisound.com/catalog/pro...oducts_id=8177

            Zaphs also tested this one and the FR looks to good for a 2k LR4 XO.




            Modeled up the Bass response in Unibox at 20L per speaker sealed which gives an F3 of around 75hz.....definately doable for surround duty.

            Click image for larger version

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            So.......fire away with comments and suggestions. I'd like to finalize everything by the beginning of next week. I've just finish building enclosures into the soffit using 3/4" MDF, and running 14/2 inwall speaker wire from the wallplate into the enclosures.

            I've got a driver total of $86 for two speakers so i'm well withing budget so far. I don't think i'll need too many XO components to shape these but you guys will be the judge of that. Thanx in advance.

            Comment


            • #7
              Re: Help with In-wall surround design

              I've tried modelling with that tweeter, and it has a really low impedance aken to 3 ohms. If you are using an MTM, and the tweeter is barely capable of keeping the sensitivity in check with the woofers in parallel, it might be a troublesome impedance in the end. If you have to pad the tweeter, it becomes a non-issue.
              My 2c,
              Wolf
              "Wolf, you shall now be known as "King of the Zip ties." -Pete00t
              "Wolf and speakers equivalent to Picasso and 'Blue'" -dantheman
              "He is a true ambassador for this forum and speaker DIY in general." -Ed Froste
              "We're all in this together, so keep your stick on the ice!" - Red Green aka Steve Smith

              *InDIYana event website*

              Photobucket pages:
              http://photobucket.com/Wolf-Speakers_and_more

              My blog/writeups/thoughts here at PE:
              http://techtalk.parts-express.com/blog.php?u=4102

              Comment


              • #8
                Re: Help with In-wall surround design

                Those midbass will work great in your application. But I would use a more robust tweeter that could cross low with the midwoofers. The flange size won't be an issue if you use a lower xover point. The North D25 will be excellent, but if you cannot obtain them, the following will do:

                http://www.madisound.com/catalog/pro...oducts_id=8300

                With this tweeter, a 1.6 kHz point should be possible. dlr has a mod for this tweeter if you're interested.

                Jay

                Comment


                • #9
                  Re: Help with In-wall surround design

                  Originally posted by jkim View Post
                  Those midbass will work great in your application. But I would use a more robust tweeter that could cross low with the midwoofers. The flange size won't be an issue if you use a lower xover point. The North D25 will be excellent, but if you cannot obtain them, the following will do:

                  http://www.madisound.com/catalog/pro...oducts_id=8300

                  With this tweeter, a 1.6 kHz point should be possible. dlr has a mod for this tweeter if you're interested.

                  Jay
                  I was considering the SB tweeter Jay.It saves me a couple more bucks as well. In order for it to fit, i'll have to offset it....i imagine the offset should be farther away from the ceiling?

                  Comment


                  • #10
                    Re: Help with In-wall surround design

                    Horizontal MTM? You should offset away from the corner closest, yes. This will yield less reflection.

                    If that's the case, you'll have limited horizontal dispersion in the surrounds, which should be a wide dispersion. Vertical is less of a concern if the tweeter is at ear-level, and then just offset away from the corner.
                    Later,
                    Wolf
                    "Wolf, you shall now be known as "King of the Zip ties." -Pete00t
                    "Wolf and speakers equivalent to Picasso and 'Blue'" -dantheman
                    "He is a true ambassador for this forum and speaker DIY in general." -Ed Froste
                    "We're all in this together, so keep your stick on the ice!" - Red Green aka Steve Smith

                    *InDIYana event website*

                    Photobucket pages:
                    http://photobucket.com/Wolf-Speakers_and_more

                    My blog/writeups/thoughts here at PE:
                    http://techtalk.parts-express.com/blog.php?u=4102

                    Comment


                    • #11
                      Re: Help with In-wall surround design

                      Originally posted by Mayhem13 View Post
                      I was considering the SB tweeter Jay.It saves me a couple more bucks as well. In order for it to fit, i'll have to offset it....i imagine the offset should be farther away from the ceiling?
                      It may depend on how close it is to the ceiling, but won't matter much. If it has to be a horizontal MTM, I recommend using a BW3 acoustic crossover for better dispersion. It will work well especially for surround speakers. With BW3, you may need to raise the xover point a bit, say to 1.8 - 1.9 kHz, since the tweeter takes a little higher load on its low end than with LR4.

                      Jay

                      Comment


                      • #12
                        Re: Help with In-wall surround design

                        Originally posted by jkim View Post
                        It may depend on how close it is to the ceiling, but won't matter much. If it has to be a horizontal MTM, I recommend using a BW3 acoustic crossover for better dispersion. It will work well especially for surround speakers. With BW3, you may need to raise the xover point a bit, say to 1.8 - 1.9 kHz, since the tweeter takes a little higher load on its low end than with LR4.

                        Jay
                        If using BW3, I recommend offsetting the crossover points by a factor of 1.2 to get a flatter power response while still achieving a flat response near the listening axis if the inter-driver delay is managed correctly. You get some very minor ripples through xover but the benefits outweigh the negatives.

                        Dave

                        Comment


                        • #13
                          Re: Help with In-wall surround design

                          Originally posted by Wolf View Post
                          Horizontal MTM? You should offset away from the corner closest, yes. This will yield less reflection.

                          If that's the case, you'll have limited horizontal dispersion in the surrounds, which should be a wide dispersion. Vertical is less of a concern if the tweeter is at ear-level, and then just offset away from the corner.
                          Later,
                          Wolf
                          Do you think i'd be better off with a horizontal TM for this application. These are for surround duty with the listening axis at 90 degrees and more.

                          Comment


                          • #14
                            Re: Help with In-wall surround design

                            Originally posted by Mayhem13 View Post
                            Do you think i'd be better off with a horizontal TM for this application. These are for surround duty with the listening axis at 90 degrees and more.
                            A coax would be best, but a horizontal TM would be better than an MTM in your situation. In fact, you could 'corner-mount' the tweeter inward and get better still in 2 planes.
                            Later,
                            Wolf
                            "Wolf, you shall now be known as "King of the Zip ties." -Pete00t
                            "Wolf and speakers equivalent to Picasso and 'Blue'" -dantheman
                            "He is a true ambassador for this forum and speaker DIY in general." -Ed Froste
                            "We're all in this together, so keep your stick on the ice!" - Red Green aka Steve Smith

                            *InDIYana event website*

                            Photobucket pages:
                            http://photobucket.com/Wolf-Speakers_and_more

                            My blog/writeups/thoughts here at PE:
                            http://techtalk.parts-express.com/blog.php?u=4102

                            Comment


                            • #15
                              Re: Help with In-wall surround design

                              I don't know if you remember me asking about DIY IN Ceiling designs Wolf, but i did think about an Eminence 8" coax in ceiling with an inexpensive CD. Would sure be loud enough to keep up with the mains if nothing else. Given the availability of a lathe (:D) i could custom machine a tweeter housing that would thread in from the front after removing the dustscreen......maybe a Dayton neo ?

                              Comment

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