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Overnight Sensations MTM in a larger enclosure. Good idea?

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  • Overnight Sensations MTM in a larger enclosure. Good idea?

    Hi, this will be my second DIY multi-way speaker build and I am pretty exited. Iv'e based it on Paul Camody's Overnight Sensations MTM but swapped the tweeter for a different one (Peerless NE19VTS-04) so that I have to design my own crossover. I did this because I liked the idea of big bass in a small enclosure, which is one of the selling points of the OS and I wanted to learn more about designing crossovers.

    I'm considering making the enclosure bigger (from 9 litres up to 13) and slightly lowering the tuning frequency to get an ever better bass response. Its probably a ridiculous question and I don't see how it could, but will that somehow ruin that OS 'magic'? It models well in comparison on WinISD with an F3 of 47Hz compared to 54Hz but the original design's claimed response doesn't match with its simulated response anyway.

    Any other tips or ideas would be much appreciated!

    Thanks!

  • #2
    Stop calling it an Overnight Sensation. It's your design with only the hivi woofers in common with the OS.

    People here can help you with your design.

    Comment


    • #3
      Haha yeah you're right. Its because I started off thinking I would make the OS and its gradually changed to become my own design. Calling it an OS made it much easier to phase my question.

      Comment


      • #4
        You'll likely run into Xmax issues with a larger box. There is only so much a 4" driver can do.

        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


        • #5
          I think your box/tuning might only lose a dB or 2 in max. output. It should be OK, probably.

          Don't look at the XO info (below) if you want to figure it out for yourself.





          You COULD just drop the 10n(ohm) resistor down to about 2n.

          But the O.A. response will be closer (to the OS MTM) if you just go 2nd order w/an L-pad:
          The shunt coil (to gnd) stays, the initial cap goes to 8uF (drop the resistor).
          The cap on the back end gets replaced by an "L": SR=3n / PR=5n.
          (The LP on the woofers stays the same.)

          Comment


          • #6
            Instead of a larger bass-reflex cabinet, you might want to look into some of the mass loaded transmission line cabinets on Paul's web-page. Nice bump in low frequency output and use about the same floor space as the OS MTM on a stand.
            If life were fair, Elvis would still be alive today and all the impersonators would be dead.
            ~ Johnny Carson

            Bungelow Ed's Photo Album http://techtalk.parts-express.com/album.php?u=8594

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            • #7
              Sweet. Thanks all for your ideas! I'll have a look at Paul's transmission line boxes but I only have very basic tools for woodworking and I wasn't planning on making floor standers. I think you are right about Xmax Wolf, I hadn't thought of that. I know Paul makes some OS tower versions with a volume around 20 L. How does he manage excursion in that?

              Cheers!

              Comment


              • #8
                I believe the OS towers have 2 woofers, and are a 2.5-way TL design.

                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


                • #9
                  They are just simple bass reflex speakers. Mine also has two woofers (MTM) but you are correct about Paul's being 2.5 way. I think they are just not designed to be played loud.

                  Comment


                  • #10
                    I built and posted a design for an MTM MLTL which Paul posted pictures of on "undefinition." Another person tool my cabinet length and cross-section to build a 6 sided cabinet.
                    If life were fair, Elvis would still be alive today and all the impersonators would be dead.
                    ~ Johnny Carson

                    Bungelow Ed's Photo Album http://techtalk.parts-express.com/album.php?u=8594

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                    • #11
                      The MTM version is a 2-way while the TMM is a 2.5-way.

                      DIY audio projects by Paul Carmody (Undefinition)

                      Comment


                      • #12
                        Originally posted by davidroberts View Post
                        The MTM version is a 2-way while the TMM is a 2.5-way.
                        Yes, You are correct in your comment about MTM and TMM cross-over types. However, my original comment was intended to address the Subject Line: "Overnight Sensations MTM in a larger enclosure. Good idea?"

                        Oh and yes, in IMO a MLTL MTM Overnight Sensation is a good idea.
                        If life were fair, Elvis would still be alive today and all the impersonators would be dead.
                        ~ Johnny Carson

                        Bungelow Ed's Photo Album http://techtalk.parts-express.com/album.php?u=8594

                        Comment


                        • #13
                          I apologize if something I typed may have ruffled your feathers but that was in no way my intention. I was actually confirming Wolf's post were he stated he thought there were different x-overs between the two designs.

                          I also wanted to supply a link to the OP so that he could SEE your design as well as the others you mentioned but had not supplied links to for the OP.

                          In the future I will make sure to use proper forum etiquette and quote the post that I am responding to so that no one feels slighted.

                          As a disclaimer, I have built a set of Ed's MLTL OS MTM's and they were very good performers.

                          For the original poster I would recommend that he run sum simulations in Unibox or WinISD to see if the changes he is proposing shows any benefits or shortcomings.
                          Want a second or third opinion about your speaker cabinet design or other audio related problem? Post your question or comment on the Technical Discussion Board. Hundreds of technicians, engineers, and hobbyists, nationwide read and discuss electronics related questions each week. We welcome your participation

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                          • #14
                            Originally posted by davidroberts View Post
                            I apologize if something I typed may have ruffled your feathers but that was in no way my intention.
                            No feathers ruffled or offense taken, though I can see why you might have thought as much. My attention was divided between this thread and family matters. Looks like I took the less diplomatic approach to conveying my point without recognizing how it might sound. Please accept my apologies as well.
                            If life were fair, Elvis would still be alive today and all the impersonators would be dead.
                            ~ Johnny Carson

                            Bungelow Ed's Photo Album http://techtalk.parts-express.com/album.php?u=8594

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