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"Speaker Terms Glossary" not working -- What does "MLTL" mean?

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  • "Speaker Terms Glossary" not working -- What does "MLTL" mean?

    When I click on the glossary link it goes to a page with no information

    Tried the "New" search and got lots of hits of MLTL but none of them explained it.

    Could someone explain it to me?

  • #2
    Re: "Speaker Terms Glossary" not working -- What does "MLTL" mean?

    Mass Loaded Transmission Line.

    As for an explanation, there are folks a lot more qualified than me around here. One of them will chime in soon, no doubt.

    Comment


    • #3
      Re: "Speaker Terms Glossary" not working -- What does "MLTL" mean?

      MLTL is a quarter wave design that uses a port to "tune" the response of the speaker.
      craigk

      " Voicing is often the term used for band aids to cover for initial design/planning errors " - Pallas

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      • #4
        Re: "Speaker Terms Glossary" not working -- What does "MLTL" mean?

        Here's a "white paper", sort of, describing an ML-TL that I wrote for the ML-TL designs I did for Dennis Murphy for his Philharmonic Audio speakers:
        http://www.philharmonicaudio.com/fol...ges/about.html
        Paul

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        • #5
          Re: "Speaker Terms Glossary" not working -- What does "MLTL" mean?

          Originally posted by Paul K. View Post
          Here's a "white paper", sort of, describing an ML-TL that I wrote for the ML-TL designs I did for Dennis Murphy for his Philharmonic Audio speakers:
          http://www.philharmonicaudio.com/fol...ges/about.html
          Paul
          That's a very good description. However, for the purpose of simplification for those new to the concept it could also be described by flip-flopping it and describing it as a traditional vented box where consideration is also given to internal quarter-wave resonances in the enclosure and their effects on the port tuning. This usually results in a port tuning that is lower than predicted by traditional box theory.

          Jeff B.
          Click here for Jeff Bagby's Loudspeaker Design Software

          Comment


          • #6
            Re: "Speaker Terms Glossary" not working -- What does "MLTL" mean?

            Originally posted by Paul K. View Post
            Here's a "white paper", sort of, describing an ML-TL that I wrote for the ML-TL designs I did for Dennis Murphy for his Philharmonic Audio speakers:
            http://www.philharmonicaudio.com/fol...ges/about.html
            Paul
            How did I get so lucky to have you help me with my speakers? I listen to them everyday and I really can't thank you enough!

            As I've said before,,,, You are a CLASS ACT! Thanks, Mark

            Comment


            • #7
              Re: "Speaker Terms Glossary" not working -- What does "MLTL" mean?

              Thanks, Jeff, I appreciate the compliment. My description does address your points, I believe, but, perhaps, not quite in a simplified manner. More to the last point you made, the port tuning is not lower, per se. Rather the system tuning frequency is usually lower due to the combined contributions from both the 1/4-wave resonance and the port's tuning.
              Paul

              Originally posted by Jeff B. View Post
              That's a very good description. However, for the purpose of simplification for those new to the concept it could also be described by flip-flopping it and describing it as a traditional vented box where consideration is also given to internal quarter-wave resonances in the enclosure and their effects on the port tuning. This usually results in a port tuning that is lower than predicted by traditional box theory.

              Jeff B.

              Comment


              • #8
                Re: "Speaker Terms Glossary" not working -- What does "MLTL" mean?

                I'm really happy that you're really happy, and I was glad to help out.:D
                Paul

                Originally posted by Psycoacoustics View Post
                How did I get so lucky to have you help me with my speakers? I listen to them everyday and I really can't thank you enough!

                As I've said before,,,, You are a CLASS ACT! Thanks, Mark

                Comment


                • #9
                  Re: "Speaker Terms Glossary" not working -- What does "MLTL" mean?

                  Originally posted by Paul K. View Post
                  Thanks, Jeff, I appreciate the compliment. My description does address your points, I believe, but, perhaps, not quite in a simplified manner. More to the last point you made, the port tuning is not lower, per se. Rather the system tuning frequency is usually lower due to the combined contributions from both the 1/4-wave resonance and the port's tuning.
                  Paul
                  I was "simplifying", what I mean is that if you measure the tuning frequency (of the system, as you said) it will be lower than expected for that size port in that box. This is usually the case with MLTL designs because part of the air in the cabinet behaves like an extension of the port, making it work like its longer than it actually is. A lot of vented designs do this too if the port is placed too close to a wall in the cabinet. The MLTL math just takes this into account.
                  Click here for Jeff Bagby's Loudspeaker Design Software

                  Comment


                  • #10
                    Re: "Speaker Terms Glossary" not working -- What does "MLTL" mean?

                    In a classic bass reflex design, the air in the box is purely a spring and the air in the port is a perfect slug of mass. This is a simple textbook single degree of freedom mass and spring system. In a ML TL design, the standing wave in the box behaves as both mass and spring. So the ML TL enclosure has more mass then is accounted for in just the bass reflex enclosure's port and a little less spring then the volume of air would imply. These are subtle differences but enough to lower the tuning a few Hz. Stretching a bass reflex design to become a tall ML TL is a gradual process, there is no clear line defining the geometry as one or the other only a gray area where the transition takes place.
                    Martin

                    Quarter Wavelength Loudspeaker Design
                    www.quarter-wave.com

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