Announcement

Collapse
No announcement yet.

Any one have experience with transmission line bass enclosures.

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

  • Any one have experience with transmission line bass enclosures.

    I have been looking for information on the positives and negatives of t line enclosures for bass drivers. I have found some highly technical info (difficult to follow) and some online calculators. I was wondering if any of our guru here had any experience with them and could offer some subjective opinions? Things like effect on box size, sound quality, difficulty of correct enclosure design.

    I am still mulling over designs for music speakers using my peerless 6 1/2" nomex buyouts as mids in a mtm and variants for the base drivers and enclosure. Highest on the list for base drivers are Peerless XLS and XXLS 10" or 12" , or possibly two Scan-Speak Discovery 26W/8534G 10" in series. The Peerless drivers are the ones I would consider using in a T line enclosure.

    Thanks, David

  • #2
    Re: Any one have experience with transmission line bass enclosures.

    Paul K is the resident guru on tls here. Depending on driver and application there may not be much to gain in using a tl over a ported enclosure. Size will definetely increase and there should be a smoother roll-off, but that may come at the expense of efficiency.
    https://www.facebook.com/Mosaic-Audi...7373763888294/

    Comment


    • #3
      Re: Any one have experience with transmission line bass enclosures.

      Originally posted by Dabspok View Post
      I have been looking for information on the positives and negatives of t line enclosures for bass drivers. I have found some highly technical info (difficult to follow) and some online calculators. I was wondering if any of our guru here had any experience with them and could offer some subjective opinions? Things like effect on box size, sound quality, difficulty of correct enclosure design.

      I am still mulling over designs for music speakers using my peerless 6 1/2" nomex buyouts as mids in a mtm and variants for the base drivers and enclosure. Highest on the list for base drivers are Peerless XLS and XXLS 10" or 12" , or possibly two Scan-Speak Discovery 26W/8534G 10" in series. The Peerless drivers are the ones I would consider using in a T line enclosure.

      Thanks, David
      I've got some experience with them and I can simulate the hell out of them. I can show you examples or answer specific questions but I'm not going to give subjective opinions, those are easily misunderstood or not understood at all (often by both the speaker and the listener).
      Don't even try
      to sort out the lies
      it's worse to try to understand.

      Comment


      • #4
        Re: Any one have experience with transmission line bass enclosures.

        Thanks guys. I'm an extreme novice at the sound game so I am doing all I can to learn about what works and why. As a victim of the economy I have a lot of time on my hands to daydream about designs. Spare time doesn't help the ADHD hyperactive mind...
        diy speaker guy, I may take you up on the help and information. I don't want to wast peoples time with "what if's" so I will keep my pestering of people to a minimum.
        I do have eight Peerless 830875 buyouts, two Peerless 830873 buyouts and two SEAS Prestige 27TBFC/G tweeters. I had a grand idea for a Paradigm S8 knock off, but I have realized using four 6 1/2" drivers in the base section was just overkill. I will probably build a shorter version with two 6 1/2", the 5 1/4" as mids and the seas tweeters. That leaves me with four 6 1/2" to use in another build, a MTMW. So I am looking at possibilities for the base section in the second speaker.
        I have also been searching this forum and others for info on the Peerless and Seas drives to see how others have used them. Yes, I have waaayyy to much time on my hands. :D

        Comment


        • #5
          Re: Any one have experience with transmission line bass enclosures.

          A specific design I have looked at as a TL is the base section of Troels Gravesen's Jenzen series of speakers. The base enclosure looks close to the measurements I get using the online calculators and the driver is similar (not exact) to the Peerless 10" XXLS. In one of the plan sections he shows how he lays out the 13 mm felt and 30 mm poly for damping. I figure the basic design built to the measurements from the online calculator should work.
          One thing I am not sure about is his use of slots and ports at the terminal end. The calculators seem to be set up for open ended termination. Some of the theory I read talked about infinite TL's and how the terminal end would actually be closed as the damping material was "soaking" up the energy from the speaker. Obviously real enclosures are not infinite and the opening size will have an effect on the TL... Thoughts using the Peerless 10" XXLS as an example for this discussion?

          http://www.troelsgravesen.dk/Jenzen-Illuminator.htm
          Last edited by Dabspok; 09-26-2012, 05:13 AM. Reason: added link

          Comment


          • #6
            Re: Any one have experience with transmission line bass enclosures.

            Originally posted by Dabspok View Post
            I had a grand idea for a Paradigm S8 knock off, but I have realized using four 6 1/2" drivers in the base section was just overkill.
            I'm not familiar with that model but here's my grand idea.



            That's not overkill, it's exactly the right amount of kill. After all, four 6.5 inch drivers only = 1 single low xmax 12 inch.

            I'm going to build this speaker one day, I just need to get off my lazy *** and do it.
            Don't even try
            to sort out the lies
            it's worse to try to understand.

            Comment


            • #7
              Re: Any one have experience with transmission line bass enclosures.

              Which online calculator are you using to simulate that? And you are talking about the tl version, not the ported version, correct?

              The Peerless xxls is probably a fine driver although I have no experience with it.

              Why do you want to copy someone else's design, especially with a different driver? What's the goal here? Usually you set out your goals first and then design something to meet these goals, not find a design you like the look of and try to make it work with equipment you have.
              Don't even try
              to sort out the lies
              it's worse to try to understand.

              Comment


              • #8
                Re: Any one have experience with transmission line bass enclosures.

                Originally posted by Dabspok View Post
                One thing I am not sure about is his use of slots and ports at the terminal end.
                It's easy enough to simulate with the right software, it's just a restriction at the end of the line. There's nothing wrong with this as long as you leave enough open space to avoid problems.

                The calculators seem to be set up for open ended termination. Some of the theory I read talked about infinite TL's and how the terminal end would actually be closed as the damping material was "soaking" up the energy from the speaker. Obviously real enclosures are not infinite and the opening size will have an effect on the TL...
                Classic transmission lines were used to suck up all the bass from the backside of the driver to get as close as possible to IB response. This was achieved by using a long line with no opening that was heavily stuffed and carefully tuned to driver fs. You don't see this approach much anymore, although there are some fancy commercial snail shell shaped ones that attempt this.
                Don't even try
                to sort out the lies
                it's worse to try to understand.

                Comment


                • #9
                  Re: Any one have experience with transmission line bass enclosures.

                  Just last week at the DIY Audio forum, there was a long thread focused mostly on Troels' Jenzen designs. Troels does not apparently use any of the available TL modeling software and his TL designs are therefore usually lacking to say the least. In the Jenzen the woofer is placed at the very beginning of the line which is not an optimum location, although if the crossover to the midrange is low enough in frequency (used primarily as a subwoofer), then the performance isn't compromised too badly. Here's the link to the DIY Audio thread:
                  http://www.diyaudio.com/forums/multi...-question.html
                  My advice? Don't build or try to emulate the Troels Jenzen TL. Let Diy Speaker Guy or me help you.
                  Paul

                  Originally posted by Dabspok View Post
                  A specific design I have looked at as a TL is the base section of Troels Gravesen's Jenzen series of speakers. The base enclosure looks close to the measurements I get using the online calculators and the driver is similar (not exact) to the Peerless 10" XXLS. In one of the plan sections he shows how he lays out the 13 mm felt and 30 mm poly for damping. I figure the basic design built to the measurements from the online calculator should work.
                  One thing I am not sure about is his use of slots and ports at the terminal end. The calculators seem to be set up for open ended termination. Some of the theory I read talked about infinite TL's and how the terminal end would actually be closed as the damping material was "soaking" up the energy from the speaker. Obviously real enclosures are not infinite and the opening size will have an effect on the TL... Thoughts using the Peerless 10" XXLS as an example for this discussion?

                  http://www.troelsgravesen.dk/Jenzen-Illuminator.htm

                  Comment


                  • #10
                    Re: Any one have experience with transmission line bass enclosures.

                    Having the driver one third distance down the line helps to keep the frequency response flat.

                    Comment


                    • #11
                      Re: Any one have experience with transmission line bass enclosures.

                      Looks sort of familiar...lol!
                      Click image for larger version

Name:	Baffle_Peerless4Base_rendering2_040612a.jpg
Views:	2
Size:	38.3 KB
ID:	1144216


                      Paradigm Signature S8...
                      http://www.paradigm.com/products/pro...s/signature-s8
                      Last edited by Dabspok; 09-26-2012, 02:23 PM.

                      Comment


                      • #12
                        Re: Any one have experience with transmission line bass enclosures.

                        Originally posted by diy speaker guy View Post
                        Which online calculator are you using to simulate that? And you are talking about the tl version, not the ported version, correct?

                        The Peerless xxls is probably a fine driver although I have no experience with it.

                        Why do you want to copy someone else's design, especially with a different driver? What's the goal here? Usually you set out your goals first and then design something to meet these goals, not find a design you like the look of and try to make it work with equipment you have.
                        Calculators I found. I used the last two.
                        http://dbdynamixaudio.com/dual-fold-...re-calculator/
                        http://www.mh-audio.nl/TML.asp
                        http://www.mh-audio.nl/bailey_tml.asp

                        Comment


                        • #13
                          Re: Any one have experience with transmission line bass enclosures.

                          Originally posted by Paul K. View Post
                          Just last week at the DIY Audio forum, there was a long thread focused mostly on Troels' Jenzen designs. Troels does not apparently use any of the available TL modeling software and his TL designs are therefore usually lacking to say the least. In the Jenzen the woofer is placed at the very beginning of the line which is not an optimum location, although if the crossover to the midrange is low enough in frequency (used primarily as a subwoofer), then the performance isn't compromised too badly. Here's the link to the DIY Audio thread:
                          http://www.diyaudio.com/forums/multi...-question.html
                          My advice? Don't build or try to emulate the Troels Jenzen TL. Let Diy Speaker Guy or me help you.
                          Paul
                          Thanks for adding your thoughts Paul. I have read a lot of your posts and studied most of your designs on your site. I value your opinions and knowledge base greatly.

                          I was looking at the supposed gains in extension and clarity described in the articles about transmission lines. Looks like I may be looking for the non-existent magic pill. It may be in my best interest to work with a sealed enclosure and move to maybe the XXLS12" to gain the slightly lower Fs.
                          What made me decide not to build the S8 knock off was the 120 liter size the Peerless 6 1/2" drivers wanted and the idea that the spl gain with the 4 Peerless bass would make it difficult to transition to the 5 1/4" peerless mid. Causing a miss matched sound. I have a lot to learn and I should probably get on with the TMWW design as it seems not quite as difficult to sort. Pete Schumacher built something similar in 2010:
                          http://techtalk.parts-express.com/sh...-way-under-way

                          Comment


                          • #14
                            Re: Any one have experience with transmission line bass enclosures.

                            Also..
                            Thanks for the link Paul. It is great to see current discussion on this topic. It is a fascinating read, reminding me that all is subjective, every one approaches a problem with a different "set of tools" and... I have a LOT to learn!

                            It reminds me of when I was a kid listening to my dad and his two friends discussing race car chassis set up for circle track racing. Dad is a Electrical engineer, one of his friends was a Physicist and the other was a old racer. You can imagine the discussions!

                            Thanks again Paul, I will have to reread that thread a couple (of dozen) times!

                            Comment


                            • #15
                              Re: Any one have experience with transmission line bass enclosures.

                              Happy to be able to help. That thread is very enlightening even though it did contain quite a bit of animosity, primarily from one poster. In the end, a TL is just one of several choices to consider when designing a box for a driver. Sometimes, a driver can be very versatile and perform well in more than one kind of box, while at other times, only one type of box is good.
                              Paul

                              Originally posted by Dabspok View Post
                              Also..
                              Thanks for the link Paul. It is great to see current discussion on this topic. It is a fascinating read, reminding me that all is subjective, every one approaches a problem with a different "set of tools" and... I have a LOT to learn!

                              It reminds me of when I was a kid listening to my dad and his two friends discussing race car chassis set up for circle track racing. Dad is a Electrical engineer, one of his friends was a Physicist and the other was a old racer. You can imagine the discussions!

                              Thanks again Paul, I will have to reread that thread a couple (of dozen) times!

                              Comment

                              Working...
                              X