Hi, This is a great design, I'd love to try it. Have been wanting to do TL for a while now. I'm also based in Melbourne - know anywhere where I could pick these up? Now that the weather is picking up, would be nice to spend a couple of weekends putting these together. Would just be difficult to choose the finish! Hey, Yeah, which is interesting since the drivers are no longer made by Tymphany.

Are they just coming out of an OEM in China now? Anyway I have sourced 4 x P17 and 2 x D25, arriving next week. So in a few weeks when the weather is on the improve, will build an enclosure as you describe here! Minus the curvature, though.

I'll let you know how it goes, though I don't have a big room to put it in really, I live in a small Victorian-era terrace house that is narrow. Anyway thanks for this article. I have been reading some of the stuff on quarter-wave.

Your blog entry makes it very simple. You might be right, I have no idea. Look forward to seeing how it goes.

diy transmission line speakers

Hi, I really like your design and I am very keen to try it. I currently work at a Jaycar store. A few months back we started stocking the vifa drivers again but still don't have the complete JV kit, only the premade enclosures.

I'm waiting out for the whole kit as it is cheaper than buying all the bits individually! Should have them in a few weeks hopefully. Thanks again for the great article and design, Adam. Yep, built them. I have a couple P17 woofers Hi Christopher, I've taken that page offline because I need to get permission to publish some of the content.

Send me a message via the contact form under feedback on the right and I will dig up some info. Hi Paul. Thanks for sharing your knowledge.This center channel turned out very nice. It was designed for a customer to go along with a floorstander group design on the HT guide forum.

An array with HiVi woofers and Dayton planar tweeters. Also pictured is the Sardonyx center channel. Another design inspired by a pricey commercial speaker. The builder in Virginia did an awesome job on the cabinet.

We designed the crossover for this one and Paul did the rest. A dipole Scan-Speak 7" with a Fountek ribbon tweeter.

diy transmission line speakers

The Vifa woofer was actually used in the first speakers from Krell. This is an older legacy design with Seas magnesium cone woofers and Fountek ribbon tweeters in the line arrays. The subwoofers have dual Scan-Speak 23W aluminum cone drivers.

diy transmission line speakers

A 2-way designed for the Anarchy woofer and Dayton soft dome tweeter manufactured by Usher I believe. Plans are available in return for a donation to honor Brandon Keele.

Home Blog Speakers Designs. Why DIY? DIY A gallery of customers who have built their own speakers from our kit designs. DB Desktop Array. Albert V A customer found inspiration in emulating a design that he liked.

Aurarray A HT designer in Dallas built this pair of arrays for a theater in his area. Australian 3-way A custom design with a Scan-Speak woofer, Accuton midbass, and Fountek ribbon tweeter.JavaScript seems to be disabled in your browser.

You must have JavaScript enabled in your browser to utilize the functionality of this website. In addition to a detailed description of complete systems, Seas also provide crossovers and sketches. Each system picture will take you to the design page on the Seas website, where you can download cabinet, crossover and technical information sufficient for you to be able to construct the kit.

Please note that we can only supply drive units and crossover components etc. Easy and economical to build, giving the very highest level of performance. The cabinet is a bass reflex with a rear vent. The cabinet is a rear vent bass reflex design. The enclosure uses a newly developed computer modelled transmission line configuration, tapered, and filled with Dacron stuffing. The two W18E woofers excite the line at slightly different points, smoothing the response and increasing the range of bass output.

The -3dB point is 45Hz, with roll off of 12dB per octave below 45Hz.

Usable in-room bass response extends well into the low 30Hz range. Only available from Falcon Acoustics. Falcon Acoustics B and T Rare hard-to-find drivers here.If you find the contents of this page to be useful, please consider making a donation by clicking the Donate button below. Quarter-wave transmission line speakers employ enclosures that are tuned to provide low-frequency extension for the speaker driver. There are several types of transmission line enclosures and one of the more popular ones is the mass loaded transmission line MLTL.

Basically, an MLTL is a quarter-wave transmission line enclosure with a port. Now, some may argue that this is a bass reflex enclosure - and the line is indeed a bit blurry.

However, rather than engaging in a lengthy discussion on naming conventions, I will use the term MLTL to describe a ported quarter-wave enclosure. Thanks to a collection of MathCad programs developed by Martin J. If you do not have access to MathCad, MathSoft makes a MathCad viewer available, which allows you to work with the programs and perform all the needed simulations. You just cannot save your results. For details, as well as other options for how to obtain MathCad, see Martin J.

King's website. King's programs. Further optimization is likely needed. I have listened to speakers that used the Alpair I really liked the sound, though, the metallic cones bother me.

The provide a boost in the mid treble that I don't care so much for. The cones are also really fragile. The Alpair 10 is classified as a 6" driver measuring mm in diameter. Much of the diameter is taken up by the surround and mounting flange. The effective area, Sd, of For MLTLs, there are three fundamental choices: Tapered with narrow top, straight pipe, or tapered with wide top.

Source: Bob Brines. With the MathCad programs it is trivial to try the different types of enclosures.

Designing MLTL Speakers

For each taper, work through the design procedure and pick the configuration that provides the smoothest frequency response. That indeed was the case with the Alpair 10P-A. This makes the resonant modes much easier to identify in the SPL graph. Once the enclosure has been tuned to the best performance, damping material is added to squelch the remaining resonant modes. Red is the combined SPL of the driver and the port. Blue dashed is the infinite baffle response of the driver.The Audio Voice Newsletter.

Augspurger Zalytron. Show more Show less. One of the most important speaker building projects published by audioXpress, THOR was designed by Joseph Joe D'Appolito, who is world-renowned for his pioneering work on MTM-based mid-tweeter-mid loudspeaker configurations.

Read the complete article here. They are essentially non-resonant enclosures, producing a deep, well-controlled bass response. For a given driver, bass response will extend well below that produced with either a vented or sealed enclosure using the same driver. Above a few hundred Hz, the line filling material completely absorbs the driver backwave, giving the TL an open, non-boxy sound.

His overall impressions stated: The speakers appear to reproduce whatever is fed them with flawless transparency. So well, they ruthlessly reveal any recording or medium deficiency. I know it has become a popular speaker, but at present I have neither the time or resources to update the design.

I believe the real contribution of the original THOR article was detailing the technique for experimental optimization of the Transmission Line. They described their new Excel line of drivers to me and asked whether I could design a flagship loudspeaker using these drivers that would highlight their extraordinary capabilities.

They wanted something other than a vanilla sealed or vented box. The advantages of TLs are well known. For a given driver, bass response can often extend well below that produced with either a vented or sealed enclosure using the same driver. Above a few hundred Hz, the line-filling material completely absorbs the driver back wave, giving the TL an open, non-boxy sound.

Unfortunately, the TL has not enjoyed wide commercial popularity due to the lack of a good design theory and the additional complexity of enclosure fabrication relative to the more conventional vented and sealed enclosures. Recently, however, work by G. Augspurger has appeared in the technical literature and in audioXpress see References that, while not providing a complete theory of design, has given us an excellent starting point.

This, coupled with modern PC-based acoustic measurement systems, allowed me to converge quickly to an optimum design for the new Excel W18EX woofers. The present design uses an MTM driver configuration in a tapered, folded line uniformly filled with Dacron pillow stuffing. Tapering the line greatly increases the frequency range of bass augmentation produced by the line.

Using two mid-bass drivers exciting the line at slightly different points reduces mid-bass ripple. The resulting line produces a uniform 3—4dB bass response lift from Hz all the way down to 20Hz with less than 1dB ripple.

Contrast this against 65Hz for a similarly damped sealed enclosure. Several hundred hours of laboratory testing and listening have gone into producing a seamless transition between the mid-bass and tweeter drivers. You literally cannot tell where the woofers leave off and the tweeter begins.Where to start with this one.

SEAS DIY Speaker Kits

What an anus of a project. It should have been an amazing build. Its should have been an absolute breeze, once I had it all figured out. It should have been a well planned, well executed joy of a thing.

How to build DIY transmission line speakers

Best laid plans and all that…. They seemed to be somewhat of a unicorn in the speaker design world. Too sensitive to room placement and tricky to tune the internal absorption and damping materials to make them a viable commercial proposition. But when done right, offering amazing performance — especially in the B. The subs I built in my sound system build were rear loaded tapped horns — similar to a transmission line, but not the same.

Horn speakers work on exactly the same principle as brass instruments, such as a trumpet, trombone or french horn.

The tapped horn subs were tuned to 25hz. Very low B. This gets very technical, very quickly. Go here and fist your mind with quarter wave theory. Fill your boots. The rabbit hole is deep. And full of science. To summarise: Sound waves — like any wave — have a wavelength.

That length is measured in physical terms cm, inches, feet, metres. The longer the wave, the lower the frequency. The shorter the wave, the higher the frequency. The greater the amplitude of the wave, the louder the sound. Crafting clever enclosures can enhance certain frequencies. Like B. Stay with me… speaker drivers generate sound waves by turning electrical energy from an audio source in to physical motion. By rapidly oscillating the speaker cone, air molecules are moved in waves.

Our ears register these pressure waves relative changes in air density as sound. All speaker drivers have a specific resonant frequency — a wavelength which the driver resonates at, which causes all sorts of problems think opera singers shattering wine glasses with their voice.

Transmission line speakers take the principle of matching a speaker driver to the correct amount of air pressure behind the cone in this case the volumetric capacity of a shaped chamber or pipeto help sort out resonance problems AND enhance certain frequencies.

Enough of that. I made some plans….I decided to give them a try and was surprised with the sound quality! Of course they did not play as loud as the bigger two-way speakers that I built before, but something else was fascinating.

Fullrange drivers seem to play music with more coherence, more life and they sound more direct. However, there are compromises with fullrange drivers; little drivers have disadvantages at the low end and bigger ones at the top end. Looking for more information about fullrange drivers, I found the Mathcad worksheets by M.

King and decided to try a speaker design of my own. My first try was a speaker using the Fostex FEEbut I never made proper cabinets for them because my wife said "No way, they are too big". Searching a smaller driver the Fostex FX, a 12 cm fullrange unit caught my eye.

There is not much information available for this driver, but the feedback from people who have used was positive. On the Fostex data sheet they show a flat frequency response without great peaks and drops.

diy transmission line speakers

The FX will need a little help on the bottom end. The goal was to let them go down to about 50 Hz. Afterwards I contacted M. King and asked him to have a look at the simulation I had completed. With his feedback "I think you have a design" I want to thank Mr. King for his kind help and advice I made some test enclosures out of chipboard. Figure 1 shows the calculated frequency response for the FX for the enclosure shown in Figure 2. At first they were a little bit harsh but after about hours they smoothed out.

I began to tune them by ear until I was satisfied with the music coming out of the speakers. I played with the length of the port and tested several values of inductors and resistors for the baffle step correction BSC circuit.

Transmission line Bluetooth speaker DIY

The BSC is necessary, otherwise the sound isn't balanced. The enclosures were made using 15 mm birch-multiplex, the front baffle and the top is 19 mm beech, and the inner plates are 16 mm MDF. Naturally you can use material of a different thickness, but be sure to adjust the dimensions in the plan.

Before I closed the box with front and top there were four things to do. First I attached nylon strings between the sides to keep the damping material from falling to the bottom. Another thing is to put in the damping between the inner and back plate as you cannot do this through the driver cut-out once the cabinet is closed.

The wiring must be in place and the hole in the back for connecting the wire with the BSC has to be sealed.


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