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MLTL-6 Mass Loaded Transmission Line Speaker Build Manual

$150.00

“…arguably the best speaker kit available” - Cheap Audio Man

This is a mass loaded transmission line speaker, that uses a 6” paper cone woofer, and either a 1” soft dome tweeter, or a dipole tweeter - both options are included. Personally, I prefer the latter, partly because it is a dipole. But the dome tweeter is excellent, and has a smoother and more extended response. It is available retail - which is key!

This speaker has the best bass quality of any speaker I have heard in my nearly 4 decades of music listening. They are essentially flat in my room to about 32Hz, and also have wonderful “unboxy” midrange, and have a spacious soundstage; if it is there in the recording. The midrange of transmission line speakers is also much more open than conventional designs; and may rival open baffle designs.

The cabinet is 9”W x 21.5”H x 16”D / 227mm x 546mm x 407mm and is made with 18mm thick material - either Baltic birch or MDF. Each finished speaker built with the Baltic birch flat pack weigh a bit less than 29 lbs / 13kg. The corners are designed to have a 12mm x 12mm chamfer; but the MDF can be left square, if you choose. See the images of the SketchUp model below, for how this will look. The chamfer also has an acoustic function of reducing edge diffraction. I can provide CAD files to make CNC cut files - the build manual includes drawings of the CNC version of the panels. It can be built with a table saw and plunge router, and/or with a CNC machine.

A strong benefit of a “folded” transmission line design is the internal baffles not only form the specific volumes and dimensions required for the correct tuning for the woofer - they also form asymmetrical bracing for the cabinet. I include a brace in the closed end, that greatly strengthens the front baffle - which is the most critical area, since the drivers are mounted there. Less obvious is the fact that the internal air pressure in a TL design is lower than an equivalent sealed, or even a ported design. This greatly reduces the panel resonances - and this is possibly why the midrange and bass are more open and clearer. The woofer has less of an “air spring” behind it, so it is more closely reproducing the music in the recording.

I have also spent a lot of time designing and refining the crossover designs. Both are a 3rd order series crossover design for both the 1” soft dome, and the dipole tweeter versions. A series crossover diverts the signal that is filtered out for one driver, and diverts it to the other driver. And so a series crossover can be slightly more efficient, and they tend to have a smoother more even impedance; which can make them better for use with tube amplifiers.

A transmission line speaker cabinet is a tuned “column” of air behind the driver - it has lower distortion and greater bass extension that conventional sealed or ported designs. I used a program called Hornresp (short for Horn Response), and carefully matched the computer acoustic model to the cabinet design, using DataCAD.

The cost of the pair of woofers and a pair of the dome tweeters is about $150, from Madisound. They are both made by SB Acoustics. I have used all air core inductor coils, and the woofer inductor coil is 14 AWG for a low DCR. This is important for the best possible bass quality. The capacitors I have used on the tweeter are the best quality that I have ever heard - they are ClarityCap CSA. The benefits of high quality crossover components cannot be overstated. The build manual includes clickable links for 3 options - “good, better, best” lists of crossover parts quality.

These speakers are fairly sensitive - the woofer is rated at 89.5dB @1W @1 meter. But the crossover lowers this somewhat, and the transmission line may increase it somewhat. I listen at a lower volume setting on my preamp than the other speakers I own. The MLTL-6 speakers are 4-6 ohm nominal impedance - the dome tweeter version is a minimum of about 4.2 ohms. The dipole tweeter has a minimum of about 4.5 ohms. I am using the amazing AkitikA GT-104 amp - it is rated at 60W/ch @ 4 ohms and ~30W/ch @ 8 ohms - it barely gets warm even after long listening sessions. Any amp that is rated for ~4 ohm speakers will probably work very well, with the MLTL-6 speakers. If you have a tube amp, it may better to use the series crossover, but these speakers are relatively easy to drive.

If you purchased the MLTL-6 build manual already and have not yet built them, and you want the current v2.6 build manual - email us to get it for your build. The update is the midwoofer is recessed. Also it now includes both straight cut panels and rabbeted & grooved panels. The manual includes drawings in inches and in millimeters, and includes a stand. I can provide the CAD files for CNC version of the panels, if you want to build it this way.

Here’s the Old Guy Hifi video review of the MLTL-6 speakers:
https://youtu.be/AEoduNaQaXk

Here’s the ABX Audiophiles’ video review of the MLTL-6 speakers that they built:
https://www.youtube.com/watch?v=gu-FuzyJ_1g

Here’s the Cheap Audio Man’s video review of the MLTL-6 speakers:
https://www.youtube.com/watch?v=jwzLeDOdoKY

Here’s the link to Part 1 of Sonnora Design’s build video of the MLTL-6 speakers:
https://www.youtube.com/watch?v=nSpSTMacz9A

For folks who want to build the MLTL-6 speakers - but do not have the tools to cut the panels, or do not want to cut them - we have flat packs available to order! They are 18mm Baltic birch, and you can select either the SB Acoustics dome tweeter, or the Linaeum dipole tweeter version - same price for either one.

The price is $375 per pair of flat packs, plus shipping via UPS. We have double wall boxes, to ship them in. They are 25" x 19" x 9" and weigh about 54 pounds.

Flat pack will be cut when you order. Expected lead time is up to 3-5 weeks to ship, from when you place an order.

Order yours here: Neil Blanchard Designs MLTL-6 Flat Pack

We are very happy to announce that you are now able to order assembled crossovers for the MLTL-6 with the SB Acoustics dome tweeter! E-Zee’s Crossovers has “good/better/best” parts lists that are similar to our build manual - all air core inductor coils, metalized film capacitors, and very low/non-inductive resistors. If you want to build one of our MLTL-6 speakers - but building the crossover was holding you back - then you have this option. Visit their website, and email them for pricing. E-Zee’s Crossovers <elon@ezeescrossovers.com>

Add To Cart

MLTL-6 Mass Loaded Transmission Line Speaker Build Manual

$150.00

“…arguably the best speaker kit available” - Cheap Audio Man

This is a mass loaded transmission line speaker, that uses a 6” paper cone woofer, and either a 1” soft dome tweeter, or a dipole tweeter - both options are included. Personally, I prefer the latter, partly because it is a dipole. But the dome tweeter is excellent, and has a smoother and more extended response. It is available retail - which is key!

This speaker has the best bass quality of any speaker I have heard in my nearly 4 decades of music listening. They are essentially flat in my room to about 32Hz, and also have wonderful “unboxy” midrange, and have a spacious soundstage; if it is there in the recording. The midrange of transmission line speakers is also much more open than conventional designs; and may rival open baffle designs.

The cabinet is 9”W x 21.5”H x 16”D / 227mm x 546mm x 407mm and is made with 18mm thick material - either Baltic birch or MDF. Each finished speaker built with the Baltic birch flat pack weigh a bit less than 29 lbs / 13kg. The corners are designed to have a 12mm x 12mm chamfer; but the MDF can be left square, if you choose. See the images of the SketchUp model below, for how this will look. The chamfer also has an acoustic function of reducing edge diffraction. I can provide CAD files to make CNC cut files - the build manual includes drawings of the CNC version of the panels. It can be built with a table saw and plunge router, and/or with a CNC machine.

A strong benefit of a “folded” transmission line design is the internal baffles not only form the specific volumes and dimensions required for the correct tuning for the woofer - they also form asymmetrical bracing for the cabinet. I include a brace in the closed end, that greatly strengthens the front baffle - which is the most critical area, since the drivers are mounted there. Less obvious is the fact that the internal air pressure in a TL design is lower than an equivalent sealed, or even a ported design. This greatly reduces the panel resonances - and this is possibly why the midrange and bass are more open and clearer. The woofer has less of an “air spring” behind it, so it is more closely reproducing the music in the recording.

I have also spent a lot of time designing and refining the crossover designs. Both are a 3rd order series crossover design for both the 1” soft dome, and the dipole tweeter versions. A series crossover diverts the signal that is filtered out for one driver, and diverts it to the other driver. And so a series crossover can be slightly more efficient, and they tend to have a smoother more even impedance; which can make them better for use with tube amplifiers.

A transmission line speaker cabinet is a tuned “column” of air behind the driver - it has lower distortion and greater bass extension that conventional sealed or ported designs. I used a program called Hornresp (short for Horn Response), and carefully matched the computer acoustic model to the cabinet design, using DataCAD.

The cost of the pair of woofers and a pair of the dome tweeters is about $150, from Madisound. They are both made by SB Acoustics. I have used all air core inductor coils, and the woofer inductor coil is 14 AWG for a low DCR. This is important for the best possible bass quality. The capacitors I have used on the tweeter are the best quality that I have ever heard - they are ClarityCap CSA. The benefits of high quality crossover components cannot be overstated. The build manual includes clickable links for 3 options - “good, better, best” lists of crossover parts quality.

These speakers are fairly sensitive - the woofer is rated at 89.5dB @1W @1 meter. But the crossover lowers this somewhat, and the transmission line may increase it somewhat. I listen at a lower volume setting on my preamp than the other speakers I own. The MLTL-6 speakers are 4-6 ohm nominal impedance - the dome tweeter version is a minimum of about 4.2 ohms. The dipole tweeter has a minimum of about 4.5 ohms. I am using the amazing AkitikA GT-104 amp - it is rated at 60W/ch @ 4 ohms and ~30W/ch @ 8 ohms - it barely gets warm even after long listening sessions. Any amp that is rated for ~4 ohm speakers will probably work very well, with the MLTL-6 speakers. If you have a tube amp, it may better to use the series crossover, but these speakers are relatively easy to drive.

If you purchased the MLTL-6 build manual already and have not yet built them, and you want the current v2.6 build manual - email us to get it for your build. The update is the midwoofer is recessed. Also it now includes both straight cut panels and rabbeted & grooved panels. The manual includes drawings in inches and in millimeters, and includes a stand. I can provide the CAD files for CNC version of the panels, if you want to build it this way.

Here’s the Old Guy Hifi video review of the MLTL-6 speakers:
https://youtu.be/AEoduNaQaXk

Here’s the ABX Audiophiles’ video review of the MLTL-6 speakers that they built:
https://www.youtube.com/watch?v=gu-FuzyJ_1g

Here’s the Cheap Audio Man’s video review of the MLTL-6 speakers:
https://www.youtube.com/watch?v=jwzLeDOdoKY

Here’s the link to Part 1 of Sonnora Design’s build video of the MLTL-6 speakers:
https://www.youtube.com/watch?v=nSpSTMacz9A

For folks who want to build the MLTL-6 speakers - but do not have the tools to cut the panels, or do not want to cut them - we have flat packs available to order! They are 18mm Baltic birch, and you can select either the SB Acoustics dome tweeter, or the Linaeum dipole tweeter version - same price for either one.

The price is $375 per pair of flat packs, plus shipping via UPS. We have double wall boxes, to ship them in. They are 25" x 19" x 9" and weigh about 54 pounds.

Flat pack will be cut when you order. Expected lead time is up to 3-5 weeks to ship, from when you place an order.

Order yours here: Neil Blanchard Designs MLTL-6 Flat Pack

We are very happy to announce that you are now able to order assembled crossovers for the MLTL-6 with the SB Acoustics dome tweeter! E-Zee’s Crossovers has “good/better/best” parts lists that are similar to our build manual - all air core inductor coils, metalized film capacitors, and very low/non-inductive resistors. If you want to build one of our MLTL-6 speakers - but building the crossover was holding you back - then you have this option. Visit their website, and email them for pricing. E-Zee’s Crossovers <elon@ezeescrossovers.com>

Add To Cart

The XSim graphs are in order:
Frequency response of the dome tweeter version - blue trace is the parallel crossover, and red trace is series crossover
Impedance of the dome tweeter version - blue trace is the parallel crossover, and red trace is series crossover
Frequency response of dipole tweeter version - blue trace is the parallel crossover, and red trace is series crossover
Impedance of the dipole tweeter version - blue trace is the parallel crossover, and red trace is series crossover
The last image is the Hornresp(onse) modeled response of the MLTL-6 - red trace is the speaker, yellow is the woofer, blue is the terminus opening, and the green vertical line is the Fundamental Frequency at 31.8Hz. Hornresp is the program I used to design the cabinet.

Please note that the bass response shown is measured in room, so it not accurate, as it is affected by resonances and reflections.

Here’s the Cheap Audio Man’s video review of the MLTL-6 speakers: https://www.youtube.com/watch?v=jwzLeDOdoKY

The black MLTL-6 are the first pair built by a customer! Ken is trying them with both tweeters, so he has an outboard crossover.

The “purple” picture is from when I had my MLTL-6 speakers at the 2022 Capital Audiofest, in the Geshelli Labs room, demonstrating their new upcoming Zoofa integrated Class A/B amplifier.

The pair with white front baffles & maple sides were built by Sonnora Design. Here is the link to Part 1 of their video series on building the MLTL-6: https://www.youtube.com/watch?v=nSpSTMacz9A
Here is Part 2: https://youtu.be/iiSEjPxBfEM?si=6TEoKbzRjQrfyi3-

The white speakers with walnut veneer front baffles were built by Robert. He built the parallel crossovers, and they look great!

The build with the black front baffle and veneered side panels with a radiused edge, are also using the series crossover.

The closeup of the inside of the front baffle shows the modified flare that we cut in our flat pack. This leaves the full depth at the woofer mounting screws - and the flare minimizes the effect on the response, by allowing the air pressure to disperse with as little compression as possible.

The “Deep Marine” semitransparent stained MLTL-6 are being reviewed by Old Guy HiFi on YouTube - keep an eye out for that!

The pair veneered with Sepele wood were built by Mike Y. Here’s what he wrote:
I wanted to express my sincere gratitude for the meticulous care and attention to detail you put into designing the MLTL-6. The instructions were incredibly clear and easy to follow. I took my time with the build process, savoring each step (I almost didn't want it to end!).

After much deliberation, I decided to veneer the speakers in Sepele wood and finish them with Osmo. The stands are filled with sand for added weight and stability.

As for the sound quality, it's simply sublime. Both my wife and I listen to the speakers for at least 12 hours every day, and they never fail to entertain us. They have this magical ability to both disappear into the background and command attention at the same time.

Thanks again,
Mike Y

We now have flat packs available to order! They are 18mm Baltic birch, and you can select either the SB Acoustics dome tweeter, or the Linaeum dipole tweeter version - same price for either one.

The price is $350 per pair of flat packs, plus shipping via UPS. We have double wall boxes, to ship them in. They are 25" x 20" x 8" and weigh about 56 pounds.

Production will be in batches of 3-4 pairs; and will be cut when you order. Expected lead time is up to 15 days to ship, from when you place an order.

Order yours here: Neil Blanchard Designs MLTL-6 Flat Pack