IPL Acoustics M1TLm Ribbon Transmission Line speaker project – Part 6

Project completed.

I’m really pleased with the outcome, the speakers look great and whilst I’m no audiophile they sound fantastic. They are incredibly detailed and don’t suffer from any of that wallowing bottom end messiness prevalent in most Hi-Fi speakers.

The whole project has been incredibly rewarding and has gone some way to restoring some faith in my ability to use my hands. My other half Mandy suggested I start the project to stave off the New Year blues in January, the result has been the discovery of a whole new set of skills and an increased feeling of self worth.

From an aesthetic point of view they look great in the front room, a proper piece of modern furniture. I’m glad I stuck with my original plan not to use the grills as they look far more tech in their naked state, however I am aware the the 5″ magnesium cones are a little exposed which could be an issue for inquisitive kids or friends that like poking things. The black surrounds of the drivers and the golden cone set the grey finish off really well, couldn’t be happier.

The IPL M1TLm Ribbon Transmission Line kit can be found on the IPL Acoustics website.

Here are some tools I couldn’t have done without:

  • Black and Decker Workmate
  • Irwin clamps
  • Decent wire cutters
  • Electric sander
  • Bosch hot glue gun + several packets of glue!

Speaker project build process

  • Phil Taylor

    Thanks for the build description. I really enjoyed it. I made a pair of the IPL M3TL some years ago – similar spec. to yours though with conventional tweeter. They have given great service but I was never happy with the quality of finish I achieved (first time I had attempted this kind of thing and was learning as I went along) Your blog has inspired me to make a new pair using the many tips you gave.

  • Thanks for replying Phil. I’m happy with my finish although it could be a lot better, I’m only a hobbyist after all. It’s like all these things though isn’t it? You only get one go at it, if you were doing it every day you’d learn from the mistakes quite quickly.

  • spencer evans

    Thanks for a really informative and detailed build thread. I really like the fact you painted the speakers, it makes more practical sense to have finish that can be re-painted if they get too marked. I have some shiny gloss speakers at the moment, they are nothing but a pain in the a*s*! Showing finger marks and dust even just after polishing them. I have just ordered myself the IPL S2tlm kit…as a hobbyist and firm believer in common sense construction your right up has given the confidence to give this ago. I shall be refering to your excellent photographs on my laptop as i go. Many thanks Spencer.

  • Thanks Spencer. For me the most invaluable tools were the Irwin clamps and the Workmate to hold the units steady whilst working.

    I took my time over them as well, thinking everything through twice and referring constantly to the instructions.

    We have a toddler running around now so I’m going to add the grills as inquisitive finger have already started poking around.

    All the best, let me know how you get on. Cheers

  • Woj

    Just found your speaker project. I am in the process of building mine S2TLK speakers. I found your tutorial quite interesting and educating. Do you still use your speakers? all the best

  • Hi Woj, thanks for getting touch. Yes, still using my IPL Speakers in the front room. Visitors always comment on them and how great they sound. A pair of daily work horses as we listen to a lot of music and watch plenty of films. Let me know how you get on, I’d be really interested to see some pictures of your project.


  • Hea∂

    Thank you for taking the time to document your build so comprehensively. I’m about to build a pair of M1TLm speakers, and your information will be invaluable. Your photos, especially, have already been exceptionally helpful.

  • Thanks very much, let me know how you get on, would be great to see some pictures of your IPL project. Have you thought about how you’re going to finish them? Cheers

  • Hea∂

    A handful of images here: https://drive.google.com/drive/folders/1Rp9OLp5VbBvu7R7Z7OIdVcLx6g58TMip?usp=sharing

    Not pictured are the speaker grilles; I chose brown cloth instead of black, and the grilles are held in place with magnets rather than the supplied fixings.

    The enclosures have been wrapped with two layers of 1000 grade lining paper, and coated with a mix of PVA and Rustins Light Oak satin wood varnish. The completed speakers have a slight 1970s look to them.

  • Cracking Job! Nice idea covering them with paper, removing any of the joins in the wood.

  • John Baddeley

    Hi, I’m impressed with your build, and very interested as thinking of building one of these kits soon, Just wanted to check that you fitted the toothed nuts to the back of the panel when you attached the drivers…. [ie not as in the photo of your cabinets when weighted after gluing up.] 🙂

  • Hea∂

    Well spotted! Yes, the toothed nuts are fitted to the internal face of the panel, not the external face as captured in the photos. I misread the instructions, which is easy to do as they are non-sequential and contain instructions for all models.

    My advice would be highlight the instructions specific to your speaker model, and to number them so you have to order of assembly correct.

    Other tips:

    • A good place to purchase adhesives, fillers, etc is toolstation.com. Prices are cheaper than DIY stores, and next day delivery is free for orders over £10.

    • Use double sided tape to fix the acoustic foam to the transmission line.

    • Seal the MDF with a 50/50 mix of PVA glue and water. Two coats works well.

    • If your soldering skills are poor, use use crimp butt connectors to keep the crossover components tightly together.

    • Double sided tape is useful for holding the crossover components in place.

    These speakers sound phenomenal. The sound they produce is open, revealing, and tuneful.

  • John Baddeley

    It’s nice to know I’m not going nuts (sorry!).
    Thanks for the extra tips, we can all learn from others’ experience.
    As an alternative to the toothed nuts, you can get a ‘nut’ that is threaded on the outside to grip the wood or mdf, and you drive it in with a hex [Allen] key. This does not require rear access, which in other circumstances may be an advantage, tho’ not obviously here. (Actually, a possible disadvantage is the need to drill a bigger hole, which if close to the driver aperture mighytht create a weakness.

  • They look fabulous Alan.

  • Ross Kearney

    Hi all my dad built these speakers for me and all was good for 3 mouths then one day the left bass cone stoped working the tweeter is fine I’ve looked at the transfer box but can’t see anything that would suggest a component has failed any ideas please thanks

  • Hi Ross, does the cone still move if you press it with your fingers? It might be worth swapping it out for the working driver on other side, if it works then you know it’s something further back. You’ve probably already tried that! Just a thought. Cheers.

  • Woj
  • Woj

    I completed mine 18 months ago. Best speakers ever. Still in daily use. As I did not know how to finish them, my daughter put some of her art on them. They are quite unique now. I am thinking about building a different set such as stand mounts for my bedroom. All the best and I hope you enjoy yours still. https://uploads.disquscdn.com/images/5aaa7c546fea01d6199df14941a6fb43074ffd78dc4c2063f1b3c103eb64a469.jpg https://uploads.disquscdn.com/images/0beebcedf51308d8e208d22eece6b8258be044971f17be633d94c57655a1a4c3.jpg

  • Woj
  • Woj
  • Wow, they look the business! Can’t believe that paint job. Totally unique.

  • Still can’t get over what your daughter has brought to your project, really good!