IPL Acoustics M1TLm Ribbon Transmission Line speaker project – Part 3

And so the project continues. We now have two MDF cabinets in their rawest form, simply glued together.

To start the next stage I forced as much wood filler into anything that even resembled a gap, as much as possible using a cheap flexible decorating scraper that turned out to be perfect for the job. Once the filler was dry I set about sanding everything as flat as I could, starting with an electric B&D Mouse before moving onto a block and paper. At this point I decided to sand some round edges to the cabinets to make them look less like they’re constructed from MDF and to make any dinks into the edges a little less obvious. I’m glad I did this and was happy with the outcome.

It’s important to use a mask whilst sanding or cutting MDF, the dust is nasty stuff and I’m told can do your lungs some serious damage.

Once the sanding process was complete I used a Ronseal wood primer to seal the MDF. I wanted to get this stage right as I’d seen other projects online with the MDF cut edges clearly showing through as a different texture under the paint. To get round this I used several coats of the primer and sanding with fine paper in between. In all I must have put five coats of primer on the cabinets.

For the finish I used Dulux Woodsheen to give a satin look and feel not dissimilar to that of our doors and architrave. I decided on a dark colour, something I had wanted right from the start of the project and settled on Night Jewels 2 (#5E5E5D).

As with the primer I used several coats of the Woodsheen to achieve a deep and pure colour throughout the cabinet. I was really pleased with the results.

Speaker project build process

  • Gilesw

    Hi Alan,

    I’m following your build to help with mine. Really useful resource. I’m a bit confused about the paint part though. You list Dulux Woodsheen but it only seems to come in specific colours, none of which are Night jewels. Did you have to get it made in a shop? I can get night jewels 2 only but just as a standard matt:-


  • Hi Giles, thanks for getting in touch.

    The paint I used was Dulux Satinwood for Wood and Metal. I had it mixed at my local hardware store but they offer this service at Homebase etc.

    I used the paint on my front door, had a load left over and liked to colour so used it on my speaker project.

    What speakers are you building yourself? I’m still chuffed to bits with mine, although I had the nephew and niece round the other day and their hands were magnetically drawn to the drivers!

    All the best

  • Gilesw

    I’m building the s2tlp cd3. They’ve got these new ribbon tweeters that are supposed to be really good. Cheers about the paint, the finish looks great so I thought why not go for the same thing! The main issue I’ve had with the build was the mdf sides not squaring off quite so I’d get them perfect at one end and the other would be at a slight angle, not sure why. I managed to get them back into shape by forcing them straight and using a glue gun to fix a wood block. Still it means I’m going to need to do some filling. My mate has actually recommended a different way of working with mdf. Sealing it up and painting on primer and then using poly filler on top off that to smooth it out.

    Did you make any changes to the crossover at all? I read this post with some interest:-


  • I’m quite happy with the finish, it can always be re done at a later stage. At one point I was going to paint them a matt finish and use a spray on lacquer to give a shiny ‘bling’ look, I may do this in the future.

    The last time I did any wood working was at school so I found putting the cabinets together the most challenging aspect of the project. I really took my time with it and tried to get everything lined up as much as possible, the Irwin clamps were invaluable. I also spent a lot of time at the filler stage, forcing as much filler into any gap before sanding smooth, although even now the outline of the MDF edges can been seen on close inspection. This wouldn’t be an issue if using veneer.

    As far as tuning goes I followed the instructions to the letter and even weighed out the correct amount of dampening wool on the kitchen electronic scales. After I fired them up I was so impressed with the detail of the sound that I haven’t given tuning much more thought. I’m no audiophile but the bottom end seems to be well controlled and the all important mid range that seems to be lacking from most Hi-Fi speakers is fantastic.

    Something to note, be careful when banging in the sockets for the standing pins as I found that cracks started to appear and I had to fill and re paint, not a big deal but I should have made the holes larger and used some glue.

    Stick some pictures up if you have a moment, would be good to see how you’re getting on.

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