Finally – A Fully Parametric Transmission Line….

1 - Final Parametric - 1

Doesn’t look like much but this is the culmination of several days of cursing & Learning!

This enclosure (pictured sideways here) dynamically changes its height and depth depending on the speaker SD and the enclosure width you chose.

You can alter the following parameters , I’ve set the above to be the number in Brackets for my PS95-8.

Continue reading “Finally – A Fully Parametric Transmission Line….”

More parametric stuff – another design

I decided to create another grid and try some  alternate ‘maze’ waveguide ideas to see if I can optimise the path…….I think I have!

The grid is made of formulas – waveguide height and wall width and entirely construction lines.

To create the purple ‘walls’ it’s easy enough to drag the mouse, highlighting the required walls and press ‘X’ twice to toggle construction lines on / off

Speaker Parametric 9

Some experimenting with sizes eventually gives a waveguide length of 770mm near enough… I can fairly easily tune this enclosure by changing the position of the hole on the rear and blocking the last part of the line.

  • 106.588
  • 79.941
  • 26.647
  • 106.588
  • 133.235
  • 26.647
  • 133.325
  • 26.647
  • 133.25

= 771, near enough to the 720mm that I want!

I now have an enclosure that’s 170mm tall by 200mm deep by 190mm wide. 6.4 Liters. Can’t see really how I can reduce the outer size by much more than this…..


Speaker Design Rev 3 part b

Ok, just figured out that I can accurately draw the path the waveguide follows by drawing a line through the midpoints of the larger squares……

This line scales with the grid scaling when it’s anchored to the midpoints! of the larger squares!

Speaker Parametric 6.PNG

I’m not sure how to automatically add up the sizes yet, but manually , here goes…

  • 100.75
  • 38.3
  • 76.6
  • 38.3
  • 114.9
  • 114.9
  • 229.8
  • ——————Subtotal of 713.55
  • 38.3
  • 229.8
  • 38.3
  • 229.8
  • 24.15
  • ———–Total of 1273.9…..


So, cutting the last couple of folds out gets me right to the dimensions I’d like to be at


Speaker Parametric 7

ah, 278 h x 163.2 d  x 120 w – Getting much closer!

Here’s the extruded ‘look’

Speaker Parametric 8

Next steps

  • optimise a little – see if I can get those outer dimensions down, particularly the height. May be that I can get a more ‘cube’ shape?
  • Start introducing some curves!
  • Finish the waveguide path
  • create the sides of the enclosure – to enclose the waveguide
  • cable routing
  • test assembly tolerances
  • make them aesthetically pleasing
  • Print
  • Get wife’s approval to put in living room?
  • Purchase set of off the shelf speakers due to lack of wife’s approval in previous step?


I’m starting to wonder if I’m ever actually going to print anything speaker enclosure this side of Christmas…………



Speaker Design – from scratch – Rev3 – Parametric!

Ok, Figiured I’m spending alltogether too long on the doodling, so lets make a fully parametric grid upon which I can ‘draw’ the enclosure and start extruding a bit to define the waveguide………….After much googling and figuring out a bit of Fusion’s formulas and parameters…………..

Speaker Parametric 1


Continue reading “Speaker Design – from scratch – Rev3 – Parametric!”

Speaker Design…Waveguide, lets start from scratch……Rev 2

Ok, another design, this time trying to use all available space AND designing to the absolute constraints of the speaker…

Waveguide of 8cm x 3.5 cm


2D folded start from scratch 7.PNG

Rough measurements are

135 + 50 + 100 + 50 + 145 + 150 + 250 = 880

+  50 + 250 + 50 + 250 + 31= 631

Total = 1551 – err, oops!, got a bit too carried away with the designing there! could have left the last two folds out! I only need 720!

on the plus side, the enclosure’s 315x315x110 = 10.9 liters! and is probably a bass monster if you can get a decent driver

Off to bed, i’ll try again in the morning!

Speaker Design…Waveguide, lets start from scratch……

20 cm x 20 cm x 25.3 cm = 10,120 cm3 = which is 10.12 Liters ..roughly a 22cm cube

Ok, Designing  a conventional enclosure would get us a volume of a less

Looking at this website –

and plumbing in a few numbers gets us a volume of 6.357 Liters for a ported enclosure

Working backwards, that 6.357 liters gets us dimensions of 15 w x 15 w x 28.5 d (ish), or alternatley a roughly a 19cm cube……a 3cm per side reduction……


So, lets see just how small we could get ‘sensibly’ –

The speaker outside physical diameter is 98.2mm – lets call it 10cm. That’s going to drive the outer dimensions of the speaker…….

The speaker ‘cutout’ is 76.8mm – lets call that 80mm

I’ll use walls of 1.5cm thickness for rigidity (may change this later)

Speaker diameter = 6cm – that’s a surface area of 28cm2

One dimension of our rectangular waveguide is 8cm. lets call that width

8cm width x ? cm Height = 28cm2

28/8 = height =

That gives us waveguide of  8cm x 3.5cm……..

Working with the above gives us the following minimal enclosure dimensions……

2D folded start from scratch 1

Continue reading “Speaker Design…Waveguide, lets start from scratch……”

Speaker enclosure design – getting there


Quick sketch showing a cross section of the curved parts and their outer constraints… Each Transmission line is 85mm in diameter, the space between them is 10mm and to form a 180 degree ‘turn’ the lines will follow a circle that has a 180mm diameter / 90mm radius


I’m currently sat with one dimension of the speaker – lets call this ‘width’

  • enclosure thickness ( 10mm ) +
  • Transmission Line Diameter ( 85mm ) +
  • enclosure thickness ( 10mm ) +
  • Transmission Line Diameter ( 85mm ) +
  • enclosure thickness ( 10mm ) +

= 200mm!


Lets work out another….Depth – from front to back

  • enclosure thickness ( 10mm ) +
  • Transmission Line curved part outer Diameter ( 95mm ) +
  • Transmission Line straight part length ( 53mm ) +
  • Transmission Line curved part outer Diameter ( 95mm ) +
  • enclosure thickness ( 10mm )

= 253mm!


Now, another dimension – Height

  • enclosure thickness ( 10mm ) +
  • Transmission Line Diameter ( 85mm ) +
  • enclosure thickness ( 10mm ) +
  • Transmission Line Diameter ( 85mm ) +
  • enclosure thickness ( 10mm ) +

= 200mm!


So, we have (in theory) a speaker of 200 x 200 x 253 (ish)


Now, lets put that into practice – Here’s the first (of many) versions of a speaker enclosure!

Speaker first version.PNG

I’ve colourised it a bit just for clarity as to what’s going on inside. The speaker’s on the left – the black disc. The ‘port’ is on the right hand side…….

Here’s a better Render

Speaker second  version.PNG

I’m thinking i’ll need to reduce that port diameter a little – I’ve read that TL speakers perform better with a gradual tapering of the line!………


I’ve just realised something though……volume wise…….

20 cm x 20 cm x 25.3 cm = 10,120 cm3 = which is 10.12 Liters ..

Vas for the speaker is 0.94 Liters!.TL total volume is ten times the VAS of the speaker….most people don’t even go 2 or 3 times …….

or, in other words, then …..Houston, we have a problem…………


Maybe I should re-think this whole TL thing and just do a normal enclosure? – MUCH smaller?

Speaker enclosure design – 3D Printing First step……

Now I’ve decided upon construction of a 3D Printed Transmission Line enclosure I need to figure out just how….

Lets start on google – and… Website

oh – Marco Reps – another youtube that I subscribe to!

Some Speaker Stuff (copied from … )

Presumably, this lot means something which will help to figure out the optimum enclosure-y stuff ‘n thingies.

Continue reading “Speaker enclosure design – 3D Printing First step……”

Speaker enclosures……A rabbit hole…

Blimey, who’d have thought……

Back in the old days, it was as simple as ‘buy a speaker’ , shove it in a box and voila…….


Nowadays though…………

There’s quite a few, including the following types…………

  • Sealed enclosure
  • Infinite baffle
  • Open Baffle
  • Free-air
  • Bass reflex
  • Ported
  • Vented
  • Bandpass
  • Transmission Line
  • Folded Horn
  • Isobaric

Each has different properties, suited for different things……some are as easy as ‘shove it in a box’, others need complex enclosure geometry and some math………

Now, considering I have 5 speaker drivers waiting to be hooked up, own two 3D printers (and a CNC), Know a bit about Fusion360 and have a penchant for overthinking and overcomplicating stuff (hey, where’s the fun when it’s simple!?)…..I figured, lets learn a little bit about speaker enclosure design……

Turns out, there’s quite a few youtube videos……….

One in particular from a channel that I’d already subscribed to a few months ago…….HexiBase – Can a 3D printed enclosure Get low

Look at the size of that box!……..It uses a Folded Waveguide type resonance chamber for the enclosure…..which appears very similar in design to a ‘Transmission line’ style of speaker.

….Challenge accepted….I’m going to build a small Transmission line speaker!

3D Printed Speaker enclosures – another rabbit hole

PS95-8After months (and months) I’ve finally been able to pull my thumb out and start a long wanted upgrade of my somewhat old Home Theater system…….With a 3D printed ‘twist’

Continue reading “3D Printed Speaker enclosures – another rabbit hole”