Speaker enclosure design – getting there

folded6

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?

Author: Bleugh

Early Fourties, Wife, two kids in primary school. Both of us work full time...5 years now we’ve been Back in Blighty after a decade away...It's a new country for everyone! Still finding time to tinker!

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