Seeking help with cabinet volume calculation for Speedsters

[lunchmoney]

Hello all,

I'm building Paul Carmody's Speedsters, and would like to know if I can get away with putting them in smaller cabinets. Speedsters are normally .19 cu ft, I'm wondering how bad it would be if they were .15 cu ft instead. I'm recycling some old cabinets; if using them at .15 cu ft is truly terrible I will perform some heroics to make the cabinets larger.

Can someone please help me calculate the F3 and optimum port dimensions for the Tang Band W4-1720 at .15 cu ft? I'm having trouble getting WinISD to behave.

Here's the spec sheet:

https://www.parts-express.com/pedocs...spec-sheet.pdf

Thank you!

[Paul Carmody]

Some rough math. But if you used a 1.375" vent, you can make it about 6.5" long, and that tunes the box up just slightly to about 58 Hz. It should retain a similar sound, but you'll lose a few Hz on the bottom end.

I also like the idea of 3D printing a thinner backplate. I think whatever you could make would be a lot nicer than the crap that came with the original speaker.

[lunchmoney]

Some rough math. But if you used a 1.375" vent, you can make it about 6.5" long, and that tunes the box up just slightly to about 58 Hz. It should retain a similar sound, but you'll lose a few Hz on the bottom end.

I also like the idea of 3D printing a thinner backplate. I think whatever you could make would be a lot nicer than the crap that came with the original speaker.

Thanks Paul! That's exactly what I needed. 58 Hz still seems really good.... and I can use it with a sub if needed.

I certainly could reprint the rear panels, and gain more volume in the process, but it's a huge amount of printing and it gives the speakers a weird proportion that I don't like. Besides, the bracing I'm adding will stiffen up the rear panels nicely.

Thanks again!

[jhollander]

Could consider an external port. I did one on my BMR-3L project.

[lunchmoney]

Could consider an external port. I did one on my BMR-3L project.

Well there's an idea... If I did so, am I correct in assuming that I would regain the inside volume of the port?

[PWR RYD]

Well there's an idea... If I did so, am I correct in assuming that I would regain the inside volume of the port?

Yes, that's the advantage. Actually you regain the outside volume of the port (port wall thickness is included). In very small enclosures like the Speedsters the volume that a decent sized port consumes is very significant. In a big ole monkey coffin speaker not so much.