Free Plan: 21" 30hz Ported Sub

I imagine this would do well under a good 15", crossover in the 60hz region.

** Everything below is theoretical and has not been built and measured yet **

Driver: Eighteensound 21LW2500
Enclosure Volume: 267.2 L 

Edited by vertx - 03 April 2018 at 12:17am

Do you have any plans available? 

I am desperately looking for a single 21" reflex cabinet i can use with my 21LW1400 driver. But so far without succes I am specifically looking for a reflex. No bandpass or horn.

Kind regards from mexico

I would if I knew what to do and how to calculate and all that stuff.
I am a productdesigner who does carpentry now on a small scale, so tools I might have.
Knowledge not so much.
Great wood - nope. 
Waterproof Marina Plywood or MDF is my best bet here.

Also I know this exists, but i do not know how to upscale it for a 21" driver.
https://eighteen.it/media/W1siZiIsIjIwMjMvMDcvMTcvMTRfMDVfNTlfMzA3XzE4U3ViX3YxXzEucGRmIl1d - https://eighteensound.it/media/W1siZiIsIjIwMjMvMDcvMTcvMTRfMDVfNTlfMzA3XzE4U3ViX3YxXzEucGRmIl1d

Driver: 18Sound 21LW1400

Freq Range: 24-2000hz
Res Freq: 28Hz
VCdiam: 4"
Xmax: 9,5mm
Rec Tuning: 30Hz
Rec Volume: 300L

Alternatively i could get this driver here:
RCF LF21X451

The only two 21" drivers available for me here. The RCF is more expensive. 
The 18sound will cost me roughly 650Usd per driver.



Edited by PHATpedro - 11 May 2025 at 10:09pm

Thank you. It will be the RCF then.
Trial and error and hopefully not lose all the money I hardly have.

I made a design but I somehow cannot figure out how to put the pictures in here.
roughly 340l
triangular ports 2x base/height 25cm 45degree, 488m long (28hz)
one u shaped brace in the middle horizontally (or is it better vertically?)

Can anybody help me to move forward?
I would love to have it built before rainseason arrives and you can watch every sheet material warp live.