First subwoofer build. Driver selection with Winisd


2020-02-26 7:24 am
Hi all,

Im looking for some advise on a suitable driver to use for one of the 2 enclosures I have lying around. It looks like there are a bunch of experienced folk on here, so any advise would be appreciated.

Enclosure 1 inner dimensions - 300x300x500 Mdf - 1.589cuft 45L

Enclosure 2 inner dimensions - 330x330x365 - mdf, with timber outer - 1.40cuft

Amp 350w RMS @4ohm

Ive attempted running various drivers with these box parameters into Winisd - but dont quit understand what its telling me, or whether the results are acceptable.

Lab 12



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For vented, [Vas]/1.44, [Fs] = vent tuning [Fb] yields the most extended bass with a sufficiently low transient response if the driver has adequate damping.

So for a 45 L gross [will be less once the driver, vent, any bracing is subtracted out] cab, let's say it's 42 L net: driver [Vas] = 42*1.44 = ~60.48 L.

[Fs] is whatever you want for the sub's tuning, such as 20 Hz for THX LFE channel.

Driver adequate damping [Qts] really depends a lot on where in the room it will be located and what it's primary use is, but generally keep it in the 0.312 - 0.38 Qts range.

In general, you'll want a vent area [Av] = ~1/3 the driver's effective piston area [Sd] and up to 1/2 for high power [high Xmax] 'subs'.

Last edited:
Hi Brad,

The question you are asking is interesting.
I am also building a subwoofer (as a dissertation project).
Is there a way to find a suitable drive unit based on the volume of the enclosure?

Yes, type of enclosure and volume.
You need also a database with parameters of all the loudspeakers drivers in the world, old and new. I use a database by Petoin Dominique.