8-inch subwoofers and strange recommendations from the manufacturer (at least for a layman)

I was studying more about subwoofers and looking at the marketplace I noticed that 8-inch subwoofers are always recommended in very low volume boxes (around 16 liters).
From what little I have studied and seen here on the forum this seems to be quite wrong, for a subwoofer to reach lower frequencies we need a reasonably large box and 16 liters is something very small...
For a 3-way project, which is what I'm studying most in the future, 16 liters would be too small to store 3 speakers (4", 8" and a tweeter).
When I got the specifications of the 8" subwoofer and put it in winISD, I put an initial 35 liter capacity at 30hz and it still worked until it was "well", this in a ducted box because reading the article on the Eminence website it said that at least QTS of this woofer, the ideal would be a ducted box...
I would like to know the opinion of the elders here on the forum, what would you do with an 8 inch subwoofer? box litter and such
There is an acceptable range of volume and tuning frequency for each driver and you get to choose what works best for you and your needs. You also get a range which helps balance trade offs. For example, enclosure volume, tuning frequency, and port size/length impact port air speed, power/SPL, port resonance, and woofer excursion. These are all things a designer would need to balance.

Personally, I have no problems sacrificing (increasing) tuning frequency to reduce the size of the port and increase the first port resonance frequency. It’s an 8” after all, so it’s not going to do much in the 20-30hz range.


Joined 2003
Calculate a T/S max flat alignment with at least a 0.5 ohm Rs for component insertion losses and up to its 'Re' rating more if planning on playing it loud for any extended periods to account for Vc heating increasing Qts (Qts'):

Vented net volume (Vb) (L) = 20*Vas*Qts'^3.3

(Ft^3 = (Vb)/~28.31685)

Vented box tuning (Fb) (Hz) = 0.42*Fs*Qts'^-0.96

F3 (Hz) = Fs*0.28*Qts'^-1.4

looking at the marketplace
If you're talking about finished subwoofers (in an enclosure, with an amp, ready to use), many are using boosted/electrically equalized designs where a large excursion driver and high power amp are used to counteract the natural roll-off of a small sealed box. It makes for a much smaller enclosure, which is more acceptable in a typical home.