8" Sub Enclosure Spec's.., What to do to improve response??

Well I have a TINY Chery QQ3, and wanted some better bass response, but cant use the limited Boot space. I chose instead to make small (0.195 cft) enclosures for under the front seats, with a pair of these 8" Subs..

Now the norm size is .6 to .8 cft, and i understand that packing the enclosure with fleecing can 'Dup' the sub into thinking it's in a bigger Enclosure..

Is there anything else that can be done (Porting as i know, is only for much bigger enclosures).

well.. it is possible to (with closed boxes) drive a speaker in a way that it sounds like if it was in a bigger box.
EQ can give that result.
But, the driver has to be able to take a lot of excursion to handle it.

a nother problem is.. one needs to know the parameters of a driver in order to even try and make a more or less proper box for them.
there is no way around this.
use drivers with known parameters and modell in software prior building anything.

Ported or not depends on speaker aligment alone.
(yes, even drivers ment for closed boxes CAN be used in a ported design if the system IS designed with that in mind.)

Best would be to utilise the boot of the car, realy.
Space saving can be achieved by using 2 drivers in iso-baric configuration, that means roughly 25-30% reduction of the final "whole box" size.

If You need help, i can.
If you want to use the exsisting speaker drivers, then we must mesure parameteres. Not easy, but not as hard as one might think.
If intrested, i can help all the way.

yeah ... no response curves/*real parameters* on the site ... hmmm ...
the first i would do is de-rate the power to 100W continuous .

yep , going to need an audio oscillator , amplifier and dmm , vtvm or 'scope .

Isobarik/isobaric configuration can cut the volume of the box required to around half the volume required for a single driver.

Stuffing the box can help too.

It basicly halhs the Vas parameter, but You must account the coupling chanber between the drivers. So the final box will not be half of the original.


Responce curve is not that important for a car sub driver..
Generaly not worth to go below 60 hz in a car.
and usualy no need for the sub to go over 120 hz.
Gotta be some realy crapy one to not manage this..
Still, T/S parameters and Xmas would be handy to have.
Otherwise.. no way anything usefull can be made.

You eighter get a box with too low volume, then it never goes deep, or a box that is too large, and can't handle power and has way too big delay.
Both are not ment for human ears.

So i found some old Sine wave sound files i created years back on my server and pumped the system with 20hz to 90hz (1hz steps) sine wave at ~75% power, and was presently surprised, the response at 20hz to 30hz is there (the whole car rattles) and as you climb up to ~50, you feel less but still hear it..

Then at 80hz the subs are moving, but there's no real audible difference to before.. however I have also cut the amount of Bass playing out the other speakers( 4" full range drivers) , as this is what normally kills them..(Replaced one set before, and the other set may may need replacing soon)..

also thinking of checking what happens to the sound if i reverse drive them, this often helps with phasing and can improve staging..

For this small car you dont need BIG drivers to get big sound. but i'd like to max the sound from the Subs with out needing to overdrive them. The main problem was that the space under the seats only allowed a small enclosure, perhaps by removing the seats and working a box around the seat mounts and chassis supports i could get a .25 - .3 cft box in there but that is way too much effort for this little project, and way more cutting than i could do with a little jigsaw, these simply slip in under the front seats and leave enough room for rear passengers to put there feet down..

Will download a few pics later...

Some pics of the enclosures...
Driver to Seat Clearance
Feet clearance
side clearance..

See how limited the clearance is..

something tells me thy do not sound at all as a subwoofer should.
Are You up to some mesurements to "cure" this effect ?

Put some fleecing into the enclosures, enough to push back on the subs a bit,, Now it sounds much better at 50 - 80 hz.. (some mirror vibration too)..

look...
http://sound.westhost.com/tsp.htm
follow this. then we get the driver parameters.

then we work out this:
http://sound.westhost.com/linkwitz-transform.htm

what You need is something that can go down to 60 hz or so.
then You can have Your bass in a small cabinet.
But be aware, powerhandling is going to be abused.
after driver parameters are known we can work out a healthy solution.

LOL .. that procedure requires the subs sitting free air.. While the Freq generator would not be a prob, (i have accurate 20 - 99hz Wave files) and the meters are not a prob either (although the one with Freq measurement is still at the office), but i'm not in the mood to pull them out now..

However with the Fleecing really packed in the enclosures, the subs are working perfectly... I cruised around and tweeked the head-unit settings, and am getting excellent bass response..

Basically i think i'm at that point where i need not worry any further about them..

I think i now got the hottest little Chery QQ3 in S.A....

winisd is a freeware. has a sine wave generator.
a dmm and a known resisitor should not be a problem to obtain.

but anways its your call