'Best' Configuration for car sub

[herulach]

Is it worth going for an EBS alignment in a car? or is cabin gain too big of a factor to notice much of a difference? Ill be using audax ap210g6 i got on the cheap at maplins (£1.98 each). I got four, but ill prob go for either stereo subs of 12 litres each, tuned to 47hz, to give an F3 56hz or a pair of 33.7l boxes tuned to 34 hz for an EBS alignment. (Ill be using the drivers in isobarik pairs to make up for the tiny xmax of 3mm. WinIsd pro reckons theyd distort between 60 and 100hz with an input power as low as 25W, assuming im reading the graph right.)

T/S parameters for the driver:
Qts 0.28
Qms 3.68
Qes 0.3
Vas 79.7 l
Fs 33.7 hz
Re 5.6 ohm
Le 1.4 mH
Xmax 0.003 m
Sd 0.023
Pe 50W
Sensitivity 91.9

Thanks
Keith

[richie00boy]

I have done a bit of modelling on these drivers as I also picked up a pair on the cheap from Maplins. I wouldn't try to get any real sub duty out of them. I back this claim up with quite a lot of practical experience with some of the very similar Audax 8 inch drivers as I played with various configurations of them as my first few subs both for car and home use.

If your car is small like a Fiesta and you just want a musical bass extension to the standard speakers you will probably be happy, but they will not perform as a sub. You can't get either the extension nor the SPL. If you are going for all 4 drivers you may be OK. Just don't spend too much time/money on the box. You will be able to beat it in extension and SPL with a much smaller box with a single 12 designed properly.

Personally, I'm not a great fan of EBS. The transient response is hideous and the (often large) droop in power handling just in the range where you need it most makes it a turn-off for me.

[herulach]

Pretty much what i was thinking myself, I actually work in maplins, if you can find them theres a few of the older eminence drivers knocking around on clearance, cant remember the codes but they dropped a load when they moved to the new catalog, in uni now, but if anyone wants codes posting leave a note and ill do it when i get home, if i remember correctly it was the alpha 10s, the one with secondary midrange cone, beta12mr i think, and also the 15 omega pro and gamma pro.

The car is only a punto, for those who dont know that means 3"s up front and 4"s in the back, so anything would be an improvement really. But i arent gonna spend a lot on it, mdf is just hanging around, and i picked up one of the maplin own brand 2 channel amps when they went on clearance for 19.98 a while ago.

Thanks the reply, just out of interest transient response is how 'tight' the bass is right? Im fairly new to this lark, but if this project turns out okay im gonna try my hand at a cinema sub using a couple of the alpha tens i know there are sat at work.

[richie00boy]

For a cheap way of sweetening up the sound in your car they are worth a go then. Another problem you face with such small drivers in the front is that they don't put out any bass so you have to stretch upto maybe 150Hz with the sub, which sounds terrible IMO. You will also find the impedance of the Audax to be a problem if you parallel them.

Transient response is the response to an impulse (a short, sharp signal). Really we should be talking about Q or damping in a sub as that's more relevant. Yes, basically it's about the tightness of the sound. The EBS tends to sound a bit uncontrolled IMO. I will have to check again, but I think the group delay of an EBS is quite bad as well.

Regarding your home sub idea, if the Eminence driver is the one with the whizzer cone then don't bother. These drivers are made for PA fullrange duty and just won't cut it as a sub, they will barely even manage to be a decent bass speaker. They don't have low enough Fs or enough excursion.

[Stocker]

I have had good results with my car's sub in the boot, with no crossover at all... I pulled the rear speakers (who needs 'em) so it sounds like there are some rear speakers back there...not terrible, not great, but OK over the road noise!

[ocool_15]

Originally posted by herulach
Ill be using the drivers in isobarik pairs to make up for the tiny xmax of 3mm.
Thanks
Keith

An isobaric configuration does not allow for more actual out put at all and 2 in a isobaric has the same Xmax of 1 driver and displaces as much air as one. The advantage of a isobaric is the increased low extension for a given box size and if mounted in a clam shell or back to back then the cancelling of some distortion.

Wow this was a old thread.... oops