View Full Version : Sub box might be too big? any way to fix?

06-09-2010, 01:18 AM
so my SA8 seems to be bottoming out on certain notes and im figuring the box might be too big...its 1 cube at 32hz off a PG xenon 600.1....

wondering if i should use expanding foam or have another box built

06-09-2010, 05:15 PM
If your bottoming out in a ported box it's usually by playing below tuning. Have you actually verified your tuning. Go play with tones and find your minimum excursion point. That's tuning, you may just be tuned to high.

06-09-2010, 05:23 PM

06-09-2010, 05:25 PM
If your box is too big start reducing the internal volume. All you need is a few blocks of wood...it will affect your tuning however

06-10-2010, 12:14 AM
i just want to go from 1 cube to .7 or .8

Bumpin' Goalie
06-10-2010, 12:30 AM
tuning will be affected. tuning will become higher. So the low's will drop off but due to roll off under tuning instead of bottoming out.

06-16-2010, 04:39 AM
ya i could also extend the aero port....but i still keeps making it and the HU i think is to blame....the sub doesnt really come alive at until i hit a high volume......i have the sub unplugged and havnet been using it haha im thinking of selling it to be honest...im gonna try and fit an AQ SDC2.510-D4 behind the seats....

06-16-2010, 05:20 PM
posted from another forum

Box size has alot to do with mechanical power handling. If you are going to be pushing your woofer beyond it's rated RMS power you need to be very mindful of this fact and put the woofer in no larger than the minimum suggested enclosure for music program.

We design our woofers for very small enclosures and power ratings are there for a reason -- you can continue to push a driver like the SA-8 beyond RMS power and it will not be stressed whatsoever thermally by the time you can cause mechanical issues. The motor, especially on the SA-8, is VERY strong -- being an 8" driver there is limited mechanical throw available. The driver retains high motor force all the way up to the point where you can start breaking it.

In any event... based on my testing so far you can expect something like the following on mechanical power handling vs. ported box size on the SA-8 :

1.25 cubic feet = 300 watts
1.00 cubic feet = 400 watts
0.80 cubic feet = ~450-500 watts
0.60 cubic feet = ~500-600 watts

You may ALSO need a subsonic filter depending on box tuning. The rated RMS power is 400 watts RMS -- if you push past that you are voiding warranty coverage. We are bringing in re-cone parts and they can be fixed, though, for those of you who like to push things. If you have any doubts about your ability to monitor your listening habits just stick to the 0.60 recommendation.

To re-iterate... they are not fragile. I have ton ALOT of testing on them with enormous amounts of power -- the above considers full bandwidth music program that can drop to very low frequencies and is a safe suggestion.

If you are an SPL competitor then you probably already know this and these suggestions don't really apply for burps @ tuning. We have put in excess of 600% of RMS power on them for SPL burps.

06-16-2010, 05:29 PM
ya i sent sundownz a pm about it asking and he never got back to me....so either i ad more stuff inside the bux to shrink it and extend the port or i scrap the SA8 and go with a ten

06-19-2010, 07:25 PM
ok im going to cut the box to shrink it to .6 but is there anyone out there who can tell me how much needs to come off

specs of the sub are
SPECIFICATIONS OF D2 Coil (D4 will be similar) :

RE: 3.28 ohms (series)
FS: 41.6 Hz
Qes: 0.513
Qms: 6.606
Qts: 0.476
Le: 2.778 mH
Vas: 3.285 L
BL: 17.138 N/A
Cms: 83.341 um/N
Mms: 175.654 g
Sens: 78.476 dB @ 1w/1m

5.25" depth
8.25" overall basket OD (no gasket)
7.375" cut-out diameter (without gasket)
7.25" cut-out diameter (with gasket)
6.25" magnet diameter

and here is the the design of the box also how much do i have to cut the port to keep the tuning to 32


06-19-2010, 11:52 PM
Bump thump

06-20-2010, 08:23 AM
wow you sure about 32hz? :o
the port will be 55.6" long in a 0,6ft box..

06-20-2010, 08:25 AM
38hz will be 38.55"

06-20-2010, 04:39 PM
Wow I thought I could cut the port lol wrong thinking

06-20-2010, 05:06 PM
if you need .6 an your using aero ports ya can try this
10x8x30 with 2 2in aero ports 16in long tuned to 34hz give or take a few hz gross is .9 net is .8 after disp of port an sub. i didn't know what the disp of the sundown 8 was so i used the p2d48 which was .030 may not be the right one but i think it should be close. i think it should work never really worked with a 10 an don't know how much room you have to work but i hope this works out for ya.

06-20-2010, 05:08 PM
or if ya go sub forward port up a single 2 inch port about 6in long would tune it about the same