killercrow

first off, hi everyone!

well, i just stumbled upon this site. looks like theres a lot of knowledgable people, which is a definite good thing!

well, ive been doing my own installs for a while now, learn a little more each time. im taking the next step in car audio, picked up an alpine mrd m500, and a re sx12 sub, with dual .7 ohm voice coils, wired in series. the deck im using is old. first one i bought, 9 years ago. its a panasonic, not sure the model #.

i have everything installed, it works, but im not happy with the results. im convinced that i built the box too small. its .88 cu/ft, not including the volume of the port, which is a slot port. if i sealed the port, total displacement would be 1.4 cu/ft.

the way it is now, the sub hits real hard but has nothing for low end... is my box doomed? or does sealing the box sound like a good idea? id hate to have to scrap it, since it turned out real good. it sits between the 2 bucket seats in my truck, and is shaped like a seat. have plans to cover it completely, with cushions and a seat belt too, catch my drift?

also, with this amp tuning.... ive never seen a digitally adjustable amp... so i dont really know what all the features do. i dont rally understand the whole first step in tuning the amp, where i gotta turn the volume up and down and up again... is it important?
the stereo shop guy said i had it pretty much the way it should be, but mentioned my deck may have too low of a pre-out voltage.

anyhow, any help or pointers would be great!
thanx for listening.

al.

veeman

iTrader: (3)

seal the box and see how it sounds, just plug the port, and if needed screw a piece of wood over the port hole. You can always remove it later.

worldind

iTrader: (17)

.88 for an sx12 is pretttttty small - .88 is actually about what RE recommends for a sealed 10"..... and did you account for the displacement of the sub as well? - I have about 2.5 cubic feet for each of my sx's, after port and sub displacement. Perhaps sealing it will produce better results (giving more space), but from what I've read, the sx yearns to be ported, and although i've never sealed mine, I can vouch that they do sound excellent in a ported box.

Your problem might also be due to your port tuning... perhaps it's a little high for what you want, although you'd have to give some dimensions of the slot and box in order to figure that out.

As for the low preouts, that can be dealt with by turning up the gain on the amp a bit, it shouldn't be a problem if the guy says its set right.

All in all, I'd say give it 2 to 2.5 cubes and port it around 30hz, and you should be much happier... that is, if you can part with your perfect-fitting box and your future plans for it... heheh. If not, just seal that port off as veeman said and give it 1.4, which falls right in the recommended range for the 12".

killercrow

hey thanx for the pointers. like i said before, i learn a little each time i build a system. i sealed the box, which did make it a lot better. a little messing with the amp... trial and error... so confusing, whatever happened to amps with like 2 ***** on them for tuning! hah! i'll get the hang of it.

my only gripe with the setup as it is now, is i think im a little underpowered. the mrd m500 runs at 500 watts rms, with 900W max... and from what i understand, the sx12 runs 1000W rms... what kind of difference am i going to notice running this sub with a bigger amp? i have my eyes on an earthquake amp. 1 ohm stable, 1000 watts at im not sure what impedance...

worldind

iTrader: (17)

Doubling your power should produce a significant change... in theory it's like a 3dB gain I think, although that probably never actually happens. A few hundred more watts went a long way with my sx's, and since you're giving yours only half its recommended wattage it should really move when you feed it 1000+

MR2NR

iTrader: (66)

You will notice far more difference with a proper box behind that sub as compared to going to a different amp. Pour some time and effort into a new box.