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i just installed a Kicker KX600.1 amp (350 rms @ 4 ohm) and an eclipse aluminum 10" sub(400 rms)

it sounds great as i thought it would but if i turn the bass boost on my amp more that 1/8 of the way the sub starts to distort. or if I turn the eq on my HU up to high it does the same thing.

My HU is a cheap pioneer with 2V preouts so i think it could be clipping, but i never had a prob with my rockford amp and subs. (200w rms punch amp, 12" 150 rms pioneer, 12" 150 rms punch)

I also made the box my self. I used winISD and it said nominal sealed enclosure size would be .7cf. so i made the box that size with .75" MDF and did a decent job, exept the hole is a little to big and only like 4 of the screws holding the sub in are tight, the others went slightly to the side and in the hole, the only air leak that i can find is where the wire goes in, but i can just barely feel the air being pushed out. Also i didnt use any bracing inside the box.

do u guys think the distortion is caused by the box or clipping, and any suggestions as to what i should do

Why the bass boost? Keep it off. You pretty much answered your own question. Turning settings on the EQ up TOO high.

my bet is that its both..

but i'm a newb.

oh yeah, i also forgot to ask, to help the clipping what would u guys recomend, getting a better HU (i like my pioneer it sounds nice) or just getting a line driver

Neither, it's clipping. You reached the maximum output for that amplifier.

"oh yeah, i also forgot to ask, to help the clipping what would u guys recomend, getting a better HU (i like my pioneer it sounds nice) or just getting a line driver"

Setting the gains correctly. That's the #1 solution. Not using EQ/Boost also aids in preventing clipping, if you do use EQ, cut surrounding frequencies instead of boosting whenever possible. The main benefit of a line driver isn't to prevent clipping, but to provide a higher resolution signal and lower the noise floor of the system, and in your case it really won't help prevent clipping.

That particular amplifier offers an 18db bass boost centered at 40hz. 1/8 of a turn on that amplifier is approaching a 3db boost. 3db takes twice the power to produce, if you're near the limit, it is extremely easy to drive an amplifier into clipping with bass boost. If you had the EQ boosted simultaneously, you could be requiring 2-10x the power that it normally would have if all controls were flat.

The box definately doesn't help matters, you need to seal off leaks. Use silicone or caulking around the wires in the back of the box to seal off that leak, or install a terminal cup in it's place. Try to get the sub mounted as tightly as possible on the front baffle, making sure no air will leak there. You'd be surprised how much of a difference a little bit of air leak will make as far as cancellation goes.

My last thought, it seems as if you're trying to get more SPL out of the system than it is capable of. If you want more SPL, I'd suggest stepping up to a ported enclosure, you'll get an increase in output and you'll get increased SQ at higher volumes due to the mechanical control of the box. Mechanical and thermal power handling increase when using a ported enclosure over sealed, assuming that you are above the tuned frequency. The Eclipse Aluminum you're using really opens up ported, in both SQ and SPL.

Jonathan wrote:"oh yeah, i also forgot to ask, to help the clipping what would u guys recomend, getting a better HU (i like my pioneer it sounds nice) or just getting a line driver"

Setting the gains correctly. That's the #1 solution. Not using EQ/Boost also aids in preventing clipping, if you do use EQ, cut surrounding frequencies instead of boosting whenever possible. The main benefit of a line driver isn't to prevent clipping, but to provide a higher resolution signal and lower the noise floor of the system, and in your case it really won't help prevent clipping.

That particular amplifier offers an 18db bass boost centered at 40hz. 1/8 of a turn on that amplifier is approaching a 3db boost. 3db takes twice the power to produce, if you're near the limit, it is extremely easy to drive an amplifier into clipping with bass boost. If you had the EQ boosted simultaneously, you could be requiring 2-10x the power that it normally would have if all controls were flat.

The box definately doesn't help matters, you need to seal off leaks. Use silicone or caulking around the wires in the back of the box to seal off that leak, or install a terminal cup in it's place. Try to get the sub mounted as tightly as possible on the front baffle, making sure no air will leak there. You'd be surprised how much of a difference a little bit of air leak will make as far as cancellation goes.

My last thought, it seems as if you're trying to get more SPL out of the system than it is capable of. If you want more SPL, I'd suggest stepping up to a ported enclosure, you'll get an increase in output and you'll get increased SQ at higher volumes due to the mechanical control of the box. Mechanical and thermal power handling increase when using a ported enclosure over sealed, assuming that you are above the tuned frequency. The Eclipse Aluminum you're using really opens up ported, in both SQ and SPL.

Also, more available power helps clipping when gains are set correctly. Insufficient charging system will result with clipping even when the gains are set correctly.

cool, thx for the help guys. i still havnt had a chance to upgrade the wiring in my charging system to 4g. i have noticed that my lights are dimming even with that 300 watt amp and 1 sub. hopefully upgrading the big 3 will help, if not ill get a higher output alternater.

did you allow for driver displacement in addition to air volume in the box volume calculations? re-cut the front panel and make the holes the right size so the subs seal properly in the box.
the poor box construction would be part of the problem.
the bass boost and EQing causes distortion as well. leave them flat.
the head unit peaks the bass boost at usually 100Hz, and those subs should be cut off about 60-80Hz.

also make sure the gain on the amp is set properly. this could also cause clipping.