I have recently installed my Alpine INA W910 headunit, Alpine MRX100 amp, and built a box for my Alpine SWR 12" sub. Box made out of 3/4" MDF, 14" width, 14" depth, and 9" tall. According to sub calculators of the enclosure puts me at .678 of volume, correct? Alpine says sealed optimum for the sub is .68 gross and .60 with the sub in. When the sub is in I have .63 of air volume? I have the amp wired with 4 gauge wire, will I be good to go to drop the sub in and not have any issues? First go around for building the box so a little nervous. Thanks for all the help!

 

Yup, you should be perfect!

 

Put half-pound of poly-fill in that box before securing the speaker in there. It really makes a difference in the lower frequencies in a sealed box.

 

Well after waiting four days (working out of town) I am finally able to install the sub into the truck! I hook the sub up, hit the key, and feel the truck rumbling from my exhaust and new found love of bass again! I play with it in the drive way for 5-10 mins then go for a drive. Been two weeks since I drove the truck anyways, so needed to be one with it again. Well I turn the bass up on the deck 2 nothces, turn my bass down on the door speakers and continue to rock out! After 20 mins my head is pounding and I feel the bass! I swing by 7-11 grab a drink, hop back in the truck and continue my drive back home. Five mins pass and the sub flat lines, is dead, does not work anymore! I am upset as I had the boxes in my room for two months looking at them and getting all my gear together. Doing returns with the faulty products and getting the time to install everything. So 30 mins I was able to enjoy bass again, I will say the Alpine SWR T12 is amazing! I plan to order another one, except this time turn down the amp settings.

I left the amp settings in the middle, didn't touch them at all, thought I was good to go! As it is 600 watts RMS at 4 ohms and 1000 watts RMS at 2 ohms. I hooked the sub up to the amp positive to positive and negative to negative. I am wondering why the sub blew, any one have a suggestion? What gauge speaker wire do you guys use for subs? I wanna say I used 14 or 16 gauge speaker wire maybe a foot long.

 

14-16 gauge is fine, I use 8 gauge though but I think the largest wire your sub will take is like 12 iirc. Keep the gain cut back some, and at least let it play for about a week with the bass down. The sub needs a break in period.

Did you make sure it wasn't the amp before you ruled the sub as the problem though?

 

Did it smell like something burning? Usually you will smell it before the speaker craps out if you really blew it. You likely would also hear distortion if you are overdriving the sub or clipping the amplifier.

 

I will grab some 12 gauge speaker wire this go around. I will turn the gain to 1/4 and let it break in. I thought I was good though with my setup and the instructions say no need for a break in period. Or is that a load of crap?
http://www.alpine-usa.com/product/view/mrx-m100/
http://www.alpine-usa.com/product/view/swr-t12/

The sub had that all too familiar burnt smell after a few hours of cool down. Based on my amp specs and sub specs I should be golden though right? As in to not over power the sub or amp.

 

Even with the power ratings matching, you can clip the amplifier with the gains set improperly or if you are using "bass boost" which spikes the output almost 18dB at 45Hz. Clipping is going to distortion the signal to the speaker and at full volume it can really damage the speaker (probably what happened).

 

The gains from the factory were set to the middle, I left them there and then adjusted my bass on the deck from 0 to +2. I will check out the amp settings tomorrow and let ya know what they are set at exactly. Wouldn't I hear the sub clipping though? I maybe had it turned up 3/4 of the way as I was just blown away with the sound quaility of my system finally all together, even if it was short lived. So sounds like I need to keep my gain at 1/4 way, Hz at? Don't wanna blow the new one again, LOL! I plan to throw the poly fill in, had it sitting there just forgot to put it in.

 

I suggest having someone who knows how to tune an amp to tune it. No one can tell you where to set the gain....it needs to be tuned for your setup

 

I can do the gain no problem it is the Hz I am reading up on and trying to figure out what does what when i input such setups. I do not trust the audio shop here in town or much of the places in this town. Majority have a rep for sticking it to ya! They wanted $300 for a box to be made then another $100 to run the wires and for them to tell me amps would not fit behind my rear seat. Lost faith in the shops.

 

Okay, set the gain about a notch below the nominal setting. Subsonic around 25ish. Low pass around 225-250ish. And keep the bass eq down. If your going to use it don't put it up past 3db. Especially since your upping it on the headunit at the same time anyways.

And alpine amps are underated too, so at charging levels (14.4v) it'll be putting out more like 800rms.

 

Subsonic at 20Hz for sealed box, low pass no higher than 80Hz. The gain needs to be set to match your headunit.

With the gain set at zero, turn on a bass heavy song and turn up your factory speakers all the way until you hear distortion (essentially the loudest you would listen to). Then at that volume, slowly turn up the gain until the subwoofer is nearing distortion, then turn the main volume back down. That will set your gain to a ballpark level. NO BASS BOOST, not even on the head unit.

 

Thanks guys! Sub should be here Monday so I will let ya know how it all goes.

 

Sub came today! Wired the new sub in with 12 gauge wire, added about ~.5, .6 of poly fill gain is turned down to 1/8 for now. Low at 60Hz, bass on my headunit is 0, and bass boost is off, if memory serves me correct. I will try to play with it some more with it this week and let it break in. Will roughly 30 mins a day work for five to six days for the first week work for the break in?