Ohm load too low ....blowing subs?

[Kurtle]

Hey everyone .... I tried making a post earlier in general but it didn't seem to work so I apologize if this ends up as a double.

as title states I'm wondering if running my amps below reccomended ohm load has something to do with cooking subs!? 

My set up is 

280 amp irragi with 2 runs of 1/0 off alt to battery bank in rear (trunk battery car; no front bat)

4 deka group 31 

2 exile audio 2400.1 amps (dd1'd)

4 ab xfl 15" dual 2 

2 skar 8" neo w/ 2 mclaren mlt-60 per door run off 2 crescendo 800.4 

Pioneer 80prs

the issue I'm asking about is that since I have started running 4 subs wired down to 1 ohm on the amps strapped (rated to be stable strapped at 2 ohm) I have been blowing up subs!? 

A bit more details now .... I ran 2 of the xfl 15s in a ported box that had 2.7 cubes net per driver tuned to 31 hz, powered by the same two amps strapped at 2ohm. They took every watt that was thrown at them and never stunk or had any issues for a whole summer. 

Then I grabbed two more subs and put all 4 in a box that was just over 3 cubes  net per driver tuned to 34hz. I wired them down to 1 ohm on the strapped amps thinking that worst case would be I kill the amps (which I was ok with because then I would HAVE to buy a new REAL high powered amp  lol and research showed that people ran the same amps .5 ohm without any problems so I figured wth I'll give it a shot) or that they would just go in protect and not operate. Well they 'work'  and/or play with the low impedance but instantly when I fired up one of my subs blew! The older two  had been sitting out of the box over the winter in my shop so I figured it was my dumb mistake and something may have gotten into the coil and fucked it up.... I ordered another one to replace it and everything seemed fine, did some testing with new box - didn't like the 34hz tuning so built another box which is two boxes in one(two chambers built to specs of my original box 2.7 per @ 31 which I knew worked and sounded right)  i started slapping ....only to have another sub blow up less than 30 minutes later!!!! The odd thing is that the sub that just blew was one of the the 3 new ones and the old one is still fine. 

I'm wondering if running the amps under rated impedance is doing something to the signal that's hurting my subs? I do have a dd1 which I've used on all my amps so I know they are set properly and the subsonic is right at 28/29 hz so I don't think that has anything to do with it. Its either that or I'm just having some bad luck ie. something got into first subs coil and fucked er (went rock solid would no longer travel and coil looked fine in color and smell) and just got a lemon which also blew (coil came unwound)  or the amps are at fault. 

Any input or info would be great to help me learn as I am have no real experience myself with running amps below lowest rated impedance and like I said I just figured the amps would blow/ catch fire or something lol 

I already order two new subs so all 4 are new with the old one for spare and as long as guy doesn't back out I'm grabbing a used nendo bc5500 this weekend so the exiles will be put to rest and no chance of screwing anymore subs if they were the culprit

let me know what you think

thanks!

[ChevyBoy95]

What tone did you DD-1 it with? -5 or -10?

Honestly, you are probably just using too much power or clipping them heavily (if you used the -5 or -10db track) due to playing higher amplitude bass songs than what you set it to play at. 

 

Edit: by what you are saying, if it blew that quick ,sounds like too much heat (so thermal issues, i.e. clipping or just too much power).

[Kurtle]

Thanks Chevyboy,

tuned it with track 7 never checked what db that ones at but that's  what I thought too ...  much heat causing the coil to melt/unwind like that. Just to ask .... even though I tune it with the dd1 can certain tunes still be causing distortion? i like a lot of decaf and got 160s

Like I mentioned though what has me stumped is how I had only 2 subs on the same two amps strapped,  so the amps are rated to do '4800' strapped @2 ohm and the two subs handled it no problem .... I know lower impedance means more power from the amp but I wouldn't think that it could be enough to over power 4 subs just by dropping that extra ohm. Unless when it's that low it's causing clipping/distortion regardless of tuning and gain settings 

Also, could too small of a box be bad for the drivers? My buddy always does the designs for me and I thought 2.7 seemed small for those subs (although first box was fine)  I always read and heard that smaller boxes had the benefit of being able to handle more power because it had the ability to provide more suspension support unless too small can't dissipate heat efficiently enough?

[8ten8]

 track 7 is -15db. Maby that's the cause along with boosted music. Try track 3, -5db.

[MrSkippyJ]

-15db is a bad combo with decaf type music.

The DD-1 only measures the effect equipment has on the signal. If the signal is recorded with lots of clipping or distortion you can still have speaker issues down the line. 

Small boxes can help with mechanical power handling but not so much with thermal power handling.

[reedal]

Retune using track 5, the -10dB @ 40hz tone. I wouldn't recommend using the -15dB tracks ever, as very little music is attenuated that much. There's a recent thread titled what is gain overlap, which will give you a better idea of what you're actually doing when using the DD-1 and setting overlap. Use the search feature on this forum to find it, and soak some knowledge

[Kurtle]

Very cool, thanks for the info guys and I will check out the overlap thread to help understand what's happening when using the dd1.  Will also try the other track for setting gains next time.