MKE

ok, as the topic states, i've smoked the voice coils on 3 subs in the past month...

2 12" mtx thunder 6000's, and 1 15" mtx thunder 6000.

both were powered by mtx thunder 4250 amps (the 2 12's on one and the 15 on another)

can anyone point out why? the only thing i can come up with is i was over-powering them. all 3 subs are rated at 300watts rms, and the amps are rated at 250watts rms x 1 @ 2ohms @ 12.5 volts, 350watts rms x 1 @ 2ohms @14.4 volts. and i've read that mtx under-rates there amps significantly so this is all i can think of.

now, in theory shouldnt that, at the most be 175 watts rms on each sub? the 2 12's were wired in parallel, making 2 ohms resistance, and the 15 was a dvc @4ohms wired in parallel making 2 ohms.

i'm assuming it's not a power issue, i've got 4 gauge power and ground, and on the battery i've got one of the gold battery terminals.

now, i work at best buy so i'm getting a hell of a discount on the alpine type r's (rated at 500watts rms, dvc @ 4ohms each). can i still use these amps? i'm getting the warrenty on them (4 year) so if they blow, ill get new ones, but i'd rather not.

KCVoRTeX

I was told that you are more likely to blow a sub by underpowering it than overpowering it... and you are definately not overpowering your subs.... you might have fried the amp though if you and burning up that many subs... I had the same problem of frying subs when I fried my amp (I fried 4 subs... 2 alpine E types and 2 MTXs all 12s) get your amp checked out before you buy any more subs.

Double_A

I would say one of two things:

1) You didn't properly "tune" your system and you've been clipping the hell out of your subs for a while. Very rarely can you just turn an amp all the way up. When you do that, most of the time you'll get clipping or distortion which, in time, will ruin any speaker. When somebody says under powering a sub will ruin it, that not totally true. If you give the sub only half of the power it asks for, but tune the amp properly, your subs gonna last along time. Now if you give your sub something less than it requires and turn the amp all the way up, then you will blow the sub. Becuase that amp will distort at a moderate to high volume.

2) Not too knock on your stuff, but from my experience, MTX just isn't that great of a company when it comes to subs. Alpine isn't something I would recommend either, but the type R's are up there in quality. I'm sure you're going with the alpines cuz you get the discount, but if not, go JL Audio.

BTW: if your not sure how to properly tune an amp, let me know via PM and I'll find the link on JL's website for you. I'm tired right now and don't feel like finding it, nor do I feel like typing it all out. So just hit me up and Ill get it later.

DTN

That's not true at all. Underpowering is not going to blow a subwoofer. What will blow a subwoofer is overpowering, or distortion. Think about it like a heater. You've got a heater coil rated at 1000W, if you're feeding it 700W, it will be good to go. It will not smoke the voice coil underpowering. If you incorrectly match the impedance from the amp to the speaker it will create distortion. If you correctly match the impedance, then a 100W amplifier can power a 10000W sub, not very well, but still can power it without blowing anything. Distortion will cause your speaker to vibrate in ways it's not supposed to.



Some things to look at-

Is your box too big or too small? Too big will increase the throw of your speaker. Too small will put stress on the inner surround that holds the coil to the cone.



Are your readings actually RMS or MAX? The way i do it is get the ACTUAL max wattage from the amp. check the max rating on the speaker, then take the amp's fuse ratings and multiply by 14.6. If the amp's fuse rating X 14.6 > Speaker's Max, then that's the problem.



Are you distorting? When you're tuning your sterio, if it sounds like ass with the trunk open, it's distorting. Don't distort your speakers or they will die a premature death.



cold climate? Inner, outter surrounds and cones will suffer if it's freezing out and you pound them.



Moisture? dont get the speaker wet



Amps fuses the same as recommended by MFG?



Alternator's voltage regulator- Below 14.7V at ALL times?

optimoprime

your serious best bet is to sell all your shit locally and start over. done try to start pickin out this and that that is causing problems. your gonna end up spending more money then whats neccisary.

1. sell your stuff
2. pick a diffrent brand ( i'm with Double_A i have never heard anything good about mtx systems. i hear their subs do knock though if u get the right ones, but their amps........)
3. spend the money u got off your shit and maybe a lil extra and u will have just as nice of a system that will probably last way longer.






now thinking of it. has anyone at all EVER heard of MTX stuff workin maybe like 3-4 years later?
i know that OLD jesen (pre-98), old Pheinex gold, and older american legacy amps. are really the only stuff that I HEAR OF that still works years and years down the road.

just something to think about

MKE

well, i am probably going to off my stuff, but i really dont plan on getting much for it.

and as for distorting it and tuning it- it was properly tuned,and when they did blow, i did not have the remote bass control up more then half way- i've never had it on full because it did sound like crap.

i dont have alot of money right now (actually-i have none which sucks) but yes, the reason i'm getting the type r's is because of my discount, they dont sound bad-actually for the price (100$ for a 12) there not bad.

now, someone mentioned about why i would blow them and said the box size could have been too small/big? would that have burnt the voice coils though? wouldnt that have done something else. i mean these were so bad that on one of the 12"s it melted the dust cover and there's a burn spot on the bottom of the box.

oh well, they are 5 years old (going soon on 6)- and i bought them all used so... (100$ for the box, 2 12"s, amp, and 4 gauge wire)

DTN

MTX Thunders are a very good speaker.



you need to retune your amp. if your remote bass control is at 1/2 then your amp is improperly tuned. Turn the remote bass control all the way up and then adjust the amp until the bass starts to audibly distort... not listening from the front of the car, from the speaker. You need to have your sterio volume all the way up and be listening to something with alot of bass to do this.



You've got your amp turned up way too high and it's distorting the hell out of your speakers.



The thing with too much air space is you can slam the voice coil around too much and it will make contact and rub off the protective coating. It will cause burning if the coil grounds itself out. The same thing happens with distortion.