Well, less than 24 hours after installing my sub, I blew it up! I was running a 15" 1000 watt us audio on a 5000 watt 2 channel powervox amp. The RMS of the sub was around the 300 mark and the RMS of the amp was around the 400 mark while running it bridged (which is what I was doing). Now, I know a little about subs and amps but not too much of the technical side, so I want to know; why would it have blown the sub and not a fuse? Isn't that what there made for? Secondly, I did get this amp of ebay, and I do know 5000 watt peak power is a load of **** as they just multiply the RMS value by 10 I think it is to fool the unsuspecting people to think it's the greatest amp ever. Was speaking to a friend at Autobarn yesterday, he recommended me a 15" soundstream which was pumping out 1500watts (not sure of RMS)... But the question is, if the amp isn't running at say the 400RMS as it says, would it still power the sub? Then cause it to blow up as it's not enough power?

Just confused as to why the sub blew up in the first place an if I buy another one an have a bit of a dodgy amp don't want it to blow up a brand new sub! Any help would be appreciated. Cheers.

PS - If any of you guys have a spare 15" sub (no box needed - just after the sub) that you wanna give away or sell for cheap, let me know. :happy:

why would it have blown the sub and not a fuse? Isn't that what there made for?

OK straight off, with some amps, they don't care what the sub is doing, i.e. blowing up.

For example, if your amp was putting out (from what I've read, and assuming your amp was a Powervox AS-2500 2CH amplifier HERE (http://www.powervox.cn/eng/vprod.asp?id=52)) closer to 500WRMS, and your sub can only handle 300WRMS, and if the build isnt very good regarding the sub, then it could easily be blown.

With regards to your issue with the fuse, there is no fuse between the amp and the sub, the amp has fuses to protect itself against power related issues, and possible over output issues, but if the amp is well within its range, then its not even going to know there is a problem.

For example, if you were to hook up a 1000WRMS amp to a 10WRMS speaker, would you expect to blow a fuse, or nuke the speaker ?

sounds like you've overworked the sub
the subs 300watts rms and your feeding 400watts rms into it?
you really wanna match the amps power to the subs, so the gain should be roughly 3/4
also how was the sub wired up?

Sigh.

As its been said, the fuse on the amp is for power side of problems, i.e short circuit.

There is no problem with running a 300wrms sub off a 500wrms amp, or a 250wrms amp.

As for your problem.

Is this a single 4ohm voice coil?

Or is it a dual 2 ohm voice coil?

How was it wired?

Secondly, its a cheap sub, not suprised it blew.

What did you have the gain on the amp set at?

Did you have bass boost on?

Did you have low frequency filter on?

DAM-088 the sub will be able to take 500WRMS of clean power no problem. An example is a Boston G5, rated at 450WRMS but Boston recommend at least 700WRMS off a GT28...

If you look at a power / THD graph you will notice that as an amp gets closer to its "max" RMS output the THD starts to spike. The harder you start pushing, the more chance you have a clipping the signal and potential sending a "square wave" to the sub. This does not give the woofer time to cool and thus, burn the fasizzle out of the coil.

I reckon the gain was almost maxed out or bass boost was turned on. :ninja:

sounds like you've overworked the sub
the subs 300watts rms and your feeding 400watts rms into it?
you really wanna match the amps power to the subs, so the gain should be roughly 3/4
also how was the sub wired up?

gain @ 3/4 at maximum preout power of say a 4V preout would result in the amp putting out about 600W of clipped, sub killing power. if you dont know enough to know that you know enough, then keep it safe, stick the gain on say 1/4, and get the pro's to sort it out if your not satisfied with the result.

Also that sub would properly only like 300W in ideal conditions, if the box is a bit too small or the porting is the wrong freq, it will unload like a bitch and cause mechanical failure with less than 300W.

DAM-088 the sub will be able to take 500WRMS of clean power no problem. An example is a Boston G5, rated at 450WRMS but Boston recommend at least 700WRMS off a GT28...

If you look at a power / THD graph you will notice that as an amp gets closer to its "max" RMS output the THD starts to spike. The harder you start pushing, the more chance you have a clipping the signal and potential sending a "square wave" to the sub. This does not give the woofer time to cool and thus, burn the fasizzle out of the coil.

I reckon the gain was almost maxed out or bass boost was turned on. :ninja:

That makes sense, thanks for the correction.

DAM-088 the sub will be able to take 500WRMS of clean power no problem. An example is a Boston G5, rated at 450WRMS but Boston recommend at least 700WRMS off a GT28...




I wanna see it play White Girls, with a clean 700W of true output without smoking :D then we can talk!

Us audio? Sounds like a cheap ebay brand (Sorry, if im wrong). Most of the time these cheap ebay products will die relatively quickly even if given the exact power requirements. They are not build to last.
My friend bought an cheapish amp of ebay last month (like $100 bucks new), and it died after about 4 hours worth of music.
Its always better to spend the extra dollar and get a decent, reputable brand for speakers and amplifiers. This way you know exactly the power requirements, output (Most cheap brands just fudge the numbers eg the ebay 5000watt amps that are like 20bucks..... hmmmm)) and you know it is built to last.

gain @ 3/4 at maximum preout power of say a 4V preout would result in the amp putting out about 600W of clipped, sub killing power. if you dont know enough to know that you know enough, then keep it safe, stick the gain on say 1/4, and get the pro's to sort it out if your not satisfied with the result.

I almost feel sorry for my rockford sub lol

Poor little sony amp is giving all its got, 90% gain, 4.5V pre out from head unit, bass boost on +3dB, and its on +6 at the deck......

All is good....new soundstream 1-1.5kw amp will be here soon :)

theres a Soundstream XXXX-6500 for sale for $1500 at a cashies near me, been in there for years, i reckon they would take $1000 cash. now that would be fun.

Hrm......

6.5kW....

Enough to power a few houses.......

Do it Woob.....you know you want to :hmm:

The gain was set at 50% an the bass boost was only on about 10%. Some one mentioned earlier about matching up the sub power to the amp power? I didn't think it was too much of an issue if the amp was more powerfull then the sub providing you have the gain set at a reasonable level, other way round, different story. The sub isn't a cheap ebay brand either. The guys at autobarn sell them an he said his never had a 15" come back. But could have just been unlucky with it. And yeah, that is the amp I got (500wrms), probably going to get the SS 1500 watt sub an see how that goes. After all the discussions with this bloke at autobarn he said his actually ganna check it all out for me so going to take it down over the next week some time. And he told me to bring me resume in an might have a job for me. Blowing this sub could turn out to be awesome :happy: So hopefully I'll get to learn alot more on the audio side and cars in general.

The gain was set at 50% an the bass boost was only on about 10%. Some one mentioned earlier about matching up the sub power to the amp power? I didn't think it was too much of an issue if the amp was more powerfull then the sub providing you have the gain set at a reasonable level, other way round, different story. The sub isn't a cheap ebay brand either. The guys at autobarn sell them an he said his never had a 15" come back. But could have just been unlucky with it. And yeah, that is the amp I got (500wrms), probably going to get the SS 1500 watt sub an see how that goes. After all the discussions with this bloke at autobarn he said his actually ganna check it all out for me so going to take it down over the next week some time. And he told me to bring me resume in an might have a job for me. Blowing this sub could turn out to be awesome :happy: So hopefully I'll get to learn alot more on the audio side and cars in general.

Did your sub have 1 or 2 voice coils? Maybe you just hooked it up wrong. Giving the sub a little extra power shouldnt really do much damage as the sub is probably capable of up to like 600wrms.... (Given that it is 1000w max), and given that it is a decent brand.

Its great that something good has come out of this though!! Now (Well if you get the job) you can get us all descounted audio gear! :P :D YAY!

Did your sub have 1 or 2 voice coils? Maybe you just hooked it up wrong. Giving the sub a little extra power shouldnt really do much damage as the sub is probably capable of up to like 600wrms.... (Given that it is 1000w max), and that it is a decent brand.

Its great that something good has come out of this though!! Now (Well if you get the job) you can get us all descounted audio gear! :P :D YAY!
US Audio is a decent brand now?? Wow.

US Audio is a decent brand now?? Wow.

Nah, I meant it could could probably take more power, given it was a decent brand. (coz I dont know if us audio is good or not)

Nah, I meant it could could probably take more power, given it was a decent brand. (coz I dont know if us audio is good or not)
OK my bad, I'll read better next time :D

The problem I dare say is a cheap amp on a cheap sub. The amp being a eBay cheaply probably isn't very consistent with it output and coupled with a cheap sub, hey its not gonna last long. 1 day is a surprise though lol

My best suggestion is cut your loss's save up for a while and get decent gear. I've gone through the "cheap" stage of buying car audio and I can tell you its not even slightly worth the effort and will end up costing you more in the end anyway than buying decent gear straight up.

OK my bad, I'll read better next time :D

Nah thanks for bringing that up dude, I think I just worded it wrong in my original post. My bad!

I wanna see it play White Girls, with a clean 700W of true output without smoking :D then we can talk!

I had mine in a 1.1cuft sealed cabinet with 600WRMS @13.8V 1%thd all day everyday for 2 years. It can handle it :woot:

Some subs are just made well... some just well aren't :D

See, Charisma, there's your problem....

It was in a sealed box.....

Real men choose ported boxes :P

lol

I think the lesson is this
Do not buy cheap car audio from ebay
It's all simply rubbish, you get what you pay for. You then bloew it up, and learn the lesson the hard way. If you had of put the original money plus a bit more in to a reputable brand from an Australian car audio store, you would not have had this problem.
Support our economy, our local business, and you'll reap the rewards of a good, solid audio install.

See, Charisma, there's your problem....

It was in a sealed box.....

Real men choose ported boxes :P

lol

Had the Boston in a ported box for a year as well running off the same amp. It was way to loud for my liking.

Hmmm well lets just say the Oz that I have is now going to go from sealed to ported so that should be very interesting. It is going in a commo wagon thou :tired:

I love the old sealed box, simple and reliable. :D

I just like the slight extention of lower notes in ported boxes.......

Perhaps with a better sub I wouldnt need a ported box, but for time being, I guess ported will do lol

I think the lesson is this
Do not buy cheap car audio from ebay
It's all simply rubbish, you get what you pay for. You then bloew it up, and learn the lesson the hard way. If you had of put the original money plus a bit more in to a reputable brand from an Australian car audio store, you would not have had this problem.
Support our economy, our local business, and you'll reap the rewards of a good, solid audio install.
amen to that!