Destroyed sub in 3 minutes why??

[AJStaples]

I installed the other sub (Polk db 1040 dvc) same way @ 2 ohm.
Running gain conservatively
It is giving off that same smell that the blown sub did. Not sure if this should be normal since it's been sitting NIB for like 7 years and the glues are heating up? I spoke again with a crutchfield tech support guy and was reassured the amp and sub are good match. Hopefully it just needs to break in or something before I can set the gain to a normal level.

 

[Jeffdachef 5,000+ posts]

It was to quick to hear Any clipping. It just sounded good until it sounded like nothing. Lol. Should prob tune it til it sounds good then dial it back I guess.

you cant hear clipping unless you have a highly trained ear. What you thought was normal was definitely clipping, you smoked the sub with a dirty signal plain and simple for this situation. Always have the gain down before you take a drive. Just because its low doesnt mean its not already past clipping , its all relative to your head unit's preout signal. half way could be clipping, 1/3 could be clipping, 7/8 could be still clean... thats why setting the gains is pretty key here.

 

[Lasherž]

I installed the other sub (Polk db 1040 dvc) same way @ 2 ohm.
Running gain conservatively
It is giving off that same smell that the blown sub did. Not sure if this should be normal since it's been sitting NIB for like 7 years and the glues are heating up? I spoke again with a crutchfield tech support guy and was reassured the amp and sub are good match. Hopefully it just needs to break in or something before I can set the gain to a normal level.

As Jeff said, it was definitely clipping. You should never set gains without at the very least a clipping indicator light, low tones it's pretty hard to hear clips. What you're probably expecting it to sound like is max excursion which you can definitely hear. The proper way to set gains is with test tones, a multimeter or oscilloscope, and no subwoofer attached. Amps will gladly produce more power than their rating all the way up until the waveform becomes square if you push them, but that's bad for the amp (generates a lot of heat) and especially bad for the woofer (low cone movement and high power will melt coils, which is what happened here).

A lot of people seem to do this thing where they say "the gain was only turned up half way" but misunderstand that a gain knob isn't a volume knob, if you feed your amplifier a 10v pre-out signal you could very well damage equipment going 1/5 of the way up. Matching voltage values is key to avoiding damage while maximizing volume.

 

[AJStaples]

Just am update. The other sub seems to be ok. After a little fine tuning, I think I have the gain set just right.
The gain was about an eighth of a turn higher before which I guess is what blew the other sub out.

 

[AJStaples]

I'll probably ask in a new thread, but I feel this sub is lacking a bit. (Polk db 1040 dvc) It's not terrible, but it just seems a bit weak. I mean... It's only a single 10 in a sealed box, so I can't expect to much.

I was considering switching the sub out for the kicker compR 10 from best buy.

My question is 2 part.
First, is my amp able to give the kicker the power it needs to perform well.
Second, would it make a distinct sound difference or would it just kinda be a little better ish.
Thanks
I'll add pics of specs.
I'm bridging the amp for the sub.

 

[Popwarhomie 5,000+ posts]

You really need a dedicated subwoofer amp. A mono block. Swapping to any other 10" subwoofer in that sealed box is not going to gain anything but less money in your pocket.

 

[hispls 5,000+ posts]

Second, would it make a distinct sound difference or would it just kinda be a little better ish.

That kicker would probably be more likely to survive what you're doing, as far as more output why don't you tell us about the box it'll be in.

 

[Lasherž]

I'll probably ask in a new thread, but I feel this sub is lacking a bit. (Polk db 1040 dvc) It's not terrible, but it just seems a bit weak. I mean... It's only a single 10 in a sealed box, so I can't expect to much.

I was considering switching the sub out for the kicker compR 10 from best buy.

My question is 2 part.
First, is my amp able to give the kicker the power it needs to perform well.
Second, would it make a distinct sound difference or would it just kinda be a little better ish.
Thanks
I'll add pics of specs.
I'm bridging the amp for the sub.

The subwoofer isn't the issue, it's the enclosure if it's sealed. I promise if you go to ported or vented you'll experience the noise level you were hoping for, but this is usually at a cost of frequency allowance. Your sub will no longer produce 300hz without sounding muddy, but it will be way louder and that's what your other speakers are for.

Also the Polk DB series is much better quality than that kicker in my opinion. The DB series has a good reputation and the Kickers are so so.

Invest in an enclosure instead if you want more volume, as you go higher wattage in sealed you get diminishing returns because it becomes over dampened.

 

[ThxOne Premium Member]

Just my 2¢... Vented pole pieces sitting for 7 years could theoretically allow small insects into the coil gap. Nesting there and having generations of insect babies could have degraded the coil to the point of damage. Just a theory.

 

[AJStaples]

The subwoofer isn't the issue, it's the enclosure if it's sealed. I promise if you go to ported or vented you'll experience the noise level you were hoping for, but this is usually at a cost of frequency allowance. Your sub will no longer produce 300hz without sounding muddy, but it will be way louder and that's what your other speakers are for.

Also the Polk DB series is much better quality than that kicker in my opinion. The DB series has a good reputation and the Kickers are so so.

Invest in an enclosure instead if you want more volume, as you go higher wattage in sealed you get diminishing returns because it becomes over dampened.

I was thinking the same thing about the box. I listen to mostly hip hop type stuff. I do like crisp bass, and I have this feeling that ill lose that with a ported box. Maybe not though. My main concern is that my vehicle is a pick up truck. And I don't have much space other than on the floor in front of the back seats. I can't fit anything under the seats, I may be able to build something for behind the back seats, but then it's like buried behind the seat and I'm thinking the seat would somehow negatively impact the sound being right up against the box. Idk. Maybe I'll make a shallow down fire box for the floor in the back....

 

[ThxOne Premium Member]

Did I miss it? What truck is all this happening in?

 

[AJStaples]

Did I miss it? What truck is all this happening in?

03 f250 crew cab.

 

[ThxOne Premium Member]

03 f250 crew cab.

I know you said there is no room under the seats... are you storing stuff there? There are several options for under seat enclosures for that truck. And behind the back seat it looks like too.

 

[AJStaples]

I think the mounting depth is the issue. The boxes I've seen I think are all like 5" or less. The Polk MD is 5 -7/16". If anyone knows where I might find plans for a shallow 10 ported/vented box I would could possible just build it...maybe

 

[1aespinoza 10+ year member]

Invest in an enclosure instead if you want more volume, as you go higher wattage in sealed you get diminishing returns because it becomes over dampened.

I noticed this in my sub as well. As I bump a bit above normal level it sounds awesome, but as I get overzealous, I seem to lose bass. It is also a sealed 10". Now I know why, thanks.