Subwoofer losing power??

[chezwez123]

Hi guys, since I put a new sub and amp in i have been having issues, I had a 250w kenwood sub/amp combo which worked great, however, I have changed to an 800W mutant sub and 500W firebird amp, and since the transition i have lost so much power its unreal, the bass works great at low volume, but as soon as I get past around 50% power the sub looses the "kick" and turns into a horrible sort of distorted grumbling noise and I have no idea why this is... both sub and amp are brand new.

Any help appreciated.

Thanks.

-C

 

[bozothenutter]

is it getting the amps it needs?

 

[TheEvilGiraffe]

Are the 6x9s still in the same box ?!

 

[JLister]

Have you checked wires, connections, fuses etc.?

 

[The Fatty]

probably an under powered amp. If the amp cant draw the current it needs, it causes the voltage to drop which then in turn makes the ap 'clip' the signal. This gives you a near DC output, which causes all the kick from the sub to disappear and in time will cause the voice coil damage. This is all based on the assumption that you are quoting RMS values and the sub isnt a 800w peak jobby thats really 150w rms being powered by a 500w rms amp..?

 

[Dink]

i'd say it's not setup right

so as you raise the volume the amp starts to clip as the gain is set too high

 

[TheEvilGiraffe]

Given your other threads... Sub+6x9s in the same box, and busted 6x9 cone, I'd say you need to have a rethink about the setup lol !

 

[Dink]

Given your other threads... Sub+6x9s in the same box, and busted 6x9 cone, I'd say you need to have a rethink about the setup lol !

like, stick to the oem head unit and speakers?:clown:

 

[TheEvilGiraffe]

I think a Walkman is a safer bet TBH !

 

[chezwez123]

Hi thanks for the suggestions, for my fans, I have reset all the sound system so I only have 2 side door speakers and 6x9's plus the sub, as for the other suggestions, the sub is 300w RMS, I have tried changing the settings and also have tried insulating the box. As for the sub not drawing enough amps, I figured that if for example I have a 1200w sub with a 250w amp, would the sub not only perform to the capabilities of a 250w amp instead of causing problems with the sound quality? And as for wiring, I have checked all the wires and ensured the all are properly wired and in good nick.

I am going to test the sub in my friends box to see if perhaps the problem is coming from the fact that the box is letting too much air in, as I have insulated it but there is still a 10" hole where my old sub was, and also a random hole in the side, which I have done my best to fill up. My friend has described it as the sub is "farting" and reckons its the box causing the problem, but with that failing I will test each component to see where the malfunction is.

Many thanks for your help.

Any further suggestions appreciated!!!

 

[Dink]

your sub box should be sealed or ported properly

this way you actually put some load on the sub itself so that it doesn't get near it's Xmax

also whoever is giving you ideas/help don't listen to them as they sound like they don't have a clue

 

[The Fatty]

Hi thanks for the suggestions, for my fans, I have reset all the sound system so I only have 2 side door speakers and 6x9's plus the sub, as for the other suggestions, the sub is 300w RMS, I have tried changing the settings and also have tried insulating the box. As for the sub not drawing enough amps, I figured that if for example I have a 1200w sub with a 250w amp, would the sub not only perform to the capabilities of a 250w amp instead of causing problems with the sound quality?

No, becasue if the amp is clipping, the sub will still break down as its seeing a DC signal and not a AC signal. A DC signal means its not allowing the sub to smoothly move the voice coil from + to - and visa versa. Also you should keep in mind that a higher wattage speaker on a small amp will sound s**t as its effectivly being under powered The spyder and basket is designed to be moved with more power, so at low wattages the speaker dosnt perform). I dont think this is your problem though, as you say the sub is 300wrms and the amp is 250wrms, so that a nice match. Im still going to go with DC breakdown... get a portable osiliscope and watch a fixed waveform to see when it starts to clip.

 

[The Fatty]

I have insulated it but there is still a 10" hole where my old sub was, and also a random hole in the side,

?! a 10" hole thats been borded up or just left open? if its left open then its effectivly running the sub in free air (not good)! If its been borded up, it need to be screwed and glued super tight else it will vibrate against the box.

 

[Dink]

well it's a square wave rather than DC.

it's either setup or the box at fault

and by setup i mean gain/eq/bass boost set to high

 

[gothy]

Get a power capacitor
1 or 2 farad would do.
It stores power to use later, I had a 2 farad for my 2x 600 watt amps to run my old soundsystem.

Consider upgrading the cable core and fuse?

 

[The Fatty]

caps are less the usefull, they discharge far to quickly (less than a second) and require the charging system to not be under load to regain a usefull charge.