help speakers move in and out

[buster82284]

i have a panasonic 8400u deck and a mtx 81000d amp i have had it in my car for a wile and when i turn it up to about 25 or when i turn up the bass on my amp my speakers start makeing a poping sound and move in and out. what causes this? is my ground bad? i know i cant be pulling to much power because i have a 150amp fuse and i only have a 1500w amp and a 130amp alt and the subs are a 1000 a piece. i have to alpine type r subs and they hit when i turn the bass up but when i up the eq and turn the volume up it starts poping and moveing in and out and will only stop when i pull the key out. i think its a ground problem but which one is it the one on my deck or my amp?

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[B@SSAN8OR 10+ year member]

turn your gains down you are making your amp peak and send dc voltage to your subs. instead of ac. so start with this. turn your gains down and turn the eg on the amp all the way up. then turn you headunit to the volume you want to listen to it at and then turn your gains up on your amp to see when it starts peeking. then you should be set

 

[hoss 5,000+ posts]

turn your gains down you are making your amp peak and send dc voltage to your subs. instead of ac. so start with this. turn your gains down and turn the eg on the amp all the way up. then turn you headunit to the volume you want to listen to it at and then turn your gains up on your amp to see when it starts peeking. then you should be set

WHAT?!?!?!?!!?!

your subs are bottoming out, this is when the voice coil(often refered to as the VC) moves farther than it should and hits the backplate. this is fairly common, and is a good implication that you are 1)using too much power, or 2) playing below box tuning. it doesent have to do with your ground or any of that, it is simply that your speakers are moving further than they are designed to do. too much of this can cause your speakers to foul... it is definitly not good and you should seriously adjust your amps to where this does not happen.

as for what B@SSAN80R said... he is way wrong... this has nothing to do with the amp... and it DEFINITLY doesent have anything to to do with your amp "peaking" and sending DC to your subs... if he knew what he was talking about, he would know that DC would only move a cone ONE way, not in and out //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif . and again, if he knew what he was talking about he would know that there is no way for an amp designed to amplify an AC signal to switch to DC. and further more, if he knew what he was trying to say, he would know that he was refering to clipping... which is not what is happening in your case.

sorry for the long post, hope it helps //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[B@SSAN8OR 10+ year member]

if the amp is clipping it can send dc to the sub. how do you think a vc gets fried??? by sending dc to it.

and yes with the sub bottoming out that is a possibilty.

 

[hoss 5,000+ posts]

if the amp is clipping it can send dc to the sub. how do you think a vc gets fried??? by sending dc to it.
and yes with the sub bottoming out that is a possibilty.

WRONG!!

when an amp goes into clipping it sends a square wave(also refered to as a clipped wave). buuuuuut... this is still an AC voltage signal, the cone will still move in and out, bacause of the alternating current(and yes, AC stands for alternating current //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif ). an amp designed to amplify an AC signal will NEVER produce a DC signal. this is simply an impossiblility. it will however produce a square wave which will cause the cone to (for example) move out, stop, move in, stop, move out, etc... unlike the normal sinusoidal motion of an Ac wave, but this is an AC voltage either way.... like i said before, a DC voltage will ONLY move the cone one way, it WILL NOT move in and out...

 

[hoss 5,000+ posts]

also, i thought you wree affiliated with http://www.gatelyaudio.com . i would think that a box building company would be more aware of a bottoming out situation... and also aware of how an amp works... i might be wrong here, but i think i remember seeing you affiliate yourself with them...

 

[ibanender 10+ year member]

If your amp is puting out DC voltage, your outputs are toasted and your power supply is probably shot too. DC voltage with the sub in phase the sub would stay outward, DC voltage with he sub out of phase the sub would stay inward. By applying DC voltage and the coil staying in 1 position with no movement, there is no cooling and heat builds up and the coil dies.

Clipping is a major cause of heat build up which kills coils (notice a trend here... HEAT), clipping can occur during AC voltage which is what the amp puts out.

And last but not least, the sub is bottoming out. It can be caused by many things like have been listed by hoss, but it can also be caused by a leaky box. I've seen sealed boxes with water damage develop loose joints so the box leaked and made the subs bottom out. Judging by your "everything wide open" settings, I'm willing to believe that is the cause though. First start by turning off ANY bass boost, then go from there.

 

[req 5,000+ posts]

turn the gains ALL the way down

turn all EQ down (to flat)

turn bass down

now turn the volume to the MAXIMUM volume you will listen to

turn your EQ to how you like it (not too high now)

(you should do this mathmetically) but turn your gains up slowly, when it stats to "pop" turn it down a few notches.

and now do NOT go above the volume your HU is set to.

better yet, go to the GAIN SETTING THREAD, and set everything CORRECTLY