Subwoofer Broken? :confused:

Prosk8er735

Hey guys looking for some help. I have a rockford fosgate p500-2 amp and a 12" p3 4ohm(i believe) wired in bridge mode. Just recently when i turn up on the volume on my headunit if i turn it up past a certain point or a bass heavy part of a song comes on the sub kind of cuts off and starts to make a rattling noise. At first i thought it was maybe just up to loud and it was clipping making the sub go into protection mode. But now it seems to do it often and its really annoying me. Is it the sub or maybe the amp? I dont have any thing turned up excessively high gain is probably 1/3 of the way up no more than half way max. LPF is set to 80hz on the deck and amp.

PLZ HALP me get my wubb wubb back!

RonRizz

Well, first off Subwoofers do not have a "protection mode" it would be nice if they did.
It sounds to me like your taking your sub into its mechanical danger zone, at or near its utmost excursion point. I have seen subs that tore through the spider, and voice coils jumped out well past point of no return, to the point where they were hung up on the basket completely out of place. I have also seen them popped back into place, with spiders glued back onto cone, and played for years after. (this happened in a friends car, and we repaired it)
I would look to see if your spider may be torn, or your tinsel leads are torn where they come through the cone, making your rattling noise.

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P99rs Head Unit--- Amps- 2 Pioneer Prs800d --- Zapco ST1000MX---Zapco ST-4XSQ---- SI BM mk5 Subs---SI TM65v2 Midbass--- SI M3 mids--- SI M25 xbl2 tweeters ----- 2016 MECA street class 3rd place at world finals

Prosk8er735

I meant to say protection mode on the amplifier, but you believe im pushing the sub too hard? As i stated the gain on the amp is probably only around a 3-4 if i remember correct but no greater than 5. Its a 500 watt amp and the p3's i thought were rated for 600 watts rms. When i say i turn the volume up its probably no more than to 29/40 on the head unit. Ive never repaired a sub before should i just invest into another one at this point? I just wanted to make sure it was the sub and not the amp.

SouthArk370Z

The driver is easy to check. Do a visual check as per RonRizz. If all looks OK, put an ohmmeter on the speaker terminals and push the cone in and out - look for sudden changes in resistance. While moving the cone, see if you can feel any rubbing/binding of the coil.

If the driver is OK, then you are probably clipping and just need to tweak your levels.

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RonRizz

Power will spike by HUGE amounts when amp is clipping, albeit in very short spurts, but more than enough to Push a speaker past its limits.

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P99rs Head Unit--- Amps- 2 Pioneer Prs800d --- Zapco ST1000MX---Zapco ST-4XSQ---- SI BM mk5 Subs---SI TM65v2 Midbass--- SI M3 mids--- SI M25 xbl2 tweeters ----- 2016 MECA street class 3rd place at world finals

SouthArk370Z

Yep. A lot of audio involves logarithmic functions. It takes ten times the power to get twice the volume. Ie, to get twice as loud as 100W, you need 1000W. A small twist of the volume knob (or slight increase of source level) means a big increase in power output.

You might want to check and make sure that the power amp's output impedance is set to match the driver. If it was set for an 8 ohm load, a 4 ohm driver can cause distortion/clipping at higher levels.

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Steering Lock Links - Search The370Z Bookmarklet - FSM @ NICOclub
Mankind has progressed past the need for war but we haven't evolved that far. - NachoMahma

RonRizz

you are wise, indeed, southark..

__________________
P99rs Head Unit--- Amps- 2 Pioneer Prs800d --- Zapco ST1000MX---Zapco ST-4XSQ---- SI BM mk5 Subs---SI TM65v2 Midbass--- SI M3 mids--- SI M25 xbl2 tweeters ----- 2016 MECA street class 3rd place at world finals

Fountainhead

And, besides all that, all volume/level controls/potentiometers on receivers are Audio taper, not linear, so you get most of the increase in the first 1/3 turn.
Most power amp inputs are linear potentiometers though. Most.

Aescen

wouldn't hurt to take a DMM to your terminals on your amp either. check to make sure you have a solid ground and 12v (Ohms from ground terminal on amp to a known good ground or negative battery terminal). Might want to check the fuse on your power wire too, I've seen some fuseholders that come loose a bit and if you don't have solid connections your amp won't be able to drive your sub properly.

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