i recently installed a single 12" 400 rms audiobahn subwoofer in my 97 f150. but theres a problem, when the weather gets pretty warm, the subwoofer starts out sounding good but then out of nowhere, its starts to sound all distorted like something ratteling. i dont know what it is. i have been wondering about the sub box, there are no ports, and it is one of those sub boxes you find at wal-mart. that may be my problem. but i think the hert of the problem is because its getting so hot that when it heats up, theres nowhere for the heat to go in the box, so it starts to sound distorted. what do you think? any suggestions would be greatly appreciated. thanks

 

Mabye you have it turned up too high. The voice coil bottoming out will make a rattling sound. Is the box the right size for the sub?

 

i dont think its turned up too high, it may be the box. i just went to walmart and picked up a 12" sub box. and there are no ports in the box.

 

is the voice coil bottoming out going to harm the subwoofer or does it just not sound good 9its a dual voice coil)

 

Every sub has certain requirements for airspace. If the box is too big or too small, it wont work right, and possibly ruin the sub from overexcursion.

 

actually it may be a ppossibility that it is turned up too high, i unscrewed the wire connector from the back of the box and it still made that noise, should i turn down my amp?

 

Yes. Either the surround will give or the voice coil. Whichever can move the least.

 

if it is not the volume, should i invest in a newer,bigger sub box, possibly bandpass?

 

It is probably both. IMO, invest in a ported or sealed box built to the subs needs, not a bandpass, unless you are looking for max volume. A bandpass will build frequences in a narrow bandwith and not much above or below that. It is also harder to hear distortion in a bandpass, so you dont know if you are overdriving the sub until its at a huge level. But a sealed box will almost always sound better
What is the subs model #?

 

AW1251T i purchased it from woofersetc.com

 

Rec. Sealed Box Dims: 1.00 - 2.00 cu.ft.


If you can, check your box to see if it falls within those numbers. If not, time to get one that is

Recommended RMS Power: 400W
If your amp is around that rating RMS, your fine and its not being overpowered. But too much volume can still hurt the sub though.

 

i have a 400w 4 ch. running to 1 dual 4 ohm voice coil subwoofer. if the coil is bottoming out, which it never did before, until i turned on the bass boost on the amp, do i just readjust the amplifier so the distortion stops? or what do yo recommend

 

thats all for tonight, ill contact you if i have more questions. thanks for all the help, i appreciate it.

 

Yeah, I would turn down the bass boost until the sub stops making noises it shouldnt. Im sure thats the problem.

 

7 times out of ten......if you hear a noise from the cone area of a sealed sub**** it is the box, even more so when you remove the terminal cup......the box is no longer sealed, and the port length (the hole you just opened) is nowhere near where it should be for the sub. Leaky boxes tend to make it sound as if the sub is damaged.

The other 3 times its the amp.

Gain, by ear. Turn deck to 3/4 volume, turn gain up till it distorts, turn back a bit and leave it.

Gain, by design. Determine the amount if V your rcas supply, match that v to the respectful position on the gain of the amp. Generally, the more v your deck puts out the less you will have to gain the amp.

Adjust gain first, then tun the BB to your liking. Low pass in the 50's. No sub sonic is needed if you have it. Doesnt work sealed.

L x W x H divided by 1728 will tell you if the box size is correct, and im betting it is close enough because sealed is VERY forgiving. (Sealed subs will handle less power as they A: dont have ventilation and B: reach mechanical capabilites earlier due to air restriction.)

Liquid nail the seams and seal her up tight, adjust the amp, and you should be fine. Still have issues? Could be the amp is failing but only when heated up....i doubt it.

A sealed box CANNOT leak.

******Some subs DO NOT work in sealed enclosures and vise versa...check with your distibutor******

What you hit the backplate it sound like a knock......when you hit the coil hanger it has a mechanical BRACKK!! sound. When it leaks it sound like something is rattling on the dust cap, muddy, and distorted.