Newbie Sub-Amp Question

[Robb]

Hey Audio Guys!

What is the wattage rating on the stock sub-amp on a 2nd gen? I think it is 80w. Just need to know if it basically matches the replacement sub I got.

I would imagine it is the same as the Expo amp. My brother blew out the sub in my dad's Expo this week and I went out and got a JL 8W0 to replace it (the Expo uses a 8"). The sub is only rated at 75w. Well, I threw it in without the batting (sp?) material in it and it did a lot of popping when hitting hard. So, I threw the batting back in and it helped a little, but it still pops a little under heavy load. It seems to have better bass response than the stock sub had, and the popping is hard to hear when sitting up front, but I just wanted to know if there is something I should try to eliminate it?

Thanks for any help!

 

[VairKing]

I know the first gens were 85 watts max I belive...Ive got no idea what the 2nd gens are though...It should be fine...

 

[dubbedexpo]

usely "popping" only occurs b/c of two things.. 1 - u are over powering the sub... or 2 - the box is to small for the sub.. like not enough air space.. i think it is the box b/c when u the crap back in the box u said it went away a lil... right?? that crap is designed to make the box "seem" bigger... that is my guess...

 

[hrbib21]

Originally posted by dubbedexpo
usely "popping" only occurs b/c of two things.. 1 - u are over powering the sub... or 2 - the box is to small for the sub.. like not enough air space.. i think it is the box b/c when u the crap back in the box u said it went away a lil... right?? that crap is designed to make the box "seem" bigger... that is my guess...

I concur. Normally you would try turning down the gain but this being a stock amp you don't have that option.

 

[Creelove]

The stuffing 'crap' that people refer to is designed to reduce resonances in the box (i.e. damp the standing waves). You should definitely keep the stuffing in the box and should more than likely add more. The amount of stuffing is a design paramter just like the size of the box and type of woofer, but to give an average value, I would recommend 50% fill (half of the box full of stuffing) -- and that means really tightly packed in. I would recommend getting a big bag of Polyfil (very cheap) from the craft section of Wal-Mart, K-Mart, etc and packing it in. This additional dampening usually cleans up the cleans of the subwoofer. You might notice a change in the output level, but this is reduction in resonances, which means a flatter response, which is good!

I don't think this will cure the problem though. JL Audio subs are excellently made, so I don't think you're bottoming it out. It could be one of two things: the first is that the amp is distorting. If you are really cranking the stereo (and you know if you are) then you are probably driving the amplifier to clip (cut off at the large audio swings or distort) which is causing the problem. But, I know that the amplifier has distortion limiting on it, so it should automatically lower it's internal gain to keep the output from distorting.

Here is the more likely scenario and I can't believe sub manufacturers haven't done something about this: the voice coil leads on the sub are probably hitting the cone. If you look on the back of the sub, you will see the leads that connect the voice coil inside the magnet to the connectors on the frame. I've noticed that most manufacturers make these leads longer than they need to be (just in case). You can see this if you move the sub from one extreme to the other of it's travel and look at the leads. Usually you will see that there is a lot of slack. When the sub starts to throw deeply, sometimes the leads hit the cone and cause a snapping sound. To remedy this, you simply unsolder where the leads connect to the frame, pull them through a little bit (still leaving enough slack) and resolder them. I've had to do this on almost all my subs. Word of caution: be VERY careful though, you will most likely void the warranty on the sub by doing this.