Mass loading the sub box, a good idea or not.

I have a JLW3v3 in a Supercrew sounds single side sub box. I notice when playing music, I have a really large cabin gain hump in the sound around 60Hz. I've played with the amount of stuffing in the box, endlessly tuned the parametric EQ on my head unit, and couldn't get rid of the hump. I finally decided to take some sound deadener that I had on hand from my install, and cut up tiles to stick to the inside of the box. I covered all the areas that I could, bottom sides and front panel and rear of the box. Then I took some CCF and lined that over top of the deadener. Pulled all the stuffing out, re-installed the sub, and now I have a cleaner, better sounding sub. Is mass-loading the box the right idea though, or should I look for another solution to this problem of the 60Hz hump?

 

How much air space is your box? Does it fall in the subs air space range according to JL?

Polyfill (Stuffing) is only tricking your sub to make it think there is more air space in the box that what is available.

If you put sound deadener in the box take it out. It isn't designed to go inside a box.

 

can you put polyfill in a ported box and how much room do you gain by putting in the polyfill?

 

Yes you can put polyfill in a ported box.

You don't gain a lot of room. Each setup is different. It's not a lot like .8ft.

 

how much do you put in the box and that only for a box with one sub or two? or it doesnt really matter?

 

Box is .65-.7 cu. ft. It does fall in the space range of the JL specs for a sealed box. You say to take it out, but after listening for a few days, it seems to have helped with the 60 Hz hump I had in the truck. I'm thinking the box itself was resonating at or near that freq., giving me that hump. I didn't put in much. Just patches on the back wall, on the front wall and on the base.

 

It sounds like you have a box resonance. The best thing for that would be to brace the box with an internal brace.

 

The problem with that idea is the basket for the W3 is so big and the magnet so large, there's no where to put a brace. Any suggestions on where I might consider it?

 

Redo the face of the box where the sub sits with 3/4 inch mdf

 

What are you running for front speakers if anything? I would say if u have decent front components and they don't have a cross over you could be getting the extra peak from them.

Put the t/s parameters in to some box building software and see what the curve is like. Also do you have all bass boost and other extras off?

 

If you have limited room for a brace it doesn't have to be a full width one. You could cut strips of 3/4" strips to sort of give it ribs on the inside. I do that sometimes depending on the setup. Just wood glue them in.

 

I'll give it a try, thanks.