Big_T

I have a 4 door sedan. The car has the Gas tank between the trunk and the rear seats. This has lead me to apply more power and a larger sub to feel the effects of the bass. I'm mostly interested in Sound quality - an even reenforced bass to complement the other sonic elements.


With an 8 inch pounding hard in a tuned ported box you could not hear a thing in the cabin, it was strange.

I cut a port hole in the rear parcel shelf and actually tied to "pipe" the bass into main cabin from the trunk with pvc pipe. (this was a failed and foolish endeavor which did nothing to the sound level or quality of bass). / feel free to point and laugh if needed.

Now I have a 12 inch infinity reference in a sealed enclosure with about 125 watts rms and I feel and I can hear and feel the bass.

My problem is : When I turn up the bass a little; the rear parcel shelf rattles to no end at least it sounds like thats where It's coming from.

I have tried: Pressing down on the shelf, putting clothing between the gas tank and shelf, tightening and loosening the child safety belt harnesses and also removing the rear brake light situated on top of the parcel shelf.


I was planning on buying a whole heap of Dynamat and going to town but today I had a revelation. I had the Trunk filled up to brim with all manor of cases and luggage. As a result the rattling was almost gone as well as the bass sounding tighter and more responsive.

Will putting dynamat have the same effect? and if so where should I apply it? Should I cover the sub box?

I'm fully prepared to ride around town with a trunk full of pillows and quilts in the name of sound quality, yet having the trunk space would be nice.

BigRedGuy

iTrader: (11)

The fast and easy way is to toss the rear speakers....this might be an issue if you have rear seat passengers.....

Failing that you will need to cut something out of your car between you and the bass ....part of the rear deck usually works.

What vehicle?

Njord

I've noticed the same with my car. In my sunfire (with the same sub/amp and box ft^3 (but not the same box) and no deadening what-so-ever) the bass was much louder and 'fuller' (term is tossed around alot, but its hard to describe) vs my current sentra.

When I drive home (3 hour drive or so) I usually bring about 4-5 large garbage bags of laundry with me that I stuff in the trunk. I notice every time my bass sounds way better; even more so then what I was use to in my sunfire.

Although what might be adding to the bad sounding bass (with empty trunk) is the amount of rattling I have(not present with a full trunk). I've deadened the trunk lid, but It seems to be the rear deck (and the 3rd brake light!) that is causing most of it.

I think the reason the bass sounds better with a full trunk VS an empty trunk is due to just that. The trunk isn't an empty void. I'm sure that adding sound deadener will stop the rattle, but not have the same 'fullness' (haha) to the sound VS a full trunk.

As for deadening the front (you didn't ask but..) it made a huge difference in mid bass. (the components are in the front doors)
And I don't have rear speakers (there currently there, but no power to them)

Hope it helped, and if you find a solution maybe it will help me out.

edit: What i'm running:
10" Type-R @ 500W RMS in a sealed ~1ft^3 box

Big_T

It's a Jaguar XJ8. I'm hoping to not cut anymore holes in the rear parcel shelf. There are no speakers in the rear parcel shelf , they are mounted in the rear doors.




Thank you for the advice , it has crossed my mind hmmm I might just do that as well. I'm am a bit afraid to take apart the doors but I will have to overcome that fear.



So you are saying even with Dynamating the entire trunk still you have the rear deck (parcel shelf) and 3rd brake light rattling?





Yes the more I think about it the more it makes sense. The same way you see many drummers put old blanked inside their kick drum to give it a thicker sound. I'm thinking of maybe getting a bunch of sound deadening foam to fill up the trunk with but man that will be a hassle to take in and out if I actually have to use the trunk.

Njord

No I only deadened the trunk lid, not the whole trunk. I don't think putting a layer all around the trunk will make a difference (With only 500Wrms on a single 10" woofer. With more cone area and more power, you probably would notice a difference because at that level, everything flexes. I could be wrong). My next task is to deaden the rear deck, and do something about the 3rd break light (its on the rear deck up against the bottom of the rear window)

jalat

iTrader: (6)

in your diagram, you show the enclosure firing into the side of your trunk... why not face it towards the brake lights (or back)

[i]con

Have you thought of stuffing your box with Poly fill? I've heard it makes a huge difference and its not to Expensive.

Synyster_13

what would the poly fill do inside of the sub enclosure? if its sealed wouldn't you need the air space inside the box for the woofer to compress the air effectively? wouldn't the poly fill throw the cone out of wack? or am i jsut talking out of my *** here.. i'm not too experienced with car audio yet but i'm learning something new every day that i come to this site :P

Big_T

Well I think I might add Polyfill anyway but I don't se how that would effect the rattling, I thought adding polyfill to the enclosure just makes the woofer sound as if it was in a larger enclosure?

I'm reading form the long and descriptive answer listed here:

http://www.answers.yahoo.com/question/index?qid=20080424113543AATgZfA