Subwoofer locations without losing the spare tire

2fast4thelaw

No problem Matt, i am not trying to put down your opinion in anyway. I just dont like it when people generalize. People who generalize are usually ignorant. You are not ignorant and are clearly an intelligent person who knows a lot about this subject.

bigaudiofanat

Thank you you seem to know a bit yourself as well.

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huff442

Question for 2fast4thelaw. Your subwoofer enclosure design intrigues me. I'm not familiar with the boundary loaded concept in a car sub. Is this similar in design to the super high output PA systems? Regardless, how did you determine the volume of the chamber in front of the speaker? What about the size off the slot opening?

2fast4thelaw

The design is heavily influenced by High Output PA speaker design. The driver is angled slightly to horn load it to disperse bass energy. I will give a little tutorial on Boundary loading and Transfer Function and how they relate.

First off everyone knows that a subwoofer placed in a corner increases its output. This is because it has more boundaries to bounce off from. The more boundaries you can create, the more bass energy can be generated. In my enclosure the sub fires directly into the floor of the vehicle and bass is forces through a small chamber with a large vent at the very rear of the car. In a since this is a bandpass enclosure but the front chamber is not calculated to produce a specific frequency.

Transfer Function is maximizing the length of your bass wave from the subwoofer to you. In my enclosure the bass wave hits the very back of the car and bounces off of the rear window which then reflects it to the windshield which then reflects back to you.

Also Matt (BigAudioFanat) pointed out something I didn’t even think of. The downfireing driver transmits energy through the floor of the car so you get a lot of tactile feel. I feel this sub more than I can hear it. It feels like its right under my seat.

Here is a good link to illustrate what I am talking about.

Measuring Transfer Function, Boundary Loading & Soundwaves

huff442

Very interesting. Do the smaller boxes on either side of the speaker chamber add a significant amount of volume to the total enclosure volume?

How long till we see these enclosures (or at least plans) for sale? This could tempt me to lose the spare and buy run-flats.

2fast4thelaw

Here are a few more. I have to get the rest from my Installer. I should have them tommarrow.

The other chambers add support to the enclosure and probably account for 1/2 the air space.

I obtained permission to give these out:

Dimensions: 32-5/8" Wide X 23" (Note this is the top measurement, the bottom is slightly different as it contours the rear of the car. I would have to pull the box out and that would be an act of God to remove it.

The Box is 8" deep

The Vent is 21" X 5"

That is all I can measure.

There are no plans, Kelly cut and fit each piece. It took him 3 days to build that box! I hope your carpentry skills are up to the challenge.

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huff442

Did you bolt it to the floor to keep it from rattling on the floor pan? Did you have to EQ the box a lot? What did you set your Xover to?

Very, very nice box. I'm truly impressed...

kannibul

Sorry, but I find a lot of humor in those two statements

huff442

I have to agree with the statement. But remember, ignorance doesn't mean stupid. It's a lack of information.