Alright bass experts, let's discuss a little theory here...

[John B]

As I am trying to finalize a sub configuration for my G-body I am curious about testing a design and would like some feedback from the experts or someone who may have already tried this.

In my opinion, when mounted in a G-body the stock size 4x10 or 6x9's (with adapter) rear speakers put out a tremendous amount of bass for their size (granted, a bit boomy) and given the fact that this is not really an optimized cone size for producing decent bass when even using the stock GM headunit. Using this size of speaker in any other vehicle that doesn't have a trunk for these size speakers to resonate in really sounds like crap on the bottom end. So, this leads me to believe that maybe the reinforcement of the trunk or the delay of sound coming through the seats somehow really magnifies the low frequencies in G-body type vehicles.

Here are my questions for discussion and debate:

• If an adapter was fabricated (similar to the Metco adapters for connecting 6x9's to the 4x10 holes in the rear deck) to connect an 8" or even a 10" sub, how would this sound?
• Would they need a cabinet (since the 4x10's and 6x9's don't use one) or would you just use an infinite baffle speaker to be safe?
• Would the bass be tight or boomy?

 

[Audiowizard]

Originally posted by John B


Here are my questions for discussion and debate:

• If an adapter was fabricated (similar to the Metco adapters for connecting 6x9's to the 4x10 holes in the rear deck) to connect an 8" or even a 10" sub, how would this sound?
• Would they need a cabinet (since the 4x10's and 6x9's don't use one) or would you just use an infinite baffle speaker to be safe?
• Would the bass be tight or boomy?

1) Not sure on the sound but for it to sound right, the speaker (8" or 10") should be a driver designed for infinite baffle (free air) and the front cone must be sealed from rear air space.

2) You will have better bass response from a driver mounted in a subwoofer enclosure verse a free-air woofer. The 6 x 9s and 4 x 10s are designed for free-air application and will not give you the same performance as a driver designed for an enclosure.

3) You will get some low bass and not very tight punchy bass from the free-air application.

 

[darkfa8]

agreed

I agree with Eddie on those points...plus...

The size of the G-Body trunk can be a give and take thing. Acoustically, its a huge enclosure...and with subs on the rear deck facing the back of the trunk...depending on enclosure design, the sound wave is actually delayed a bit before reaching the passenger compartment since the wave travels towards the rear of the trunk and then reflects back towards the passenger compartment.

You can experiment with this phenomina buy running the stereo with the trunk open...then closing it...listen to the sound difference.

I have been trying to come up with some answers myself, in terms of changing the delay of that bass wave and moving it closer to the passenger compartment.

According to an article by Eddie Runner at installer.com, if you position your sub enclosure a few inches from the back of the trunk (tail light side) and face the subs towards the back of the car, the delay is reduced...the wave doesn't have to travel as far to reflect off the back of the trunk and then go towards the passenger compartment.

So what I was thinking was building a shallow, but wide sub enclosure that would take up the rear deck shelf and then put a face of 1/2" plexi glass or some other material in to actually seal in the subs...kinda like making a artificial "back of the trunk".

Acoustically, it should work...and I'd put some acoustical foam on the back of the trunk and then cover it over with some speaker grille cloth...

Also..another side idea with the acoustic foam... get some under-dash panels from a Regal and cover them with acoustic foam and grille cloth and it will help raise the front stage of your kick-pod speakers