Once again the car environment rears it's ugly head.

Positioning a sub in a car can be a very person issue of taste. Some of you may actually prefer the output of the sub facing directly into the passenger cabin. But, the issue above sounds very much like cancelation. There isn't much room in a car for most people to play with baffle placement, and most still like to have a trunk to use.(some of it) So the easy route for most vehicles is to face the sub to the rear.

I will admit that it does increase response, but it isn't linear. The boost in output will be similar (but not exactly the same) as the effect of loading a driver into a bandpass box. The boost will have a center frequency, and that is governed by the dimensions of the vehicle.

Due to the increased efficiency, and high frequency dampening properties of a rear facing sub, I would agree that for most people it does make sense. But for people looking for fast transient response, and the ability to have superior control of sub frequencies, facing the sub forward works. (Most of the time)

I cheated. My forward facing drivers are completely separate from the trunk. In fact, I went to great lengths to seal the trunk compartment off from the passenger compartment. It's not for everyone, but it worked for me.

Adam

 

It is the old Venetian blind effect. As you move around a room listening to a test tone the sound gets louder, and then quieter, then louder then.... this will also happen in a car but the interior is such a complex shape the cancellation nodes can not be mathematically derived as easily as in a rectangular room (I HATE advanced math). Now consider a subwoofer producing a complex bass passage (real music) in the complex automotive interior. It is reasonable to assume that some freq are canceling and some are peaking at the driver’s seat. That is why the RTA plots of your system look like roller coasters instead of that nice flat frequency response curve that convinced you to buy subwoofer X. Add to that the sympathetic vibrations of the vehicle and some folks need an EQ.

 

If you are really interested in exploring this topic further, the article "Bass Principles" by Richard Clark in the May 1995 issue of Autosound 2000 Tech Briefs is a very enlightening read.

Cheers!

 

Anyone have much success with the sub facing up? Like if it was installed into the floor facing the roof of the hatch/trunk?

 

Very favourable results in most hatchbacks.

Needs to be experimented with in the trunk as results vary. Some good results firing up with the port firing to the side or back of vehicle instead of both sub and port on same plane.

 

I've had my sub facing upwards with the port also facing up and it sounded great. The difference between facing it back and up isn't even noticeable. I'm in the process of building a box with the port facing back and the sub still up, I'll let you know how it sounds...

 

I've always had best luck with my subs facing to the rear of the vehicle, although the output is lower with front facing woofers, they do seem to sound more accurate.

One thing I never quite understood is why people would completely seal their trunks off with fancy glass work and then aim their woofers to the rear. (Sealed, not ported enclosures) I suppose there are always leaks that will allow sound waves to enter the cabin, but I would imagine this would greatly affect output.

 

i got a question for us truck guys, what is the real reason why the bass in my truck almost doubles, when i open the passenger side window. i've had all kinds of subs in my truck, which is a regular cab, i've had three eights, three tens, four tens and two tens, and even tried one twelve, and all had the same problem, windows up,,decent bass, windows down,,,perfect bass. i've heard all sorts of reasons, from improper box size, to the wavelength theory. anyone got any suggestions, or is it the same for cars and trucks?