Are their any advantages sound quality wise to having an inverted or down fireing sub? Also, will there be more bass if the sub were to be faceing toward the back of the car, as opposed to up toward the hatch glass?

 

inverting your sub will give your box more useable airspace because the basket and magnet are not taking up volume.

as far as i know it will sound better firing upwards rather than backwards but it all depends on the install...im sure people can have good results firing forward

 

whether the sub faces into the box or is mounted conventionally makes no difference IF the overall volume is the same. If you use the same box, the volume will differ slightly, although it won't be likely to be enough to matter.

Facing the subs & enclosure in different directions can have different effects. In a car with a trunk, it's pretty widely accepted that facing the subs toward the back of the car will provide additional output. I've read various theories on it, but I'm convinced that it's just because they wind up being closer to the "mouth of the horn". The trunk shape acts as a mini horn that dumps into the interior, and the closer you can get the subs to that "mouth" the better. Similar results can be achieved in a hatch back, and especially in a thirdgen by getting the subs as far back and as low in the well as possible.

Beyond potentially higher SPLs (we're talking MINOR differences here in most cases), I also prefer to point the subs away from the listening position to get a mechanical filtering effect. It's inevitable that all transducers have resonances and produce mechanical noise other than the signal being played. Run a 10hz test tone through a sub and you'll know what I mean. It's a mechanical device that's moving. All moving things make unwanted noises. ANYWAY... (I babble when I haven't had my morning coffee), all of these noises, though not audible above the sound of the bass, are recognized by the brain and are what allow you to pinpoint where the sound is coming from. Since the goal is to get your bass to sound like it's coming from the same place as the highs, this is bad. By facing the subs backwards, a lot of these noises are attenuated and can result in cleaner sounding bass that blends better with the midbass.

Of course, in a thirdgen the plastic interior panels out back make so much noise that it's hardly worth worrying about the mechanical sub noise.

 

i have a infinity 12"'s facing the glass and my amps and wiring under the lid... it looks really clean but the only problem is when the hatch it open the subs have no air to compress, so in turn no bass. but who drives around with the hatch open anyway????

 

no matter what way you face them, if the hatch is open you won't get bass. It's a fact of life, just like with convertables and jeeps.

 

unless you have a great deal of cancellation when the hatch is closed

 

Right, but since that's impossible, it's not a concern. The wavelength of typical bass frequencies is larger than the physical length within a car, so you won't get cancellations from reflected waves (i.e. standing waves) like you do at home. The only type of cancellation you can get is if one sub is out of phase, or if your box is not sealed well enough to completely isolate the negative wave of the sub.

 

mixing sub sizes or pointing subs in different directions could cause cancellation

 

if you drive a school bus or a motor home, maybe. If you drive a normal car, the length of your interior is smaller than the length of the soundwaves coming out of your sub, so this is a non issue in a typical car environment.

I'm too lazy to do the math right now, but if somebody proficient in transmission line systems feels like piping up, here's your basic setup.

W----Y-------------X---Z

W and Z are the extreme parts of your interior - dashboard and back of the trunk.

Y is your seated position.

X is the sub position.

For there to be cancellation, you need for the direct wave (X to Y) to be 180* out of phase with the reflected wave ([X to Z to Y] or [X to W to Y] or [X to Z to W to Y] at the listening position.

Since W-Z is a shorter distance than your typical low frequency sound wave (I did the math once and I think somewhere around 100hz is where the cabin size equals the wavelength in a typical car), you can't ever get a full cancellation effect.

 

full cancellation isnt possible but partial cancellation is very common with poorly designed setups

 

At 100hz (the highest frequency your subs should EVER see), the wavelength is 11.3 feet. Cancellation will be minimal if any exists at all within a thirdgen, and will probably only be noticable if the subs are placed close to the driver (i.e. in the back seat) as opposed to anywhere within the rear area. With the subs in the back seat, you wind up with enough distance between the subs & the rear of the car for the potential for some cancellation to occur.

But I guess that just reinforces my feelings that back-seat sub enclosures should be avoided.

 

boooo...walls are the way to go

 

The wall effectively eliminates the back half of the car, making it a completely different issue.

Of course, I have my own reasons for not liking walls, but my above-mentioned explanation isn't it.

 

just play around with ur box.. if u get one.. i got a free sub -in-tube from my friend and yes i can hear better( boomier?) bass when it faces teh hatch... ... would we as 3rd gen dudes be able to hear the diff between a 3rdgen camaro box( in teh dip) or a traditional box facing the window.?? assuming the same box capacity and same equipment...

 

If you still have that tube, I'd like you to try something. Assuming that there's no port on the back side (which would screw up this test), I'd like you to face the woofer forward and back like you did before, but instead of making sure that the BOX is in the same spot, make sure the WOOFER is in the same spot. If you do that I think you'll find that the direction it's pointing has less of an effect than the woofer's actual position in relation to that back wall.

In most cases, facing the woofer toward the back of the car puts the woofer closer to the back of the car... and personally I feel that is why you're getting more output.

 

the tube is ported not on the back but in the front like another tube next to the woofer.... i did what u said and i fell there is a diff...