A question for the audio/acoustic gurus.

[WildWilly]

Through the course of my "Battle with the Rattle" I turned the subs 180 and built a forward firing enclosure. The enclosure is actually a housing that my original box slides into, very tightly. I first wrapped it in carpet padding, mainly concerned about the floor and rear seat panel or 'contact points. I'm actually going out to get carpeting to finish it as soon as this thread is started.

My situation:

My original box slides into a housing which is open only to the rear of the seats, and accomplishes my goal of separating the sound waves and avoiding bass cancellation. While doing this I set the original box back into the 'sleeve' a few inches, for nothing more than cosmetic purposes and the possible addition of LED lighting.

Questions:

With the above mentioned (I'll snap+post a pic for a visual")

Does the the area to the front of the speakers, containing the inches between the seats and rear panel plus the distance the speakers are set back into 'Sleeve', act as its own sealed enclosure?

If so would adjusting the depth of the speakers in the 'sleeve' actually tune it by adding/removing volume?

and my main reason for asking..

If I added LED lighting, and made an opening in the rear cup holder area to see them, would the opening act as a port, thus making it a bandpass box, and need to be tuned?

The first two questions are simple enough to just play around with, but when it comes to cutting the rear seat I would like an expert's opinion on whether or not it will affect the sound negatively.

I'm sure the principals are the same no matter what, but FYI my system is nothing crazy. 2 RE Audio 12s with a 1000W (falsely advertised I'm sure) Profile amp. I'm not sure on the speaker specs, but I'm sure its a lower grade of the RE line. REX perhaps...

Any input?

Pics:

[WildWilly]

Bump.... I'm sure someone has some experience with this.. how about some finished pics, instead of the mess I had going on above..

[scorp]

The space between the seat and the subs wont act as an enclosure mainly because it isnt sealed. Airflow will still move through the seats.

[theRealist]

The box you mount the subs in is the enclosure. I see what you're trying to do but you need to change the way you're looking at this. It's all about the acoustic abilities of your trunk and using them to your advantage. If possible, you should have your trunk treated with something like Hush Mat or Dyno Mat. This ensures the sound will not escape the trunk. Secondly, you should face the subs towards the biggest opening of the trunk. Whether you face the subs towards the backseat from the rear of the trunk, or face the sub towards the back of the trunk from right behind the seat makes no difference. Technically, if you sealed the trunk off like you're trying to do and face the subs into the cabin with the seats folded down, you will acheive a higher SPL. However subwoofers are what you would call omnidirectional which means it doesn't matter if you face them through the seats or not. Low frequency sound waves are longer and a normal human cannot tell the difference in distance. They work best when the sound has a proper acoustic chamber with more space than just the few inches between the back seats you're trying to go for. The sound waves will reflect and reverberate off of surfaces. Basically the sound waves would be bouncing back and forth between the front of the subs and the seats at such a short distance and could cause phase cancellation. You should try making a port that will pipe the sound into the cabin if that's really what you want, because always having your seats down for the sake of the subs is just silly. You have to be concerned about the acoustics of the cabin and speakers as well and having the seats down will alter the acoustics of the cabin. The only way to get around this is to remove the seats. I've seen it done, but I don't think you want to go down that road... Just get your trunk treated and ensure the enclosure is built properly. Most amps also have a phase control that will help you tune it depending on the acoustics of the trunk.

[WildWilly]

I agree that removing seats/ driving with them folded down is silly. Hell, it's downright tomfoolery! haha.

Anyway I asked a friend who's owned a local stereo shop for years, and he confirmed that if I were to port into the cabin through the armrest it would essentially make what I have a 4th order/ Single Reflex bandpass. Something I was hoping my port area would be large enough to avoid.

The verdict: It sounds fine just the way it is. I'm not looking to win competitions, or to heard by for the better part of a mile. I attained my goal, which was a complete sound, and minimal rattling at high volume. I do plan on treating the trunk, to quiet the last little rattles, but that is the end of the road for this adventure.

and to be honest, for the past week I hardly turn the stereo on anyway. My stereo is under the hood, the speakers are rolled down windows, and I control the volume with my right foot.


Thanks for the detailed reply though man! I'd still like to keep the thread going in case anyone else has questions.