plz help - Port Questions

[powerslide 10+ year member]

Hi there I have a few questions about my ported box.

It was originally a sealed box but I have since decided to port it.

Before I explain I'll fill you in- its a 1.5ft^3 box with front firing subwoofer that is placed right behind my fold down seats in a coupe. My goal is SQ and I am running a great SQ sub that also gets some great SPL. I am porting to ~34Hz

I understand that the sound in a ported box comes from the port, not the sub.

My question, if I port the box so that the port faces the front, I know that this way the bass will fire directly at me. However, when the back seats are in closed position, which will happen often, the port will be effectively blocked (mabye 1/8 inch clearance). What will happen in that situation?

Another option I am considering is porting upwards through my old rear speaker spots. However, this will mean that the bass goes straight out onto the rear window and doesnt fire at the passengers. How will this affect quality of sound etc?

Finally, is it important to port on the same plane as the sub is facing? IE the sub faces right, port should face right as well?

thanks very much for the help!

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[jellyfish420 10+ year member]

bass fre. doesn't fire in only one direction. it fires it all directions. no matter where you sit you will still hear the bass.

 

[DFW40 10+ year member]

If you plan on having your seats up part of the time then I would consider turning the box to face the taillights. The port will need a few inches of clearance to work correctly. I would have the woofer and the port facing the taillights and that way the sound waves will bounce off the back of the trunk and through your rear deck and back seats.

Most of the sound comes out of the port at the tuning frequency which would be 34hz for you. When it is playing above that the woofer and port share the output.

 

[powerslide 10+ year member]

Havingfun - thanks for clearing up about when the woofer and port are playing.

However, I need to face my ports towards the cabin since I have a car that is very solid and loses huge amounts of bass when facing into the trunk (BMW). Ive tried many set ups and found that the best ones face in to the cabin.

How would porting the rear speaker deck sound? Of course, with the rear seats down it will soudn better since the sub is visible, but there is still clearance from the sub to the back of the seats (~1/2 ft) when they are closed. Perhaps I could port into that area instead and leave the rear speaker holes open so that soudn still gets into the cabin?

 

[DFW40 10+ year member]

I have a 2001 325i and I know what you are saying about bass getting trapped or lost. You can take out the rear speakers and any of the factory (6x9 subs). This will give you some more sound into the car. I would be careful with where you point the ports because of the noise that can be associated with doing this. The ports would need a few inches of clearance so they can operate properly also without extra noise. Make sure you cut or punch the holes all the way through underneath the rear speakers, they have a heavy carpet pad type material that will eat up bass and not let it pass through.

After you have added some holes into your rear deck then see which way the box sounds best. With the seats up and the rear deck with holes I'd try the box with sub and ports facing the back of the trunk.

 

[powerslide 10+ year member]

yeah I'll give it a try.

Unfortunately at this point though its impossible for me to face the sub the other way due to my trunk set up.

Wish I had some pics to explain.

But right now I think my best bet is to port to behind the seats but leave enough room so that it will be able to vent around the box and through the speaker deck if the seats are up

thanks for the help!