Port location

[edouble101 314]

My next subwoofer enclosure setup in my Hyundai Elantra will be a subwoofer forward firing into the cabin sealed from the trunk. Would there be any disadvantages to having the subwoofer mounted behind the back seat and the port firing up through the rear deck (both sealed from the trunk)? I do not know if having the port and subwoofer that far apart and on different planes will cause any weird cancellation or any phase issues.

[Punkeyboozter 19]

why cant u do port back and sub back; in my opinion this sounds the best for a ported box out of a trunk.

What are your goals? #'s SQ or just daily

[edouble101 314]

I do not see how goals would affect the outcome of the answer to my question.

[altoncustomtech 773]

I don't either, and honestly I've always liked the sub/port sealed into the cabin myself. The sound is cleaner, there's less/no trunk rattle, and depending on the car sometimes it's louder, or sometimes it's not quite as loud.

I've done them both with the port up and the port forward with the sub. In my limited experience the ones with the port up semmed to depend upon the size of the car and the shape of the rear deck/window angle as to whether or not it affected the sound any or not. On the half dozen cars I've done it to the ones that seemed to have cancellation problems were smaller cars and had a straighter angle back window. I'm sure there were many other factors as well and I'm no engineer, but that's what I noticed when I've done them.

[ssh 924]

I don't see why there would be any issues.

[edouble101 314]

Thanks for the responses. I am curious if there would be a lose in acoustic coupling between the port and sub.

[ssh 924]

I could be full of it, but:

Imagine your enclosure was twice the size, so it took up the entire trunk area and rear deck area. Your port would still be on top of the box (where it would be coming out of the rear deck), and your driver would be mounted facing forward.

This imaginative enclosure would be nothing special, only difference is, your enclosure volume is smaller.

Your talking about a loss of output due to the distance between the port and driver, not impedance, correct?

[Kanaworm$ 292]

Really shouldn't make a difference as long they are both sealed off from the rear. Advantage will be the port loading off the rear window.

[edouble101 314]

I could be full of it, but:

Imagine your enclosure was twice the size, so it took up the entire trunk area and rear deck area. Your port would still be on top of the box (where it would be coming out of the rear deck), and your driver would be mounted facing forward.

This imaginative enclosure would be nothing special, only difference is, your enclosure volume is smaller.

Your talking about a loss of output due to the distance between the port and driver, not impedance, correct?

That sounds logical to me.

I have no idea how to calculate system impedence curves based on port area and placement.

[edouble101 314]

Really shouldn't make a difference as long they are both sealed off from the rear. Advantage will be the port loading off the rear window.

Bingo. I do not know how this will affect the frequency pathlengths at the listening position - front seats.

[ssh 924]

Really shouldn't make a difference as long they are both sealed off from the rear. Advantage will be the port loading off the rear window.

Bingo. I do not know how this will affect the frequency pathlengths at the listening position - front seats.

I would think it would be immaterial at these frequencies. Your talking about a few millisecond in delay.

[Kanaworm$ 292]

As Steffan stated it will be a slight delay that will not be noticable. Actually you will be surprised at the gain it creates as the wavelength develops in addition to cabin gain.

[Duran 387]

Well, your port should act as another woofer. Depending on the installation there can be delay or not, it could even go unnoticed, or it may only sound different when your vehicle is exactly 53 degrees F. Try it, find out, just make sure its removable.

[ssh 924]

Well, your port should act as another woofer. Depending on the installation there can be delay or not, it could even go unnoticed, or it may only sound different when your vehicle is exactly 53 degrees F. Try it, find out, just make sure its removable.

What would happen at 53 degrees? Shouldn't the delay between these two sound sources always remain the same, regardless of temperature? Sure the speed of sound changes in relation to temperature, but both sources are effected.

[Duran 387]

I used 53 degrees as an example. Resonant frequency, air density, etc. are all effected by temperature change, enough to measure? Not always.

[ssh 924]

I uses 53 degrees as an example. Resonant frequency, air density, etc. are all effected by temperature change, enough to measure? Not always.

Oh okay, I just misread.

[teambrownnote 2]

Interesting answers. I asked a very similar question about sealing off the trunk of my '06 KIA Spectra a couple of weeks ago. Let us know how it goes, OP.. As soon as warm weather returns, I just may go ahead with mine.

[edouble101 314]

Thanks for everyone's input!

This is my current setup

I am planning on having the sub firing forward and the 8" port firing out of the rear deck. Now to start planning!

[Punkeyboozter 19]

I do not see how goals would affect the outcome of the answer to my question.

Well since you asked and I never build a trunk car you obviously know better.

[edouble101 314]

I do not see how goals would affect the outcome of the answer to my question.

Well since you asked and I never build a trunk car you obviously know better.

Instead of reply with a useless answer, since you know better, please enlighten us with your knowledge.

[Punkeyboozter 19]

I do not see how goals would affect the outcome of the answer to my question.

Well since you asked and I never build a trunk car you obviously know better.

Instead of reply with a useless answer, since you know better, please enlighten us with your knowledge.

NAH you had the opportunity, id rather not argue with with internet coons.

good luck with your project.

[edouble101 314]

I do not see how goals would affect the outcome of the answer to my question.

Well since you asked and I never build a trunk car you obviously know better.

Instead of reply with a useless answer, since you know better, please enlighten us with your knowledge.

NAH you had the opportunity, id rather not argue with with internet coons.

good luck with your project.

Racist slures will not get you anywhere on internet forums but will get you a fat lip around my town