Question about port location

[SomeguyinPDX 10+ year member]

View attachment 26537859View attachment 26537860Working on a box for 2-15" XFL's. My question is about port placement in relation to the sub. My box is only 32" wide so I don't have room to put the ports and subs facing back Here are a couple really rough sketches of a couple of ideas that I would like to get the forums opinion on. These are not to scale and measurements are a guestamate.

First pic shows the top view of my trunk outline and how the box will sit. Port placement is to give the port breathing room.

The second is a drawing of a port placement I never see, Sub facing the rear and port on the oppisite end directly behind the woofer with ports facing into the back seat/cabin. Will this port location even work properly?

please post you thoughts or if you have a better idea, please post it.

Click to read more...

 

[neonblack 10+ year member]

Port placement is to give the port breathing room.

This statement doesn't make sense. Port placement is used for accommodation of quick air flow/pressure into/out of the enclosure.

If you look at home stereo ported speakers/enclosures the ports are usually centered/aligned in the box so the port does not favor pressure/flow on one side over the other side (which would cause unwanted air turbulence and possible interference with the natural movement of the driver).

I would keep port centered as much as possible in the box. (Older speakers (JBL) were ported a little differently.) I'm sure there are tutorials out there wrt port placement to minimize interference with movement of the driver(s).

 

[Dtrom 10+ year member]

I've heard port on drivers side works best for output

 

[SomeguyinPDX 10+ year member]

Sorry for the confusion when I said "Port placement is for breathing room". What I meant is my port has to be as far back as possible right behind the sub otherwise it will be up against the side of my trunk with "no room to breath". In my crappy first drawing you can see the rough outline of my trunk (top view).

 

[THATpurpleKUSH 5,000+ posts]

what kind of vehicle is that box going into? its best to always have one single port if possible

 

[SomeguyinPDX 10+ year member]

what kind of vehicle is that box going into? its best to always have one single port if possible

This is going in a 2001 Ford Taurus.

What about subs facing the rear of the trunk with one large Aero aimed forward at the back seat or through the fold down armrest? I will post some pics of the trunk layout later tonight after work.

 

[neonblack 10+ year member]

PDX, you can place the port opening almost anywhere you want: on front of the box, on the side. If you've seen some subs for PC's they're placed on the side or fire downward.

You might be able to fit the port opening on front with the subs. And port can be angled inside box for correct length. (Flaring one or both ends reduces port noise: http://www.subwoofer-builder.com/port-flares.htm. There are tutorials out there to make your own flared port with heat gun.) Or you can opt for a sealed enclosure.

 

[THATpurpleKUSH 5,000+ posts]

I dont think you can fit 2 15s ported in that car unless you fire forward and seal off the trunk.

 

[keep_hope_alive Premium Member]

I dont think you can fit 2 15s ported in that car unless you fire forward and seal off the trunk.

which would provide the best results anyway.

firing back while taking up all of the available space just means you waste a lot of bass to the outside through the trunk.

consider firing forward, sealed against the opening, with a large aero through the rear deck.

 

[SomeguyinPDX 10+ year member]

View attachment 26537881View attachment 26537883View attachment 26537882

which would provide the best results anyway.
firing back while taking up all of the available space just means you waste a lot of bass to the outside through the trunk.

consider firing forward, sealed against the opening, with a large aero through the rear deck.

I would love to seal off the sub to the cabin but it is impossible in this particular trunk. I made a cardboard mockup to show where the box sits in the trunk

(32"W x16"T x 28"D) In the pic of the trunk w/o the box you can see the opening into the cabin, it is only 12"T x 30"w. Also the unibody support between the strut towers also is in the way.(I'm not cutting structural sections of the body). With previous systems I have ran 2-15's sealed and 2-10's ported, I ran both boxes facing forward and backwards and so far it has always been noticeably louder to my ear with subs facing the rear(never metered).

In the picture looking from the back seat you can see the mockup is about 10-12" back from the opening into the cabin. Would this be a good spot for 1 or more Aero's firing into the cabin? Or a square or slot vent?

 

[keep_hope_alive Premium Member]

you can still fire forward - same box, subs on the front, but then build some wood sides/top to create an opening that matches up to the smaller opening. it would work much better than backwards.

 

[SomeguyinPDX 10+ year member]

Ok, if I run the subs forward, where do I put the port? Out the side or back? Planning on a 6" or 8" aero port or whatever is best for this application.