Single 12" ported box for an MK7 Golf GTI

[Kinser]

Hi folks,

As title states, I own a 2016 Mk7 Golf GTI.

I just a had a Lightning Audio Storm X2 motor (TC 3HP Neo) rebuilt on a 12" Ti frame with fresh soft parts.

I also have aside a PSP 4" aeroport kit and a Ground Zero 2k mono to power it.

Box spec will be roughly 2ft^3 net tuned to 30-34 Hz

I've been having major dilemma as to where the sub/port should be firing - Sub up port up, sub back port back, sub up port side, sub back port side?

In my previous car, an Mk2 Seat Leon (same platform as Mk6 Golf) I had very good results with sub and port firing up. When I tested it firing back it sounded awful. boot had much more height though.

Amps are located under false floor, so I have only 15.7" height (keeping the boot cover), 15.7" depth (to keep box symmetrical) and up to 35" wide.

I have been unable to find anything online regarding sup/port firing in the mk6/7 - if anyone has some input, I'd really appreciate it.

Thanks

[Kinser]

No one?

[CstrokerV]

nope try both is all i can suggest

[3vil]

Make a test box and play around also might want to try putting the port on a different face than the sub, like sub up port back. A single 4" aeroport sounds small, like you'll be getting a lot of port compression.

[Kinser]

I'd love to do a 6" aero but with a max port length of 18" and 2ft^3 of volume it would yield tuning frequency of 40hz or so.

I'm planning on 30-34hz as I do play alot of slowed music.

I just might do a test box and an external port and see how it sounds.

[3vil]

I'll wait until Trit or JoeX chime in a they each have such a deep knowledge of enclosure design. It just seems like 12ish square inches of port is really small for a 12 on 2k watts.

[Kinser]

It is fairly low.

On my old box I had around 37 square inches of port @2.2ft^3 for a psi platform 3 12" on the same amp. I loved the way it played.

I do know that with aero ports you can get away with less port area per cubic foot because of the aerodynamic characteristics of port as well as the flares.

Worst case I'll have to purchase a 6" port and run it firing to the side but I still see available length as an issue.

For now I'll wait on input from the members you had mentioned.

[Kinser]

Bump for an experts opinion!

I have looked into using a 6" aero port, but as the PSP port has only 17" usable length, I'd need at least 3ft^3 net volume to achieve a mid to low 30Hz tuning range.

With a 2ft^3 net volume and a 4" PSP port @ full length my port ratio sits on roughly 6.5 sq inches per cube - this is not ideal or high but seems the only feasible way to tune low with the dimensions I have to work with.

[Triticum Agricolam]

A single 4" aeroport is going to be way, WAY undersized for you application. You will basically have a sealed box, I don't think you will be happy with the performance.

With a 2 cu ft box and a 2,000 watt amp you are right at a 1,000 watts per cube, which is the spot I've found that getting enough port area can become very difficult. This type of situation is going to require as much port area as you can make work while keeping tuning where you want and keeping the port from getting excessively long (over 44" can start to be a problem). While you can get away a little less port area with well flared round ports (aeroports), its only a little bit less (20% is the number I work with).

Since you have plenty of space, my suggestion would be a large, 3-common wall slot port. If you could get close to 40 sq in of port area that would be a good place to be. Here are some suggested specs.

[Kinser]

Thanks for the response!

I do appreciate your advise, although I think it 19sq in of port per foot is a bit extreme for my application.

I guess I can only determine final box dimensions once I test a sub in the car facing different positions - that won't be an easy task with a ported enclosure.

From floor to the shelf is 15.7" and i'd need to clear at least 1.5-3 inches to allow clearance for cone movement and port if I do decide to go with sub up port up.