Need some basic help with a 15" Type-R and a ported box

[miska_man 10+ year member]

Hi, I'm new to car audio within the last 6 months or so and already have somewhat of a system going. After ready miscellaneous information spewed around the interwebz, I figured joining a forum might be a better idea.

I'm on my second box (custom designed and built by me and friends to fit in MY cars trunk). Right now it's sealed, but I'm in the process of redoing it to make it ported. My goal is LOUD and IMPRESSIVE on a budget.

Basically what I'm trying to figure out is the proper port length to accomplish my goal, but I keep on coming up with different numbers in WinISD and other calculators. Right now I have a 3" OD round port (2.45" ID) and my goal is to tune to 30hz. Can anyone give me some recommendations or tips/hints?

My current setup consists of the following:

• Alpine Type-R 15" (750RMS, 2000 max)
  
• Kenwood KAC-9104D (supposedly an 1800 watt amp, looks like it's limited to 900watts at 1ohm) was running a 4 ohms, when the box is finished I plan on 1ohm
  
• 4 gauge Rockford Fosgate wiring
  
• Rockford Fosgate battery terminals
  
• Cheapo Sony Xplod headunit (want to upgrade to an Alpine)
  
• 5.5 cubic ft external, 4.3 cubes internal volume box; 3/4" MDF custom built (36"x24"x11")
  (made to fit under my rear shelf which is 12.5" from floor)
  
• Big three upgrade in the works (4 gauge combined with stock wiring)
  

Woofer is firing upwards (won't fit under shelf firing backwards/forwards) and I want to have my port facing into the cabin through a hole in the rear armrest (Is this a good idea?)

Click to read more...

 

[misfit138 5,000+ posts]

Gonna need more than a single 3" aero, man.

This is pretty useful for figuring out lengths and such.

Products Menu

 

[marcotheclepto 10+ year member]

3" port will be too small. id recommend a pair of 6s or at least 3 4's.

 

[RAM_Designs 5,000+ posts]

Tuning that low with aeroports is a pain because you'll need to go out and buy stuff in order to make it bend inside the box to get the port length you need, which will inevitably be longer than the 17" port they provide you . You would have been better off doing a slot port.

 

[RAM_Designs 5,000+ posts]

And like said earlier, a single 3" port(I hope you're not thinking of using PVC) is nowhere near enough port area.

 

[miska_man 10+ year member]

And like said earlier, a single 3" port(I hope you're not thinking of using PVC) is nowhere near enough port area.

At first I though PVC, but I figured there might be port noise because of the non flared ends. This is what I have right now (x2)

TWO 3 INCH SUBWOOFER SPEAKER BOX AIR PORT TUBES 3 INCH - eBay (item 120547301701 end time Aug-19-10 18:50:48 PDT)

The problem is that hole in the armrest is only 8" x 9" so I can't really do a huge port (2 6"s).

 

[RAM_Designs 5,000+ posts]

At first I though PVC, but I figured there might be port noise because of the non flared ends. This is what I have right now (x2)
TWO 3 INCH SUBWOOFER SPEAKER BOX AIR PORT TUBES 3 INCH - eBay (item 120547301701 end time Aug-19-10 18:50:48 PDT)

The problem is that hole in the armrest is only 8" x 9" so I can't really do a huge port (2 6"s).

You could use a single 6" aeroport from partsexpress.com, but then you'll end up with the port being in the way of the sub since you have the sub in the middle as well. Those little 2.75" ports just aren't going to cut it. Not to mention if you use both you don't have enough length to tune as low as you want, and if you do one it'll be port noise to high heaven.

 

[marcotheclepto 10+ year member]

THESE TUBES ARE USED TO VENT AIR FROM A SPEAKER BOX MAKING THE BASS MORE CLEAR AND RESPONSIVE.

that being said.... id agree with RAM a slot port wouldn't hurt... but you'd have to pretty much rebuild entire box :/

 

[marcotheclepto 10+ year member]

You could use a single 6" aeroport from partsexpress.com, but then you'll end up with the port being in the way of the sub since you have the sub in the middle as well. Those little 2.75" ports just aren't going to cut it. Not to mention if you use both you don't have enough length to tune as low as you want, and if you do one it'll be port noise to high heaven.

could have most of the port external. but would look funny 6 inch aero through the armrest //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[RAM_Designs 5,000+ posts]

could have most of the port external. but would look funny 6 inch aero through the armrest //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

True, but he could get down to a 31hz tune with a full length 6"er.

 

[RAM_Designs 5,000+ posts]

that being said.... id agree with RAM a slot port wouldn't hurt... but you'd have to pretty much rebuild entire box :/

Yeah, he'd have to do a new box entirely if he went that route. It'd be a more complicated build, but he'd be happier with the results.

 

[marcotheclepto 10+ year member]

Yeah, he'd have to do a new box entirely if he went that route. It'd be a more complicated build, but he'd be happier with the results.

i agree hed be happier. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif sometimes however (knowing from personal experience) the wallet says no. lol

to the OP if you would like ill do ya a free slot port design if your willing to rebuild.

 

[misfit138 5,000+ posts]

I don't think I'll ever use a slot port again. Aero ports are just too damn easy to work with...

 

[marcotheclepto 10+ year member]

I don't think I'll ever use a slot port again. Aero ports are just too damn easy to work with...

i fail at cutting aeros... lol

 

[miska_man 10+ year member]

Oops, box design has changed a bit. I accidentally uploaded an older picture. Here's the current build. As you can see I moved the woofer over and have enough room to throw an additional one in if need be.

What's the problem with having a smaller port like this? Do you guys think there would still be too much port noise?

I'd also like to keep the build simple as possible, so I don't really want to throw out a perfectly good box and start over with a slotted port.