View Full Version : 4th order on a Harley Road King...

05-19-2012, 12:01 AM
i have a customer who wants more bass on his harley. i am thinking of a 4th order using one of his
fiberglass side bags. im guessing i need to make the sealed side the size suggested from rockford,
its a shallow p3 btw, and make the ported side as big as i can. which isnt much the whole bag is about 1.4 cubes. and rockford suggests .25 for sealed.
does anyone have experience doing this? whats the ratio from sealed chamber to ported chamber?
do i tune the ported side like a regular vented box? any better ideas? how will a band pass sound in an open field like this?

Sub Woofin
05-19-2012, 12:21 AM
i would like to see pics when its completed. ive only seen subs on a donkey! or was it a mule?

05-19-2012, 12:03 PM
sure np. pics coming soon

05-19-2012, 12:21 PM
There is no certain ratio or tuning for 4th orders. It changes depending on driver, vehicle, and goals. The P3 has a high qts so it should perform well in a 4th order. Not sure how being in an open field will affect it.

05-19-2012, 02:27 PM
Moble Enclosurs

05-19-2012, 03:12 PM
Would be well worth paying a few bucks for a plan from one of the guys who designs a lot of 4th orders. OR if you're ambitious you could download winISD and throw in the specs.

Generally speaking volume of sealed chamber will determine low extension and ported chamber is tuned to the frequency at which you want it to roll off on the high side.

Seems the best option on a motorcycle. Definitely tuned in for pics.

05-19-2012, 03:18 PM
How does he plan on hearing any bass over the exhaust of the bike?

05-19-2012, 03:23 PM
Very interesting. Hopefully it's not too weird riding with a bunch of extra weight on one side haha.

05-19-2012, 03:25 PM
Very interesting. Hopefully it's not too weird riding with a bunch of extra weight on one side haha.

Normally I would say it would be (thinking about sportbikes) but with most of those big Harleys, I kind of doubt a speaker would make that much of a difference...

05-20-2012, 02:04 PM
sorry guys no pics. he took it to a bike this morning so i had to work all night, and i didnt have my camera.

yeah u cant hear much over the exhuast but it sounds pretty good when just the ignition is on.

the weight wasn't an issue cause the amp was on the other side.

05-20-2012, 07:48 PM
If it were me, I would just find a better sub that works in the space. If you are working with about 1.4 cube in the bagger, I would look at something like a DD 1508 ported. I would get loud, has good bass and would fit your space. I just think the hassle of trying to fit a 4th and pulling out the most you can from a not so great slim woofer might be more of a waste and a whole lot of trial and error.