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View Full Version : having many small ports same as one big port?



C1500martin
04-11-2014, 12:53 AM
Im in a bit of a pickle here i want to build a custom box for my truck (single cab gmc c1500) but for the specs needed for the FI q12 i bought i need 2.5 c ft and to be tuned to 32 Hz i need roughly 25-35 port air space (so ive read) with the dimensions i have that isnt possible because the port end up being like 60 inches long. would having 2 or 3 small ports in different areas be the same thing?

Dmac1991
04-11-2014, 01:40 AM
I'd use one 6" port

It's usually more efficient to use 1 single port compared to multiple smaller ones

what dimensions are you working with?

phemps
04-11-2014, 01:52 AM
A 6 inch aero only needs to be 20 some inches for 2.5 cubes net and that tuning

phemps
04-11-2014, 01:56 AM
just a a bit over 25 actually

Dmac1991
04-11-2014, 02:10 AM
yep aero ports usually call for 7-11" of port depending on your listening goals

C1500martin
04-11-2014, 02:10 AM
I'd use one 6" port

It's usually more efficient to use 1 single port compared to multiple smaller ones

what dimensions are you working with?

itll be 2 wedge boxes together these are the dimensions, would 1 6" in diameter aero port with 25" length on the edge of the longer box work?

C1500martin
04-11-2014, 02:12 AM
just a a bit over 25 actually

would that give me the air space needed for this subwoofer to sound good though? id mostly listen to hip hop and corridos and occasionally rock

phemps
04-11-2014, 02:15 AM
This is your gross volume then?

---------- Post added at 01:15 AM ---------- Previous post was at 01:14 AM ----------

If its gross volume (before the ports displacement and you want to do internal ports your gonna lose a lot of box space

C1500martin
04-11-2014, 02:16 AM
This is your gross volume then?

---------- Post added at 01:15 AM ---------- Previous post was at 01:14 AM ----------

If its gross volume (before the ports displacement and you want to do internal ports your gonna lose a lot of box space

yes gross is 2.64 and after sub displacement it is 2.48

i have to incorporate the ports displacement? so in reality ima have less volume? how much exactly is the port taking up? is an external port possible? like a long rectangle or aero port coming out on the top?

phemps
04-11-2014, 02:18 AM
yes gross is 2.64 and after sub displacement it is 2.48

so if you want the sub to see 2.5 cubes, youll need to do this port externally so none of it affects the boxes voume, or make the enclosure larger to account for the ports displacement. That is if you have the room in your car

Dmac1991
04-11-2014, 02:18 AM
with those dimensions you gave, there's no way you'd be able to get a 2.5cf enclosure

C1500martin
04-11-2014, 02:23 AM
so if you want the sub to see 2.5 cubes, youll need to do this port externally so none of it affects the boxes voume, or make the enclosure larger to account for the ports displacement. That is if you have the room in your car

how exactly would an external port work? would it be like a snorkel on the hood of a car or something (not sure if you get the picture)

---------- Post added at 10:23 PM ---------- Previous post was at 10:22 PM ----------


with those dimensions you gave, there's no way you'd be able to get a 2.5cf enclosure

according to my calculator it adds up to it? unless im doing my math wrong..

phemps
04-11-2014, 02:27 AM
yea essentially a snorkel i guess you could say. The beginning of the port would just start at the box and instead of making its length inside of it, you would have it outside of the box in the cabin

phemps
04-11-2014, 02:29 AM
The port could then travel and bend in the configuration you see fit, outside of your box

C1500martin
04-11-2014, 02:35 AM
oh okay i was not aware that was possible, does it sound the same though its essentially the same thing just inside out? or is there other lenths and what not to be how i want it?

phemps
04-11-2014, 02:59 AM
oh okay i was not aware that was possible, does it sound the same though its essentially the same thing just inside out? or is there other lenths and what not to be how i want it?

Its exactly the same as having it in the box, except that it doeskin take away from your boxes volume. You can also do ports partially in the box/ partially out of the box and account for how much displacement the port has that is physically inside the box

C1500martin
04-12-2014, 05:53 PM
Its exactly the same as having it in the box, except that it doeskin take away from your boxes volume. You can also do ports partially in the box/ partially out of the box and account for how much displacement the port has that is physically inside the box

Cool so does this seem right to you? If so im planning on building the box with the sub facing up and the external port below it aiming towards the dash on the floor. Would you reccomend an aero port or just a rectangle flat against the floor? Saving space would be prefferable.

phemps
04-15-2014, 01:34 AM
Cool so does this seem right to you? If so im planning on building the box with the sub facing up and the external port below it aiming towards the dash on the floor. Would you reccomend an aero port or just a rectangle flat against the floor? Saving space would be prefferable.

Either work, an aero may be easier for building being as it will be external. and as far as firing it foward towards the dash im not sure if that will give you the best results or not you'd have to hear from someone that has a similar setup since every vehicle behaves differently. I know some truck setups fire the port rear towards the back wall