Port tuning

ok now i have some problems that are confusing me, when tuning a port you usually set it around 45hz for street bass. now if i were to use the equivalent of a 4inch round port it would come to something like a 10inch long port. how the hell to spl tuners get their ports to be something like 35inches long. do you just use a wider port which will increase the length. the main part that confuses me is the fact that when u increase the frequency the port will get shorter, so how do you manage to get the port so long. if i think what i think it is then i am stupid for asking this question lol thanks

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6* Rockford T2's
6* POWER AMPs
BLACK CORRADO
BAANNGGIINN

I'm trying to figure out why you want a port 35" long...

You know, this site has a port length calculator (over on the left column).  Play around with some numbers...

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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.

Well us "SPL tuners" usually tune to a quite high frequency.     An SPL system is normally, 95% of the time is not lisitinable in daily driveing.

Normally I stick with slot ports for a street box, but I tune much much lower, around 30-35hz

Ar you still buiding with the Re MT?

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2009 0-1000 Trunk WR 154.0DB 2009 1001+ Trunk WR
2007 USACI World Champion
2007 World Record
2006 USACI Finals 2nd Place

yep i am hav the mt, now i've made two boxes for it, a normal 2.2cubic foot ported tuned to 43hz and another which is around 8cubic feet and i want the tuning frequency for spl so i can compete, im thinkin of gettin another 3 of them. i was thinkin around 70hz?

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6* Rockford T2's
6* POWER AMPs
BLACK CORRADO
BAANNGGIINN

first you need to find the tuning freq of your vehicle.


The best way to do this it to take a smaller sub that you can run to RMS power and put it in a 1-1.5 cu ft box

run it on a meter and see where your car peaks (frequency)

from there, lower the peak freq, by about 8-10hz and set your port frequency there.

from there you might need to adjust the freq roughly 3-4hz, but this is the way we begin to work on any SPL vehicle we do.    Start, then it is all testing and box work from there. Somtimes the occasional amps get changed too.


I will talk to some people next week at USACi finals and get back with you on some good MT box designs, send me a PM with your vehicle info so I know what you are working with

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2009 0-1000 Trunk WR 154.0DB 2009 1001+ Trunk WR
2007 USACI World Champion
2007 World Record
2006 USACI Finals 2nd Place

thanks alot jeff, i gotta admit u r one of da safest blokes on this site, nuf respect. the car is actually a golf tdi estate so i've got sh*t loads of room. and the other enclosure is in a vw lupo, this isnt avaliable in america so jus try a search on it. thanks again. ermm wat do u mean by running a meter, what kind of meter is this? any name or model number will do, thanks

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6* Rockford T2's
6* POWER AMPs
BLACK CORRADO
BAANNGGIINN