Benefits of a larger port area

[PhatTonyDeMarco 5,000+ posts]

im missing something .. where are you getting the 16 from.. Am i wrong with saying a 9^ft box with 100 square inches of port is about a 20"x5" port

Ruckus was commenting on my box, not DVR's box.

 

[nVRuckus 5,000+ posts]

im missing something .. where are you getting the 16 from.. Am i wrong with saying a 9^ft box with 100 square inches of port is about a 20"x5" port

ohh you quoted him talking about phat tony with 4cubes @ 102" or whatever I thought you were saying phattony's was normal. misunderstood the part of the quote you were talking about.

 

[nVRuckus 5,000+ posts]

i think theres a limit as to how much port area a sub can have.ithink if u have 2 much port area the sub will act as if it was free air imho
80

thats how I think it is too but wouldnt every sub be different? I actually need to find out from RE on the MT.

 

[PhatTonyDeMarco 5,000+ posts]

i think theres a limit as to how much port area a sub can have.ithink if u have 2 much port area the sub will act as if it was free air imho
80

Yeah, there is a limit to how much air the driver can move in a single pulse. More port means more air will be moved, but too much and the driver will not be able to move it effectively causing loss of output and unoptimal performance from the drivers.

It will vary greatly from speaker to speaker, I am just experimenting with different enclosures for my current subs to see what they like and what works. So if they happen to dislike all this port, then I'll tone it down a bit...

 

[hzsogood 5,000+ posts]

ohh you quoted him talking about phat tony with 4cubes @ 102" or whatever I thought you were saying phattony's was normal. misunderstood the part of the quote you were talking about.

i got confused for a second there

Yeah, there is a limit to how much air the driver can move in a single pulse. More port means more air will be moved, but too much and the driver will not be able to move it effectively causing loss of output and unoptimal performance from the drivers.
It will vary greatly from speaker to speaker, I am just experimenting with different enclosures for my current subs to see what they like and what works. So if they happen to dislike all this port, then I'll tone it down a bit...

Can u find out from a T/S sheet on a sub to find or calculate how much would be optimal for that certain sub.. Im doing the testing on a 12w7 since i am now unemployed ( layed off for a month ) and have nothing better to do , so im trying not to spend hundreds on glue and mdf , for obvious reasons //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif .. The one i have now was based off the JL spec box. @ 2.2 ^ft and 25 sq inches of port tuned to abut 31 .. Did the testing in my buddies grand am and pulled a 143.6@ 46 hz on the TL but blew a fuse during testing , Capable of alot more im assuming since it is a trunk car in a low tuned box

 

[iamamp3pimp 5,000+ posts]

my 15's like 200 squares just fine.

i wouldnt give more port area than cone area tho

 

[nVRuckus 5,000+ posts]

my 15's like 200 squares just fine.
i wouldnt give more port area than cone area tho

that would be alot of area if I did cone area on my 18 LOL thats like 280sqin right?

 

[hzsogood 5,000+ posts]

my 15's like 200 squares just fine.
i wouldnt give more port area than cone area tho

what is the cone area on ur 15

 

[germanyt 10+ year member]

I have 114 sq in in an 8 cube box @ 32 Hz. Seems pretty nominal.

 

[hzsogood 5,000+ posts]

i wanna have about a 4-5 net enclosure with about 80-100 inches of port for 2 12 w7s.. just dont want to give too much port

 

[MK3XXX 10+ year member]

i wanna have about a 4-5 net enclosure with about 80-100 inches of port for 2 12 w7s.. just dont want to give too much port

You wont need that much port area for daily. With those subs and that size box i would say 50 would be a good amount. Maybe 75 if you really wanted to use more port. You could always try more but from personal experience you shouldnt need it.

 

[hzsogood 5,000+ posts]

You wont need that much port area for daily. With those subs and that size box i would say 50 would be a good amount. Maybe 75 if you really wanted to use more port. You could always try more but from personal experience you shouldnt need it.

I hear ya on that ive done lots of testing and builds for my w7 and they are a picky sub in the sense for me at least ive had a hard time gaining much spl no matter what size box they are or what size the port is. id like to give each sub at least 36 inches of port just to try so a minimum of prolly 80.. What did you have problems with them

 

[MK3XXX 10+ year member]

I hear ya on that ive done lots of testing and builds for my w7 and they are a picky sub in the sense for me at least ive had a hard time gaining much spl no matter what size box they are or what size the port is. id like to give each sub at least 36 inches of port just to try so a minimum of prolly 80.. What did you have problems with them

No problems, i had a single 12w7 for the first sub i every owned. I used like 20-25 sq inches on every box i used and it worked great. From other experiences with different subs ive seen where a ton of port area isnt always a good thing.

 

[hzsogood 5,000+ posts]

No problems, i had a single 12w7 for the first sub i every owned. I used like 20-25 sq inches on every box i used and it worked great. From other experiences with different subs ive seen where a ton of port area isnt always a good thing.

yea, the first box i built for mine was about 1.9 cubes tuned to 31 with 25^inches of port.. Didnt sound bad, and put up descent numbers , just room for improvement

 

[CBFryman2 5,000+ posts]

Tenths on the mic are gained...that is about it in most casses. Once you reach ~80% of the driver's Sd you will no longer gain SPL and may begin to loose SPL depending on the port and driver arrangement. Once you get over 100% of the driver's Sd the sub may begin to act "free air".

Best advice for daily is enough to where you wont get any port noise. A peak modled velocity of 60ft/sec or less in WinISD with maximum power is usually subsiquent in the real world (though velocity calculatons are usually innacureate).

Excess port area isnt always good either. More port area means faster roll off below tuning. Some HT set ups actually cut back port area to keep the driver from unloading below tuning so the infrasonic frequincies can be reached with out destroying the driver while keeping a flat respocne instead of a shelf responce.