New Sub enclosure Please help

Im thinking about building a new sub enclosure but i want to try aeroports...i really dont know anything about using them. If I build a 6.5cuft enclosure, to tune it to 40 or so hz using 6in ports i came up with this:

6.5 cuft enclosure
2-6in ports 10.25 L
tuned to 40hz

or

6.5 cuft enclosure
3-6in ports 17.5 L
tuned to 40hz

Does this right to you, any help is greatly appreciated.
Thank You,

Brian

yepp... but like ive said before, im a firm believer that port length is power/vehicle/eqpt. dependant for making numbers... music is another story..

hey alan when you say port length is power would you care to elaborate more on that, i have heard that somewhere else before but never really fully understood it. thanks a bunch bro.

he means its


power, vehicle, woofer/equipment dependant.

not port length=power

as far as port being power, no its not,

what port will do is increase or decrease effieincy of an enclosure if properly or im properly tuned. So in essence if you didnt know any better, you could mistake it for more power because you got louder.?@!!!

yeah, just meant that your whole set up might like a different port length then anothers. that you cant really say. " oh you have this car... tune the box to this freq" and be done.. YOUR set up might enjoy some off the wall port design..

so i suppose the only way to come to a conclusion on port length or port design would be to test different ports. an port lenghts

yessir...

supadave wrote:

so i suppose the only way to come to a conclusion on port length or port design would be to test different ports. an port lenghts

There are proper equations to get exact tunes, the vehicle will change it some degree but it shouldn't be to far from the "figured" port volume. Make small changes in port vlolume to find if you need more or less port. Then increase or decrease till you peak.

supadave wrote:

hey alan when you say port length is power would you care to elaborate more on that, i have heard that somewhere else before but never really fully understood it. thanks a bunch bro.

Port length is dependent on power. Very slight. If you double you power and don't retune your box your burp freq may change up to 2hz but thats an extreme case.

Its just one of those after you change anything test and retest.

im talking about peak SPL... im not going to turn this into a pissing match.. you guys do what you ill do what i do.. but i bet you can look at 5 differents CRXs with 5 completly different port set ups.. and all share pretty close to the same burp Freq..

AceFrealy wrote:

supadave wrote:

hey alan when you say port length is power would you care to elaborate more on that, i have heard that somewhere else before but never really fully understood it. thanks a bunch bro.

Port length is dependent on power. Very slight. If you double you power and don't retune your box your burp freq may change up to 2hz but thats an extreme case.

Its just one of those after you change anything test and retest.

i said more than just power.. i bet with the same box and ports.. at 1/4 volume/power your car shows a different peak than at full tillt...the more power you pack on a woofer the more you may have to change the port to let it work, or not blow up,or control IMP rise for peak SPL... like i said.. you all are welcome to tune how ever you want..but id like you know how you guys know what note a box tuned to 40 hz peaks at in your car...

Alan wrote:

AceFrealy wrote:

supadave wrote:

hey alan when you say port length is power would you care to elaborate more on that, i have heard that somewhere else before but never really fully understood it. thanks a bunch bro.

Port length is dependent on power. Very slight. If you double you power and don't retune your box your burp freq may change up to 2hz but thats an extreme case.

Its just one of those after you change anything test and retest.

i said more than just power.. i bet with the same box and ports.. at 1/4 volume/power your car shows a different peak than at full tillt...the more power you pack on a woofer the more you may have to change the port to let it work, or not blow up,or control IMP rise for peak SPL... like i said.. you all are welcome to tune how ever you want..but id like you know how you guys know what note a box tuned to 40 hz peaks at in your car...

I was'nt tring to argue. Just tring to elaborate the power idea for Supadave.

but, did you read my reply? run out side and test it ..

hey alan i don't think he was trying to undermind you man he was being helpful an i appreiciate it keith an alan.
i am in the middle of testing now for sb an as much as i hate to say this i have considered burp boxes hell might as well join the crowd rite lol?
i use bass box pro 6 to design my boxes the one i have now is for 2 12's 2.6 or smaller after displacement, using 4 4in aero's at 10 in it would be peak at 63 an has a db drop off at 53hz. thats using aero's which i have heard work great in trunks lol.
the slot port is the one i have to do some work on cause i have to take it out an change port length after every test. any tips guys.
an let me know what you think on the first design , i am thinking of doing a "getting ready for finals build log later" you know i don't keep Dung Pile a secret lol thanks guys.

i personally would start with the ports longer just in case.. 4 4inch ports sounds like alot for just 2.6cubes... unless you mean per sub.

i dont think he was underminding me .. i just think hes wrong ..

well the box is 2.6 cubes total 4 4aero's around 10 in long tunes the box at 63hz

Alan wrote:

i personally would start with the ports longer just in case.. 4 4inch ports sounds like alot for just 2.6cubes... unless you mean per sub.

i dont think he was underminding me .. i just think hes wrong ..

I AGREED with you. if I miss worded something correct me other wise WTF.

Supadave Alen is right and 1/4 volume my peak is at 72hz at full I'm at 70hz n the box peak at 1/4 volume 73hz and at full im at 70hz. This is very important for peak spl, I haven't played with street beat. I hope that helps.

no im thinking that you just didnt read all of the post. and i dont read where you agreed .. you said it was minimal and an extreme case for it to change with power..

i said its power/eqpt/vehicle dependant .. either way, i have seen alot broader changes in freq..like 72hz 1/4 vol.. 66hz full volume.. the point in all this is. i really dont think you can say .."my car peaks at 65hz.. so i need this box tuned to 58hz" i think your woofer brand..size..and power your using will effect the real life tunning of the box for what that set up personally likes for peak spl.. your box might really like some off the wall port size and length for the simple fact of imp. rise.. most off us never really do the testing to find out "why" the change was louder.. but just know its louder and sometimes give credit to the wrong box change..been working on a crx .. and 3 different port lengths all played the same freq..and very simlular spl scores.. but had a good change in ohm rise.

like angles in corners.. if it happens to gain.. is it because its smoothing out the corners? or fine tuning the enclosure airspace? most really dont know .. .. we just know it helped or not ..

I agree that tuning is power/equipment/vehicle dependant. I was just tring to elaborate on the power issue. My experince differed from yours. I used the word extreme case because I hadn't seen that much difference before. Not trying to take away from its importance. I used the term slight because the differences I saw were smaller and an easily overlooked change.
I was tring to figure out how was tring to agree with you and was wrong
Your definitely right theres no magic formula for port length for SPL. Theres way to many variables.

okay guys was wondering also whats up with box peaking i hear guys talking of this but haven't really seen it done correctly. lets say for instance i have a 3cube box with 2 12's, do i test the box sealed first then go from there, or do i need to start with 2 aero's.

i must say if i haven't already that i use bass box 6 pro an it has been accurate so far on my tuning,

Theres got to be a better way than the way I do it but if you don't get am answer that you like call me 573 223 2374.

just build it dave..

Yep build it and test dave period.....on a side not I used 6 4" aeroports in 4 cubes total for 2 9515's in my truck before and it did well. I think 4 4" aero's is a good place to start.

its in the build stage guys but i dont' think the 4' will be enough area for what i want gonna go with sanding an slot port. being doing some testin all nite last nite till my recone i done, the spyder let loose an broke the tinsel leads, come to find out one of spyders was not glued all the way down. oooopppss my bad lol but its fix now an will resume testing an building tomorrow after work.

2003f150 wrote:

Yep build it and test dave period.....on a side not I used 6 4" aeroports in 4 cubes total for 2 9515's in my truck before and it did well. I think 4 4" aero's is a good place to start.

surely this was 100% spl? that had to sound like total ass...

Yes alan that was my version of a crx style box but in my F150....it was fun but peaked @ 64hz....not my style at all.