hey, you guys say you've got ported boxes in your xB's? i've got an IDMAX 12" running @1000W rms in a sealed enclosure, but i'm looking to build my own ported enclosure for my xB. I've been using winISD to try and make a suitable design, but i keep finding myself with it telling me to make 200" long ports. how do i make a ported box that'll work correctly? (and fit in my xb) thanks.


oh yeah, and where would i buy/how would i make cylindrical ports? bent?


sorry i'm new to the ported stuff.

 

i made my ports out of pvc.

 

do slot ports and tube ports sound different? one better than the other? i know you need to make the slot from MDF, which means hard, but is it worth it?

also, do i need to make sure that the ports will allow the air not to flow faster than 5% the speed of sound?

call me dumb, i'm new

 

i have had both slot and ported boxes and i can not tell the difference. do you work at e-tronics?

 

nope, but they've got a great store, and so i have it on there because of my good experiences with them.

 

b from them a while back and when i installed it it crackled, i tried it in several different boxes but it never went away. i never returned it because i just did not want to deal with them after the gave me such horrible customer service.

 

really? i ordered something and ended up not needing it and i got 100% money back - shipping.

 

if your going to build a ported box here is some tips:

make the box to the recommended cuft or bigger just not smaller...
pick your tuning freqency....
select a round or a slot port.....(i prefer a slot port because its easier to make the port fit in the box)

after you figure out what your tuning freqency is and you know what style port your going to use figure out your port length

 

is there some rule that the port should be it's diameter away from all the walls when it ends? also, what about air speed coming out of the ports? what is an acceptable level for a port speed? 50 ft/s? 20 ft/s? 100 ft/s?

 

well first off the rule about keeping the port away from walls is true you must keep the opening and the end of the port clear of any obstruction so if you have a 3" port you can't have a wall within 3" of the end of the port and nothing within 3" of the mouth of the port

as for the port speed the higher the number the more your box will whistle

i have my box setup at 15 m/s at full power but im also running a huge port and deep tuning

i would say and acceptable level is no higher than 20 m/s

 

okay, so the mouth can't be it's width or closer to any of the walls, and it can't be it's height or closer to either top or bottom? and same thing with the vent inside? does it matter how far away it is from the wall that it comes off of? should it be in the relative center? can i offset my woofer to compensate for a 40 inch vent?

 

a 40" vent?????

why the hell so long

 

i'm using winISD, and to tune to 27hz in a 4ft box with 1 IDMAX 12" @1000w and a 10"x5" vent to keep air speed low, they say i need a 40" vent.... do you have the formula? how do i calculate this thing? better program?

 

okay, screw it, would somebody give me a step by step or a program that will offer a step by step because apparently 40 inches of port isn't right.... thanks a lot

 

first of all your tuning freq. is super close to your fs on the sub id tune it to about 29 just to be safe...


just go 4 x 10 x 26.69 the velocity is around 25m/s at full power

plus you'll want to run a subsonic filter @ about 28hz to protect your sub from playing harmful signals

 

what is the method behind the subsonic? how do i set it according to hz, because i'm thinking about tuning it to 32hz. any suggestions on what i should tune it to? 29? 32? i'm going to stop asking questions soon i'm going to try and build it tonight. thanks a lot

 

the method behind a subsonic filter is its basically a filter that takes out any unwanted freqencies...if you look at you subs fs i think its like 27.4 hz you dont want to go below that because freqencies below that can cause damge to your sub....like i said before tune your box to 29hz and get a subsonic filter set at 28hz you will be very happy with the end result

 

peep this make the port 8 inches deep and 4 to 6 inches wide. I'd probally go with the 4 inch port make the box about 32 inches long, 15 inches deep and about 14 inches high. Trust me it will bass like you would not belive. I have 2 10' in a box that I built and I beat 4 12 in competetion all the time. I won first place last week end. put the port verticle in the between the speakers and the car should bass some where around 60 Htz

 

oh yeah, and what about port placement? should it be pointed up or towards the back of my car? the mouth of the port should be in the middle facing the front of the box?

so 28hz low pass & 29hz tuned with a 4x10 port?

thanks a lot

 

when i had my single 12 in a slot ported box i had it facing towards the front that is where i was getting the most sound. now that i have my three twelves the subs face forward and the ports are facing up.