re 8's

[traitorhound]

i too am another person wanting to thank brian ?(bryan)? lol hopefully i got the name right

for the re groupbuy

i picked up 6 re 8's but now im having a dilemma on designing a ported box for it while working aorund the damn space contraints of the p5 hatch (there are these stupid nubs on the floor that kill some of the width to mount it flush to the seat

EDIT: false floor height will be 4.5 in i think as my cap is 3.75 and i will try to use 1/4in plywood to make the amp rack


my 2 options are 37.5x18.5x10 givng around 3cu
problem is that with the false floor going up 4-5 inches my front mounting face for the subs now shrinks to 37.5x13.5 (worst case scenario)

the other is 32w x 9top depth x 14 bottom depth x 18.5 h (~3.4 cu, this can be changed to be 3.0cu obvisously. . 3.4 was the max i could get out of space constraints)
same thing with the false floor taking up some of the mounting areas


so i was thinking maybe i can place some of the subs (2 of the 8's) on the top of the box essentially having 4 on the front face and 2 on the top

would that mess up the sound any with the speakers not all being on the same plane? or should i just give up and go with 5 subs since that would be easier to /fit

and can anyone help me find the right port lenght i would need for a good musical tune ~32hz? should i go with a bigger air space. . man if this was sealed i would already be done. . .oh well this is why im here


6 subs on one plane would be cool if i could fit it (ill try to find out def false floor height)

[blue LEDz]

why not just use 4? i had 4 tang band 8's doing about 140 dB's on my old term lab USB meter, so it would have been about 146-147 dB's on a mic based meter in a 2 cu ft enlcosure tuned to 33 hz.

[traitorhound]

lol cause i bought 6. .im gonna be good and ditch the cap. . .the false floor is now only 3in high

15.75 x 37.5 i hope i can fit them all. . i just think it would look cool to have 6

would they be alright in a smaller box though (2.75) and just use a longer port to tune it down lower. . or is that a bad idea?

worse comes to worse i will use only 4

[traitorhound]

or maybe ill just use 5 of the 8. .. 3 on bottorm row 2 on top with ports on the sides next to it. . .2.5 cu, 2 4in round ports. . .how long should they be?

and can i just buy one long flex port and cut it in half to make two. . or do you need the flanged end on both sides.. .meh im trying to make this look pretty too. . which is hard when iver never done this before. . ..like i wanted to try a slot port (don't have to buy anything) but making the port seemed hard sine 3 in of it would be covered by the amp rack. . so i figued i would just do some rounded ports. . .hole saw and be done with it

[blue LEDz]

6 should be able to fit in that area. and yeah, it's ok to make the enclosure a little smaller.

with 2.75 cu ft and a tuning of 33 hz, you'd need a single 4" port that is about 8.5" long, two 4" ports that are about 19.75" long, or two 3" ports that are about 10.5" long.

and yeah, it's brian, btw.

[traitorhound]

hmm. . would one 4in port suffice or would i need two to combat port noise... .am i at the critical velocity if i only use one port?

[blue LEDz]

you would be very close to the highest velocity with a single 4" port. you'd definintely want to use flared ports if you are going that route.

[traitorhound]

ok....i got it. . what about 2 ports and have one tuned for spl when i close the other port. . .i really havent read up on this stuff. ..but ive decided to use 5 for now and keep one for a new project

so 5 8's in a 2.5 cu box. . .does the port count as part of the 2.5 cu or does air space need to be accounted for that?

so one will be tuned for daily driving ~30 hz and then plug the other port to spl what 45hz. . im just guessing there

[blue LEDz]

when you've got the 2 ports open, it'll be tuned higher, not lower, so when you close the port, it'll be tuned for daily driving. with the single 4" port, you'd need it about 12" long for 30 hz tuning. 2 ports at 12" long would be 42-43 hz. but keep in mind that when you cover up one port, it adds to the air space of the enclosure. it's a bit more complicated when you get into covering ports. my 18 had 3 ports, all different areas, and that was a bitch to work out.

[phatprotege]

Good grief!!!
And here I am.... just worried about tuning 2 RE12's correctly!!!
LOL!!!!
(And find a cheap decent amp to drive em well!)

[traitorhound]

alright. . for the first ported box i make ill keep it simple then. . . .just tuned for daily driving, just 2 4 in ports. so you saying i have to account for the port in the box space of 2.5 cu. . or winisd already did that for me with the numbers you gave me for 5 8's in 2.5 cu

[blue LEDz]

with just 5 of the subs, i'd just run one flared 4" port. and no, you have to add the port volume into the over volume of the enclosure, unless the port is completely outside the enclosure.

[traitorhound]

Awsome They Came Today

[blue LEDz]

sweet.

[traitorhound]

so after messing with winisd (finally figureing stuff out) ive been able to get the numbers you quoted me. ~12in for a 30hz tune @ 2.5cu

what irked me with that program was that you would put in the specs of the sub and it would say some stuff about qms or qts specs being incorrect so i was wary of using it (just a bug?)

anyways, im gonna build a box for the 5 in the next coming weeks, need to order a port (i want a pretty bezel on the front)
Is there any difference between a regular flaired port and a flex port with "aerodynamic flanges"
I ask this because a normal flaired port would not fit @12 in long since my box will only be 9 in deep. could i cut the port and put a 4in pvc elbo in and get around it that way?
or would i be better off just getting a flex port and be done with it?

also with the face of the box (assuming i use the subs to the full potential) should i double up the mounting area with 2 layers of mdf as opposed to 1 layer with the rest of the box?

bracing? ive never done this with any other boxes but ive always only made small sealed enclosures that didnt' need bracing so yea

thanks