eric21
I built a ported box for 4 12" alpine type r's to go in the back of my crew cab pickup and the bass output is quite lacking imo. Each sub is getting about 750 watts each so 3000 total which should be plenty. Note that this is only for strret pounding and not SPL.
The enclosure is 8.5cu.ft. net and has a port that is 15" x 6" and 22" long. The bass is ok from about 25-35 hertz (still not impressive though) and all other frequencys totally blow.
I've tried the box pointed foward, back and up with the best results being from having the box point up.
I assumed that maybe my port was tuned too low so I made it 12" long instead of 22". It still plays about the same as before believe it or not.
I've noticed that the speakers quickly begin to stink and at many frequencys sound like they are playing freeair. So i'm thinking that I have too much port area for these subs (i know its only 90 sq.in.) but they sound like they need alot more back pressure.

Guys please take a look and see if you notice any places for cancelation or other flaws that might make this box sound so poor. Any design change ideas would be qreatly appreciated.
Thanks!!
Picture of box without speakers
Picture of the inside of the box
Quote 0 0
pimpin at my house
it's ur port it is too close to the back wall.

you have several other problems there. you need bracing! that baffle needs to be several layers thick too. what i would do with that box is take the baffle off and cut the port out. make a double thick baffle and use 2 6" aero ports. 1 at eather end with subs placed evenly so there isnt loading issues.
use alot of dowel rod to make the box ridged.

on ur baffle use mdf the depth of the type r motor to seperate the woofers to help it load better OR do 2 seperate chambers or ur gonna have loading issues.
Quote 0 0
D-Bass
try less box volume. stack some bricks and boards in the bottom
Quote 0 0
Neill Barber
I would have done that size port around 13-15 inches deep.


NeillBArber
Quote 0 0
eric21
Quote:
Originally posted by pimpin at my house:
it's ur port it is too close to the back wall.

you have several other problems there. you need bracing! that baffle needs to be several layers thick too. what i would do with that box is take the baffle off and cut the port out. make a double thick baffle and use 2 6" aero ports. 1 at eather end with subs placed evenly so there isnt loading issues.
use alot of dowel rod to make the box ridged.

on ur baffle use mdf the depth of the type r motor to seperate the woofers to help it load better OR do 2 seperate chambers or ur gonna have loading issues.
Thanks, I think you are right about the loading issues because when I disconnect 1 set of woofers it sounds about the same as when both are going and I know its not a polarity issue because if I switch them the bass totally dissapears.

Do you think it would work ok if I divide it up into 4 chambers with each chamber having a 4" aeroport (which would be just sightly less area then the 2 6" ports for the entire box)? The 4 chambers would really help with the bracing also, I knew I should have braced it but I got lazy.

Dbass - I'm going to try and shrink the airspace before I do anything just to hear the difference. Just for my own learning, how come making the box smaller may help with output? I've always though big ported boxes played more efficently?
Quote 0 0
eric21
Quote:
Originally posted by Neill Barber:
I would have done that size port around 13-15 inches deep.


NeillBArber
I tried cutting it down to 12" because I thought the same thing and its tuning stayed about the same (at least it sounded equally crappy). I cannot figure that out at all?????
Quote 0 0
pimpin at my house
would be louder with 2 chambers and 2 6" aero's. loading issue for sure.
Quote 0 0
eric21
Quote:
Originally posted by pimpin at my house:
would be louder with 2 chambers and 2 6" aero's. loading issue for sure.
Thanks man, thats what i'm gonna do then.
One question - is it better to run all the subs in a perfectly straight line across the bottom of the box (I have them stagered in the picture)and should the port be centered directly above the two woofers in one chamber.
I just wanna get this right because I build mostly sealed boxes and ported sound sick when done right.
Thanks!
Quote 0 0
eric21
Ok here's an update - since i'm gonna build a new box anyway, I made a port insert that had an opening of 12"x4.5" and 10" long and put that in the old port hole. The difference was huge, the speakers kept in control much better, the voice coils didn't stink as easily and the output was alot louder.
Then after I added some wood to the inside of the box to lessen the volume and that helped too by seeming to make them sound more musical over a larger frequency range.
Still one thing I noticed is that the 2 outtermost subs seem to be moving more then the inner 2 subs, so i'm guessing there is some big pressure differences in the box because of the position on the port.
Quote 0 0
DefenderMack
I had a very similar setup with those subs and a s10. I noticed they really shine at about 3.0-3.5 each driver
Quote 0 0
eric21
Quote:
Originally posted by DefenderMack:
I had a very similar setup with those subs and a s10. I noticed they really shine at about 3.0-3.5 each driver
Wow thats a huge box for each 12" woofer! I'm sitting at about a little over 2 cu.ft. per and people were telling me that I had too much airspace. Thats good to know though.

I started my new box and hopefully this one sounds better. It's 2.1 cu.ft. per with 2 woofers each sharing 1 6" areoport 12" long. Should be tuned to about 33 hertz.
[img]http://img4.imageshack.us/img4/7961/newsubbox.jpg" class="bbc_img" rel="lightbox[1298876917]">[/IMG]
Its birch ply and each woofer will be mounted along the bottom face of the box in the picture between each divider. I put the dividers in to help with loading and for some bracing. The areoport will be mounted directly above and in the middle of each pair of woofers. If you see any problems with this design let me know.
Thanks
Quote 0 0
eric21
Heres an updated picture of my new box. The ports are going above the woofers on the same face in the middle. Gonna finish and carpet it this weekend, I hope it sounds good. [img]http://img48.imageshack.us/img48/8246/subboxwithholescut.jpg" class="bbc_img" rel="lightbox[1298876918]">[/IMG]
Quote 0 0
pimpin at my house
looks good bro...
Quote 0 0
eric21
Quote:
Originally posted by pimpin at my house:
looks good bro...
Thanks man I appreciate your advise that you gave me. I finished it up and I gotta say it really sounds much cleaner and is substantially louder. It's really impressive from 30-45 hertz and these subs seem to take a good beating and handle it well. It definately hurts my ears

[img]http://img106.imageshack.us/img106/8654/finishedbox.jpg" class="bbc_img" rel="lightbox[1298876920]">[/IMG]
Quote 0 0
davor-ri
Quote:
Originally posted by DefenderMack:
I had a very similar setup with those subs and a s10. I noticed they really shine at about 3.0-3.5 each driver
about 2,3cu ft is enough....3,5is way too much for 12" type R...
Quote 0 0
Contact Us | Legal Notices | Privacy