Hey guys,
I just built my self a slot port box for my sub. I built it to specs and it sounds ok. However the bass isn't as smooth as it used to be when i had the sub in a sealed box. A friend told me that poly fill might work and i have a bunch in the older box. Will the poly fill help smooth out the bass?
By the way i know to keep the poly fill away from the vent so that i dont have it coming out of the port. Any opinions or ideas would help.
-Will Ong
What are the box dimensions...and how long is the port (also what are the port dimensions)?
I think your box is probably tuned too high.
RE Audio
The topic of polyfill was discussed at least once already:
http://www.j-body.org/forums/read.php?f=4&i=117849&t=117332#117849
In that thread I posted a pretty good article (and a short summary) by Tom Nousaine discussing the use of polyfill that was published in a 1995 issue of CSR:
http://web.archive.org/web/20020808224043/integra.cyberglobe.net/caraudio/resources/fiberfill/
http://www.moodym.com/audio/fiber.html
Polyfill is most often used in smaller-than-optimal enclosures, the majority being sealed boxes (they seem to get the most benefit from using polyfill).
According to Nousaine's article, it can benefit subs in ported enclosures as well (but not nearly as much), but using polyfill in ported enclosures impedes the flow of air to the port(s), which can be detrimental to SPL . I've only used polyfill in the sealed boxes I made; I've never bothered with it in my ported enclosures (mainly because most were for SPL).
Hope this helps!
The 50-50-90 rule: Anytime you have a 50-50 chance of getting something right, there's a 90% probability you'll get it wrong.
speaking of box tuning i need my L7 boxes tuned
these are the demensions and what i got from this box design site
http://accelerator-pedal.com/ported-box.asp?Ew=22&Eh=14&Dia=6&Xmax=9.7&Vd=.083&NumW=1&Vb=1.06&Fb=38.2&Qts=&Vas=&Fs=&CE=0
Send To Printer
Net Volume: 1.06 cubic feet
Tuning Frequency: 38.2 Hz
Port Width: 1.5 inches
Port Area: 18.75 Square Inches
Port Length: 29 inches
External Dimensions: 22 wide x 14 tall x 12.25 deep.
Board Dimensions and Quantity
Color Count Width Height
Top and Bottom 2 22 inches 12.25 inches
Red 1 19.75 inches 12.5 inches
Yellow 1 11.5 inches 12.5 inches
Black 1 20.5 inches 12.5 inches
Green 1 12.25 inches 12.5 inches
Teal 2 9.25 inches 12.5 inches
Violet 1 4.5 inches 12.5 inches
Number of 49x97 Sheets of 3/4" MDF: 0.375
-Will Ong
1.... that box is COMPLETELY too small for a 12" sub!!!
2....you really should have a port area of around 30-35 sq.in....right now you only have 18.75"
3....it's tuned too high for what youre looking for. Somewhere around 32-33 would be good for you
4...those zig zag ports suck. they ALWAYS add port noise. try to stick with a "L" shape or use rounds.
I can figure something out for you if you want.
RE Audio
buda wrote:speaking of box tuning i need my L7 boxes tuned
'
If you want...
Send me dimensions of your box and the tuning you want..... I'll figure out a port area and length for you.
RE Audio
Thanks for all your help Lash. If you could come up with some plans i should be able to build another box in this weekend or something. Do you need any of the specs of the sub, like Qts, Vas or Fs. I guess I could drive around with that box for about a week or so.
Unholysavage the article really help too. Thanks.
-Will Ong
Yeah...just let me know what sub you have and give me the MAX dimensions you are willing to work with.
RE Audio
I have a pioneer premier TS-W125C single voice coil 400 watts rms. I am willing to make a box as big as 32x15x15 or do a wall but I dont know if i have the skills for a wall.
Thanks Lash
-Will Ong
A wall would be a waste for that sub.
I'll run some nubers for a box.
RE Audio
