View Full Version : Multi bandpass question Box and Freq

04-12-2007, 08:02 AM
OK i have alot of question in my Mind and would be greetful if anyone can help me with it .

I want a FLAT box . Instead of the Classic Square looking Box .

if i build a box 5 inch tall - 30 inch width . and 14 inch across .

Fitting it with a small 8 inch woofer ( measuring 4.2 inch height )

the top and bottom of the box would be extremely close to the surface of the bottom and surface of the woofer.
would i get negative effect ?

i am using fiber glass instead of the classic wood or MDF .
would i need have alto of sound different ?

my Tuning freq is at high as 60- 65 Hz

and the result i got from is

0db - 41.79 hz
-3db - 37.79 hz
Peak at 2db 50 hz
and go down
back to 0db at 91.53hz
flat at 67-82 hz ( 0.6 db )

i am not sure if this is a good result .
is a simple sub .

The box is .9 cuft
rear chamber 0.4 and front chamber is 0.5

front chamber refer to the chamber the woofer surface is facing right ?
Rear chamber refer to the chamber the bottom end of the woofer is facing ?
i am new sorry for the silly question but is better silly and not ask and keep assuming .

Here is a idea of the box


Here is also some Data of the Subwoofer - in case anyone can come up with a better idea or suggestion ..

Qts 0.663
Qms 3.87
Qes 0.8
Vas 1.010 Cuft
Fs 36.6 hz
Re 4 ohm

04-12-2007, 11:24 AM
I am not coming anywhere close to the output that you are getting with the calculations. What program are you using?

With a passband that you are talking about your gain with in the passband is is going to be to high (I get around 9 dB, 3 dB will be the highest that I would go to be safe)

As far as the drivers placement, you want to have it at min the diameter of the magnets vent away from obstruction or you will have problems.

04-12-2007, 12:41 PM
wow if u have 5inches to work with i would do a bandpass...wat i would do is a down firing sealed box....and have a 2inch gap from the floor to the box....thats as close as u going to get from a bandpass
heres a pic of a box i built yrs ago with 2 mojo 12's
this is a down firing sealed box


04-12-2007, 04:58 PM
pardon me i forget to say that the Subwoofer is only a 8 "

i am using winisd

What would you suggest for the smallest thinest flattest box i can build for the subwoofer .


a front and rear chamber measurment would be nice .