BIB Calculators:

BIB_Calculator* Updated

BIB_166_GM_v2.xls

How to calculate your own BIB - Thanks GM!

Greets!

Sure, it's what we're here for.......

'zdriver' is normally a fixed value, L*0.217, but is somewhat flexible to keep the driver somewhere around ear height.

'L' is typically a function of Fs, 13560"/Fs/2, which tunes it ~an octave below Fs, but this too is flexible to keep the folded height reasonable when using low Fs drivers.

'Sm' is derived from the net Vb required based on a complex function of the driver's Vas, Qts. Reducing this lowers LF gain BW, which I don't recommend as it limits your tuning flexibility, though some cabs are so large it's unavoidable to either fit in the room and/or keep peace in the family.

An example:

L = 13464.54/2/70 = 96.175"
folded height = 96.175"/2 = 48.088"
Vb = 20*0.29*0.445^1.25 = 2.10804 ft^3
Sm = 2.10804*1728/48.088 = 75.751"^2
depth = SQRT((75.751*SQRT(2)) = 10.35"
width = 75.751/10.35 = 7.319"
zdriver = 96.175*0.217 = 20.87"
a-b-c = 10.35/2 = 5.175"

GM

Thank you lovechild for providing this accurately scaled drawing of a BIB!

Thanks Planet10 for this illustration!

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*Drawing not to scale

Stuffing options

Test Tones:

Here is a link to a website containing frequency test tones from 30Hz to 16kHz.

http://www.phys.unsw.edu.au/jw/hearing.html

If your computer is connected to your stereo you can fine tune your BIBs. Your BIBs are designed to balance out the sound of your full/wide range driver by enhancing bass frequencies. When stuffing your BIB you want to hear frequencies from approximately 300Hz down. Anything above this will begin to alter the midrange. Stuff your BIBs accordingly to reduce or eliminate anything above 300Hz. Too much stuffing and you will reduce the bass output - too little and you begin to spoil the midrange. This is a great way to ensure proper stuffing of your BIB!