Solve for Fb help

[Boboblittz 10+ year member]

Okay im simply playing around here and i want to find the tuned frequency of an already built box. I simply have no idea how to rearrange the equation though so if someone better in math than I am could help me, id be happy

Can you show me how to solve for Fb?

Lv=[23562.5 x Dv^2 x Np/(Fb^2 x Vb)] - (K x Dv)

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[bubbagumper6 5,000+ posts]

I come up with...

Fb = sqrt[(23562.5 x Dv^2 x Np)/(Vb x (Lv + K x Dv))]

//content.invisioncic.com/y282845/emoticons/nerd.gif.c6fa51ddf7ff75f1c0371fbc648f70ae.gif

 

[Boboblittz 10+ year member]

I come up with...Fb = sqrt[(23562.5 x Dv^2 x Np)/(Vb x (Lv + K x Dv))]

//content.invisioncic.com/y282845/emoticons/nerd.gif.c6fa51ddf7ff75f1c0371fbc648f70ae.gif

Here's what doesn't make sense to me; shouldn't (K x Dv) be negative?

Would you mind showing your whole process? //content.invisioncic.com/y282845/emoticons/confused.gif.e820e0216602db4765798ac39d28caa9.gif

 

[winkychevelle 10+ year member]

Why not just use a box calculator

 

[bubbagumper6 5,000+ posts]

Here's what doesn't make sense to me; shouldn't (K x Dv) be negative?
Would you mind showing your whole process? //content.invisioncic.com/y282845/emoticons/confused.gif.e820e0216602db4765798ac39d28caa9.gif

The first thing you do is bring K x Dv to the other side which negates it.

I'm going to call 23562.5 C for Constant just for ease of solving

Lv = [(C * Dv^2 * Np)/(Fb^2 * Vb)] - (K * Dv)

Lv + (K * Dv) = (C * Dv^2 * Np)/(Fb^2 * Vb)

1/(Lv + (K * Dv)) = (Fb^2 * Vb)/(C * Dv^2 *Np)

(C * Dv^2 * Np)/(Lv + (K * Dv)) = Fb^2 * Vb

(C * Dv^2 * Np)/(Vb * [Lv + (K * Dv)]) = Fb^2

Fb = sqrt[ (C * Dv^2 * Np)/(Vb * [Lv + (K * Dv)]) ]

 

[Boboblittz 10+ year member]

okay that's much easier to understand now, thanks for the help!

 

[Boboblittz 10+ year member]

Why not just use a box calculator

Unless you have a calculator that calculates frequency of existing ports, that really wont help

 

[winkychevelle 10+ year member]

Yea most box calculators can do that