Spring-Mass Frequency Calculation?

[ssashton]

Hi,

I'm building a loudspeaker and I want to support the Woofer and front panel from a steel strut, which is fixed to the sub-woofer box below. Please see the drawing attached.

The strut is made from 20mm x 20mm steel bar.

I would like help to calculate the resonance frequency of the woofer and panel hanging on that strut, as I'd like to make sure it is above the working range of the woofer (to avoid resonance).

To do this I assume we need the physical dimensions (in the drawing), the weight of the item on the strut and the stiffness of the spring (the steel). I don't know how to put that all together though!

Units are mm.

Some general info for steel is available by searching goggle, I didn't provide it here as I don't know exactly the info you need. Young's modulus maybe?

Thanks!

 

[eljose79]

Hi there,

Calculating the resonance frequency of your loudspeaker system can be a complex process, but I can provide some guidance to help you get started.

Firstly, you are correct in assuming that you will need the physical dimensions, weight, and stiffness of the steel strut to calculate the resonance frequency. Young's modulus, also known as the elastic modulus, is a measure of the stiffness of a material and is typically denoted by the symbol E. It is a key factor in determining the resonance frequency of a system.

To calculate the resonance frequency, we will need to use the formula:

f = 1/(2π) * √(k/m)

where f is the resonance frequency, k is the stiffness of the steel strut (in N/m), and m is the mass of the woofer and front panel (in kg).

To find the stiffness of the steel strut, we can use the formula:

k = E * A/L

where E is Young's modulus, A is the cross-sectional area of the steel strut (in m^2), and L is the length of the strut (in m).

To find the mass of the woofer and front panel, you will need to weigh them separately and add their masses together.

Once you have all of these values, you can plug them into the first formula to calculate the resonance frequency. Keep in mind that the resonance frequency of a system can also be affected by other factors such as the stiffness of the sub-woofer box and the damping of the system.

I hope this helps. Good luck with your project!