1.2 Driver study
Force factor (BL), the mass (weight) of moving parts, the stiffness of cone and the compliance of suspension system, all these parameters shape how a speaker sounds like. An obvious requirement, for example, high sensitivity, deep bass or low distortion… etc. will give the direction for driver design or the modifications to fine tune. Driver designers first arrange the key parameter and later balance with others to come out the qualified speakers.
Building the simulation model to predict the frequency response in specific driving voltage and distance,The impedance curve tells low frequency performance the driver has and how much inductance of coil might impact on high frequencies.
If there are problems to cause a glitch or peak and dip on the frequency response, we’re able to analyze the modes on issued frequency then implement solutions to fix or damp it.
An animation (.GIF) illustrates the modes of diaphragm on the frequencies which have problem.
The asymmetry suspension system which includes driver’s surround and spider will cause Total Harmonic Distortion (THD) become higher especially in low frequencies.
The plot of stiffness (Kms) versus displacement indicates the symmetry or asymmetry of suspension when diaphragm moves front and back. To take the considerations for keeping the symmetry of both Kms (or Cms) and BL versus displacements are the most important ways to achieve low distortion. To adjust one parameter usually influences another or even others, the simulated results can directly and simply let designer realizes which ingredient should be fine tuned.