Hi there,
I have some questions about the surrrounds on a woofer. As stupid as that sounds, how do you know all the technical data? So how do you calculate how thick the surrounds have to be etc? If you want to have a resonance frequency of 22 Hz you have to calculate the mass and the surround stiffness. And for the surround stiffness I would need the thickness and the material. But how do you get such information?
I have some questions about the surrrounds on a woofer. As stupid as that sounds, how do you know all the technical data? So how do you calculate how thick the surrounds have to be etc? If you want to have a resonance frequency of 22 Hz you have to calculate the mass and the surround stiffness. And for the surround stiffness I would need the thickness and the material. But how do you get such information?
Learning about loudspeaker Thiele/Small parameters will perhaps answer your questions, or at least get you started with the technical data involved in loudspeaker transducer design and calculations.
Thiele/Small parameters - Wikipedia
Thiele/Small parameters - Wikipedia
You buy a good book and hope you understand the complicated engineering involved! 😎
Book Review: How to Design and Specify Loudspeaker Drivers | audioXpress
Book Review: How to Design and Specify Loudspeaker Drivers | audioXpress
Remember, the voice-coil spider assembly has its own parameters we must take into account, it's not a "perfectly" linear device...assuming of course your building a driver "from scratch" & not just replacing a bad surround.
-----------------------------------------------------------------------------Rick...
-----------------------------------------------------------------------------Rick...
1) no need to know thickness because anyway that leads to surround stiffness; knowing it is enough, and it can be measured.
2) you also need to know "the other" stiffness, which comes from the spider, and can also be measured.
3) if you want to measure it the simple "mechanical" way, no Electronics used, just applying Statics, you can simply push cone in 1mm and measure required force, then follow with extra 1mm steps and draw a graph, which will show you not only force needed by itself but also linearity.
Do the same the other way for a complete picture, which will also show you symmetry (or lack of it).
4) mass is easy: just weigh all moving parts: cone - voice coil - edge - spider - dust cap - adhesives.
You´ll need a slight correction since not all suspension or edge move 100% since edges are glued to frame, but you can approximate that and in any case cone and VC are the heaviest components moving.
5) having both will let you calculate free air resonance.