Mechaical Resistance of Passive Radiator

I have some passive radiator samples and want to use them for another full-range driver. From measurement and simulation, I realized not need to add mass (straightforward), but also adjust the Q. I need to lower the Q of the passive radiator. This is equivalent to increase the mechanical resistance of surround. Correct? How can I do that with the existing passive radiators?
I also have boxes built for the original full-range driver. I want to reuse the box and passive radiator for another full-range of identical mounting hole size. I have tried to increase moving mass of the passive. The alignment is better. Simulation showed that the peak can be avoided by lowering Q of the passive.
Last edited:

Ron E

2002-06-27 10:41 pm
You could try things like radial strips of silicone or some other goo on the spider (assuming it has one). Or as the PR you could find a driver the same size as the PR, and short the coil with various value resistors. Put mass on the cone or knock off the magnet and maybe put it inside the coil to tune it...You could even drill some holes in the box or PR to make the box leaky...Tuning it lower might fix your issue, or gluing blocks of wood or something inside your enclosure....Add a bucking magnet to the back of your fullrange to lower its Q?

You would get a lot better answer if you show us the data that led to your conclusion that you need a low Q PR.