Passive Radiators (where at buy/how to build)

[Puggie]

I'm looking for some passive radiators for very small (4" and tweet in <2l cabinet) reflex cabinets, conventional ports end up with looooooooooooong port and resonance issues.

So where can I buy passive radiators in the UK?

Or (in the true DIY way) how do I go about making a suitable passive radiator fom a cheap driver with the magnet removed and loading the voicecoil with mass to tune it? What should I look for in a driver?

Thanks everyone.

[Cal Weldon]

Hey Puggie,

1. If you are using a 4" driver then you want at least a 5.25 inch passive.

2. Where to buy? I have no idea, I live in Canada.

3. Making yourself is trickier than you might think. You need to start with a sloppy driver. The best effect I've had is to cut little pie shaped pieces out of the spider to loosen the suspension and pouring white glue in the back of the dust cap for extra weight. I also painted the back of the pulp cone with a cut-back glue to stiffen it.

With that said, I've not seen 5.25 inch drone cone. I think they start around 8"

Cal