I've read recently about DIY projects making electrostatic loudspeakers (example). The membrane of the speaker should be supplied with bias DC voltage between 1 and 5 kV, roughly. There is virtually no current needed, only for charging the membrane.
With old CRT screens and photocopiers being short supply, how does one get such a voltage? Around here, only step-down transformers are easily bought, and I don't really want to be using any of those the other way around (effectively putting the rated voltage on the secondary coil).
I can imagine getting nearly 1 kV directly using a 1:1 transformer and voltage quadrupler, but this may prove inadquate. So the question is whether there is another way to get high DC voltage when I can't get my hands on an up-to-spec transformer.
Europe here, so 240V on the tap.