There is another way to stop your eardrums bleeding. All speakers with a whizzer cone have a rising output from between 4 and 7 khz until they drop off a cliff between 10 and 15khz. The fix is a simple inductor plus a paralled non-inductive resistor inseries with the speaker. A value of between .82 and 1.25 mH (standard air-cored inductors) will roll off the hf from between 2 and 4khz depending on the driver impedance and to suit to your taste / drive unit, add a paralled 10 watt resistor of between 4 and 12 ohms. The inductor should be of as low impedance (below .5ohm) as possible to minimise the loss in sensitivity. Copper foil inductors are best but expensive. There still may be a problem with the edges of your whizzer, particularly if it is straight rather than curvilinear.

Sept 21, 2020 11:29:40 GMT 12 peter0c said:

There is another way to stop your eardrums bleeding. All speakers with a whizzer cone have a rising output from between 4 and 7 khz until they drop off a cliff between 10 and 15khz. The fix is a simple inductor plus a paralled non-inductive resistor inseries with the speaker. A value of between .82 and 1.25 mH (standard air-cored inductors) will roll off the hf from between 2 and 4khz depending on the driver impedance and to suit to your taste / drive unit, add a paralled 10 watt resistor of between 4 and 12 ohms. The inductor should be of as low impedance (below .5ohm) as possible to minimise the loss in sensitivity. Copper foil inductors are best but expensive. There still may be a problem with the edges of your whizzer, particularly if it is straight rather than curvilinear.

Thanks peter0c. That's a bit of work more than the sponge clip, but would be interesting to see how it works out. Will have to learn how to make a filter like these some day as well.