Sorry try this

or this

and these

or this

and this ------------sorry

Hi,
In my pic, the series cap is 0.4uF, the parallel resistor 22Ohms for an attenuation of 5dB@20KHz and 9KHz x-over. Attention that the quartz reactance might not be the same for a Single section piezo horn.

The treble section of the pro speakers was short on highs that's why I added the piezos. Regards

• My other white DIY disco speaker

Hi Bill,
Sorry to be so late. I worked out a simulation for you in Spice (thanks Wayne!) for your piezo series. It gives an atten. of (about) -3dB at 20KHz and a xover frequency around 10K. You get about (with a 93dB flat-simulation- speaker output)
+/- 87dB@10KHz, 89dB@15KHz and 91dB@20KHz.

Looks good on this side (of the highs). Make shure your wire wounds are not inductive or you will end with a pretty crazy bell-shaped-curve with a peack at 95 dBs.
Regards.

Thats really kind of you ,I only played around with what I,d had in my rubbish (based on info about piezos ,here and elsewhere) until they sounded about right.I must wind some air cored inductors on my little lathe and chop the upper mids from the wharfedales. I think they could then be rather fine little speakers.