Is it necesary special sensor to measure Spike Energy data? I have got sensors with the resonance frequency at 18 kHz, Are they able to measure Spike Energy or the signal measured will be distorsioned by the sensor resonance?
Thank you

Are you talking about SPM's Measure of Spike Energy? If Yes, then yes you do have to have a special transducer. If not then I don't know

If you are talking about IRD (Entek/ird) spike energy, then you may use the sensor with 18khz natural freq. The thing to remember is wherever you use that sensor to collect gSe, you must continue to use it there. Your overall reading will vary depending on the resonance freq of the transducer. However, the spectrum will be the same. If you use the same transducer, then you can trend the overall just like you would any other reading.