i've google'd for the answer but haven't came up with any useful info.

i've tried the circuit, using my mother's lil 'ankle-biter', missy, as my 'lab rat', but she just lay's there and looks at me, then goes back to sleep, so im not sure that the piezo speaker is actually producing the sound. the thing im not sure of it that the piezo speaker is capable of producing frequencies in that range. spin, using the PropLab design platform, and verified the frequency is being generated as desired with a o'scope. I've got the circuit and programming made in. basically, it produces a frequency between 30khz to 60khz that dogs can hear, whenever a loud sound is detected with a microphone, (like a dog's bark) that is supposed to irritate dogs to make them stop barking (supposedly). The higher the frequency, the higher pitch the noise is.Hi all, im working on a project to generate a swept audio frequency from 30khz to 60khz through a piezo speaker, like the BarkOff contraptions for sale. It is flexing such a little distance that you cannot see it, but you can lightly feel it! The piezoelectric buzzers have a frequency of approximately 3800 Hertz meaning that the piezoelectric element is flexing 3800 times per second.Since the mechanical buzzers rely on the metal armature, there is more variability in their individual frequencies. The mechanical buzzers have a frequency of approximately 2600 hertz meaning that the metal armature is moving up and down 2600 times per second.We tested 5 of each type of buzzer with a frequency analyzer app and found that: A frequency of 10 hertz means that there are 10 cycles per second. A frequency of 1 hertz means that there is 1 cycle (vibration) per second. The pitch generated from a buzzer is called its frequency and is measured in hertz. The buzzer applies a voltage across the piezoelectric element thousands of times per second which flexes the piezoelectric element to create noise. Piezoelectric buzzers rely on this process to create vibrations. Conversely, if you apply a voltage across a piezoelectric element, it will slightly flex. As the name implies, a piezoelectric element will create a small amount of electricity when it is pushed or flexed. Piezoelectric is derived from the Greek word ‘piezo’ which means pressure or push. Piezoelectric buzzers do not have a metal armature, but instead rely on a piezoelectric element. You’ll notice if you push the buzzer against a ridged surface, it will be louder because it has a surface to resonate the vibrations. This happens thousands of times a second and creates vibration which in turn creates the ‘buzzing’ noise. When the electromagnet turns off, the armature springs back up. When the electromagnet turns on, it attracts the armature pulling it down. Mechanical buzzers create their noise by moving a metal tab (or armature) up and down using an electromagnet. If you compare the noises they create side-by-side, the mechanical buzzer creates a low pitch buzz, meanwhile the piezoelectric buzzer creates a high pitch beep. What’s the difference? Not just the shape of the case! The difference is how the buzzers create noise. But you’ll notice that there are two types – a mechanical buzzer and a piezoelectric buzzer. Buzzers add noise to our Squishy Circuits.

Piezo buzzer frequency response