How does the frequency of an active Buzzer change?

Hello,

I would like to play a 2 voiced melody using an Arduino Uno and two buzzers, one being passive, the other being active. Since the active Buzzer is a lot louder than the passive one, I added a resistor to make it less loud, but to me it sounds like the resistor is changing the frequency and therefore the tone the buzzer is actually playing, which makes perfect sense to me.
Now I'd like to know how I can calculate the actual frequency the Buzzer is outputting in dependance of the resistor value, so that the harmonies of the two buzzers are actually sounding well.
Sure, I could go any buy another passive or active Buzzer, but I actually like how different the two of these sound and I think I could make some cool 8-bit-music with them.

I hope, someone can help me!
Thanks in advance

Madv0x:
Hello,

I would like to play a 2 voiced melody using an Arduino Uno and two buzzers, one being passive, the other being active. Since the active Buzzer is a lot louder than the passive one, I added a resistor to make it less loud, but to me it sounds like the resistor is changing the frequency and therefore the tone the buzzer is actually playing, which makes perfect sense to me.
Now I'd like to know how I can calculate the actual frequency the Buzzer is outputting in dependance of the resistor value, so that the harmonies of the two buzzers are actually sounding well.
Sure, I could go any buy another passive or active Buzzer, but I actually like how different the two of these sound and I think I could make some cool 8-bit-music with them.

I hope, someone can help me!
Thanks in advance

An active buzzer contains a transistor and some capacitors and resistors to make an audio oscillator which drives the piezo element.

You can find the frequency by reading the data sheet or the manufacturers spec for the device.

You cannot "calculate" the frequency, but you can measure it by using a microphone and an oscilloscope.

Paul

Active buzzers shouldn't be used to play a 'tone'.
It's like trying to use the claxon of a car as a loudspeaker.

Google tells me that an Uno can play up to three tones simultaneously.
So use two passive buzzers piezo speakers.

Or use a resistor DAC to play your 'melodies'.
Leo..