Why do different instruments playing the same pitch sound different?
Different instruments emphasize different harmonics/overtones. They emphasize some overtones louder than others. The waveforms of different instruments have different amplitudes, which also shapes the sound. Also, remember that air is able to support many sound waves simultaneously. This variation in the combination of waveforms played simultaneously also shapes the sound we hear.
In our diagram examples, we've looked at sine waveforms. There are many kinds of waveforms. Instrument plugins can generate different types of waves, such as square waves, saw waves, and any sort of strange concoction developers can think up. The type of waveform will affect the resulting sound.
When you experiment with synthesizer plugin instruments, what the plugin is doing is creating different wave shapes. It adjusts the wavelength, amplitude, frequency, harmonics, and what combination of waveforms it plays. Once the waveform...