[djeiasbsbo]

Yes, you got it. Important is that a wave has a frequency and also a shape (e.g. sine, square, etc.). Even if the shape is different and the frequency is the same, the "pitch" is the same. The shape is the "timbre", or what makes the instruments sound different.

You can deconstruct any given sound wave into its partial sine waves. This is typically done using a Fourier Transform algorithm (FT).

Of course, we can also do it the other way around, create a signal out of many sine waves. In practice, this is called additive synthesis.

Instruments not only sound different because of the timbre. Another thing to look at is the loudness over time, e.g. when plucking a string. We usually do this with an ADSR representation (Attack, Decay, Sustain, Release).

Knowing these chracteristics is enough to recreate an instrument with a synthesizer. Of course, it gets more complex when there are inharmonics and if they are irregular (different depending on each tone). That's why synthesizing instruments realistically is a pretty time consuming science.

[dwd]

...and why guys like Martin Galway were absolute genius in the music they could get out of the C64 SID.