This patch map simulates a classic two-tone doorbell.
Sine4 and Mus6 produce a pure sinewave tone at musical note G (octave 4). This is put through a short attack-decay envelope, Adsr2, to produce the "ding" of the doorbell.
Similarly, Sine5, Mus7 and Adsr3 produce a lower pitched "dong" as the second tone of the doorbell.
The 2 signals are combined in the sequencer Seq1. This is set to delay the second input (input B). This means that the first "ding" occurs at the start of the sound, but the second "dong" occurs 0.3 seconds later
Experiment by changing the pitch of the 2 tones (using Mus6 and Mus7), or altering the delay in Seq1.
If you wanted to make the sound more realistic, it would probably be a good idea to use better bell sounds - a simple sine wave does not sound all that realistic, it is only used here for simplicity.
[Patch Map doorbell.pm] [WAV File doorbell.wav]