- Spectrum and Envelope
After silence, that which comes nearest to expressing the inexpressible is music – Aldous Huxley
Question to ask yourself: If two sounds have the same loudness and pitch, will they always sound the same?
Not necessarily. The same note sung by a human and played by an instrument will not sound the same. Those experienced in music can distinguish a note played by a guitar from the same note played by a piano or violin. So there is definitely something else that allows us to make this distinction.
This is timbre. Also called tone quality, color or texture. Yes, it is a subjective thing. Some people have mockingly called it “the multidimensional waste-basket category for everything that cannot be labeled pitch or loudness”.
Timbre is objectified and studied by a spectrograph, the result of which is shown above. The second property used to define timbre is the envelope:
The thick red line is the envelope – which unfortunately has its own weird definition. If you map the sound to the time domain, then the envelope is the overall amplitude structure of a sound, as shown above. It’s hardly anything to go by, so don’t kill yourself if you can’t understand or care.
Duration is the amount of time a sound is heard, or the time interval between two sounds. It’s just…duration, nothing special. However, this is what allows us to have beats in music. It is the basis of Rhythm.
Rhythm is made up of sounds and silences put together to form a repeated pattern. This to us manifests itself as a beat, when the effect is strong, like when we hear drums or percussion instruments. A single voice singing will not have an audible beat, yet it has a rhythm dictated by the musical composition.
Rhythms fascinate us for the same reason all cyclical events fascinate us, as Professor Sampler might have told you. Even our heartbeats have a rhythm, which is tied to our emotional and physical being. Is this the basis for music? Who knows?
- Timbre is the quality of sound that allows us to distinguish between two tones of the same loudness and pitch.
- Duration is the amount of time a sound is heard, or the time interval between two sounds.
- Rhythm is made up of sounds and silences put together to form a repeated pattern.
Links for further study: