On Sun, 11 Dec 2011 22:19:13 +0000 Fons Adriaensen <fons@xxxxxxxxxxxxxx> wrote: > On Sun, Dec 11, 2011 at 10:52:31PM +0100, Julien Claassen wrote: > > > This sounds valuable. My first experiments - mainly trial and error, > > based on basic theory - weren't good at all. :-( > > Depends on what you consider 'basic theory'. The simple fact is > that the partials of a bell sound are _not_ a simple harmonic > series. In its most basic form, a bell sound will consist of > five partials: > > 1. Nominal - this is the nominal frequency of the bell. > 2. Prime - one octave below the nominal. > 3. Hum - two octaves below the nominal. > 4. Tierce - a minor (sometimes major) third above the prime. > 5. Quint - a fifth above the prime. > > There will be higher components as well in many cases, in > particular higher thirds and fifths, but these are never > exact harmonics of the lower ones. > > This is a much simplified model. In most cases the two > octaves are not exact (the 'hum' is usually higher) and > this does not necessarily mean a bad sound. Same for the > smaller intervals. > > The reason why inexact intervals are perfectly possible > and do not produce an ugly sound is that none of these > partials have significant higher harmomics - they are > pure sine frequencies. So there is no beating of higher > harmonics, which is what makes most detuned instruments > sound bad. > > Except for the 'hum', these components will usually > have a normal exponential decay (roughly). The 'hum' > is different: it starts at low amplitude, and rises > during a second or two before decaying. > > Ciao, Absolutely fascinating! I always knew that bells were 'strange' but I never realised just *how* strange! -- Will J Godfrey http://www.musically.me.uk Say you have a poem and I have a tune. Exchange them and we can both have a poem, a tune, and a song. _______________________________________________ Linux-audio-user mailing list Linux-audio-user@xxxxxxxxxxxxxxxxxxxx http://lists.linuxaudio.org/listinfo/linux-audio-user
