linuxaudio.org

On Sun, 11 Dec 2011 22:19:13 +0000

Fons Adriaensen  wrote:
> On Sun, Dec 11, 2011 at 10:52:31PM +0100, Julien Claassen wrote:

quoted text
>

> > 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@lists.linuxaudio.org

http://lists.linuxaudio.org/listinfo/linux-audio-user