Dear Alan:

        I wouldn't exactly call this scientific, but I'll take a stab at defining your colour/timbre descriptions(at least imho):

Dark--a sound with multiple harmonics sounding simultaneously, not to be confused with:

Flat--a false *dark* sound produced by playing a note slightly flat, which removes the upper partials of the sound

Warm--a sound which incorporates the use of a gentle vibrato to add color to the sound(aka *sweet*, especially at lower dynamics)

Cool/Cold--a sound devoid of any type of vibrato(aka *straight*)

Bright--a sound which is played very much in the center of the pitch, with emphasis on the higher harmonics(aka *piercing*), occurs at any dynamic

Edge--see *bright* above, but also refers to the crisp, marcato attacks used to *punch* the sound out of the horn, occurs more at louder dynamics

Big--a *dark* and *warm* sound, which maintains its richness even at louder dynamics(as opposed to a *bright* sound, which may develop *edge* at higher dynamics)

        Perhaps the most important thing to remember when addressing timbres is that they are relative in nature....

fwiw

Alan Rouse wrote:
> I believe that all the shades / colors we discuss are simply different
> amplitudes of the various harmonics.
>
> I accept that some of this might be related, not to an instantaneous
> "snapshot" of the balance of harmonics, but the changing of this balance
> over time as you attack and sustain a note, use vibrato, etc.  But let's
> start simple...
>
> Ok, if you accept that, then here's my question:  In terms of harmonic
> amplitudes, what do we mean by
>
>  - big
>  - warm
>  - dark
>  - edge
>  - bright
>  - sweet