Inharmonicity in other instruments

[Billbrpt@aol.com]

In a message dated 6/10/98 8:49:40 AM Central Daylight Time, rscott@wwnet.net
 writes:

<<...the fact is that inharmonicity is
 a phenomenon that is unique to struck instruments, like the piano,
 the harpsichord, the xylophone, bells, dulcimer, guitar, etc.  There is
 no inharmonicity in instruments that produce a continuous sound
 from continuous excitation, like the violin, the pipe organ, horns,
 woodwinds, and accordians. >>

Thank you for your input.  I was very surprised to read this, for more than
 one reason.  However, it does explain one thing to me.  Years ago, Rick
 Baldassin demonstrated that if you could bow a piano string, there would be
 significantly less inharmonicity, or none, according to what you have said.  I
 have always wondered how the same string could be different with regards to
 its inherent qualities.

I am not at all a scientist but I like to experiment and question what is
 regarded as fact and like to see if there might be something better than what
 most people accept as the norm.  This is why I use non-equal temperaments and
 creatively stretched octaves.  I have always understood that an instrument has
 its characteristic sound because of its harmonic structure.  That is what
 would distinguish two instruments of the same pitch such as a clarinet and an
 oboe from each other, for example.  I have known for many years that a bell
 usually has a great amount of inharmonicity, that is at least one reason why
 their pitch is so difficult to identify. According to what you have said, if
 one could take a rosined bow and draw it acroos the sharp edge of a bell, you
 would expect the sound to be quite different and a more identifiable tone to
 be heard.

You talked about "continuous excitation" being the difference.  A harp,
 harpsichord, or any other plucked instrument such as guitars, lutes,
 mandolins,etc. have inharmonicity because their strings are not continuously
 excited.  But does not the rosin and the microscopic sized barbs of a bow
 actually "pluck" the string too?  How rapidly does the "excitation" have to
 occur for it to be considered "continuous"?  If you give the piano key a rapid
 series of strokes such as when playing a trill, would the inharmonicity ofthe
 strings involved decrease or go away?

Could the back and forth motion of a reed also be considered as individual
 movements, the same as being struck or plucked?

The reason I ask this is that I do not doubt what you have said but if a reed
 has no inharmonicity, then how could my SAT pick up the difference between the
 fundamental of a G2 reed and the same reed as read on G3, G4, G5, and G6 and
 show an increasin difference of 6¢ at the highest partial that was measured?
 When the bellows are pushed forcefully, that 6¢ again flattens considerably.

When I play the G2 button and push the bellows normally, the other 4 reeds
 sound in octaves that are apparently beatless. When I push forcefully, they go
 out of tune with each other.  You can hear beats within the octaves.

If there is inharmonicity or a phenomenon which is equivilant to it or at
 least produces an effect which mimicks inharmonicity,  I would naturally be
 inclined to investigate a tuning scheme which would stretch the octaves.
 However, if it turns out that only the lower reeds  have this "inharmonicity"
 or they are the only ones where it can really be heard in the range where all
 the intrument's harmony occurs, then stretching the octaves would only make
 this "bellows effect" worse.  The lower reeds would go all the more flatter
 against the upper reeds.

I am interested to read what you have to say about this.

Bill Bremmer RPT
Madison, WIsconsin