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Discussions => Instrument Design, Construction and Repair => Topic started by: Stockaryd on March 06, 2017, 09:42:37 PM

Title: Why reeds get out of tune
Post by: Stockaryd on March 06, 2017, 09:42:37 PM

Why does a reed get out of tune eventually?

vibrations? air? corrosion? dust?    or . . . . . . ?  Time?    :o

Title: Re: Why reeds get out of tune
Post by: Theo on March 06, 2017, 09:58:49 PM

Yes
 ;)

Title: Re: Why reeds get out of tune
Post by: Kimric Smythe on March 07, 2017, 05:07:23 AM

I suspect "work hardening", fatigue due to over extension and microscopic cracks. The stiffness of the valve changing will cause the tuning to shift too.

Title: Re: Why reeds get out of tune
Post by: Cag on March 07, 2017, 08:10:56 AM

I was writing this and took a while and in the meantime Kimric has posted similar comments but I'll post it anyway.

My understanding is constant movement of the reed leads to redistribution of stresses in the metal and results in changes to the bending characteristics and the preload. Changes in the valve ie. hardening or softening over time can shift pitch also.

Title: Re: Why reeds get out of tune
Post by: MatlockBather on March 07, 2017, 08:46:57 AM

Quote from: Kimric Smythe on March 07, 2017, 05:07:23 AM

I suspect "work hardening", fatigue due to over extension and microscopic cracks. The stiffness of the valve changing will cause the tuning to shift too.

I suspect you are correct! Scratching the surface of the reed to tune it, rather than removing material is breaking the compressive work hardened layer formed by repeated oscillation and aging and thus allows the reed to vibrate more easily.

Si