[Harp-L] Re: Stretch

[Steve Baker <steve@xxxxxxxxxxxxx>]

I tune all my harps on a Korg chromatic tuner originally developed  
for piano tuners with a choice of three sets of built in stretch  
parameters, a bit like small, medium and large. I always use the  
"small" one (i.e. minimal stretch) from top to bottom of all harps in  
all keys and that works absolutely fine for me. So far, no-one has  
ever complained about a harp I tuned for them being out of tune.

In my view it's essential to tune the lower draw notes slightly sharp  
in relation to the other notes if, and this is very important so I'll  
repeat it, if and only if you are tuning using minimum air pressure.  
I always tune like that, as the only truly reliable guide to the  
actual pitch of the reed is its free-swinging frequency, and the only  
way to obtain that pitch is with minimal air pressure. When you play  
with "normal" air pressure, the reed will sound considerably lower  
than its free-swinging pitch (will vibrate slower than at its free- 
swinging frequency, as the air pressure acts as a brake). This means  
it's essential to compensate by tuning these bendable reeds slightly  
sharp. How sharp is dependent on the key, as reeds of low pitch will  
likely go flatter than higher pitched reeds.

If you tune with regular playing pressure you'll almost certainly be  
flatting the lower draw notes already, so then there's no need to  
compensate. However, if tuning for others you'd better be using a  
comparable pressure to those players, otherwise the pitch may well be  
right for you but too low or too high for their accustomed air  
pressure/intonation. Any tuning values I may give always refer to the  
pitch when using minimal air pressure.

Fine tuning any instrument is about achieving a viable compromise  
which works in practice and reflects the needs of the player. It  
isn't an exact science and experience is the best teacher.

Steve Baker
www.stevebaker.de
www.european-blues-masterclass.com
www.harmonica-masters.de