Agraffes / prssure bars

[Roger Jolly]

Hi Kieth,
              I could be mentioned that capo or pressure bars are used in
the treble on many grands to add forward duplexing, or an added dimension
to tone colour and sound output.
Agraffes in the tenor and bass, firmly fixes the string position this is a
big plus when using wedged damper felt.
Flat sewn damper felt is used in the treble of most grands, whilst less
efficient than wedged felt, it is less important with shorter strings.  It
has the added advantage of giving a wider variation of tone when half
peddling.
Most good quality grands will have agraffes through out the tenor section,
and may have wedge damper felt part way up, and a combination of wedge and
flat sewn felt in the higher tenor section.  The combination is used for
half peddling reasons.
Roger 

>I indicated these are subjective differences from my point of view between
>agraffes and pressure bars where applicable, Calin.  However, I personally
>wouldn't hesitate to consider agraffes in the bass and tenor sections on
>grand pianos as more advantageous than pressure bars.
>
>If you want scientific reasons, I'm not the guy to ask.  I just trust the
>majority of manufacturers that build them that way, and the years that I've
>spent tuning the ones that they build.
>
>Keith McGavern
>Registered Piano Technician
>Oklahoma Chapter 731
>Piano Technicians Guild
>USA
> 
Roger Jolly
Saskatoon, Canada.
306-665-0213
Fax 652-0505