Piano Firing Missiles at Church Congregation

[Richard Brekne]

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Ron Overs wrote:

> Bill Bremmer wrote;
>
>> . . .  I need some opinions on what to do about it.  It is a
>
>> Young Chang Grand model G-185, only a few years old.  It is
>> meticulously
>
>> cared for but early in it's service, the pianist at this,
>> shall we say,
>> "spirit filled" church complained of bass strings breaking
>> and shooting out
>
>> of the piano.
>
>  Broken bass strings shoot out of the piano when the string
> breaks at the agraffe and the hitch pin is angled back suitably
> to steer the projectile-string out of the piano. Bosendorfer
> Imperials are famous for this, breaking at note C4  (in the
> Bos' this note is actually not the forth string on account of
> the extra bass notes) which is strung at nearly 400 lb tension
> with 1.35 diameter core wire. I've had two Cs go off and
> frighten the hell out me. I actually tune these pianos with my
> body off the line of the string to avoid wearing it.
>
>> I have tried all of the usual.  I filed the hammers.
>
>  This is not the problem
>
>> A monitor feeds back
>
>> sound to the pianist.
>
>  This will help.
>
>> When I explained to the church directors that it is
>
>> the "vigorous" style of playing that sometimes causes strings
>> to break, the
>
>> pianist resigned.  . . . . . . . .
>
>>
>> I am thinking that these wound strings must have particularly
>> high tension.
>
>> Does anyone know if this is so?
>
>  The tension is not the problem. The pianist may be part of it,
> but not all. Very often, small grands are built with rediculous
> string angles at the front bearing bar between the tuning pin
> and agraffe (in the bass only). While these angles can be
> tolerated in a home piano which might only be tuned biennially,
> when such a piano is tuned every other week it will invariably
> develop wire fatigue at the bearing bar and agraffe.
>
>> Over the years I have heard of other such
>
>> instances that were cured by replacing the wound strings with
>> a set of
>> lighter gauged, "happy" strings.  It would seem to me that a
>> lower tension
>> would solve the problem but in reading the recent post about
>> "replacement
>> strings", I am confused.  Some of these strings have been
>> breaking at the
>> bass bridge termination point rather than the agraffe.  That
>> seems very
>> unusual to me.
>
>  Wire breakage at the bridge would tend to indicate that the
> wire is fatigued through playing also. Church pianists, like
> the congregation, can get pretty overenthusiastic at times. The
> feed back monitor can help here.
>
>> Should the manufacturer supply a new set of wound strings and
>> if so, should
>
>> they be a set designed for lower tension?  I presume that
>> heavier gauged,
>
>> higher tension strings provide a bigger, bolder sound.
>
>  A heavier wrap will produce a 'fatter', longer piano sound,
> while a heavier core will raise the inharmonicty to produce a
> more 'growly' tonal quality. The G185 bass is not a
> particularly high tension scale (no piano with a 135 cm
> speaking length can be). I would advise against rescaling. In
> any event, it's not necessary. The problem lies elsewhere.
>
>> What effect would
>
>> lower tension have?  Just as a theoretical question, would
>> tuning the
>
>> instrument to a lower pitch, say 100 cents lower prevent this
>> from happening
>
>  Percentage of breaking strain !!! The use of a lower tension
> bass will not only give the piano a 'gutless' high
> inharmonicity bass, but it will lower the percentage of
> breaking strain of the bass section (particularly if the same
> core wire guage is retained), resulting in a slight reduction
> in the tuning stability in response to temperature and humidity
> variations. Mind you, there should be some percentage of
> breaking strain variation when the string scale crosses from
> trichord plain to bichord covers to facilitate tonal equality
> at the cross (there should also be a reduction in speaking
> length of between 10 - 15% at this point also - it is for this
> reason that pianos which use bichord covers for last couple of
> notes on the treble bridge, without any step reduction in
> speaking length, are always a scaling disaster)
>
>> It is also interesting to note that to date, only wound
>> strings have broken,
>
>> no plain wire.
>
>  You will also be interested to observe that the extreme string
> angles, caused by the too-high bearing bar, only occurs in the
> bass. If you restring the bass and reduce the bearing bar
> height to reduced the string angle deflection to 15 degrees or
> less (I prefer around 12.5 degrees), the problem will go away.
> Don't forget to replace the agraffes as well, the silly string
> angles will have destroyed the agraffe string hole shape (just
> cut one through the lower half of the holes with a hack saw and
> investigate the upper bearing surface with a looking glass -
> you will be astonished at the damage). We have done this
> bearing bar fix many times to small Kawai and Yamaha grands in
> commercial service - to good effect. Regards, Ron O  --
> Overs Pianos
> Sydney Australia
> ________________________
>
> Web site: http://www.overspianos.com.au
> Email:     mailto:ron@overspianos.com.au
> ________________________

--
Richard Brekne
RPT, N.P.T.F.
Bergen, Norway
mailto:Richard.Brekne@grieg.uib.no


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