Decibel Levels

[Carl Teplitski]

Point:            Sound levels attained by opening a Grand lid.

Exposing the soundboard, strings, must have an effect
on perception of total sound available. Possibly because
more frequencies are apparent. Agreeing with the thought
that out of tune unisons seem louder. Also, some  pianos
provide a lid opening prop in order to allow more frequencies/sound 
to escape ?? Is that what happens ?

Had occasion to tune a very badly out of tune upright a long time ago.
Sounded like an out of tune honky tonk (how could that be ) instrument.
I use that term very loosely. I was very new to the business, so what
happened next really upset me. I handle it much better now. After
tuning,
the woman who owned the piano sat down to play, looked at me strangely,
and said, you,ve taken all the tone out of this piano!! At that instant
I,m
sure I became more caucasian than I normally am. I now can spar with
a lot more conviction than I did then. Anyway ,she thought the piano
was anemic and dull sounding compared to before the tuning. I didn,t
think I could return the piano to where it was, though I sure would
have liked to.    I,ve gone so far as to make a recording of a piano
before tuning, so a comparison could be made later. The customers
don,t think the piano is that bad, but others suggested that it needed
correction. Usually, she/he sees a big difference, or at least says so.
Octaves,4th,5th, don,t sound as loud as 3rds.!!     ( My opinion.)
So in conclusion;   I think ear plugs must attenuate some frequencies,
which of course lowers the total sound reaching the nerve endings.
Very interesting subject. Needs a lot more discussion. I will be
looking for same.

Carl



Delwin D Fandrich wrote:

> ----- Original Message -----
> From: "Kevin E. Ramsey" <ramsey@extremezone.com>
> To: <pianotech@ptg.org>
> Sent: December 30, 2000 6:01 PM
> Subject: Re: Decibel Levels
>
> >     Once again, Thanks to Del for the informative post. Concerning the
> > loudness of the larger piano, I would have instinctively (intuitively)
> > thought that the larger soundboard would have caused a greater volume of
> air
> > to be displaced, thus creating more "volume". I was under the impression
> > that volume and loudness are not necessarily the same thing.
> -------------------------------------------------
>
> Kevin,
>
> Only in the very low bass would soundboard size become an issue--or, more
> accurately, any lack thereof--and even here soundboard size is adequate in
> even the smallest piano sizes. There are other factors that limit the
> acoustical power of the piano starting with the hammer/action/key mechanism
> and how much energy can be transferred from the pianists fingers to the
> various strings.
>
> There is probably some minimum practical size for the piano soundboard, but
> the physical characteristics of the piano generally determine its actual
> size and, to some degree, its shape. That is, within some limits, it is
> generally the requirements of the scale layout that determine the basic
> shape and size of the rim and, hence, the soundboard. And these factors
> generally ensure that the soundboard size is more than adequate. At least in
> the grand, uprights are another issue. Here the maximum soundboard size is
> determined by the size--the height and width--of the basic box unless the
> designer restricts that size by the use of various cutoff bars as I did with
> the Fandrich Vertical. Generally, attempts at making the soundboard larger
> by making the grand rim 'fatter' are counterproductive. (I know, this is
> difficult to actually prove since it would involve making another, otherwise
> identical, piano to use as a direct comparison. Still, from my own
> experimental work, I have found this to be generally true.)
>
> If all other factors were exactly the same, your assumption, "the larger
> soundboard would have caused a greater volume of air to be displaced," would
> be correct. However, the amount of air that can be displaced by a soundboard
> is limited by many factors other than simply its size--mostly by its
> mobility and by its tendency to distort and break up into various resonances
> as its size increases. These issues are determined by the overall design of
> the soundboard assembly--the specifics of the bridges and their placement on
> the board, the size and shape of the ribs and their placement on the board,
> etc. It is also affected by the stringing scale--its overall tension,
> backscale configuration, degree of bridge loading, etc. An
> appropriately-sized soundboard design takes all of these factors into
> consideration. An overly large soundboard will have considerable flexibility
> unless it is made extraordinarily stiff. Either extreme presents problems.
>
> The question of volume vs. loudness brings up a whole other issue. Are we
> talking about absolute acoustic power as measured by Ron's new toy? Or
> power/loudness as perceived by our ears? If the latter, then we have to
> consider how our ears detect sound and we have to factor in the shape of the
> sound envelope and the harmonic structure of that sound envelope.
>
> Del