Musical Soundwaves

[Carl Meyer]

Keith,  If a speaker cone (not the magnet) does move anyway but in and out, it does it because of imperfections or other anomalies but not because any amplifier is telling it to.  A soundboard will move in strange ways as well due to resonances, impedance difference at some spots etc etc.  

A microphone capturing sound waves can be recorded these days very accurately and can be reproduced with great fidelity.  Compare modern sound systems to the Gramophone of yesterday.  Wouldn't  equal progress in piano design and manufacturing be mind boggling?  I wish!

Carl Meyer  Assoc. PTG
Santa Clara, California
cmpiano@attbi.com  


----- Original Message ----- 
From: "Keith Roberts" <kpiano@goldrush.com>
To: <pianotech@ptg.org>
Sent: Friday, August 02, 2002 9:31 AM
Subject: Re: Musical Soundwaves


> Ron,
> My observations on sample sound are not scientific. I have a Yamaha keyboard
> with sample sound. The friend I play with has a couple Kawai speakers that
> are reminiscent of the old Altec Lansing "Voice of the Theater' speakers and
> meant for the full range of sound needed for reproducing a piano sound. They
> amaze people as to how close to a real piano the sound is. I think in a
> sample, all the information is there but the compromises that are made in
> low or mid grade systems has a lot to do it. Terry should think again about
> stating that the speaker magnet 'only moves in and out'. Looking at the
> thing on my speakers it's obvious the thing is dancing and trying to twist
> and turn. The primary motion is in and out due to the restraints on the
> system as that is needed to move the air necessary to produce volume.
> Keith R
> ----- Original Message -----
> From: "Ron Overs" <ron@overspianos.com.au>
> To: <pianotech@ptg.org>
> Sent: Friday, August 02, 2002 8:19 AM
> Subject: Re: Musical Soundwaves
> 
> 
> > Greetings Terry,
> >
> > You wrote:
> >
> > >Why does a flute sound like a flute? Why does an obo sound like an
> > >obo? Why does a guitar sound like a guitar? And last, but certainly
> > >not least, why does a piano sound like a piano?
> > >
> > >Does anyone have a simplistic explanation for what is the cause of
> > >unique sounds/tones among various instruments? If you play A4 at a
> > >pitch of 440 Hz on any instument, you will hear the pitch of 400 Hz.
> > >But they will all sound different. So I guess they all do something
> > >different to the soundwave that reaches your ear. What is that
> > >difference? How does a speaker reproduce these differences of they
> > >only move in and out?
> >
> > Basically, all musical instruments will tend to produce tone with the
> > harmonics or partial series present with the fundamental tone. Even a
> > flute, which has a more pure tone than many instruments, still has
> > harmonic content. The volume of the partials relative to that of the
> > fundamental tone will vary from one type of instrument to another.
> > Just try the simple test of holding down a piano note to lift the
> > damper, while playing the notes which most closely match the
> > frequencies of the harmonic series for the held note, ie, octave,
> > octave and fifth, double octave, double octave and a third, " and a
> > fifth, " and a seventh, triple octave. You will notice that some
> > harmonics induce much more strongly into the held note than others.
> > This variability will reflect the harmonic content of 'piano' tone.
> > If it were possible to conduct a similar test with another type of
> > instrument, you would find that the harmonic content would be
> > slightly different, according to the tonal characteristics of that
> > instrument.
> >
> > The reason why A440 sounds like A440 on a piano, voice and mandolin,
> > is that our ear locks onto the lowest frequency, the fundamental, to
> > identify the pitch of the note. So while the tonal characteristics of
> > the instruments might be very different, an A440 played on each
> > instrument will still cause our ears to identify the pitch for what
> > it is. One reason why it is very difficult to discern the pitch of
> > note A1 on a short piano, is that there is virtually no fundamental
> > tone present. Furthermore, the harmonic content will have such high
> > inharmonicity, that a serious pitch crisis will exist between the
> > fundamental tone and the harmonics, to make pitch identity even more
> > difficult. Try this simple test, on a concert piano play the lowest
> > minor third C to A, then repeat the same test on a 'sawn off' piano.
> > The minor third interval is easy to hear on the concert instrument,
> > but nearly impossible to discern on the shorter 'sawn off' variety.
> >
> > While the harmonic content variability allows our ears to discern
> > which particular instrument the tone is coming from, as some other
> > writers have mentioned, the decay and attack characteristics will
> > also vary according to the instrument in question. Furthermore,
> > inharmonicity also introduces an added dimension to the
> > characteristics we hear.
> >
> > I also suspect that when sampled tones are recorded, the volume of
> > the harmonics is reproduced faithfully but not the inharmonicity. If
> > this is the case, it would readily explain why sampled piano sounds
> > do not sound exactly like pianos. Does anyone else have something to
> > add to this? If this is not correct regarding sampled tone I would
> > appreciate a subsequent post on the matter.
> >
> > Best,
> > Ron O.
> > --
> > _______________________
> >
> > OVERS PIANOS - SYDNEY
> > Grand Piano Manufacturers
> >
> > Web: http://overspianos.com.au
> > mailto:info@overspianos.com.au
> > _______________________
> >
> 
>