Music – Instruments – Automatic
Reexamination Certificate
1999-09-30
2001-08-07
Donels, Jeffrey (Department: 2837)
Music
Instruments
Automatic
Reexamination Certificate
active
06271447
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a velocity determining technology and, more particularly, to a velocity calculating system for moving object widely varied in velocity, a method for correcting the velocity and a keyboard musical instrument equipped with the velocity calculating system for accurately determining the loudness of sounds.
DESCRIPTION OF THE RELATED ART
While a pianist is playing a piano, he or she selectively depresses the black/white keys and, thereafter, releases them so as to generate acoustic tones. The depressed black/white key actuates the associated damper mechanism and the associated key action mechanism. The depressed black/white key lifts the damper felt, and the damper felt is spaced from the associated set of strings so as to allow the set of strings to vibrate. On the other hand, the key action mechanism drives the associated hammer for rotation, and the hammer felt strikes the set of strings. Then, the strings vibrate so as to generate the acoustic tone. When the pianist releases the depressed black/white key, the black/white key returns toward the rest position. The released black/white key brings the damper felt into contact with the set of strings, again, and damps the vibrations of the set of strings. This results in the extinguishment of the acoustic tone. If the pianist depresses pedals, i.e., a damper pedal, a sustaining pedal and a soft pedal, the pedal mechanisms impart predetermined effects to the acoustic tones. Thus, the acoustic piano repeats the loop having depressing a black/white key, striking against the strings, releasing the black/white key and damping the vibrations during the performance, and the pedals selectively impart the expressions to the acoustic tones.
An automatic player piano is the acoustic piano equipped with a recording system and a playback system. While a pianist is playing the acoustic piano, each of the black/white keys generates the acoustic tone through the above-described loop, and the pedal mechanisms selectively impart the expressions to the acoustic tones. The recording system monitors the black/white keys so as to generate pieces of music data information representative of the performance. The pieces of music data information are stored in a suitable information storage medium. Otherwise, a tone generator and a sound system produce electronic sounds on the basis of the pieces of music data information in a real time fashion. When the pianist instructs the automatic player piano to reproduce the performance, the playback system reads out the pieces of music data information from the information storage medium, and the actuators selectively actuate the black/white keys and the pedals. In order to exactly reproduce the performance, it is important to exactly monitor the key motion and the pedal motion in the recording mode.
The prior art automatic player piano is equipped with key sensors and pedal sensors. The key sensor is the combination of a shutter plate and a photo sensor such as a photo interrupter. The shutter plate is attached to the lower surface of the black/white key, and the photo sensor is mounted on the key bed. The shutter plate is aligned with the gap of the photo sensor, and intersects the optical beam radiated over the gap. When the shutter plate intersects the optical beam, the photo sensor varies the key position signal representative of the current shutter position, i.e., the current key position, and a controller determines the shutter speed and a timing for generating the tone. If the player simply depresses the black/white key from the rest position to the end position, the key motion is fairly corresponding to the hammer motion, and the key velocity at a certain key position is proportional to the hammer velocity at the strike against the strings. For this reason, the controller determines the loudness of the tone on the basis of the key velocity at the certain key position. However, when the pianist gives rise to a special key motion such as, for example, a repetition of a black/white key in a shallow region, the pieces of music data information tend to represent a different loudness and tone generating timings different from those of the acoustic piano. The shallow repetition has a short stroke, and the acoustic piano does not generate a loud tone. On the other hand, when the pianist gives rise to the shallow repetition in the automatic player piano, the automatic player piano gives a large loudness to the electronic sound, because the black/white key is moved at a high speed.
A hammer sensor eliminates the discrepancy from the electronic sounds.
FIG. 1
illustrates a typical example of the hammer sensor incorporated in an automatic player piano of the type having an upright piano. The prior art hammer sensor also comprises a shutter plate
1
and a photo sensor
2
. The shutter plate
1
is attached to a hammer shank
3
of a hammer assembly
4
, and is movable with respect to the key bed (not shown) together with the hammer assembly
4
. The shutter plate
1
is generally rectangular configuration, and has a leading edge
1
a
. A window
1
b
is formed in the shutter plate
1
, and is spaced from the leading edge
1
a
by a predetermined distance. The hammer assembly
4
has a hammer head
4
a
, and a set of strings
6
(see
FIG. 2
) is struck by the hammer head
4
a.
On the other hand, the photo sensor
2
is attached to a bracket
5
, and is stationary with respect to the key bed (not shown). A slit
5
a
is formed in the bracket
5
, and the photo sensor
2
radiates an optical beam
2
a
across the slit
5
a
. The shutter plate
1
is inserted into the slit
5
a
, and the leading edge
1
a
intersects the optical beam
2
a.
When the leading edge
1
a
intersects the optical beam
2
a
, the hammer head
4
a
reaches position H
2
, and is spaced from the associated strings
6
as shown in FIG.
2
. The hammer assembly
4
is further rotated, and the hammer head
4
a
reaches position H
3
. Then, the window
1
b
allows the optical beam
2
a
to pass therethrough. The hammer assembly
4
is further rotated, and the hammer head
4
a
reaches position H
4
. The shutter plate
1
intersects the optical beam
2
a
, again. The photo sensor
2
abruptly reduces the photo current at position H
2
, and recovers the photo current from the small quantity to the large quantity at position H
3
. The photo current is reduced at position H
4
, again.
The photo sensor supplies a hammer position signal representative of the amount of photo current to a controller (not shown), and the controller determines the timing at the position H
4
to be an impact timing Ht of the strings with the hammer head
4
a
, i.e., a timing to generate the sound. As described hereinbefore, the distance between the leading edge
1
a
and the window
1
b
is known. The controller clocks the lapse of time between the position H
2
and the position H
4
, and calculates the hammer velocity Hv. Then, the controller generates a piece of music data information representative of the impact timing Ht, the hammer velocity Hv, the key code assigned to the depressed key and a lapse of time from the initiation of the performance. The piece of music data information is stored in a suitable memory.
Although the prior art hammer sensor is appropriate to the depressed black/white key, a key sensor is still necessary for the released black/white key. The key sensor monitors the black/white key so that the controller determines the timing to damp the sound. The controller generates a piece of music data information representative of the timing to damp the sound, the key code and the lapse of time from the initiation of the performance. The piece of music data information is also stored in the memory.
FIG. 3
illustrates the relation between the shutter position and the hammer position signal. As described hereinbefore, the hammer position signal is changed from a low level L to a high level H at position H
2
, from the high level H to the low level L at position H
3
and from the low level L to the high level H. Th
Fujiwara Yuji
Oba Yasuhiko
Ura Tomoyuki
Donels Jeffrey
Morrison & Foerster
Yamaha Corporation
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