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Description  |
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to tuning devices for musical instruments and
singers, and more specifically, to electronic tuning devices for
indicating the tuning of almost any type of musical instrument including
band and orchestra instruments such as wind instruments along with
stringed percussive instruments like guitars, pianos, harps, etc.;
electronic musical instruments which have microphone pickups and
amplifiers to generate acoustical sound vibrations in the air by speakers;
and musical notes produced by a singer.
2. Description of the Prior Art
Traditional tuning of instruments is often done with one or more tuning
forks, or other accurate tone sources, and a trained ear. In this process,
the artisan often uses the phenomenon of "beats" to fine tune the
instrument. A beat is an apparent oscillation of the loudness of a
perceived tone when that tone is produced by two simultaneous tones of
nearly, but not exactly the same frequency. Beats occur at a frequency
equal to the difference between the two generating frequencies. For
example, if a tuning fork is vibrating at a frequency of 440 Hz (440
cycles per second or in musical terms an A note) and a piano string is
simultaneously vibrating at a fundamental frequency of 443 Hz, a definite
rising and falling in the volume of the perceived tone will occur at a
rate of three cycles per second. As the two tones approach the same
frequency the beat frequency will reduce to zero. At a beat frequency of
zero there is simply no variation in the volume of the combined tone. When
a beat frequency occurs there is no way to tell which of the two tones
(the tuning fork or the piano) is the higher frequency. When a three Hertz
beat occurs the technician can only be sure the string is three Hertz off
from the standard tone. Whether the string is sharp or flat still had to
be determined by ear. Many times a trial adjustment was made and if the
beat got faster, the knowledge was gained that the adjustment was in the
wrong direction. The traditional method of tuning instruments left a lot
to be desired and was entirely dependent on the skill of the tuning
technician.
An electronic tuner for musical instruments has been marketed by Sabine
Musical Manufacturing Company, Inc. of Gainesville, Fl. since about 1987.
For tuning traditional musical instruments, i.e. non-electronic
instruments, the tuner is set on a table top and uses a built-in
microphone to sense tones produced by the musical instruments. For tuning
electronic instruments, a signal output from the instrument or amplifier
is directly connected by a cable to the electronic tuner. The LED display
of this prior art tuning device consists of a bottom row of twelve lights
corresponding to the twelve musical notes in an octave, i.e. A, A# (Bn),
B, C, C# (Db), D, D# (Eb), E, F, F# (Gb), G and G# (Ab). A separate top
row of three lights is provided for indicating flat, in-tune or sharp
tuning conditions, respectively. One of the twelve LEDs in the bottom row
is lit to indicate the note of the incoming tone while one LED in the
upper row is lit to indicate whether the incoming tone is in-tune, sharp
(above the in-tune range), or flat (below the in-tune range). The flat and
sharp error indicating lights are operated at blink rates proportional to
the magnitude of error. During tuning the musician must constantly monitor
both rows of LED's, and in the absence of such concentration, a change to
the wrong note can be overlooked resulting in tuning of the instrument or
string to the wrong note.
Electronic tuning devices of the above type generally have a relatively
small in-tune range or window, for example plus or minus three or four
cents, in order to prevent annoying beat frequencies and dissonance
between tuned instruments. Such tuning devices are most suitable for
string instruments such as guitar, piano, harp, etc. However, these tuners
are generally not used in tuning band and orchestra instruments such as
wind instruments including brass instruments and woodwinds like single and
double reed instruments and flute type instruments. Only highly
experienced or talented band and orchestra musicians can hold a tone
within plus or minus four cents on wind instruments. There is a need for
beginners and students in bands or orchestras, such as high school bands
and orchestras, to have a low cost tuner producing a visual indication of
the in-tune or out-of-tune condition of their instruments, particularly
those playing wind instruments. Additionally there is a need for a similar
tuner for indicating musical notes produced by singers during practice and
the deviation of the vocal notes from standard musical notes.
The prior art, in U.S. Pat. No. 3,861,266, discloses a musical tuning
instrument for persons of lesser skill, such as members of high school
bands. The tuning instrument has selector switches for setting the
frequency (note) and sensitivity. When sensitivity is set at the most
sensitive position, a pattern of eight lit LEDs in a circular array of
sixteen LEDs rotates once per second when the incoming tone is exactly one
Hertz greater or less than the set frequency. At the least sensitive
position, the one second rotation of the pattern occurs when the incoming
tone is sixteen Hertz greater or less than the set frequency.
SUMMARY OF THE INVENTION
The invention is summarized in an electronic tuning device for a musical
instrument wherein the tuning device has a variable in-tune range which,
in one mode, is indicated by lights in a display of a row of light
sources. When an incoming tone is sensed by a transducer, one light in the
row of lights is lit in a second mode to indicate the corresponding
musical note. The light indicating the musical note is also operated in a
manner, such as by blinking and/or selective color emission, to indicate
the in-tune or out-of-tune condition of the incoming tone.
Accordingly, it is a principal object of the invention to provide a musical
instrument tuning device with selectable in-tune ranges enabling use by
beginners, students and accomplished musicians to tune band and orchestra
instruments and voice.
Another object of the invention to provide an electronic tuning device with
a single row of display lamps, such as light emitting diodes (LEDs), which
indicate the width of a tuning window along with the frequency or note of
a incoming tone and its in-tune or out-of-tune condition.
One advantage of the invention is that the spacing between a pair of
energized light emitting sources in a row of light emitting sources
indicates the width of a set in-tune range.
Another advantage of the invention is that an in-tune range or window is
selected by depression of a calibration or range switch to step a tuner
through the selectable in-tune ranges.
Additional features of the invention include the provision of three-color
light sources for indicating notes in a scale of notes wherein the color
indicates sharp, flat and in-tune conditions of the notes; the provision
of blinking light sources for indicating notes in a scale of notes wherein
the frequency of the blinking light indicates the deviation of the
incoming tone from the nearest note.
Other objects, advantages and features of the present invention will be
apparent from the following detailed description of the preferred
embodiments and the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is top plan view with a portion broken away of an electronic tuning
device in accordance with the invention.
FIG. 2 is a front elevational section view of the electronic tuning device
of FIG. 1.
FIG. 3 is a block diagram of electrical circuitry in the electronic tuning
device of FIGS. 1 and 2.
FIG. 4 is a step diagram of a program employed in a microprocessor in the
circuitry of FIG. 3.
FIG. 5 is a step diagram of a subroutine called by the program in FIG. 4.
FIG. 6 is a diagram of a row of LEDs with corresponding note indicia in the
electronic tuning device of FIGS. 1 and 2.
FIG. 7 is a table listing pairs of blinking lights in the light row of FIG.
6 with the corresponding in-tune range set by the electronic tuning device
.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
As shown in FIGS. 1 and 2, an electronic tuner for use in tuning a musical
instrument is constructed in accordance with one embodiment of the
invention and includes a casing 20 in which is mounted a display,
indicated generally at 22, with a row of light sources, such as twelve
red-green dual light emitting diodes (LEDs) 24 which correspond to
respective musical notes A, A# (Bb), B, C, C# (Db), D, D# (Eb), E, F, F#
(Gb), G and G# (Ab). The tuner includes an electronic circuit 28, FIG. 3,
mounted in the case 20 wherein a microphone or transducer 30 converts an
incoming tone from a musical instrument into electrical signals which are
amplified by an amplifier 32, filtered in a frequency response amplifier
34, detected by a zero crossing detector 36 and analyzed by a
microprocessor 38 which operates the LED display 22.
In a first mode, the microprocessor 38 determines the fundamental frequency
of the incoming tone, computes the nearest musical note, and operates the
corresponding light source 24 in the display 22 in manner indicating the
in-tune or out-of-tune condition of the incoming tone. For example, the
microprocessor 38 controls the operated light source to select a color
indicating an in-tune condition or a deviation such as flat or sharp
condition of the tone from the nearest musical note and/or to blink the
light source proportional to the deviation of the tone from the nearest
musical note.
In a second mode, the processor 38 operates the LEDs in the display 22 to
indicate the width of the in-tune range to which the tuner is set. One
example of indicating a set range selected from several in-tune ranges is
illustrated in the table of FIG. 7 wherein pairs of the LEDs 24, see also
FIG. 6, are turned on, flashed or blinked; the spacing between the
activated LEDs indicates the set in-tune range so that the broadest
in-tune range is indicated by the LEDs A and G# on the ends of the row 22
and the narrowest range is indicated by the two innermost LEDs D and D#.
Referring back to FIGS. 1 and 2, the casing 20 has approximate outside
overall dimensions of about 3 inches.times.1.5 inches.times.3/8 inch (7.6
centimeter.times.3.8 centimeter.times.1 centimeter). Casing 20 is made up
of top member 50 with side walls 52 and a bottom plate 54 suitably secured
in the side walls. Casing 20 is preferably molded from a durable plastic
material. Side walls 52 extend slightly below the bottom edge of floor
plate 54 to provide protection for the edges of rubber feet 56 which are
secured on the bottom surface of the bottom plate 54.
The top and bottom members 50 and 54 together with the side walls 52 define
an enclosed box structure within which are mounted the electronic
components forming the circuit 28 of FIG. 3. A circuit board 60 is mounted
in the casing 20 and serves as a support and connection bus for the row of
twelve two-color LED's 24 which selectively illuminate correspondingly
labeled portions of a frosted face plate 62. Alternatively the
illumination may be accomplished in many different ways such as by
providing small cutouts in the top plate, by making portions of the top
plate transparent, or many other ways. As shown in FIG. 6, the individual
LED's may be labelled with indicia such as:
A.smallcircle.BC.smallcircle.D.smallcircle.EF.smallcircle.G.smallcircle.
where the letters represent white keys on a piano and the ".smallcircle."
symbols represent the black keys. Of course the exact form of labeling is
arbitrary and a matter of design choice. The scale does not have to start
with A but can start with any other note such as C which would then end
with B.
A battery 64, shown hidden in FIG. 1, supplies power for the electronic
circuit. A door 66, FIG. 2, is provided in the bottom plate 54 for
enabling the battery 64 to replaced. Top member 50 also has two openings
for mounting push button range switch 70 and push button power switch 72.
Suitable indicia identifying these switches are formed on top 50. Push
buttons 70 and 72 are designed to make contact with inner spring biased
switch elements 74 and 76, respectively, when manually depressed. As can
be seen in FIG. 2, inner switch elements 74 and 76 are supported on
circuit board 60. The microphone or transducer 30 is centrally mounted on
the inside of the top member 54.
The program for operating the processor chip 38 of FIG. 3 is illustrated in
FIG. 4. Operation begins at the step 90 when the power switch 72 is closed
and proceeds through power up initialization 92 to step 94 where it is
determined if the power switch 72 is depressed. The power switch must
remain depressed sufficiently to distinguish from an incidental induced
signal; otherwise the program branches to step 96 and a power down
sequence. In the initialization step 92, the in-tune range is set to the
widest range, for example, from plus 49 to minus 49 cents as shown in FIG.
7 corresponding to LEDs A & G#, FIG. 6. Alternatively, the set in-tune
range can be set equal to the in-tune range at which the tuner was set
when last turned off.
If step 94 is true, the program branches to step 98 where it is determined
if the calibration or range switch 70 is also depressed. If the
calibration switch is not depressed, a power shut down timer or timer-1 is
started in step 100. The power shut down timer will later power down the
tuner after a predetermined time, for example about ten minutes. Normal
operation of the power switch 72 initiates the power down timer which
automatically shuts down the tuner after the set delay. Then in step 102
the tuner indicates that the normal timer power shut-down mode, for
example by momentarily turning on the green D# LED such as for one to
three or more seconds. When the calibrate switch 70 is depressed before
the power switch 72 is depressed and the calibrate switch is held
depressed as the power switch is depressed, the program will bypass the
timer-1 initiating step 100 so that the tuner can operate continuously.
Continuous operation is desirable for tuning some instruments, for
example, harps, pianos, etc., where more time is needed for tuning than is
provided by the standard turnoff delay. In step 104, the tuner indicates
the continuous mode where the normal power down mode is not active, for
example by momentarily turning on both the green C# and D# LEDs such as
one to three or more seconds.
From step 102 or 104, the program proceeds to step 108 where the program
waits until the power switch 72 is opened; the range switch 70 must also
open before the program proceeds from step 108. After sensing the open
condition of the switches, the program proceeds to step 112 where the
program calls a range subroutine illustrated in FIG. 5. In step 114 of the
range subroutine, the lights or LEDs illustrating the current in-tune
range setting are turned on. For example, the table in FIG. 7 lists six
in-tune window widths or ranges along with the corresponding LEDs used to
indicate each range. The spacing between the activated LEDs indicates the
width of the set in-tune range. If the current in-tune range is .+-.49
cents, then the LEDs A and G#, FIG. 6, are turned on.
In the next step 116, a range display timer or timer-2 is set. The range
display timer is set for a duration equal to a selected time for display
of the in-tune range, for example about three seconds or any other shorter
or longer desirable time period for indicating the in-tune range. From
step 116, the program proceeds to step 118 where the program waits until
the range switch 70 is found open whereupon step 120 determines if the
time set in range display timer has expired. If true the program returns
to the step in the main program of FIG. 4 following the point where the
range subroutine was called. Otherwise the program proceeds to step 122
where it is determined if the calibration or range switch 70 is closed.
When the switch 70 is open, the program continues to cycle through steps
120 and 122 until timer-2 expires. Thus when the tuner is powered up, the
in-tune range is displayed for the duration of timer-2.
The musician can change the in-tune range by pressing the range push button
switch 70 during the display of the in-tune range. Closing the range
switch 70 causes the program to branch from step 122 to step 124 where it
is determined if the present set in-tune range is the narrowest range in
the possible in-tune ranges, for example plus or minus five cents in the
table of FIG. 7. If false, the program in step 126 selects the next
narrower range as the set in-tune range. Contrarily if true, the program
in step 128 selects the broadest in-tune range such as plus or minus
forty-nine cents in the example of FIG. 7. From step 126 or step 128, the
program goes back to step 114 to change the in-tune range displayed by the
display 22 to the new setting. Steps 116, 118, 120 and 122 are then
repeated. By repeatedly depressing and releasing the range switch 70, the
musician can successively select narrower tuning ranges until the
narrowest range is selected whereupon the next operation of the switch 70
selects the broadest in-tune range.
Referring back to FIG. 4, after return from the range subroutine in step
112, the program in step 132 determines if the calibration or range switch
70 is closed. From the main program of FIG. 4, the musician by pressing
the range switch 70 causes the program to branch from step 132 to step 134
which calls the range subroutine of FIG. 5 to display the in-tune range at
anytime even when the tuner is detecting a tone. Furthermore re-pressing
the range switch in rapid succession (before timer-2 expires) results in
changing the in-tune range. As described above, the musician can thus
select successively narrower in-tune ranges while timer-2 remains active
in the range subroutine until the narrowest range is reached whereupon the
next depression of the range switch selects the broadest range. From step
134 of FIG. 4, the program returns to the step 132.
When the range switch is found open in step 132, the program in step 138
determines if a tone is being sensed, for example, by determining if the
output of the zero crossing detector 36 is a repeating pattern. When an
incoming tone is present, the processor then begins procedure 140 to
determine the fundamental frequency of the input signal from the
transducer 30. The procedure 140 is a conventional procedure wherein the
arriving output of the zero crossing detector 36 is used by the processor
38 to determine the fundamental frequency. For example, the fundamental
frequency can be determined by first determining the appropriate octave
and then determining the cent value (logarithmic) relative to the note "A"
in that octave. After determining the fundamental frequency of the tone,
the nearest standard musical note on a stored scale of notes is determined
in step 142. Alternatively, step 142 can determine the nearest note by a
conventional algorithm based upon frequency or cent value of one note, for
example "A" in the corresponding octave. Next in step 144, it is
determined if the sensed frequency is above the nearest standard note by
more than the set upper limit of the in-tune range, for example see FIG. 7
wherein the set upper limit is one of the limits of plus 49, 40, 30, 20,
10 or 5 cents above the standard note. If step 144 is true, the red LED of
that standard note is turned on in step 146. Otherwise the program
proceeds to step 148 where it is determined if the sensed frequency is
below the nearest standard note by more than the set lower limit of the
in-tune range, such as below the standard note by more than minus 49, 40,
30, 20, 10 or 5 cents. If step 148 is true the program will proceed to
step 150 where both the red and green LEDs corresponding to the nearest
standard note are turned on. The mixture of red and green gives an amber
color. From step 146 or step 150, the program proceeds to step 152 where
the corresponding LED or LEDs are turned off and on at a blink rate which
is proportional to the absolute value of difference of the tone frequency
from the nearest standard note. If steps 144 and 148 are both false, the
program in step 154 turns on the green LED; i.e., the green LED indicates
that the fundamental frequency of the tone being sensed is within the set
range (plus or minus the corresponding window width of FIG. 7) of the
nearest musical note. Additionally the green note is maintained on steady
and not turned on and off at any blink rate to contrast the green in-tune
condition from the out-of-tune conditions of sharpness (red) and flat
(amber).
After operating the appropriate LED, the program in step 156 determines if
the timer-1 set in step 100 is now expired. If time has expired the
program proceeds to the power down procedure 96 where any LEDs are turned
off. Additionally in the power down procedure 96, the energization of the
processor is placed in a minimum or quiescent power condition, and where
appropriate, other circuit components are turned off. When step 156 is
false, the program in step 158 determines if the power push button switch
72 has been operated. If it is now pressed the unit is powered down by the
power down procedure 96. Thus the power switch 72 acts as a toggle with
the first press turning the unit on and a successive depression turning
the unit off. If false, then the program branches back to step 132 to
begin another cycle.
When no incoming tone is detected in step 138, the program branches to step
170 where the corresponding red LEDs of LEDs 24 for the set range, such as
in the table of FIG. 7, are flashed or blinked. The dual blinking red LEDs
indicate the idle condition, and the spacing between the blinking LEDs
indicates the set in-tune range. A slow blink rate, such a one second or
other long duration delay between flashes, is easily recognized as the
idle state where no incoming tone is sensed.
Aspiring musicians playing wind instruments in bands and orchestras can
improve their intonation by playing long steady tones while watching the
tuner. By practicing various techniques during tuner operation, the
musician can determine which techniques make the instrument more sharp and
which make the instrument more flat. Beginning students are challenged to
keep their instrument in tune even with the widest window. As proficiency
improves, narrower windows are selected to further improve intonation. In
time, students become accustomed to hearing the correct pitches and to
experiencing the necessary techniques needed to play in tune. The
assistance provided by watching the tuner during long tones make learning
to play a band instrument easier and faster.
Since many variations, modifications and changes in detail can be made to
the above described embodiments, it is intended that the foregoing
description and the accompanying drawings be interpreted as only
illustrative and not as limiting to the scope and spirit of the invention
as defined in the following claims.
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