System and method for adjusting MIDI volume levels based on

System and method for adjusting MIDI volume levels based on
US 20070074622Al
(19) United States
(12) Patent Application Publication (10) Pub. No.: US 2007/0074622 A1
Honeywell
(43) Pub. Date:
Apr. 5, 2007
(54)
SYSTEM AND METHOD FOR ADJUSTING
MIDI VOLUME LEVELS BASED ON
RESPONSE TO THE CHARACTERISTICS OF
AN ANALOG SIGNAL
Publication Classi?cation
(51)
Int. Cl.
G10H 7/00
(52)
US. Cl.
(2006.01)
.............................................................. .. 84/645
(76) Inventor: David Honeywell, Lincoln, CA (US)
Correspondence Address:
(57)
JOHN P. O’BANION
O’BANION & RITCHEY LLP
400 CAPITOL MALL SUITE 1550
An apparatus and method of controlling note velocity Within
an electronically controlled player piano in response to the
SACRAMENTO, CA 95814 (US)
ABSTRACT
analog characteristics (level, strength, amplitude, etc.) of a
(21) Appl. No.:
11/241,240
received audio signal encoded With a MIDI (or similar) note
stream. The invention alloWs conventional audio playback
(22) Filed:
Sep. 30, 2005
Which drives the actuation of the keys of the player piano.
devices to be utiliZed as a source for MIDI information
10\
Patent Application Publication Apr. 5, 2007 Sheet 1 0f 5
US 2007/0074622 A1
FIG.1
Patent Application Publication Apr. 5, 2007 Sheet 2 0f 5
US 2007/0074622 A1
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Patent Application Publication Apr. 5, 2007 Sheet 5 0f 5
US 2007/0074622 A1
Apr. 5, 2007
US 2007/0074622 A1
SYSTEM AND METHOD FOR ADJUSTING MIDI
VOLUME LEVELS BASED ON RESPONSE TO
THE CHARACTERISTICS OF AN ANALOG
SIGNAL
the instrument is generated by having the control unit
modify or augment MIDI stream for sending to the actuator
electronics. HoWever, it should be appreciated that even
When the actuator electronics are con?gured to receive a
data stream, such as MIDI, modi?ed MIDI, or augmented
CROSS-REFERENCE TO RELATED
APPLICATIONS
[0001] Not Applicable
MIDI, doing so Would circumvent velocity compensation
and other adaptations performed by the control unit for
improving playback on the particular instrument.
[0010]
STATEMENT REGARDING FEDERALLY
SPONSORED RESEARCH OR DEVELOPMENT
unit not having MIDI functionality.
[0002] Not Applicable
NOTICE OF MATERIAL SUBJECT TO
COPYRIGHT PROTECTION
[0003] A portion of the material in this patent document is
subject to copyright protection under the copyright laWs of
the United States and of other countries. The oWner of the
copyright rights has no objection to the facsimile reproduc
tion by anyone of the patent document or the patent disclo
sure, as it appears in the United States Patent and Trademark
Of?ce publicly available ?le or records, but otherWise
reserves all copyright rights Whatsoever. The copyright
oWner does not hereby Waive any of its rights to have this
patent document maintained in secrecy, including Without
limitation its rights pursuant to 37 C.F.R. §l.l4.
BACKGROUND OF THE INVENTION
[0004]
1. Field of the Invention
Accordingly a need exists for an apparatus and
method for interfacing betWeen a MIDI device and a control
BRIEF SUMMARY OF THE INVENTION
[0011] An aspect of the invention is an interface apparatus
for communicating betWeen a non-midi controller, such as
an olf-the-shelf media player, and a MIDI compatible instru
ment. The apparatus comprises a demodulator con?gured to
demodulate a MIDI data stream from an audio signal input
from the controller, and a signal monitor con?gured to
measure the amplitude of at least a portion of the audio
signal. The apparatus further comprises a processor con?g
ured to control a MIDI volume level of the instrument
according to the measured amplitude of the incoming audio
signal. Controlling the MIDI volume level of the instrument
may be achieved by adjusting at least one MIDI velocity in
the MIDI data stream, or by injecting a MIDI command (eg
a channel volume control message or custom system exclu
sive message).
[0012] Generally, the MIDI data stream comprises a plu
[0005] This invention pertains generally to player mecha
rality of MIDI messages. In one mode of the present aspect,
the processor is con?gured to modify the MIDI messages
nisms for acoustic instruments, and more particularly to
based on at least one stored parameter.
controlling playback characteristics of a digital MIDI based
instrument.
[0006] 2. Description of Related Art
[0007] Acoustic instruments having electronics Which
alloW them to be played autonomously, such as What is often
referred to as “player pianos”, typically have a dedicated
control unit Which receives data from a data storage unit,
[0013]
In one embodiment, the MIDI-compatible instru
ment may be an electronic piano drive system, Wherein the
drive system is con?gured to play notes on a piano according
to the modi?ed MIDI messages. Preferably, the interface
apparatus is con?gured to adjust note velocity of the player
piano in response to the measured amplitude of the audio
signal.
Which is often integrated into the control unit, for controlling
[0014]
the notes and characteristics. The data is normally encoded
?rst channel having a modulated MIDI component and a
in the musical instrument digital interface (MIDI) protocol
second channel having an audio component. Preferably, the
demodulator and the signal monitor only effect or respond to
the ?rst channel.
Which encodes a series of note signals, velocities, and
optionally other information. The control unit stores impor
tant playback characteristics and provides output Which is
often adapted for the speci?c piano (or other acoustic
instrument) being played. It Will be appreciated that all
speci?c characteristics of the device are handled by the
traditional control unit. For example, one of the main
functions of the player-speci?c control unit is to alloW the
In one embodiment, the audio signal comprises a
[0015] The signal monitor is generally con?gured to mea
sure the amplitude of the modulated MIDI component. In a
preferred embodiment, the signal monitor comprises a volt
age comparator or an A/D.
[0016]
In another embodiment, the second channel is
user to adjust the playback volume of the piano.
coupled to a mono-to-pseudo stereo converter to separate the
[0008]
audio component into left and right channels. For example,
the audio component may comprise audio accompaniment
Control units are coupled to actuator electronics in
the acoustic instrument for controlling actuators during
playback. One form of control unit communicates With the
actuator electronics in the instrument using proprietary
hardWare interfaces, Wherein only a speci?c controller from
that manufacturer is compatible With the instrument.
[0009] Alternatively, the controller may modify the
for a MIDI performance.
[0017] In yet another embodiment, the controller com
prises a portable media player, Wherein the media player is
con?gured to output the audio signal via a line out. Alter
natively, the controller may be any device capable of playing
incoming MIDI stream and output another digital data
audio, such as a stereo CD player, or computer.
stream for use by the actuator electronics Within the instru
ment. For example, one form of digital data stream sent to
[0018] In one aspect of the current embodiment, the signal
monitor is adapted to measure the signal strength from
Apr. 5, 2007
US 2007/0074622 A1
media player such that an increase in the signal strength
from the media player affects a corresponding increase in
note velocity of the player piano.
[0019] Another aspect of the invention is a method of
controlling a MIDI compatible instrument. The method
comprises inputting an audio signal comprising a MIDI data
stream, monitoring the audio to measure the amplitude of the
MIDI data stream, and controlling the MIDI volume of the
instrument according to the measured amplitude of the
monitored audio signal. Controlling the MIDI volume may
be achieved by injecting a MIDI command (eg a channel
volume control message or custom system exclusive mes
The audio component may include audio accompaniment,
Which may be output to a pair of speakers.
[0028] Yet another aspect of the invention in an apparatus
for modulating note velocity Within an electronic player
piano in response to received analog signal amplitude. The
apparatus includes means for demodulating an audio signal
to extract a MIDI data stream, means for monitoring the
audio signal to measure the amplitude of at least a portion of
the audio signal, and means for adjusting playback note
velocity of the player piano in response to the amplitude of
the received audio signal. The apparatus may further include
means for actuating the keys of a player piano mechanism in
sage) into the data stream, or by modifying at least one MIDI
velocity in the data stream.
response to said extracted MIDI data stream.
[0020] The method may further include demodulating a
modulated MIDI data stream. In a preferred mode, the MIDI
data stream is monitored and demodulated simultaneously.
rality of MIDI messages. In one embodiment the apparatus
[0021] Generally, the MIDI data stream comprises a plu
rality of MIDI messages. At least one of the MIDI messages
comprises a MIDI velocity message, Wherein in one
parameters.
[0030] In another embodiment, the apparatus comprises
embodiment the MIDI velocity is modi?ed according to the
measured amplitude of the MIDI data stream.
player. The media player, e.g. CD player or mp3 player Will
[0029] Generally, the MIDI data stream comprises a plu
includes means for storing one or more system parameters,
and means for modifying at least one of the plurality of
MIDI messages in response to one of the stored system
means for controlling the audio signal such as a media
have a volume control that adjusts the amplitude of the
[0022] In a preferred embodiment, inputting an audio
signal comprises inputting an audio signal from a media
player. For example, the audio signal may be inputted from
a media player by modulating the MIDI ?le for audio
playback, loading the modulated MIDI ?le onto the media
player, and playing the modulated MIDI ?le for output via
a line out of the media player. The volume on the media
player may be increased to increase the amplitude of the
MIDI data stream.
[0023] In some embodiments, the MIDI ?le is compressed
prior to modulation. Preferably, the MIDI ?le is compressed
as an mp3 ?le at a bit-rate higher than 192 bit/ sec, or other
?le at an equivalent bit-rate.
[0024] The modulated MIDI ?le may be loaded as CD on
to a CD player, Wherein the CD contains the modulated
MIDI ?le. Alternatively, the MIDI ?le may be loaded as a
mp3 on to a mp3 player, Wherein playing the modulated
MIDI ?le comprises decompressing the mp3 ?le for play
back via the line out.
[0025] In another embodiment, at least a portion of the
plurality of MIDI messages are modi?ed according to at
least one stored parameter. The MIDI-compatible instrument
may be controlled via the modi?ed MIDI messages. Fur
thermore, the note velocity of the MIDI-compatible instru
ment may be controlled according to the modi?ed MIDI
velocity.
[0026] In a preferred embodiment, the MIDI-compatible
instrument comprises an electronic piano drive system to
play notes on a piano according to the modi?ed MIDI
messages.
[0027] In another embodiment, the inputted audio signal
comprises a ?rst channel having a modulated MIDI com
ponent, and a second channel having an audio component.
Preferably, only the ?rst channel is the demodulated and
monitored. The audio component of the second channel may
be converted the from mono-to-pseudo stereo, such that the
audio component is separated into left and right channels.
received audio signal.
[0031] The apparatus may further include means for
modulating the MIDI data stream prior to playback on said
media player, and means for compressing the modulated
MIDI data stream prior to playback on said media player. In
embodiments Where the audio signal comprises a MIDI
channel and an audio channel, the demodulating means and
the monitoring means only affect the MIDI channel.
[0032] Further aspects of the invention Will be brought out
in the folloWing portions of the speci?cation, Wherein the
detailed description is for the purpose of fully disclosing
preferred embodiments of the invention Without placing
limitations thereon.
BRIEF DESCRIPTION OF THE SEVERAL
[0033]
VIEWS OF THE DRAWING(S)
The invention Will be more fully understood by
reference to the folloWing draWings Which are for illustrative
purposes only:
[0034] FIG. 1 shoWs a portable media player interfacing
With a Piano Interface Device (PID) installed inside a piano
in accordance With the present invention.
[0035]
FIG. 2 is a How diagram of a MIDI ?le preparation
process for playback by a media player.
[0036]
FIG. 3 illustrates a schematic vieW of a PID in
accordance With the present invention.
[0037] FIG. 4 is a How diagram illustrating a method of
controlling a MIDI compatible instrument using a portable
media player.
[0038]
FIG. 5 illustrates a portable media player interfac
ing With a PID via a Wireless connection in accordance With
the present invention.
DETAILED DESCRIPTION OF THE
INVENTION
[0039] The consumer market is ?ooded With loW-cost,
easy-to-use media players such as portable CD players and
Apr. 5, 2007
US 2007/0074622 A1
MP3 players. Rather than designing a new one to compete
With this market at high cost, the existing market may be
leveraged by use of a Piano Interface Device (PID) With
translates audio signals to MIDI and vise versa, While at the
same time, changing the MIDI velocities based on volume
adjustments made by the music player.
[0040] Referring more speci?cally to the draWings, for
illustrative purposes the present invention is embodied in the
apparatus generally shoWn in FIG. 1 through FIG. 5. It Will
be appreciated that the apparatus may vary as to con?gura
tion and as to details of the parts, and that the method may
vary as to the speci?c steps and sequence, Without departing
from the basic concepts as disclosed herein.
[0041] Referring initially to FIG. 1, a player piano 10 is
verted into a format the media player 20 can understand and
use. This is because the MIDI ?le does not contain the
sampled audio data, but rather contains only the instructions
needed by a midi piano driver, synthesiZer, or like instru
ment, to play the sounds. These instructions are in the form
of MIDI messages, Which instruct the MIDI device Which
sounds to use, Which notes to play, and hoW loud to play
each note. The actual sounds are then generated by the MIDI
instrument.
[0047] The MIDI data stream may be a unidirectional
asynchronous bit stream at 31.25 Kbits/sec. With 10 bits
transmitted per byte (a start bit, 8 data bits, and one stop bit).
There are a number of different types of MIDI messages.
[0048] The bulk of the performance transmission Will
shoWn in accordance With the present invention. The player
occur through Channel Messages that are used to send
piano 10 includes a housing 12 supported by plural legs 14.
A piano interface device (PID) 18, described in further detail
beloW, is preferably located inside the housing 12. Although
musical performance information. Typical messages that are
used in piano driver system include the Note On, Note Oif,
Velocity and Pedal On/Olf messages. Additional messages
the PID 12 may be located external to the piano 10, or
attached to an external surface of the piano 10, it is generally
may include: Polyphonic Key Pressure, Channel Pressure,
Pitch Bend Change, Program Change, and the Control
aesthetically preferable to have the unit inside the piano.
Change (SysEx) messages.
[0042] To alloW a controller such as a portable media
player 20 to act as a control unit and interface With the PID
18, housing 12 may include an access panel 16 that the
media player 20 to connect to one or more input ports 24 of
[0049]
the PID 18. For example, the output from the media player
may have an audio line out 26, Which may be plugged in to
input ports 24 in console 16 via RCA or similar cables 22.
Input ports 24 may be routed internally to the PID 18
location by use of internal cables 38.
[0043] It is to be understood that the player piano 10
further includes a drive mechanism 76 (FIG. 3) for “playing”
the piano. The drive mechanism may be any of those
commonly used in the art, but generally comprises high
precision electromagnetic actuators that operate the keys (88
for the typical acoustic piano) and pedals, based on MIDI
signals from the PID 18. The PID 18 acts as a “black box”
In MIDI systems, the activation of a particular note
and the release of the same note are considered as tWo
separate events. The Note On status byte is folloWed by tWo
data bytes, Which specify key number (indicating Which key
Was pressed) and velocity (hoW hard the key Was pressed).
[0050] The key number is used in the receiving synthe
siZer to select Which note should be played, and the velocity
is normally used to control the amplitude of the note. When
the key is released, the keyboard instrument or controller
Will send a Note Olf message. The Note Olf message also
includes data bytes for the key number and for the velocity
With Which the key Was released. The Note Olf velocity
information is normally ignored.
[0051] Referring to FIG. 2, the MIDI data must ?rst be
encoded or modulated (step 60) to make the MIDI data
to interface betWeen the media player 20 and the piano drive
readable by an olf-the-shelf media player, Existing data
mechanism. In addition, an optical system (not shoWn) may
be used for detecting hoW the piano 10 is manually played
modulation techniques, such as those described in US. Pat.
by a user.
No. 4,953,039, incorporated herein by reference in its
entirety, may be used to encode the MIDI stream to a format
[0044] The system may also optionally include audio
output ports from the PID 18 for simultaneous playback of
music accompaniment out of left right speakers 32, 34. In
addition, if the piano has recording capabilities, MIDI data
from the performance may also be output line out ports 30,
and recorded by the media player or other external recording
device With such capabilities.
[0045] The media player 20 may comprise any number of
readable by most media players. Alternatively, other encod
ing techniques such as Frequency Shift Keying (FSK) and
Phase Shift Keying (PSK) may be employed. FSK utiliZes
frequency modulation to transmit digital data, i.e. tWo dif
consumer items commonly available in the industry, such as
CD, DVD, LD, cassette tape, MP3 player, or even a home
1 Standard MIDI Files.
computer. These players commonly generally have control
[0052] For mp3 playback, the data is further compressed
(step 42) With any number of commercially available codecs
functions to drive audio playback, i.e. play, pause, fast
forWard, reWind, skip etc. In addition, many media or MP3
players Will have a user interface With menu options that
alloWs the user to scan a database of songs, and select a
particular song, album or playlist. Once a song is chosen for
playback, the media player 20 sends a signal to the audio
jack or output 26. RCA or similar audio cables 22 then
transmit the outputted signal to the input of the PID 18.
[0046] Since most olf-the-shelf media players do not have
integrated MIDI functionality, MIDI data is preferably con
ferent carrier frequencies are used to represent binary Zero
and binary one. Data encoded by these techniques may be
compressed and played back at a Wide variety of signal
levels (from quiet to loud). Furthermore, the techniques
described above can manage and play both Type 0 and Type
to a compression format such as MP3, WMA, ACC, Ogg
Vorbis, etc. Because the compression process removes data
from the original ?le, the ?le is preferably compressed at a
high bit-rate so that MIDI signal data loss is minimized.
Mp3 compression standard bit rates of eg 192 bit/sec or
higher Were found to be sufficient in retaining the integrity
of the original MIDI data stream.
[0053] Once the music has been encoded, it can be stored
on the media player for playback (step 44). The user may
Apr. 5, 2007
US 2007/0074622 A1
then select a particular recording of interest, and play the
recording (step 48) having the encoded MIDI ?le in the same
data input step 90 separately and simultaneously. If the audio
signal from the media player has audio accompaniment, it is
Way as Would be done on a typical audio ?le. Regardless of
processed to convert the mono signal to pseudo-stereo at
the encoding method used, the audio output signal Will be
affected by all device commands, including volume. For
mp3 players or the like, an additional decoding step 46 is
performed to uncompress the encoded ?le for playback.
step 92. The accompaniment audio stream is thus split into
left and right channels and output to speakers at step 94.
Alternatively, the pseudo-stereo signal may by output to
another audio source such as an ampli?er, Which then
outputs the signal to speakers.
[0054] FIG. 3 illustrates an exemplary PID 18 in accor
dance With the present invention. The PID 18 includes CPU
[0061]
or microprocessor 60. A memory module 62 may be con
taneously demodulated (98) and monitored (96) for signal
nected to the microprocessor 60 to provide logic means for
The ?rst channel having the encoded data is simul
the microprocessor. In a preferred embodiment, the logic is
level. These signals are then combined at step 100 Where the
CPU controls the MID volume level according to the value
stored on a PIC chip, electrically erasable read-only memory
from the monitored audio signal.
(EEPROM) or like technology. Alternatively, the logic of the
present invention may be stored on a magnetic tape, hard
[0062]
disk drive, optical storage device, or other appropriate data
achieved in a number of Ways. In one embodiment, the CPU
storage device or transmitting device.
adjusts MIDI velocities to re?ect the incoming signal level,
[0055]
The PID 18 has audio input 64 for at least one
audio channel. Preferably, the input comprises tWo channels,
Wherein the ?rst channel 67 contains the encoded MIDI data,
and the second channel 66 contains audio accompaniment.
[0056]
The PID 18 also comprises a signal monitor mod
ule 70 for use in adjusting MIDI velocities in response to the
amplitude of the media player MIDI signal, and a demodu
lator module 72 Which decodes the MIDI data to a readable
form. Both the signal monitor module 70 and demodulator
module 72 operate on the ?rst channel 67 and output to the
CPU 60 for processing.
Control of the MIDID volume level may be
and makes other MIDI adjustments based on the pre-de?ned
system parameters for the particular instrument (piano).
Alternatively, a MIDI command message, such as a channel
volume control message or custom system exclusive mes
sage, may be injected into the data stream to adjust the
volume level in response to a change in the media player
volume level.
[0063] The output from the media player may vary from
player, but Will generally range from 0V to 1.0V rms,
although the method of the present invention may also Work
on ampli?ed signals as Well (eg a 40 Watt audio signal). The
voltage measured from the voltage comparator 70 is pro
[0057] The signal monitor module 70 generally comprises
cessed at the CPU Which may access a lookup table to assign
a voltage comparator or similar device (eg A/D) that
measures the amplitude of the incoming modulated MIDI
a MIDI velocity (or channel volume control message)
according to the measured amplitude. For example, the
signal from the media player.
MIDI standard alloWs for 128 different velocity levels, so
[0058] The CPU 60 is also coupled to a Universal Asyn
chronous Receiver/Transmitter (UART) 74 for transmission
to the piano drive system 76. The PID 18 may also comprise
an audio data output 80, and modulator 78 for outputting
recorded MIDI data from the piano. If the piano has record
ing capability, the piano sends recorded MIDI data to the
CPU via the UART 74. The CPU 60 formats the data, Which
is then encoded/modulated by modulator 78 for monaural
data audio output. The data output 80 may be connected to
a media player’s line input to record piano performances
each of the 128 MIDI velocities may be assigned a corre
(assuming the device has line input functionality).
sponding amplitude measurement. Thus, turning up the
volume media player increases the MIDI velocity of subse
quent notes. Correspondingly, turning doWn the volume
decreases the MIDI velocity of subsequent notes.
[0064] Prior to playback, the system may be calibrated to
the media player 20 input in addition to uploading system
setup parameters, shoWn at step 88. Preferably, a setup CD
or ?le (for mp3 player) having a setup softWare routine is
accessed via the media player. For example, the setup
routine may alloW for determination of the max and min
[0059] Referring further to FIG. 3, the second channel 66
containing audio accompaniment data is coupled to a mono
to-pseudo-stereo converter 68, Which splits the mono input
output voltage of the media player by pressing a set button
at the loWest and highest volume output levels. In addition,
to a left channel 82 and right channel 84 Which connected to
audio out 86. The mono to pseudo stereo converter typically
US. patent application Ser. No. l0/407,869, ?led Apr. 3,
2003, such as adjusting the Weight of the piano keys, may be
input by simply playing a particular track, e.g. “track 15.”
converts the mono audio accompaniment input to pseudo
stereo using a ?lter. For example a shelf ?lter may be used,
in Which loW frequencies are directed to a ?rst (e.g. left)
channel, high frequencies are directed to a second channel.
Alternatively, a comb ?lter may be employed, in Which a
delayed signal is added to the left channel and subtracted
from the right channel. The second channel need not be
encoded or decoded, since the media player is compatible
With the data Without need for further processing.
[0060] FIG. 4 illustrates a method of method of control
ling a MIDI compatible instrument via a media player in
accordance With the present invention. As seen in FIG. 4, the
PID processes the ?rst and second channels 67, 66 from the
controller code for the “Silent Drive” settings as detailed in
The Silent Drive CPU board stores all MIDI settings inter
nally via memory module 62. Thus, there is no need for the
control unit to store and adjust playback parameters. All
settings are controlled by the CPU board, With the media
player acting as a storage and playback device.
[0065] Because the amplitude of the incoming audio
stream is measured separately by the signal monitoring step
98, the demodulated MIDI data from step 96 may be read
independently of the shape or amplitude, i.e. the data may be
read according to period siZe by locating the Zero-crossings
in the signals. Although many compression algorithms may
distort the amplitude of the signal, Zero-crossings are gen
Apr. 5, 2007
US 2007/0074622 A1
erally left in tact as long as the bit-rate is high enough. Thus,
higher bit-rate compression of the MIDI signal Was found to
be effective in
[0066]
After the CPU processes the MIDI data based on
the system parameters and monitored signal in step 98, the
modi?ed MIDI data is transmitted to the piano drive system
via the Universal Asynchronous Receiver/Transmitter
(UART), shoWn as step 102.
[0067]
As an alternative to, or in combination With the
Wired con?guration shoWn in FIG. 1, the PID may be
equipped With an FM receiver as shoWn in FIG. 5 to achieve
2. An apparatus as recited in claim 1, Wherein the pro
cessor is con?gured to inject a midi command into the MIDI
data stream to control the MIDI volume level.
3. An apparatus as recited in claim 2, Wherein the midi
command comprises a channel volume control message.
4. An apparatus as recited in claim 2, Wherein the midi
command comprises a custom system exclusive message.
5. An apparatus as recited in claim 1, Wherein the pro
cessor is con?gured to adjust at least one MIDI velocity in
the MIDI data stream according to the measured amplitude
of the audio signal.
6. An apparatus as recited in claim 5:
Wireless data transmission. In this con?guration, the PID 18
is coupled to an FM receiver 110 that can be programmed to
an unused band on the FM dial (Within FCC limits). The
media player 20 may be coupled to an FM transmitter 112
(such as ItripTM tm by Gri?in Technologies). Other remote
Wherein the MIDI data stream comprises a plurality of
MIDI messages; and
Wherein the processor is con?gured to modify the MIDI
messages based on at least one stored parameter.
transmission means, such as RF or IR, may also be imple
mented.
7. An apparatus as recited in claim 6:
[0068] Although the description above contains many
Wherein the MIDI-compatible instrument comprises an
electronic piano drive system; and
details, these should not be construed as limiting the scope
of the invention but as merely providing illustrations of
some of the presently preferred embodiments of this inven
Wherein the drive system is con?gured to play notes on a
tion. For example, the above description is directed prima
8. An apparatus as recited in claim 7, Wherein the interface
rily at use With a MIDI-compatible piano. HoWever, the
apparatus and methods of the present invention may be used
With any MIDI-capable instrument or device. Therefore, it
Will be appreciated that the scope of the present invention
fully encompasses other embodiments Which may become
obvious to those skilled in the art, and that the scope of the
piano according to the modi?ed MIDI messages.
apparatus is con?gured to adjust note velocity of the player
piano in response to the measured amplitude of the audio
signal.
9. An apparatus as recited in claim 1, Wherein the audio
signal comprises:
present invention is accordingly to be limited by nothing
a ?rst channel having a modulated MIDI component; and
other than the appended claims, in Which reference to an
element in the singular is not intended to mean “one and
only one” unless explicitly so stated, but rather “one or
a second channel having an audio component.
10. An apparatus as recited in claim 9, Wherein the
more.” All structural, chemical, and functional equivalents
to the elements of the above-described preferred embodi
ment that are knoWn to those of ordinary skill in the art are
expressly incorporated herein by reference and are intended
to be encompassed by the present claims. Moreover, it is not
necessary for a device or method to address each and every
problem sought to be solved by the present invention, for it
to be encompassed by the present claims. Furthermore, no
demodulator and the signal monitor effect only the ?rst
channel.
11. An apparatus as recited in claim 10, Wherein the signal
monitor is con?gured to measure the amplitude of the
modulated MIDI component.
12. An apparatus as recited in claim 11, Wherein the signal
monitor comprises a voltage comparator.
13. An apparatus as recited in claim 9:
element, component, or method step in the present disclo
sure is intended to be dedicated to the public regardless of
Whether the element, component, or method step is explic
itly recited in the claims. No claim element herein is to be
construed under the provisions of 35 U.S.C. 112, sixth
Wherein said audio component comprises audio accom
paragraph, unless the element is expressly recited using the
phrase “means for.”
14. An apparatus as recited in claim 7:
Wherein the second channel is coupled to a mono-to
pseudo stereo converter to separate the audio compo
nent into left and right channels; and
paniment.
Wherein the controller comprises a portable media player;
What is claimed is:
1. An interface apparatus for communicating betWeen a
controller and a MIDI-compatible instrument, comprising:
a demodulator;
said demodulator con?gured to demodulate a MIDI data
stream from an audio signal received from a controller;
a signal monitor con?gured to measure the amplitude of
at least a portion of the audio signal; and
a processor con?gured to control a MIDI volume level of
the instrument according to the measured amplitude of
the audio signal.
and
Wherein the media player is con?gured to output the audio
signal via a line out.
15. An apparatus as recited in claim 14, Wherein the signal
monitor is adapted to measure the signal strength from
media player such that an increase in the signal strength
from the media player affects a corresponding increase in
note velocity of the player piano.
16. A method of controlling a MIDI compatible instru
ment, comprising:
inputting an audio signal comprising a modulated MIDI
data stream;
Apr. 5, 2007
US 2007/0074622 A1
monitoring the audio signal to measure the amplitude of
the MIDI data stream; and
31. A method as recited in claim 23, further comprising:
controlling a MIDI volume level of the instrument accord
?ed MIDI messages.
32. A method as recited in claim 31, further comprising:
ing to the measured amplitude of the monitored audio
signal.
17. A method as recited in claim 16:
Wherein the inputted audio signal is modulated; and
Wherein the method further comprises demodulating the
modulated MIDI data stream.
18. A method as recited in claim 17, Wherein controlling
the MIDI volume comprises modifying the demodulated
MIDI data stream according to the measured amplitude of
the modulated MIDI data stream.
19. A method as recited in claim 17, Wherein controlling
the MIDI volume comprises injecting a MIDI command into
the data stream according to the measured amplitude of the
modulated MIDI data stream.
20. A method as recited in claim 19, Wherein the midi
command comprises a channel volume control message.
21. A method as recited in claim 19, Wherein the midi
command comprises a custom system exclusive message.
22. A method as recited in claim 17, Wherein the MIDI
data stream is monitored and demodulated simultaneously.
23. A method as recited in claim 17:
Wherein the MIDI data stream comprises a plurality of
MIDI messages;
Wherein at least one of the MIDI messages comprises a
MIDI velocity message; and
Wherein the MIDI velocity is modi?ed according to the
measured amplitude of the MIDI data stream.
24. A method as recited in claim 17, Wherein inputting an
audio signal comprises:
inputting an audio signal from a media player.
25. A method as recited in claim 24, Wherein inputting an
audio signal from a media player comprises:
modulating MIDI data for audio playback;
loading the modulated MIDI data onto the media player;
and
controlling a MIDI-compatible instrument via the modi
controlling note velocity of the MIDI-compatible instru
ment according to the modi?ed MIDI velocity.
33. A method as recited in claim 31:
Wherein the MIDI-compatible instrument comprises an
electronic piano drive system; and
further comprising playing notes on a piano according to
the modi?ed MIDI messages.
34. A method as recited in claim 24, further comprising:
increasing the volume on the media player to increase the
amplitude of the MIDI data stream.
35. A method as recited in claim 17, Wherein the inputted
audio signal comprises:
a ?rst channel having a modulated MIDI component; and
a second channel having an audio component;
Wherein only the ?rst channel is the demodulated and
monitored.
36. A method as recited in claim 35, further comprising:
converting the audio component from mono-to-pseudo
stereo; and
separating the audio component into left and right chan
nels.
37. A method as recited in claim 36:
Wherein said audio component comprises audio accom
paniment; and
further comprising outputting said audio accompaniment
to a pair of speakers.
38. An apparatus for modulating note velocity Within an
electronic player piano in response to received analog signal
amplitude, comprising:
means for demodulating an audio signal to extract a MIDI
data stream;
means for monitoring the audio signal to measure the
amplitude of at least a portion of the audio signal; and
playing the modulated MIDI data for output via a line out
of the media player.
26. A method as recited in claim 25, further comprising
compressing the modulated MIDI data prior to modulation.
27. A method as recited in claim 26, Wherein the modu
lated MIDI data is compressed as an mp3 ?le.
28. A method as recited in claim 25, Wherein loading the
modulated MIDI data comprises:
loading a CD on to a CD player;
said CD containing the modulated MIDI data.
means for adjusting playback note velocity of the player
piano in response to the amplitude of the received audio
signal.
39. An apparatus as recited in claim 38, further compris
ing:
means for actuating the keys of a player piano mechanism
in response to said extracted MIDI data stream.
40. An apparatus as recited in claim 39:
29. A method as recited in claim 27:
Wherein the MIDI data stream comprises a plurality of
MIDI messages; and
Wherein loading the modulated MIDI data comprises
loading the mp3 ?le on to a mp3 player; and
Wherein the apparatus further comprises:
means for storing one or more system parameters; and
Wherein playing the modulated MIDI data comprises
decompressing the mp3 ?le for playback via the line
means for modifying at least one of the plurality of
MIDI messages in response to one of the stored
out.
system parameters.
30. A method as recited in claim 23, Wherein at least a
portion of the plurality of MIDI messages are modi?ed
according to at least one stored parameter.
41. An apparatus as recited in claim 38, further compris
ing:
Apr. 5, 2007
US 2007/0074622 A1
means for storing one or more system parameters; and
means for injecting a MIDI Volume control command in
response to one of the stored system parameters
42. An apparatus as recited in claim 41, further compris
ing means for controlling the audio signal.
43. An apparatus as recited in claim 42:
Wherein the means for controlling the audio signal com
prises a media player;
Wherein the media player comprises a Volume control;
and
Wherein adjustment of the Volume control adjusts the
amplitude of the received audio signal.
44. An apparatus as recited in claim 43, further compris
ing means for modulating the MIDI data stream prior to
playback on said media player.
45. An apparatus as recited in claim 43, further compris
ing means for compressing the MIDI data stream prior to
playback on said media player.
46. An apparatus as recited in claim 38:
Wherein the audio signal comprises a MIDI channel and
an audio channel; and
Wherein said demodulating means and said monitoring
means only affect the MIDI channel.
47. An apparatus as recited in claim 46, further compris
ing a means for converting said audio channel from mono to
pseudo-stereo for output to at least one speaker.
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