Music – Instruments – Electrical musical tone generation
Reexamination Certificate
2002-12-27
2004-02-24
Donels, Jeffrey (Department: 2837)
Music
Instruments
Electrical musical tone generation
C381S059000, C381S103000
Reexamination Certificate
active
06696633
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an electronic tone generating apparatus and signal-processing-characteristic adjusting method for use with the apparatus which can impart an acoustic feel, sounding effects peculiar to a natural musical instrument, etc. to tones to be generated, utilizing acoustic conditions of the interior of a room or other space in which the electronic tone generating apparatus is installed.
The acoustic feedback system has been known which performs tone control, such as extension of reverberation, on the basis of existing indoor acoustic conditions in an electric acoustic manner, and principles of such an acoustic feedback system are illustratively shown in FIG.
1
. In the acoustic feedback system of
FIG. 1
, a speaker
12
and microphone
14
are installed an appropriate distance from each other in the interior of a room
10
, a tone picked up by the microphone
14
is supplied, as a picked-up tone signal, to an FIR (Finite Impulse Response) filter
18
via a head amplifier
16
, to thereby generate a reverberation signal (primarily, initial reflected sound signal). Then, the generated reverberation signal is output via an amplifier
20
to the speaker
12
, so that the amplified reverberation signal is audibly reproduced by the speaker
12
and the thus audibly-reproduced tone is again picked up by the microphone
14
. By repeating such a sequence of the tone processing, the acoustic feedback system permits increase in a tone volume feeling (i.e., increase in a tone pressure level), increase in a reverberation feeling (i.e., extension of a reverberation time), increase in an expansion feeling (i.e., increase in sideways reflected sound energy), etc. Thus, with the acoustic feedback system, it is possible to crease a sound field feeling as if tones were being performed in a large hall or other large space, although the room
10
is small in fact.
Sound field control apparatus employing the above-mentioned acoustic feedback principles perform processing to adjust frequency characteristics of picked-up tone signals generated by the microphone
14
picking up tones, in order to secure stability against undesired howling. Contents of the frequency characteristic correction process, to be performed on the picked-up tone signals generated by the microphone
14
, would differ depending on installed conditions of the microphone
14
and speaker
12
. Thus, where the sound field control apparatus used is of a type designed to perform only predetermined contents of the frequency characteristic correction process, it can not carry out appropriate signal processing if there has occurred a change in the installed conditions of the sound field control apparatus, which would invite inconveniences such as howling. Even in the case where the sound field control apparatus used is of a type capable of varying the frequency characteristic correction process as required, it is necessary for the user to adjust, after installation of the control apparatus, the contents of the frequency characteristic correction process through manual operation in accordance with the installed conditions of the apparatus.
SUMMARY OF THE INVENTION
In view of the foregoing, it is an object of the present invention to provide an electronic tone generating apparatus and signal-processing-characteristic adjusting method for use with the apparatus which can impart an acoustic feeling etc. to a tone to be generated using acoustic conditions in the space of an existing room, and which can also automatically prevent inconveniences, such as howling, even when an installation environment etc. of the apparatus have changed.
In order to accomplish the above-mentioned object, the present invention provides an electronic tone generating apparatus comprising an electronic tone generator for generating tone signals of a first channel and second channel, and a first speaker and second speaker for audibly reproducing tones corresponding to the tone signals of the first channel and second channel, respectively, generated by the electronic tone generator. The electronic tone generating apparatus further comprises: a first microphone provided at a position corresponding to the first speaker; a second microphone provided at a position corresponding to the second speaker; a first signal processing section that performs predetermined signal processing on a picked-up sound signal generated by the first microphone picking up a sound and thereby outputs a processed picked-up sound signal; a second signal processing section that performs predetermines signal processing on a picked-up sound signal generated by the second microphone picking up a picked-up sound and thereby outputs a processed picked-up sound signal; a third speaker, provided at a position corresponding to the first speaker, for audibly reproducing a sound corresponding to the processed picked-up sound signal output by the first signal processing section; a fourth speaker, provided at a position corresponding to the second speaker, for audibly reproducing a sound corresponding to the processed picked-up sound signal output by the second signal processing section; and a setting section that, when an instruction for setting contents of signal processing is given, supplies a measuring sound signal to the third speaker and fourth speaker, and sets contents of the signal processing to be performed by the first signal processing section on the basis of a picked-up sound signal generated by the first microphone during a predetermined measuring period when sounds corresponding to the measuring sound signal are being audibly reproduced by the third speaker and fourth speaker, and contents of the signal processing to be performed by the second signal processing section on the basis of a picked-up sound signal generated by the second microphone during the predetermined measuring period.
In the electronic tone generating apparatus thus arranged, as tones corresponding to tone signals of two channels are audibly reproduced, i.e. as stereo reproduction of the two-channel tone signals (including monaural reproduction of a same tone signal through two channels) is performed, the audibly-reproduced tones are picked up by the first and second microphones to generate picked-up tone signals, then the picked-up tone signals of the first and second microphones are processed by the first and second signal processing sections, respectively, and then the resultant processed picked-up tone signals output from the first and second signal processing sections are audibly reproduced via the third and fourth speakers, respectively. Namely, if each of the first and second signal processing sections performs a reverberation impartment process etc., there can be achieved reverberation impartment etc. utilizing acoustic characteristics of an installation environment, such as the shape of a space, in which the tone generating apparatus of the invention is installed; namely, there can be achieved the so-called “acoustic feedback”. Thus, the present invention can faithfully reproduce sounding effects peculiar to a natural musical instrument, reverberation produceable in a space surrounding a performing stage, etc. Generally, in the case where the acoustic feedback is utilized, it is necessary to adjust contents of processing to be performed by the first and second signal processing sections, in accordance with the installation environment of the apparatus. However, the tone generating apparatus of the invention is arranged to automatically adjust the contents of the processing by means of the setting section once an instruction for adjusting the contents is given. Here, the contents adjustment is performed on the basis of measured results of stereophonically-reproduced two-channel measuring sounds, namely, the contents of the processing to be performed by each of the signal processing sections are adjusted on the basis of the measured result including signal components of the other channel, with the result that the adjustment can be performed taking into account acous
Kawakami Fukushi
Miki Akira
Miyagishima Satoshi
Sawara Shinichi
Shibukawa Takeo
Donels Jeffrey
Yamaha Corporation
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