JPS599273Y2 - Filter circuit in electric musical instruments - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a filter circuit for an electric musical instrument, such as a stringed electric piano.

Pianos have loss in the bridges, soundboard, etc., so the sound decays quickly, whereas string electric pianos have insulators, frames, and other components with low loss, so the sound decays slowly. There were drawbacks.

Therefore, for example, as shown in FIG. 1, a U-shaped frame 4 with a damping material 3 interposed near the tuning pin 1 and pressure bar 2 is arranged, and the string 5 is attached to a first support point 6 provided at the upper part of the frame 4. and a second support point 7, or the string 5 is stretched between a first support point attached to the frame via a damping material and a second support point fixed at a distance therefrom. By doing so, it was possible to extract musical tones with a damping envelope similar to that of a piano through the pickup 8, but as a result, the level of high overtones became extremely low as shown in Figure 2A.

(Figure 2B shows the envelope characteristics of the strings strung on a string pillow installed in the frame.) For this reason, when played on a forte, it is difficult to get a forte feel, and the tone is similar to that of a piano or pianissimo. However, the sound tends to lack the sense of dynamic range (the sense of hearing when the tone changes depending on the size of the sound, such as a round sound in pianissimo and a bright tone in fortissimo), which is the result of an actual piano. was there.

The purpose of the present invention is to provide a string-type electric piano that can move through a damping envelope similar to that of a piano while also providing a sense of dynamic range. In an electric instrument in which a damping material is inserted between the frame and the string vibration is converted into an electric signal by a pickup and the sound is emitted from a speaker, etc., the fundamental frequency of each key is connected to the connection circuit between the pickup and the speaker, etc. The present invention is characterized by intervening a plurality of low-pass filters that cut low-order harmonics or higher, and a bandpass filter having a resonance point between 2000 Hz and 10000 Hz, which is connected in parallel with the low-pass filters.

In this invention, in order to give a sense of dynamic range, (1) the overtone composition (harmonics), especially the overtones (harmonics) above 2000 Hz change, and (2) the harmonics from 2000 Hz to 10
The level of several harmonics among the higher harmonics up to 000 Hz must not be lower than 200 dB from the fundamental wave level (this is because if the level is too low, they will be masked).

) is necessary.

An embodiment of the present invention will be described below with reference to FIG.

PU1... is a certain pickup from a piezoelectric element that generates an output corresponding to the vibration of the string by pressing each key, 10 is an impedance converter, and 11 is a pickup from 2000 Hz to 10
A bandpass filter (BP) with a resonance point up to 000 Hz
F), 12 is a low-pass filter (
LPF).

The resonance frequency of the bandpass filter 11 and the low-pass filter 12 (
Setting examples of fR and cutoff frequency fc are shown in the following table.

As shown in the figure, pick up files PU1 to PU13 corresponding to 13 keys of A to A2...1 to A# to A3
By mixing the pick-up outputs of each group of pickups PU74 to PU85 corresponding to two keys through each impedance converter 10 and passing it through each low-pass filter 12, low overtones that act as masking elements are cut, and only the fundamental frequency of each key is mixed. is highlighted and output,
On the other hand, the outputs of each pickup are all mixed together through an impedance converter 10 and a common bandpass filter 1
2000 Hz to 10000 H by passing through
Only the harmonics up to z are emphasized and output, and the combined output is transferred to the speaker via an amplifier, so that the speaker emits a clear and dynamic musical tone like a piano.

In this way, the present invention has the advantage of being able to produce musical tones that decay quickly and have a sense of dynamic range, like a piano.

[Brief explanation of the drawing]

FIG. 1 is a side view of an example of an electric musical instrument used in the present invention, FIG. 2 is an attenuation characteristic of an electric musical tone, and FIG. 3 is an electric circuit diagram of a filter circuit of the electric musical instrument of the present invention. 3... Damping material, 4... U-shaped frame, 6... First support point, 7... Second support point, 8... Pickup, 10... Impedance converter, 11 ...Band filter, 12...Low pass filter, PU...Piezoelectric element pickup.

Claims (1)

[Scope of utility model registration request] In an electric musical instrument in which strings are stretched on a frame and a damping material is inserted between the support point of the strings and the frame, vibrations of the strings are converted into electric signals by a pickup and sound is emitted from a speaker or the like. In the connection circuit between the key and the speaker, etc., a plurality of low-pass filters are connected in parallel to the low-order harmonics of the fundamental frequency of each key and have resonance points between 2000 Hz and 10000 Hz. A filter circuit for an electric musical instrument, characterized by intervening a bandpass filter.