US 3788649 A
A balance adjusting device for a four-channel stereo system comprises a pair of linear potentiometers mounted one above the other at right angles to one another. The lower potentiometer has its control shaft connected to the bottom of the upper potentiometer which is movable relative to the lower potentiometer. The physical location of the knob on the control shaft of the upper potentiometer is used as an indication of the balance of the sound field of the system.
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Description (OCR text may contain errors)
United States Patent Hirano [451 Jan. 29, 1974 ONE-POINT-BALANCE ADJUSTING DEVICE  Inventor: Takeshi Hirano, lwaki, Japan  Assignee: Alps Motorola Inc., Tokyo, Japan  Filed: Aug. 9, 1972  Appl. No.: 278,962
 US. Cl. 274/1 R, 338/128  Int. Cl ..G11b  Field of Search 338/128; 274/4 D, 1; 179/1 GQ [5 6] References Cited UNITED STATES PATENTS 2,842,645 7/1958 Dalgleish 338/128 3,701,963 10/1972 Kasazima 3,629,775 12/1971 Kindred 179/1 GQ 2,971,762 2/1961 Zorn 274/4 D Primary ExaminerSamuel B. Rothberg Assistant Examiner-A. Jason Mirabito Attorney, Agent, or FirmMueller, Aichele & Gillman ABSIRACT A balance adjusting device for a four-channel stereo system comprises a pair of linear potentiometers mounted one above the other at right angles to one another. The lower potentiometer has its control shaft connected to the bottom of the upper potentiometer which is movable relative to the lower potentiometer. The physical location of the knob on the control shaft of the upper potentiometer is used as an indication of the balance of the sound field of the system.
4 Claims, 3 Drawing Figures PAIENIEDJANZQIQH FIG/ W'l'n ONE-POINT-BALANCE ADJUSTING DEVICE BACKGROUND OF THE INVENTION Heretofore, adjustment of the balance of sound in a four-channel stereo system having four sound sources and called quad sound or in a multi-channel stereo generally depended on the intuition of the person making the adjustment. When the balance adjusting device is located at the center of a listening room, at the four corners of which sound sources are arranged, the difference between the adjustment depending on the intuition of a listener and the real balanced value is comparatively small. The selection of the sound field is also easy. When the balance adjusting device is not located at the center of the listening room, however, it is difficult to obtain real balance and selection of a suitable sound field.
Furthermore, when the location of the balance adjusting device and the location of the listener are different from each other, balance adjustment often requires the listener to move back and forth between the two 10- cations before a desired adjustment can be obtained. This is a very troublesome procedure.
SUMMARY OF THE INVENTION BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a front view of an example of one-pointbalance adjusting device according to a preferred embodiment of this invention;
FIG. 2 is a profile view of the same device shown in FIG. 1; and,
FIG. 3 is a front view of another example of a guide plate.
DETAILED DESCRIPTION A preferred embodiment of the invention will now be described with reference to attached drawing.
In FIGS. 1 and 2, (I) and (II) designate a pair of slide type variable resistors or potentiometers within which the variable resistor (II) is fixed to a separate supporting frame I so that it cannot be moved. The variable resistor (l) is interposed between separate guiding members (not shown), and at the bottom 2 of the variable resistor (l), a sliding shaft 3 of the variable resistor (II) is inserted. Furthermore, on the shaft 4 of the variable resistor (I), a location indicating knob 5 is mounted. A
guiding plate 6 defines a hole 7 for limiting up-anddown and right-and-left movements of the knob 5. The hole 7 is so configurated that it simulates a listening room having sound sources on the four sides. A terminal 8 of the variable resistor (I) is connected to an amplifier for controlling, for instance, right and left sound sources (loudspeakers). Terminals 9 of the variable re sistor (II) are connected to an amplifier for controlling, for instance, front and rear sound sources. Various indicators 10 are used to designate room position, quad balance, room balance, and the like.
The operation of the balance adjusting device will now be described.
In FIG. 1, when a balance between the right and left sound sources is desired to be adjusted, the knob 5 is moved to either one of the right and left directions in the hole 7 of the guide plate which simulates the sound field in the listening room on the four sides of which the sound sources are disposed.
When a balance between the front and rear sound sources is desired to be adjusted, the knob 5 is moved to either of the upward or downward direction so that the knob 5 is set to a suitable point in the hole 7. The movement of the knob 5 in the upward or downward direction moves the entire variable resistor (I) together with the knob 5. The shaft 3 for the variable resistor (II), inserted in the bottom 2 of the variable resistor (I) is thereby moved vertically along the variable resistor (II). In either of FIGS. 1 and 2, portions indicated by broken lines designate new positions of the knob 5 thus displaced.
It is apparent that the above described right-and-left balance adjustment and the up-and-down balance adjustment can be carried out with either of the two being started earlier than the other, or these two adjustments can be carried out simultaneously with the knob 5 being moved obliquely. In either of the cases, since the hole 7 of the guide plate 6 simulates the listening room having four or more sound sources around the room, and because the relative position of the knob 5 in the hole 7 corresponds to an actual listening location of the listener, a person who wants to adjust the balancing device can do it visually without listening at the position of the balance adjusting device.
Furthermore, since the rightward and leftward adjustment and the frontward and rearward adjustment of the balance can be carried out continuously by means of a single knob 5, the troublesome procedure as in the case of conventional devices having independently provided knobs for sound sources is substantially eliminated.
The one-point-balance adjusting device simplifies the adjustment of the balance between the sound sources, and hence it contributes much to the popularization of the multi-channel stereo which previously has been appreciated only by audiophiles.
Furthermore, the hole 7 of the guide plate 6 is not necessarily limited to the above indicated rectangular configuration as shown in FIGS. 1 and 2, but it may be of another configuration having a horizontal groove 11 and a plurality of vertical grooves 12 as shown in FIG.
3. In this case, the shaft 4 of the variable resistor (l) is made into a circular cross-sectional configuration, whereby the shaft 4 may be moved to anywhere in the grooves by shifting the knob 5 manually. When the guide plate 6 having the above described grooves is employed, the variable resistor (I) is supported by the knob 5' and the guide plate 6 and no separate guiding members for the vertical movement thereof is required.
1. A balance adjusting system for controlling the balance of sound of a sound system having a plurality of channels, including in combination:
frame means having a guide plate with an opening therein;
first and second linear slide variable resistors, each having a linearly movable control shaft operable for varying the resistance;
means for mounting said first variable resistor on said frame in a predetermined fixed position relative to said opening;
means for movably mounting said second variable resistor at right angles to said first fixed variable resistor with the control shaft of said second variable resistor being located in the opening in said guide plate, said second variable resistor being movable by said control shaft relative to and along the length of said first variable resistor; and
means for attaching said movable control shaft of said first fixed variable resistor to said second movable variable resistor, whereby movement of said second variable resistor along the length of said first variable resistor by said control shaft slides said control shaft of said first variable resistor to vary the resistance thereof, and movement of said control shaft of said second variable resistor in a direction transverse to the position of said first variable resistor varies the resistance in said second variable resistor with said control shaft of said second variable resistor providing a visual indication of the point of balance for said sound system.
2. The combination according to claim 1 wherein the opening in said guide plate is in the form of a predetermined pattern of guide slots through which the control shaft of said second variable resistor extends.
3. The combination according to claim 1 further in cluding a control knob attached to the control shaft of said second variable resistor.
4. The combination according to claim 1 further including means for connecting said first and second variable resistors with the sound sources of a plurality of channels in a sound system.