JPS6019198B2 - headphone device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a headphone device for playing back a program source such as a record or magnetic tape and listening to it through headphones.
In a headphone device that localizes the sound image outside the head, similar to listening to a program source through speakers while listening to the program source through headphones, we have created a headphone device that localizes the sound image outside the head more clearly by using special headphones. This is what we provide.

Figure 1 shows how a program source such as a cord or magnetic tape is played back and listened to through speakers indoors. In Figure 1, 1 is a playback device that plays back the program source, and 2 and 3 are respectively Speakers 4 converting left and right signals reproduced by the reproduction device 1 into sound waves; 4 is a listener; 5
, 6 are the listener 4, and the sound waves emitted from the speakers 2 and 3 are heard by the ears 5 and 6 of the listener 4, and the listener 4 produces a sound image at a point outside the head of the listener 4, for example, point A. Recognize.

Figure 2 shows the same program source as in Figure 1 played back by the playback device 1.
This shows how to play it back and listen to it through headphones 7.
As shown in FIG. 2, when listening with headphones 7, the listener 4 recognizes a sound image at a point in the listener's head, for example, point B.

In FIG. 2, reference numerals 8 and 9 indicate left and right electroacoustic transducers of the headphones 7, respectively. As shown in FIG. 2, the present invention provides a headphone device that allows the listener 4 to recognize a sound image outside the head even when listening through the headphones 7 in the same way as when listening through the speakers shown in FIG. be.

FIG. 3 schematically shows the case where the speaker is screened inside the room 10.

As shown in FIG.
, 13 to reach the left and right ears 5, 6 of the recipient 4. Note that the blue line 11 is the path through which the sound radiated from the speaker 3 reaches the ears 5 and 6 earliest, that is, the direct sound path, and the sound rays 12 and 13 are the path through which the sound radiated from the speaker 3 reaches the walls of the room 10, etc. This is the path of indirect sound that is reflected by the sound and reaches the ears 5 and 6, and this indirect cost reaches the ears 5 and 6 later than the above-mentioned direct support sound, and is also reflected when it is reflected by walls etc. Due to the acoustic asymmetry of the room, the indirect sounds reaching the left and right ears often have different phases. However, in the headphone reception shown in FIG. 2, the indirect sound received by the speaker is not included, and therefore, in headphone listening, the sound image is localized in the head.

In view of the above points, the present invention creates a signal corresponding to the indirect sound when listening to the speaker (hereinafter referred to as an indirect green signal), and adds this indirect sound signal to the signal equivalent to the direct sound (hereinafter referred to as the direct sound signal). The present invention provides a headphone device that can more clearly localize a sound image outside the head by applying it to special headphones.

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

In FIG. 4, 15 and 15' are input terminals to which the stereo signals reproduced by the reproduction device are applied, respectively, and 16 and 1
6', 16'', 16 are delay circuits, 17, 17', 17
'', 17 is a phase shifter, 18, 18', 18'', 18 is an adder 19, 19', 19'', 19 is also an adder, 20,
20' is also an adder, and 21 and 21' are resistors.

In FIG. 4, the signal applied to the input terminal 15 is divided into two at point a, resulting in two direct sound signals, and each direct sound signal reaches adders 19 and 19'.

Also, a part of the direct cost signal is branched at points b and b' and sent to adders 19 and 19' via delay circuits 16 and 16'.
The outputs of the delay circuits 16, 16' are fed back to the adders 18, 18' via phase shifters 17, 17'. As described above, delay circuits 16, 16', phase shifters 17, 1
The signal applied to the adders 19, 19' via 7' is
This is a signal (indirect cost signal) corresponding to the intermittent sound in the speaker listening, and this indirect sound signal and the direct green signal are added by adders 19 and 19'. Similarly, the signal applied to the input terminal 15' of the aircraft is also applied to the delay circuit 16'.
, 16 and phase shifters 17'' and I7'', and the indirect green signal and the direct blue signal are added by adders 19r and 19.

The outputs of adders 19' and 19'' are connected to resistors 21 and 21, respectively.
The outputs of the adders 20 and 20' are added to other channel signals via the adders 20 and 20'.The outputs of the adders 20 and 20' are applied to the left and right electroacoustic transducers 8 and 9 of the headphones 7, respectively. As shown in Fig. 4, in the headphone device of the present invention, an indirect blue signal is generated via a delay circuit and a phase shifter, and the indirect blue signal and the direct blue signal are added and applied to the headphones. According to this embodiment,
Since all the signals corresponding to the direct sound and indirect sound shown in FIG. By adjusting 21', the direction of the sound image can be arbitrarily adjusted.

As described above, when the indirect green signal and the direct sound signal are applied to the pond channel and listened to through headphones, the sound image is localized outside the head, but it is difficult to get a clear sense of the direction of the sound image.

Generally speaking, when playing with normal speakers, it is desirable to make the speaker's sound frequency response flat over the entire range from 20 KHZ to 20 KHZ. Even if a speaker has a frequency characteristic, if the speaker is placed 30 degrees in front of the listener 2 and a probe microphone is placed at the entrance of the ear canal of the listener 2 as shown in Fig. 1, the resonance of the ear canal,
Due to the diffraction of sound waves by the head and the diffraction phenomenon by the auricles, the sound wave has a single frequency characteristic with a peak near Uta HZ and 4KH2, and the level difference between the peak value and the low range is between 6 and 17 dB. .

Therefore, when listening with headphones, using headphones with such a sound frequency characteristic can provide the same sense of direction of the sound image as when listening through speakers. In view of the above points, the present invention adds an indirect blue signal and a direct blue signal, and adds this mixed signal to other channels. arc day 2
It is applied to and received by headphones having a sound pressure-frequency characteristic with two peaks between HZ and HZ, and a level difference between the low range and the peak value of about 7 to 7 degrees. Headphones having the above characteristics can be obtained, for example, by having the structure shown in FIG.

In FIG. 5, 30 is a support part, 31 is a headphone case that is slidably attached to the support part 30', 32 is an earmuff made of elastic material such as foamed urethane provided in front of the case 31, and 32a, 32b. 3 is a hole formed in the earmuff 32;
3 is a plate having a center pole 33a, 33b is a center hole of the center pole 33a, 34 is a magnet, 3
5 is a top plate, 36 is a frame, 37 is a diaphragm, 3
8 is a voice coil disposed within the magnetic gap formed between the center pole 33a and the top plate 35;
39 is a damping material housed between the case 31 and the speaker, 40 and 41 are air chambers on the front and rear surfaces of the diaphragm 37, and 42 is a damping material provided at the end of the center pole 33a.

Here, the inertance due to the center hole 33b of the center pole 33a is m^, the mass of the diaphragm 37 is mc, the mass of the voice coil 38 is mv, and the acoustic resistance due to the damping material 42 is r.
^, the acoustic resistance due to the earmuff 32 is r^, the acoustic resistance due to the earmuff 32 is r8, the acoustic resistance due to the damping material 39 is rc,
The inertance due to the holes 33a and 33b of the earmuff 32 is m
,, m2, the acoustic capacity of the air chamber 40 is C, the acoustic capacity of the air chamber 41 is Co, the radiation impedance is z^, and the driving force applied to the vibration system is F, then the equivalent circuit in FIG. It will look like the figure.

In this embodiment, by changing the inertance m by the center hole 33b of the center pole 33a, the fox HZ
By creating a peak in the vicinity and changing the inertance m, m2 due to the holes 32a and 32b of the earpiece 32, 4KH can be obtained.
A peak is created near Z, and further acoustic resistance formations r^, r8,
By controlling the value of rc, the fox HZ, 4KHZ and overall braking are applied, and as shown by the solid line in Fig. 7, 2K
It is possible to obtain a tone frequency characteristic that has a peak at HZ and 4KHZ and a level difference between the peak value and the low frequency range of 6 to 17 degrees. The broken line in FIG. 7 shows the characteristics in a free sound field with the speaker arrangement shown in FIG. The characteristics are almost the 7th
This is close to the solid line in the figure, and as a result, the sound pressure-frequency characteristics of the headphones are the same as those near the ear in a free sound field. It is possible to get close to the frequency characteristics. of course,
Similar characteristics can be obtained by changing other inertances and acoustic resistances, but in any case, 1. We confirmed that if there are two peaks between Uta HZ and Uta HZ, and the level difference between the low range and the peak value is about 17 dB, it can be heard with the same feeling as a natural sound field. FIG. 8 shows another embodiment of the present invention, in which the same parts in FIG. 5 as in FIG. 4 are given the same numbers.

In Fig. 8, 22, 22' are resistors, 23, 23'
is an adder, and the signals applied to terminals 15 and 15' are sent to adders 23 and 23 via resistors 22 and 22', respectively.
' and is applied to the adder 20, 20' as a direct cost signal.

On the other hand, the signals applied to terminals 15 and 15'
4, adder 18, delay circuit 16, phase shifter 17
The signal is divided into two parts via a variable resistor 25, and applied to phase shifters 26 and 26', respectively.
The signal is added to other channels at 8', added to the direct sound signal at adders 20 and 20' as an indirect blue signal, and applied to the left and right electroacoustic transducers 8 and 9 of the headphones 7.

By adjusting the variable resistor 25, the sound image can be changed from inside the head to outside the head or vice versa. As described above, in the present invention, two channels of direct sound signals obtained by reproducing a program source and those signals are supplied to a circuit consisting of a delay circuit and a phase shifter inserted in its feedback path. The indirect green signal is mixed with the direct green signal of the corresponding channel, or the indirect sound-containing signal obtained by distributing this indirect green signal and 1. Adding the indirect sound-containing signal of the added pond channel to the indirect sound-containing signal, and mechanically adding this mixed signal to the pond channel by selecting a component. It is applied to headphones that have two peaks between the Uta HZ and the mother KHZ, and a level difference between the low range and the peak value, which has a sound frequency characteristic of & old ~ 17 ships, and according to the present invention, the sound image This has the advantage that the sound image can be localized outside the head, and the sense of direction of the sound image localized outside the face can be more clearly recognized.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a speaker listening state, FIG. 2 is a schematic diagram showing a headphone listening state, FIG. 3 is a diagram showing a sound path in speaker listening, and FIG. 4 is a diagram showing a headphone listening state in an embodiment of the present invention. A block diagram of the device, FIG. 5 is a cross-sectional view of headphones used in the headphone device of the present invention, FIG. 6 is an equivalent circuit diagram, FIG. 7 is a frequency characteristic diagram of Douon Shoichi, and FIG. 8 is a block diagram of an embodiment. be. ４．・・・Receiver, 5,6．．．Ear, 7．．．
...Headphones, 8,9...Electroacoustic transducer,
16, 16', 16^, 16'''...Delay circuit, 17
, 17', 17^, 17'''... Phase shifter, 18, 18
', 18'', 1 8''' 1 9, 1 9', 1 9''
,1 9'''2 0,2 0'... Adder, 2
1, 21', 22, 22', 27, 27'...
Resistor. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8

Claims (1)

[Claims] 1. Two channels of direct sound signals obtained by reproducing a program source and those signals are supplied to a circuit consisting of a delay circuit and a phase shifter inserted in its return path to obtain an indirect sound signal. The indirect sound-containing signal obtained by mixing the sound signal with the direct sound signal of the corresponding channel or by distributing this indirect sound signal and the indirect sound signal of the other channel, which is respectively applied via a resistive attenuator. This added signal is mechanically adjusted between 1.5 KHz and 5 KHz by selecting the component parts.
It has two peaks, and the level difference between the low range and the peak value is 6 dB ~
A headphone device that supplies sound pressure to a headphone with a sound pressure-frequency characteristic of 17 dB.