JPS63226200A - Measuring instrument for headphone characteristic - Google Patents

Abstract

PURPOSE:To measure a miniature headphone characteristic, in the same state as hearing of a human ear, by adding an acoustic leak impedance element to an artificial ear. CONSTITUTION:An acoustic impedance element 1 formed by an air gap or a thin-diameter opening tube for simulating an acoustic leak is added to an artificial ear 2 having an external auditory meatus part for simulating an external auditory meatus of a human ear, or a ear hole cavity (depression) 7 for simulating an ear hole cavity. That is, the air gap or the thin diameter open tube (thin hole) generates an acoustic leak through the external auditory meatus part of an artificial ear 2 and open air, at the time of attaching a miniature headphone to the artificial ear 2. In this case, by adjusting suitably the thickness, width and length of the air gap or the radius of the thin-diameter opening tube, the acoustic leak quantity to the open air from the external auditory meatus part can be controlled. In such a way, the miniature headphone characteristic can be measured in consideration of the accoustic leak in the human ear.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method for measuring headphones attached to audio playback equipment.In particular, a headphone characteristic measuring device suitable for measuring small headphones worn in the concha cavity of the ear. Regarding.

['Conventional technology]

Conventionally, regarding artificial ears for measuring headphone characteristics, IEC Publication Code 318-1970 (1
970) (IBCPubl 1cations)
51a-i q70). This artificial ear can be used when wearing conventional large over-the-ear headphones, white-on-the-ear headphones, or a telephone receiver.
It is made so that the acoustic load impedance seen from the handset is equal to that of the human ear, and is used to easily obtain characteristics equivalent to those when headphones or a handset are worn on the human ear.

The structure of the measuring artificial ear 51 of the above-mentioned prior art includes a bowl-shaped main cavity 52 and two sub-cavities 55 and 54 with volumes of 18 cc and 15 cc connected to this by a cavity and a thin tube. .

On the other hand, in recent years, portable audio books have developed,
Small headphones (φ15-17) used for this 6
2 is often shaped like the one shown in Figure 3, with the shape shown in Figure 4 GU (
As shown in El) 0), it is used by being attached (inserted) to the concha cavity (or concha cavity) 59 of the external auditory canal 58 of the human ear 57.

However, the outer diameter dimension ψ of these small headphones 62 is so small that they fall into the main cavity 52.
i63, electrical signal input lead ll1164 is artificial ear 5
The problem is that the mounting position is unstable on the slope of the main cavity 52 of No. 1, and a large amount of acoustic leakage (#i leakage) 61 occurs from the outer periphery of the small headphone 61, making it difficult to properly set the shelf. there were.

These small headphones 62 are inserted into the concha cavity 59 of the human ear 57.
When inserted into the small headphone 62 as shown in FIG.
7) and the concha cavity 59 are poorly matched, resulting in acoustic leak 61 as shown by the arrow. This acoustic leak-561 varies from person to person. When a miniature microphone is inserted into the vicinity of the eardrum 60 of the human ear 57, the aforementioned small headphone 62 is further inserted into the concha cavity 59, and an electrical signal is applied to the small headphone 62, a tympan g7 occurs in the microphone.
The frequency characteristics of the equivalent sound pressure applied to &60 are as shown in FIG. In FIG. 5, a shows a case where a small headphone 62 is normally inserted, and shows characteristics that cause an acoustic leak 61.

In addition, b uses clay (or strongly inserts) acoustic leak 61
1 compared to a when sealed to prevent the occurrence of
The sound pressure level below 000Hz is increasing. When a small headphone 62 is attached to an artificial ear, it is easy to create a sealed state, but as shown in FIG. Therefore, in order to appropriately measure the small headphones 62, it is necessary to add an acoustic impedance element section to the artificial ear that simulates the acoustic leak 61 that occurs when the artificial ear is worn on the human ear.

In the conventional artificial ear 51 already shown in FIG. 2, a thin tube (φ0.3, length 9 mm,
An acoustic resistance value of 5000 CO2ohm) 55 is provided. This is to prevent the measurement microphone 56 from being damaged due to pressure changes in the main cavity 52 when the headphones are worn, and to avoid changing the acoustic impedance of the cavities 52, 53, 54. Since it is made to have a resistance value and a thin wire is further inserted during headphone measurement, it is not possible to simulate the acoustic leak 61 described above.

[Problem that the invention seeks to solve]

The artificial ear 51 of the above-mentioned prior art has been designed with consideration given to the measurement of the small headphones 62 in terms of size, shape, and acoustic leakage.
However, as mentioned above, there was a problem that the measurements were inappropriate.

An object of the present invention is to add an acoustic impedance element to the artificial ear that simulates the acoustic leak that occurs when it is worn on the human ear, in order to measure the small headphones 62. Characteristic 4 that matches.

The purpose of this invention is to construct a headphone characteristic measuring device that can measure the characteristics of headphones.

[Means for solving problems]

The above purpose is to install an acoustic impedance element formed of a void or a small diameter open tube to simulate acoustic leak into the external auditory canal to simulate the external auditory canal of the human ear or the concha cavity (indentation) to simulate the concha cavity. This can be achieved by adding it to an artificial ear that has.

[Effect]

The void or narrow open tube (pore) provided in the acoustic impedance element causes acoustic leakage through the external auditory canal of the artificial ear and the outside air when the small headphone is attached to the artificial ear. At this time, the amount of acoustic leakage from the external auditory canal to the outside air can be controlled by appropriately adjusting the thickness, width, and length of the gap or the radius and length of the small-diameter open tube.

Therefore, by adjusting the dimensions of the gap or the small diameter open tube so that the acoustic impedance of the acoustic leak in the concha cavity is equivalent to the acoustic impedance of the acoustic leak in the concha cavity when a small headphone is attached to the human ear, acoustic leak in the human ear can be taken into account. This makes it possible to measure the characteristics of small headphones.

Furthermore, by providing such an fq# impedance element in the artificial ear, the acoustic leakage can be kept constant when measuring small headphones, so stable sub-determination and reproducible characteristics can be expected.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. 1st
In the figure, a small headphone θ to be measured is attached to an artificial ear 2 via an acoustic leak impedance element 1. The artificial ear 2 has an acoustic V (for example, φZ5, length 22
The external auditory canal 3 consists of a terminal impedance 4 consisting of an acoustic tube (for example, φ4, length 4 m) narrower than the external auditory canal 5, and a microphone 5 provided near the terminal end of the external auditory canal 5.

The acoustic leak impedance element 1 is empty as shown in FIG. This was realized using Ji6. At this time, this sky 1
! The acoustic impedance Z8 of J(S is given by equation (1)7
゜ko＼, μ: total air viscosity (dyne-8101) 1: void length cm) t: void thickness sub) W: void @ (m) ρ: density of air (f/m) j : f〒 ω: Angular frequency (rad/s). C shown in FIG.
d is the measured average value of the acoustic leak impedance that occurs when the device is attached to
．． 5crns = 0.08cm, t = α1
(acoustic impedance value calculated as m), and the two agree well. However, it is clear from equation T1) that a similar acoustic impedance value can be achieved with a different combination of W and 1°1.

Further, when a small-diameter opening is used, its acoustic impedance 2° is given by equation (2).

8.

Here, μ: Total air viscosity (dyne/cd) 1: Open tube length (cm) r: Open tube radius (cm) ρ: Air density (t/cm) ω: Angular frequency (rad/s ) π: Pi ratio t, -r=〒. A similar acoustic impedance value can be achieved by appropriately adjusting the radius r and length 1.

Figure 8 shows the measurement results for small headphones. e is an average characteristic measured with a human ear, and f is a characteristic measured using an acoustic leak impedance element 1 with a gap having the above-mentioned dimensions and an artificial ear 2, which agrees well with the measurement result e in a human ear.

As described above, according to this example, by using the acoustic leak impedance element, the measurement characteristics of small headphones using an artificial ear have the effect of obtaining characteristics that match the hearing characteristics of the human ear. be.

[Example 2] This example is based on the acoustic leak impedance element 1 and the artificial ear 2 of the small headbond 62 in the above-mentioned Example 1.
The adapter 8, which has a recess 7 as shown in FIG. 9 that simulates the concha cavity 59 of a human ear 57, is fitted to the artificial ear 2, and the small headphone 62
This is an example of how to reproduce the positioning of

At this time, the shape of the acoustic leak impedance element 1' is adjusted to the outer diameter and shape of the small headphone 62 and the shape of the recess 7 of the adapter 8 of the artificial ear 2, as shown in FIG. 10(A).
CB (Q (I) etc.) The dimension of the -1° gap 60 can be determined by formula (1) or (2) as in Example 1.
) can be calculated using the formula.

Further, when the outer diameter dimension φ of the small headphone 62 is significantly smaller than the inner diameter dimension φi of the recess 67, the acoustic leak impedance element 11 has the shape shown in FIG. As shown in (2), the notch 9 and the small diameter open tube (pore) 1o may be used.

In addition, the above-mentioned void 6, notch 9, and open canal 10 are the concha cavity 5.
The same effect can be obtained even if the groove 9 is directly provided in the recess 7 simulating the groove 9 .

As described above, according to this example, by adding a concavity simulating the concha cavity to the artificial ear and further adding acoustic leak impedance, the characteristics of small headphones measured using the artificial ear are This has the effect of providing reproducible characteristics that match the hearing characteristics of the human ear.

[Example 3] This example will be explained using FIG. 12. In Fig. 12, 11 is a pseudo head, and an artificial auricle 12 is attached to the outer periphery of the artificial head.
is installed. There is an artificial auricle 1 inside the pseudo head 11.
2, an acoustic tube 13 corresponding to the external auditory canal is provided, an acoustic tube 14 having a diameter smaller than that of the acoustic tube 16 is connected to the terminal end of the acoustic tube 13, and a microphone 14 is attached to the side surface near the terminal end of the acoustic tube 13. Ears 16 are provided. This artificial ear 16 was filed in Japanese Patent Application No. 57-814 by the same applicant as the present invention.
A patent application has been filed as No. 01.

A recess 17 simulating the concha cavity 59 is provided in the artificial auricle 12 of the artificial ear 16, the acoustic leak impedance element 1 is inserted into the recess 17, and a small headphone 62 is worn. Regarding the shape of the acoustic leak impedance element 1,
By using the same shape as in the first and second embodiments described above and making it into an adapter-like structure that can be attached and detached, measurements of conventional ear-memory type and ear-white type headphones can be performed using the same measuring device.

Further, when the small headphone 62 of a specific size is used exclusively, a cutout or an open tube corresponding to the acoustic leak impedance element 1 may be provided in the recess 17 of the artificial auricle 12 corresponding to the concha cavity.

Furthermore, the same effect can be obtained by using an adapter 8 provided with a recess 7 simulating the concha cavity 59 described in the second embodiment as a structure in which the artificial auricle 12 can be attached and detached.

By using the pseudo-head 11, it is possible to measure the sound emitted from the small headphones 62, including the influence of the human head, and it is possible to grasp the characteristics in a situation very close to the state in which the headphones are actually worn on the human ear. There is.

Furthermore, it is preferable to provide the simulated guide on the simulated torso.

, 11.

〔Effect of the invention〕

According to the present invention, by adding an acoustic leak impedance element to the artificial ear, the measurement of the characteristics of small headphones, for which measurement was inappropriate in the past, takes into account the acoustic leakage that occurs when the small headphones are attached to the human ear. This can be done under the same conditions as the human ear. Acoustic leakage that occurs when listening with human ears varies depending on the shape of the listener's pinna, and has the disadvantage of mismatching with the shape of small headphones and greatly varying depending on how the small headphones are worn, but the average By using an artificial ear equipped with an acoustic leak impedance element that simulates the acoustic leak of the human ear, the acoustic leak remains constant, making it possible to measure the characteristics of small headphones stably and reproducibly. .

In addition, if we eliminate individual differences in acoustic leakage in the human ear and prepare several types of elements with different acoustic leakage impedance values, 1. This has the effect of being able to evaluate changes in the characteristics of small headphones due to the amount of acoustic leakage.

12°

[Brief explanation of drawings]

Fig. 1 is a sectional view of an acoustic leak impedance element and an artificial ear according to an embodiment of the present invention, Fig. 2 is a structural sectional view of a conventional artificial ear, and Fig. 3 is a front view, a sectional view of a human ear, and a sectional view of a human ear. 4 is a front view and a side view of the small headphone, FIG. 5 is a characteristic diagram when the small headphone is worn on the human ear, and FIG. 6 is the main feature of the present invention. Figure 7 shows a comparison of the acoustic impedance of the acoustic leak occurring in the human ear and the acoustic impedance of the acoustic leak impedance element shown in Figure 6. The figure shows a comparison of the characteristics measured by the human ear and the headphone characteristic measuring device of the present invention. FIG. 12 is a structural diagram of an acoustic leak impedance element attached to the artificial ear shown in the figure, and FIG. 12 is a structural diagram of an artificial ear according to another embodiment of the present invention. 111', 1#...acoustic leak impedance element,
2...Artificial ear, 6...gap, ω...width of gap,!
... Length of gap, t... Thickness of gap, 7... Concave simulating concha cavity, 8... Adapter, 9... Notch, 10... Open tube, 16 ... Artificial ear, 12 ... Artificial auricle, 17 ... Recess provided in artificial auricle, 51 ... Artificial ear of conventional technology, 55 ... Thin tube, 61 ... f-resonating -
ku, 62...small headphones, 57...human ears, 59
... Concha cavity, a, b... Characteristics of small headphones in the human ear, C... Acoustic impedance of acoustic leak in the human ear, d... Acoustic impedance of the acoustic leak impedance element, e ...Characteristics of a small headphone measured by the human ear, f...Characteristics measured by the headphone characteristic measuring device of the present invention. 15゜Takul eyes 5th flash 5th liquid number CHz) 4th concave (A) t 5> ?Flash 1st θ concave (,Q) (5)(C1(D
) 11th (A) J7・2

Claims (1)

[Scope of Claims] 1. A device for measuring the characteristics of headphones, characterized by comprising an artificial ear equipped with an acoustic impedance element that simulates the acoustic leak that occurs when headphones are worn on human ears. measuring device. 2. A headphone characteristic measuring device, wherein the acoustic impedance element according to claim 1 comprises a gap, a notch, or an open tube. 3. A headphone characteristic measuring device characterized in that the artificial ear according to claim 1 has an artificial pinna or a concave that imitates the pinna or concha cavity of a human ear. 4. A headphone characteristic measuring device characterized in that the artificial ear according to claim 1 is installed in a pseudo-head equivalent to a human head.