DE9310205U1 - Headphones with variable listening event location - Google Patents

Description

HEADPHONES WITH VARIABLE LISTENING EVENT LOCATION

The invention relates to a headphone with variable auditory event position, which is based on two sound transducers, each in front of the auditory canal and starting from there, arranged in the viewing direction at the bottom and front and controlled via a control loop.

It is known that the development of stereo headphones with the essential requirement of sound neutrality has been almost exhausted for about 15 years. Using conventional recorded sound, these offer an unnatural sensation of the location of fictitious sound sources, called in-head localization.
15

Efforts have recently been made to overcome the in-head localization characteristic of conventional (studio) headphones, which contradicts the natural listening experience, in favor of a front localization that is adapted to the natural listening experience. This was achieved, for example, by means of directional mixing consoles based on expensive, digital filter technology, which were implemented at great expense for recording studio purposes. This also results in disadvantageous, unnatural sound distortions.

Another solution that has already been used previously involves a so-called free-field or diffuse-field equalization of the entire head-related recording-playback transmission path, which primarily contributes to a tone-neutral headphone sound reproduction. The relevant individual post-equalization is, just like the first example of the directional mixing consoles implemented, very costly and labor-intensive. Achieving pre-localization of auditory events without binaural individual equalization is controversial and highly dependent on the individual.

- &Igr;.&Lgr; ^:

A successful and cost-effective solution for realizing pre-localization of auditory events using stereo headphones is finally described in WO-91/01616, which goes back to the applicant. These headphones essentially involve the effort mentioned at the beginning. Accordingly, a pre-sensation of sound events is achieved by a technically surprisingly simple measure, namely by the fact that the sound transducers of the stereo headphones, starting from the conventional arrangement of sound transducers, are arranged opposite the ear canal, shifted forward and predominantly downward. By iteratively changing the arrangement of the sound transducers in the headphone housing that rests on the ears, the quality or extent of the pre-localization of stereophonic sound structures can be optimized and, if necessary, even adapted to the individual, binaural hearing ability of the respective user (DE-PS 4110902).

DE-PS 4310075 describes an equalization guideline for headphones with front localization of auditory events and, for example, sound transducers placed at the bottom and front, which is comparable to the usual design of headphones (with top-of-the-head localization). This is essential for four-channel headphones, for example for multi-channel playback of HDTV or DOLBY surround sound signals (based on WO-91/01616), since in this case, in addition to the representation of an auditory event quarter sphere located at the front (in the horizontal and median plane, from the frontal plane at the front), the sound image quality (regardless of location) should be constant.

Surprisingly, in special applications of the four-channel headphones, it has been found that when the position of the auditory event varies in the above-mentioned horizontal/median/vertical planes, a volume fluctuation occurs, which is remedied according to the invention with an adapted level distribution using a control loop.

The present invention, as embodied by the features of claim 1, therefore solves the problem of achieving a constant listening volume even when the listening event position varies by means of four-channel headphones that have two separate stereo loudspeaker pairs.

Advantageous further developments of the invention are characterized by the subclaims.

It is also advantageous that the choice of the impedance values of the resistors used for each control channel is made with reference to the inherent impedance of the headphone transducers to be controlled.

The advantages that can be achieved with the help of the invention over the prior art are that

a) which require little implementation effort and

b) when regulating/adjusting the listening event level, a constant listening volume is maintained.

The invention will be explained in more detail below using the drawing ; it shows:

Fig. 1 shows the side view and top view of a left auricle using a probe placed behind the ear.

Small headphone concept for pre-localization of auditory events.

The elements 1 to 6 shown in Fig. 1 describe a stereo headphone according to the invention with variable auditory event position, which is based on a stereo headphone with pre-location of auditory events. In Fig. an open, right-hand headphone capsule 4 is shown, without ear pads and visible dust protection foam rubber, which a sound transducer holder 7 (including an injection-molded bridge part equipped with felt) as well as a centrically (intersection of the FRONT axis with LOT) and decentrally (mainly at the bottom and at the front) arranged

Sound transducers 5 and 6 are shown. The sound transducer 6 (when used alone) creates the auditory event at the front, whereas the sound transducer 5 creates the usual auditory event located at the top of the head, for example by playing stereo sound signals from a compact disc (via amplifier). In this case, the use of headphones with two binaural sound capsules is logically intended (see elements 4 to 7 also for the left ear).

The power supply and control of the sound transducers 5 and 6 is carried out by means of a volume control circuit 1; two are provided for each headphone capsule. For the right headphone sound channel shown in Fig. 1, a signal INPUTi is present (L stands for input level at the input of the volume control circuit 1 ), which is fed to two special voltage dividers equipped with active and/or passive components 2 and 2a.

In a simplified implementation of the volume control circuit 1, the voltage division function is created using a stereo potentiometer with reversed connection assignment. These stereo potentiometers usually have three connection contacts, whereby the assignment of the two contacts (levels > 2, 2 _a ) can then look like this:

- Supply of transducer 5 >> use of contacts I and II;

- Power supply of sound transducer 6 >> use of contacts II and III. This means that when the potentiometer is turned, a voltage/level division and thus also a variable auditory event position is achieved depending on the voltage/loudspeaker control factor, but this is given without taking into account the listening volume, which is preferably independent of the control of loudspeakers 5 and 6 and remains the same or constant. In Fig. 1, element 3 is inserted in level control circuit 1 for this purpose, which represents the reverse, i.e. inverse (= "-1">> X ^-1 ) contact assignment. The common input signal INPUTi or INi is thus divided via the two stereo potentiometer levels 2 and 2 _a into OUTi or OUTPUTi and OUT ₂ or OUTPUT ₂ (then supply line to the sound transducers 5 and 6).

In order to remedy this non- constant listening volume according to the invention, a stereo rotary step switch (with additional, active amplification electronics) is preferably created in such a way that the values of individual resistors, per stage and per stereo rotary step switch level (per element 2 and 2 _a ) are firstly inversely proportional (per level) and secondly, with regard to the sum of the total resistance, calculated from the resistance values "2 plus 2 _a ", are not constant . This means that when "fading" the given auditory event positions of the headphones from "top of the head" to "front" (or vice versa), a special, targeted level reduction is created as a function of the control of the loudspeakers 5 and 6. For example, using a linear stereo potentiometer, the resulting resistance values would be "Rtotal = R2 + R2a = 17 Ohm + 13 Ohm = 30 Ohm", whereas with a volume control circuit optimized according to the invention, the resulting total resistance values would be greater or less than 30 Ohm (across all control levels 1 to X).

The volume control electronics 1 are either implemented outside the headphones or the headphone capsules 4 (including controllability using a remote control, among other things) and/or installed directly in the headphone capsules 4 behind the sound transducer holder 7.

Furthermore, due to the higher, impractical cable feed effort, a four-channel light wave and/or infrared sound signal transmission is provided from the control electronics 1 to the headphone transducers 5, 6.

Claims (6)

Aixs &rgr;&tgr;? ii cIxe 1 . Headphones with variable auditory event position, characterized in that a control circuit, via a voltage mixing function, feeds the two sound transducers provided in a headphone capsule for external ear sound and creates a constant listening volume for different auditory event situations. 2 . Headphones with variable auditory event position according to claim 1, characterized in that two sound transducers [5, 6], per headphone capsule [4], are fed via a level or volume control circuit [1] equipped with active and/or passive electronic components [2, 2a] and divides the input signal into two output signals. 3 . Headphones with variable auditory event position according to claim 2, characterized in that the two output signals of the volume control circuit [1], which feed the two sound transducers [5, 6], provide a sound transducer voltage sufficient to maintain a constant sound event volume when the auditory event position varies and preferably deviate from a simple voltage division. 4 . Headphones with variable auditory event position according to one or more of claims 1 to 3, characterized in that a stereo potentiometer and/or stereo step switch takes over the voltage division with reduced implementation effort. 5 - Headphones with variable auditory event position according to claim 4, characterized in that the stereo potentiometer is connected in inversely proportional manner with respect to its two connection contact or resistance levels, whereby the sum of the resulting stereo potentiometer total resistance of the two levels remains constant when the potentiometer position is varied. 6 . Headphones with variable auditory event position according to one or both claims 4 and 5, characterized in that the stereo step switch is provided with step resistances deviating from the inverse proportionality with regard to its two connection contact or resistance levels, based on values, whereby the sum of the resulting stereo step switch resistance is not constant when the stereo step switch position is varied, whereas the listening volume remains constant. V . Headphones with variable auditory event position according to one or more of claims 1 to 6, characterized in that preferably in the capsules of the headphones [4] two sound transducers are arranged, one directly in front of the auditory canal or centrally [5] and the other in the direction of vision and predominantly below the auditory canal [6] by means of a sound transducer holder [7]. Headphones with variable auditory event position according to one or more of claims 1 to 7, characterized in that the transmission of the four audio signal channels preferably takes place by means of optical fiber and/or infrared FM and/or infrared PCM transmission systems, based on a light carrier enclosing the entire audio signal information. Headphones with variable auditory event position according to one or more of claims 1 to 8, characterized in that a volume control circuit [1] is controllably or adjustably housed in the headphone capsules [4] or externally.