SPEECH INTELLIGIBILITY

In rooms intended for listening to speech, its intelligibility is of primary importance. Speech intelligibility is the relative or percentage of speech elements correctly received by listeners out of the total number of spoken ones. The elements of speech are syllables, sounds, words, phrases. Accordingly, syllabic, sound, verbal, semantic intelligibility of speech is distinguished.

Determination of speech intelligibility is carried out using special articulation tables read by the announcer in the test room. Therefore, this research method is called articulation. Samples of articulation tables of syllables are given in App. IV (Table I, 2). The number of listeners is determined by the size of the room. Usually, at least 20 listeners participate in the study, evenly distributed throughout the room. Listeners write down the elements of speech on the forms as they heard them. Then the listeners change places and write down the following articulation tables. Statistical processing of the obtained results makes it possible to evaluate the intelligibility of speech in various places in the room.

In rooms where syllabic intelligibility is equal to or greater than 85%, speech intelligibility is considered excellent. Poor speech intelligibility (about 40% syllabic intelligibility) corresponds to approximately 90% intelligibility of phrases.

An accelerated method for assessing speech intelligibility has been developed - the method of choice. It differs in that words similar in sound are grouped into tables (see Appendix IV, Table 3). The announcer reads out only one word from each group of similar words, and the listeners, having tables, mark the word that, in their opinion, was read out, then determine the percentage of correctly received words. This method requires less trainee training, but is less accurate than articulation.

Speech intelligibility is affected by the following factors: reverberation time, speech volume, the ratio of extraneous noise (inside the room or penetrating from the outside) and the speech volume level, as well as the shape and size of the room. Taking into account these factors, the method for calculating speech intelligibility proposed by Knudsen is based. So, with a reverberation time of about 0.5 s, speech intelligibility is greatest; as the reverberation time increases, speech intelligibility deteriorates by about 10% for every second of time.

The best speech intelligibility is observed at a speech level of 70-80 dB. If the levels of speech and interfering noise are approximately the same, speech intelligibility is reduced to 60%.

Based on the foregoing, the reverberation time T cannot increase indefinitely, since the intelligibility of sound signals deteriorates. Therefore, for rooms, depending on the sound source, the maximum volume should be set according to Table. 2, and depending on this volume and reverberation time - the maximum intelligibility of speech (Fig. 46).

The Knudsen method allows you to evaluate speech intelligibility without conducting articulation tests, that is, at the design stage.

The accuracy of the method is not high, and recently a number of more advanced methods for calculating speech intelligibility have been proposed, the authors of which are Reichard, Nize and others.

The clarity and intelligibility of speech in the hall, as well as the quality of perceived musical sounds, depends on the strength of the direct sound and the first useful sound reflections. These are reflections that arrive at the listener with a delay compared to direct sound, no more than 0.05 s for speech and 0.15 ¸ 0.20 s for music. The energy of early sound reflections, like the energy of direct sound, refers to useful sound energy. "Useless" refers to all the rest of the sound energy, which is the reverberant background in the room.

Rice. 46. ​​Influence of reverberation time T on speech intelligibility P depending on the volume of the room, m (according to Knudsen):

a - 707; b - 11300; in - 45200

The resulting effect of the perception of sound in a room in terms of its intelligibility depends on the magnitude of the relative effect on the listener of the useful and "useless" parts of the sound energy. This ratio is called the intelligibility coefficient, the value of which is determined by the formula (15)

where - sound absorption at 100% room occupancy for frequencies of 500-2000 Hz;

α - average sound absorption coefficient under the same conditions;

The path of the first reflections from the sound source to the observation point, which arrived during the first 0.05 (0.15¸0.20) s;

α 1 , α 2 , ... α n - sound absorption coefficients of surfaces from which direct useful reflections came.

Comprehensibility and intelligibility of speech

Speech intelligibility- the main characteristic that determines the suitability of the path for speech transmission. The direct determination of this characteristic can be carried out by a statistical method involving a large number of listeners and speakers. Quantification of speech intelligibility - intelligibility.

speech intelligibility the relative or percentage number of correctly received speech elements out of the total number transmitted along the path is called. The elements of speech are complex sounds, words, phrases, numbers. Accordingly, they distinguish syllabic, sound, verbal, semantic and digital intelligibility. There is a statistical relationship between them. In practice, syllabic, verbal and semantic intelligibility is mainly used.

To measure intelligibility, special tables of syllables have been developed, taking into account their occurrence in Russian speech. These tables are called articulatory. Intelligibility is measured using a trained team of listeners without hearing and speech impairments by conducting subjective-statistical examinations. In this case, measurements can be carried out by various methods, for example, the scoring method, the method for determining the percentage of correctly received words, etc.

The relationship between speech intelligibility and its intelligibility is given in Table. 16.1. In this table, speech intelligibility is rated in four grades:

1) excellent, if the intelligibility is complete, without asking questions;

2) good, if the listeners have a need for separate re-questions of rare words or individual names;

3) satisfactory, if the listeners reported that it was difficult for them to understand, there were frequent repeated questions;

4) the maximum allowable, if repeated interrogations of the same material were required with the transmission of individual words by letter at full strain of hearing.

Table 16.1

The reasons for the decrease in intelligibility are acoustic noises in the room, interference from reverberation and diffuse sound, insufficient amplification of the signals of the primary sound source.

Sound and sound amplification systems must provide the required intelligibility of speech. When transmitting information programs, holding rallies and meetings, excellent speech intelligibility is required, which is provided with 80% syllabic and 98% verbal intelligibility. For dispatcher communication, full speech intelligibility (satisfactory intelligibility) is obtained with 40 ... 50% syllabic and 87 ... 93% verbal intelligibility. Therefore, when calculating the dispatching communication, they are guided by smaller values ​​of intelligibility than when calculating systems of wide application.

There is a relationship between speech intelligibility, reception conditions, and characteristics of the transmission paths, which was established using the formant theory developed by Fletcher and Collard.

Areas of energy concentration in a particular part of the frequency range are called formants. Their location depends both on the position of the sound in a word or phrase, and on the individual characteristics of the human articulatory apparatus. Each sound has several formants. Formants of speech sounds fill the frequency range from 150 to 7000 Hz.

It was agreed to divide this frequency range into 20 bands, in each of which the probability of the appearance of formants is the same. These frequency bands are called stripes of equal legibility. They have been defined for a number of languages, including Russian. It has been established that the probability of the appearance of fomants obeys the additivity rule. With a sufficiently large amount of sound material, the probability of the appearance of formants in each band is 0.05.

Formants have different levels of intensity: they are higher in voiced sounds than in deaf ones. As the level of acoustic noise increases, formants with low levels are masked first, and then with higher ones. As a result of masking, the probability of formant perception decreases. The coefficient that determines this decrease in to- th band, is called the coefficient of perception or intelligibility to f. In other words, in to-o-band probability of receiving formants

where is the formant perception coefficient to f depends on the level of sensation, which in turn is determined by the difference between the average spectral level of speech In r in the band of equal intelligibility and the spectral level of noise and interference in the same band H w:

E f \u003d V p -V sh.(16.2)

The coefficient of perception (intelligibility) can be determined from the graph shown in fig. 16.1. This graph shows the levels of sensation E f and their corresponding perception coefficients to f.

For sensation levels 0-18 dB to f can be determined approximately by the formula k f =(E+ 6)/30.

Figure 16.1. Integral distribution of speech levels.

In general, for each band of equal intelligibility, the perception coefficient will be different. The overall formant intelligibility in the speech frequency range is determined from

(16.3)

Figure 16.2. Dependence of syllabic intelligibility on formant.

The relationship between formant and other types of intelligibility was found experimentally. Such dependence for syllabic intelligibility is shown in Fig. 16.2. This figure shows that almost complete intelligibility of speech (syllabic intelligibility is 80%) is obtained by receiving only half of all formants (formant intelligibility is 0.5), which indicates the redundancy of speech and the combinational ability of the brain.

The definition of speech intelligibility for sounded rooms is primarily carried out for points of the sounded surface with a minimum level of direct sound and a maximum level of acoustic noise. The spectral level of direct sound from a listener located at such a point,

,(16.4)

where In rm- spectral level of speech at the microphone (determined from the tables);

,

where r m - removing the microphone from the speaker; - spectral level of speech at a distance of 1 m (determined from reference tables); - gain index (path index - the difference between the sound levels created by the loudspeaker of the sound reinforcement system at the listener's ear and the primary sound source at the microphone input).

These data are determined for each band of equal intelligibility. For the same bands, the spectral levels of noise and interference at the listening position

(16.5)

where In ash- spectral level of acoustic noise (determined from reference tables); In p- spectral level of interference from speech (speech self-masking),

(16.6)

where is the correction for interference from diffuse sound (R- acoustic ratio at the design point); N d- diffraction correction, correction for reflection from the listener's head (determined from reference tables); - correction for reverberation interference (T p- reverberation time).

The level of acoustic noise does not depend on the tract index, while the level of speech interference increases with increasing tract index (16.4), (16.6). Therefore, to increase the level of sensation, it is advisable to increase the tract index. After reaching the condition

V p \u003d Vash + 6 (16.7)

a further increase in the tract index is not rational, since the level of sensation in the limit can increase by only 1 dB. This condition, taking into account (16.4), (16.6), (16.7), determines the path index

(16.8)

This path index is called rational. It is mainly determined by the maximum value of the acoustic ratio at the calculated point and the reverberation time.

With rational amplification, it follows from (16.5) that

H w \u003d V p + 1, (16.9)

those. acoustic noise contribution In ash the overall level of noise and interference is negligible.

The resulting expressions allow you to determine the intelligibility and intelligibility of speech. To do this, according to formulas (16.4), (16.6), (16.9), the levels of speech, noise and interference are found, and then, according to formula (16.2), the level of sensation of formants is determined E f for each band of equal legibility. The graphic dependence presented in fig. 16.1, allows you to find the coefficients of intelligibility to f, corresponding to the received values E f. General formant intelligibility BUT in the speech frequency range is found from expression (16.3), and the corresponding syllabic intelligibility is determined from fig. 16.2. The intelligibility of speech is determined by the table. 16.1.

Acoustic characteristics of speech

A speech signal is a complex frequency and amplitude modulated noise process characterized by the following parameters: sound pressure, frequency range, speech signal level, dynamic range.

Sound pressure - additional pressure that occurs in the medium during the passage of sound waves. Propagating in a medium, a sound wave forms condensations and rarefactions, which create additional changes in pressure in relation to its average value. Sound pressure is the main quantitative characteristic of sound. Sound pressure level - the value of sound pressure measured on a relative scale, referred to the reference pressure p0 = 20 μPa, corresponding to the hearing threshold of a sinusoidal sound wave with a frequency of 1 kHz:

Dynamic range - the ratio of the maximum value of the instantaneous signal power Pmax to the minimum value of the instantaneous power Pmin, or in logarithmic units:

In this expression, the value of Pmax is taken to be such a value of the signal power, which can be exceeded only during 2% of the total transmission time, and the value of Pmin is taken to be such a value of the signal power, which must be exceeded during 98% of the total time. Dynamic range of audio broadcasting program transmission signals:

Speaker's speech - 25..35 dB;

Artistic reading - 40..50dB;

Vocal and musical instruments - 45..55dB;

Symphony orchestra - up to 65dB.

The energy spectrum of a speech signal is the frequency range in which the main energy of the signal is concentrated (Figure 2.2). It follows from the figure that speech is a broadband process, the frequency spectrum of which extends from 50..100 Hz to 8000..10000 Hz. It has been established, however, that the speech quality is quite satisfactory when the spectrum is limited to frequencies of 300..3400 Hz. These frequencies are taken as the boundaries of the effective speech spectrum. With the specified frequency band, syllabic intelligibility is about 90%, intelligibility of phrases is more than 99%, and a satisfactory naturalness of sound is maintained.

Figure 2.2 - Spectral composition of speech.

The most important parameter characterizing the spectrum (distribution of energy or amplitude over frequencies) of a speech signal are formants (Figure 2.3), which are defined as the concentration of energy in a limited frequency region. The formant is characterized by frequency, width and amplitude. The frequency of the formant is taken as the frequency of the maximum amplitude within the formant. In other words, the formant is some amplitude burst on the spectrum graph, and its frequency is the peak frequency of this burst.

Figure 2.3 - Formants of speech.

Speech intelligibility and methods for measuring it

speech sound acoustic intelligibility

Intelligibility is the ratio of the number of correctly received speech elements to the total number of transmitted elements. Since sounds, syllables, words and phrases are taken as elements, respectively, sound, syllabic, verbal, phrasal, semantic and formant intelligibility are distinguished. All of them, when testing the same system, will be expressed by different numerical values, since the percentage of correct estimates for a foreseen message is always higher than for an unforeseen one - the degree of foresight when listening to a phrase is higher than when listening to individual words.

Intelligibility is measured with the help of a special trained team of listeners by conducting objective statistical examinations.

Table 2.1 shows the relationship between intelligibility and intelligibility.

Table 2.1

The intelligibility of speech is a phonetic characteristic of intelligibility and is determined in the process in the negotiation process of untrained listeners.

Clarity grade:

Excellent - complete clarity without asking questions;

Good - there is a need for separate re-questions of rare words or names;

Satisfactory - it is difficult to talk, repeated questions are needed;

Maximum allowable - multiple re-questions of the same material are required with the transfer of individual words by letter at full strain of hearing.

So, in accordance with GOST 50840-95, understanding of speech transmitted over a communication channel with a high tension of attention, repeated questions and repetitions is observed with syllabic intelligibility of less than 25-40%, in the case of syllabic intelligibility of less than 25%, there is illegibility of a coherent text (communication breakdown). Considering the relationship between verbal and syllabic intelligibility, it can be calculated that communication breakdown will be observed when verbal intelligibility is less than 71%.

The task of estimating the channel of speech information leakage and, accordingly, the degree of its security is precisely reduced to measuring or calculating speech intelligibility and comparing the value with the required one. The protection of information itself consists in reducing the intelligibility of speech in the channel of information leakage by weakening the level of the useful signal.

articulation method. This method is based on assessing the degree of fulfillment of the main requirement - ensuring the intelligibility of the transmitted speech. A measure of intelligibility is a value defined as the ratio of the number of correctly received speech elements to a sufficiently large total number of transmitted ones and expressed as a percentage or in fractions of a unit - speech intelligibility. The method for determining these quantities is called the articulation method.

Legibility measurements are carried out by specially selected and trained teams. The tests consist of transmitting a series of tables consisting of articulatory elements of speech, recording what was heard and calculating the average percentage of correctly received elements. Depending on the articulation tables used (syllabic, verbal, phrasal), the following types of intelligibility are measured:

intelligibility of sounds - D;

intelligibility of syllables - S;

legibility of words - W;

intelligibility of phrases - J.

At the end of the transmission and reception cycle, the received and transmitted tables are compared and the percentage of correctly received elements is calculated.

For a sufficiently large volume of measurements, i.e. when the percentage of intelligibility is calculated over a large number of accepted syllables (on the order of several hundred and more), the influence of various random factors and the subjective characteristics of individual operators is averaged and articulation measurements give stable, objective and repeatable results. The intelligibility values ​​obtained from such measurements are an estimate of the quality of the path under test. This estimate characterizes the tested path (in our case, the airspace of a dedicated room + building structures). Due to the lack of semantic meaning in the transmitted syllables, the influence of many subjective factors is largely eliminated.

It has been established that for each national language all types of intelligibility: sound - D, syllabic - S, verbal - W and phrasal - J are connected with each other by unambiguous functional dependencies of the form S=f(D), W=f(S), J= f(W), which remain unchanged for any transmission conditions on real-life paths. From the fact that there are unambiguous dependencies for such types of intelligibility as D, S, W, J, which can be directly measured using articulation tables, we can conclude the following: measurements with different types of tables do not complement each other, but are simply equivalent to each other (in the sense of the information about the quality of the path that can be obtained as a result of these measurements). This means that it is not necessary to measure all types of intelligibility. It is enough to measure only one of these quantities, and the rest can be obtained from the corresponding ratios or graphs. Therefore, the most appropriate is the measurement of the type of intelligibility, which in this particular case is the most economical, i. with the same measurement accuracy, it requires a minimum expenditure of effort, money and time for their production. However, when conducting articulation tests, the use of syllabic and verbal intelligibility is more preferable, because. provide less dependence of test results on the subjective characteristics of articulators (for example, such as memorability).

The above experimental studies have shown the following relationships between different types of intelligibility of Russian and English speech:

Figure 2.4a - Dependence of the intelligibility of syllables on the intelligibility of formants.

Figure 2.4b - Dependence of the intelligibility of syllables on the intelligibility of sounds.

Figure 2.4c - Dependence of the intelligibility of words on the intelligibility of sounds.

Figure 2.4d - Dependence of the intelligibility of phrases on the intelligibility of syllables.

Figure 2.4e - Dependence of the intelligibility of phrases on the intelligibility of words.

The advantage of the articulation method, which led to its wide practical application, is that this method gives an objective quantitative assessment of the quality of speech transmission according to its main feature - intelligibility, and this assessment can be carried out with a fairly high degree of accuracy.

Thus, the limiting value of formant intelligibility, at which it is possible to understand the meaning of a speech message, is 15%, which corresponds to 25% of word intelligibility. The task of estimating the leakage channel is reduced to measuring or calculating the intelligibility of speech in the analyzed channel and comparing the obtained value with the required one.

All methods for measuring speech intelligibility are conditionally divided into subjective and objective. “Conditionally” - since there are at least two interpretations of the “subjectivity-objectivity” of the method.

First interpretation. According to the first interpretation, with the subjective method, speech intelligibility is assessed according to the results of a single experiment - hence the inevitable influence on the measurement results of the characteristics of speech and hearing of the people participating in the tests. To objectify method, you need to carry out many experiments with various speakers and subscribers, and then average the measurement results.

The intelligibility of transmitted speech is evaluated on a five-point scale of the International Advisory Committee for Radiocommunications (CCIR):

· illegible;

· legible at times;

legible with difficulty;

legible;

quite legible.

An example of the objectification of measurements of speech intelligibility are modern methods for assessing the quality of speech transmission over communication paths, set out in the State Standard of the Russian Federation, according to which at least 3 speakers and 4-5 auditors must participate in the tests, satisfying a number of conditions (the absence of pronounced defects speech and hearing, lack of training). For example, when evaluating phrase intelligibility, the speaker reads one table of phrases at a normal pronunciation rate (one phrase in 2.4 seconds) and the second table at an accelerated pace (one phrase in 1.5-1.6 seconds). The pause between phrases should be 5-6s. The auditor listens first to the table read by the speaker at a normal pace, then the table read by the same speaker at an accelerated pace. The correctness of the reception of phrases is determined by the receipt transmitted over the telephone channel. The measurement cycle consists of transmission by all speakers of 10 tables each, and acceptance by all auditors of all transmitted tables. A phrase is considered incorrectly received if at least one word is received incorrectly, omitted or added. Phrase intelligibility is determined by calculating the percentage of correctly received phrases for normal and accelerated pronunciation rates according to the formula

where j i - the result of a single measurement of phrase intelligibility,%; N is the number of single measurements; J H - phrasal intelligibility at a normal rate of pronunciation,%; J Y - phrasal intelligibility at an accelerated rate of pronunciation,%.

Methods like the one described above are called articulatory. When using them, it is necessary to have special articulation tables, the compilation of which is an independent difficult task. Another disadvantage of articulation methods is the long testing time, which is several weeks.

The obvious advantage of articulation methods is their simplicity, which allows operators with a relatively low level of technical skill to participate in the tests.

Second interpretation. In the second interpretation of the “subjectivity-objectivity” of the method, all methods are called subjective, in which a person is an integral part of the measuring path, and objective methods are those in which the entire measuring process is carried out by instruments without the participation of human senses. To this end, the transmitting and receiving operators must be replaced by artificial equivalents ("artificial voice", "artificial ear").

tone method. This paper describes two methods for measuring speech intelligibility based on this interpretation of objectivity. In the so-called "tonal method" several announcers are replaced by a single artificial voice that generates pure tones. An artificial voice is an ordinary loudspeaker without a cone, excited by a tone generator in such a way that the level of sound pressures generated at different frequencies would correspond to the formant spectrum curve. The transmission room and the reception room of speech signals are artificially noisy - thereby providing the required signal-to-noise ratio, at which the system under test should function normally. Reception of information is still carried out by a team of auditors. Wherein the task of auditors is simplified: instead of comprehending and recording the sound combination they hear, they are only required to determine whether the signal is heard at a given frequency or not. In addition, operators must measure the feel of the formants - this is done quite simply by introducing positive or negative attenuation into the communication path. If a signal is heard, the attenuation is made positive until the signal is no longer audible. Conversely, if the signal is not heard, the attenuation is made negative until the signal becomes audible. Further determination of the value of speech intelligibility is carried out analytically, using graphs and simple formulas.

Thus, the tonal method, in contrast to the articulation method, can be attributed to indirect methods legibility measurements.

Advantages of the tonal method:

1) articulation tables are not used;

2) a significant reduction in measurement time.

Disadvantages of the tonal method:

1) increased requirements for technical literacy of the personnel organizing the tests;

2) the person has not yet been withdrawn from the measuring system.

As indicated in, the tonal method is regulated by GOST No. 8031-56. By now, perhaps, this GOST has been replaced by a more advanced one.

objective method. In another method called "objective" use both an artificial voice and an artificial ear. In this method, as we see, the person is completely removed from the measuring system. It should be noted that the artificial ear is a device common in the acoustic measurement technique used in testing telephones and which makes it possible to reproduce the acoustic load created on the telephone by the natural ear. Thus, it is possible to measure the sound pressure created by a sounding telephone in the ear.

The general order of measurements in this case is as follows:

1) With the help of a noise generator and a loudspeaker, a noise level is created corresponding to the operating conditions of the receiving end of the path under test. Measure the noise level at the output of the artificial ear in the critical frequency band of hearing, and the average frequency of this band is equal to the frequency of the measuring tone.

2) The noise generator is turned off, and instead, a tone signal is fed to the input of the "artificial voice - transmission channel - artificial ear" path. The sound intensity level at the microphone is taken such that, at conditional zero on the attenuation controller, the sound pressure distribution corresponds to the formant spectrum curve.

3) By adjusting the attenuation, the level of the signal at the output of the artificial ear is the same as the level of the noise. The damping controller readings are the result of measuring the level of sensations.

The objective method is more accurate and faster than the tonal method, it does not require operators (announcers and auditors). Finally, the objective method fundamentally makes it possible to fully automate the measurement procedure on the basis of modern computers.

Like the tonal method, the objective method is indirect, i.e. speech intelligibility is assessed not by counting correctly recognized speech units, but by conducting a special measurement experiment with sound signals in the form of tone and band noise, during which the levels of sensations in several frequency bands are measured. Speech intelligibility is calculated based on the results of experimental measurements.

In view of the undeniable advantages of the objective method, as well as due to the above-mentioned fundamental similarities between TPR and TKUI, at present, the objective method in one modification or another is used both in assessing the quality of communication channels and in assessing the effectiveness of protecting speech information. Therefore, it is advisable to consider in detail the idea underlying the indirect methods discussed above for measuring speech intelligibility. At the same time, it is also advisable to recall some provisions of the psychophysiology of speech and hearing, on the use of which indirect methods are based.

Similar information.

What is speech intelligibility

Today, there are more than 500,000,000 people in the world with a hearing impairment. That is why the problem of hearing aids is very common.

Hearing sounds and listening to speech are two completely different concepts, although they have the same physical characteristics ( frequency spectrum, acoustic pressure level). When talking about a decrease in the level of human auditory activity, a certain number of criteria are implied, one of which is the intelligibility of human speech. Therefore, hearing aids are required to provide high-quality amplification of sound signals, as well as to improve the intelligibility of human speech.

Speech intelligibility is a set of continuous work of the ear organs, auditory nerves and the center of hearing in the cerebral cortex. The failure of at least one of these components entails changes in speech intelligibility. Without focusing on the brain, it is safe to assume that properly selected and adjusted hearing aids compensate for hearing loss qualitatively.

The science that deals with the problems of hearing has established that in the space of frequencies of acoustic vibrations, human speech has a peculiar spectrum. After the research, the so-called " speech intelligibility peaks". Thanks to such data, it became possible to distinguish human speech from background sounds, thereby improving the quality of overall intelligibility. Hearing aids are primarily aids in communicating with people.

Improving speech intelligibility

There is a common misconception that the creation of hearing aids is limited to a fairly simple solution - a microphone, an amplifier and a speaker. What could be even easier? What is the purpose of producing complex computer models that cost about ten and even hundreds of thousands of rubles? Therefore, there are such people who provide themselves and their relatives with products, so to speak, of their own or " homemade» production, which, of course, cause irreparable damage and harm to the hearing of a hearing-impaired person. For a similar reason, it is not recommended to buy hearing aids on the side or " from the hands”, but only in specialized medical centers.

In our country, you can find on sale hearing aids from different manufacturers from very cheap to expensive beautiful ones. Hearing aids of the company widex» these are original, convenient, high-quality and easy-to-use devices. Thanks to the latest innovations in digital signal processing and electronics, today's hearing aids " widex» are so tiny that they fit comfortably in the ear canal.

Hearing Aids " widex» have the ability to shift the range of human speech intelligibility. This feature is available for all types of hearing aids. widex»: both for behind-the-ear hearing aids, and for in-the-ear and in-ear hearing aids.

The problem of hearing prosthetics and increasing the intelligibility of a person’s speech should be solved under the strict supervision of specialists (audiologist) in specialized centers where individual characteristics of a person are taken into account and, most importantly, a person’s desire to regain lost hearing.