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Online hearing tests conducted in home settings on a personal computer (PC) require prior calibration. Biological calibration consists of approximating the reference sound level via the hearing threshold of a person with normal hearing.
The objective of this study was to identify the error of the proposed methods of biological calibration, their duration, and the subjective difficulty in conducting these tests via PC.
Seven methods have been proposed for measuring the calibration coefficients. All measurements were performed in reference to the hearing threshold of a normalhearing person. Three methods were proposed for determining the reference sound level on the basis of these calibration coefficients. Methods were compared for the estimated error, duration, and difficulty of the calibration. Webbased selfassessed measurements of the calibration coefficients were carried out in 3 series: (1) at a otolaryngology clinic, (2) at the participant’s home, and (3) again at the clinic. Additionally, in series 1 and 3, puretone audiometry was conducted and series 3 was followed by an offline questionnaire concerning the difficulty of the calibration. Participants were recruited offline from coworkers of the Department and Clinic of Otolaryngology, Wroclaw Medical University, Poland.
All 25 participants, aged 2235 years (median 27) completed all tests and filled in the questionnaire. The smallest standard deviation of the calibration coefficient in the testretest measurement was obtained at the level of 3.87 dB (95% CI 3.524.29) for the modulated signal presented in accordance with the rules of Bekesy’s audiometry. The method is characterized by moderate duration time and a relatively simple procedure. The simplest and shortest method was the method of selfadjustment of the sound volume to the barely audible level. In the testretest measurement, the deviation of this method equaled 4.97 dB (95% CI 4.535.51). Among methods determining the reference sound level, the levels determined independently for each frequency revealed the smallest error. The estimated standard deviations of the difference in the hearing threshold between the examination conducted on a biologically calibrated PC and puretone audiometry varied from 7.27 dB (95% CI 6.717.93) to 10.38 dB (95% CI 9.1112.03), depending on the calibration method.
In this study, an analysis of biological calibration was performed and the presented results included calibration error, calibration time, and calibration difficulty. These values determine potential applications of Webbased hearing tests conducted in home settings and are decisive factors when selecting the calibration method. If there are no substantial time limitations, it is advisable to use Bekesy method and determine the reference sound level independently at each frequency because this approach is characterized by the lowest error.
Sound systems of modern home electronic equipment, such as a personal computer (PC), tablet, or smartphone, offer opportunities to conduct hearing examinations at low cost and on a large scale [
Hearing tests conducted remotely in home settings on PCs can be divided into 2 groups depending on the necessity of conducting prior calibration. The examinations which do not require prior calibration are usually screening tests represented by speechinnoise tests [
However, most hearing tests, including the basic examination in the form of puretone audiometry, require prior calibration of the system, and its omission leads to significant measurement errors [
Honeth et al [
The error analysis of the puretone audiometry conducted on a PC calibrated by the biological method showed significant influence of the calibration error [
The application of puretone audiometry based on biological calibration depends significantly on the measurement error. Because of the much larger error of biological calibration than tolerance required by the standards (ie, ±3 dB in the frequency range 125 Hz to 5 kHz [
This paper presents 7 methods of measuring the calibration coefficients. All measurements were performed in reference to the hearing threshold of a normalhearing person. For each method, the measurement error was determined, as well as the timeframe for its calibration and the difficulty level. Next, 3 methods were proposed for determining the reference sound level on the basis of these calibration coefficients and an error analysis was conducted for each.
The proposed methods of biological calibration consist in measuring the calibration coefficient that describes the threshold sound level of the reference person. Seven calibration methods were proposed: (1) calibration using an amplitudemodulated signal, (2) calibration using 2 sounds differing by 5 dB, (3) calibration using 2 sounds differing by 2 dB, (4) the ascending method with a 5dB step, (5) the ascending method with a 2dB step, (6) calibration based on Bekesy audiometry using the continuous signal, and (7) calibration based on Bekesy audiometry using an amplitudemodulated signal. In methods 15, the assessment was conducted for the following frequencies: 125 Hz, 500 Hz, 1 kHz, 2 kHz, 4 kHz, 6 kHz, and 8 kHz. In methods 6 and 7, the frequency was changed in a continuous way from 62.5 Hz to 16 kHz. The sound signal was presented bilaterally.
In the calibration with amplitudemodulated signal (method 1), the presented signal was amplitudemodulated using rectangular envelope with frequency of 1 Hz and modulation depth of 100%. The task of the reference person was to set the volume marker in such a way that the generated sound be barely audible. The step of the volume marker was 1 dB.
During calibration with 2 sounds differing in intensity (methods 2 and 3), 2 tone signals with a given frequency and a duration of 1 s were presented in turns. The task of the reference person was to set the volume marker in such a way that the louder of the 2 sounds was still audible, and the quieter inaudible. In method 2, the signals differed by 5 dB, whereas in method 3, the difference was 2 dB. The step of the volume marker was 1 dB.
The ascending method (methods 4 and 5) was based on the ascending algorithm used for the assessment of the hearing threshold in puretone audiometry [
During calibrations based on Bekesy audiometry, the frequency of a presented signal was increased at the speed of 1 octave/60 s, simultaneously with the change of its intensity. The task of the reference person was to press a button on hearing the signal and keep it pressed for as long as the sound was audible. The intensity of the sound was reduced at a speed of 2 dB/s when the sound was audible, and increased at the same speed when the sound was inaudible. The value of the calibration coefficient was determined as the mean of the values of the sound intensity at which a change in the status of the button occurred, after rejecting the outliers on the basis of the Grubbs’ test [
All 7 methods were implemented in Java technology in the form of applets embedded in a Web browser. The calibration coefficients expressing the sound intensity in decibels, together with the duration of examinations, were recorded in the database. On completion of all the tests, the participant filled in an offline questionnaire (
In addition to the 7 methods of measuring the calibration coefficients, 3 methods were proposed for determining the reference sound level: (1) the reference sound level determined independently for each frequency depending on the value of calibration coefficient measured at this frequency, (2) the reference sound level estimated by a model fitted to calibration coefficients determined at all frequencies, and (3) as (2) except the model was fitted to a single coefficient determined at the frequency characterized by the smallest measurement error.
Participants were recruited offline from coworkers of Department and Clinic of Otolaryngology, Wroclaw Medical University, Poland, using facetoface prompting from September 2012 to March 2013. The eligibility criteria were age younger than 35 years, lack of previous hearing problems, owning headphones and a PC at home and basic skills to operate it, and the willingness to participate in the research. Each participant performed calibration using all 7 methods 3 times. In series 1, the study was carried out in a sound booth with the use of notebook Dell Vostro 1310 with Microsoft Windows 7 operational system and Technics RPF290 headphones; in series 2, each person was asked to perform calibration on their own home computer using their own headphones in the quietest conditions possible, preferably late in the evening or at night to minimize background noise level and to create conditions close to those in the sound booth; and series 3 was the repetition of examinations from series 1. Because of the relatively long duration of the series, the participants were informed about the option of taking a break when they felt tired, and most of the participants took advantage of this. In series 1 and 3, puretone audiometry was performed with the use of a clinical audiometer Interacoustic AD229e and TDH39 headphones calibrated in accordance with ISO 3891:1998. The hearing threshold was determined by using the ascending method in accordance with ISO 82531:2010. Additionally, based on the puretone audiometry, the bilateral hearing threshold was calculated by choosing for each frequency the threshold of the ear that heard better at this particular frequency.
A testretest analysis of calibration coefficients was conducted, as well as 1way ANOVA for measurement duration and difficulty. Calibration errors were determined by means of variance estimation. Statistical analyses were performed on the basis of confidence intervals that were estimated in the same way. Estimation of the variance was conducted based on measurement variances and their confidence intervals calculated from the variance and the sample size [
The 25 participants (11 men, 14 women), aged between 22 and 35 years (median 27), who took part in the study completed all the examinations and filled in the questionnaire. All participants were skilled in computer use. On the basis of series 1 and 3, a testretest analysis was conducted. For each method, a mean difference, standard deviation of the difference and corresponding confidence intervals were calculated (
Mean difference and standard deviation of the difference with corresponding confidence intervals at
Method  Difference (dB), 
Difference (dB), 






Right ear  –0.38 (–1.13, 0.38)  5.40 (4.92, 5.99) 

Left ear  0.13 (–0.62, 0.87)  5.34 (4.86, 5.92) 

Both ears  –0.13 (–0.65, 0.40)  5.37 (5.02, 5.77) 

Bilateral  –0.35 (–1.04, 0.34)  4.92 (4.48, 5.46) 





Modulated signal  –0.09 (–0.78, 0.61)  4.97 (4.53, 5.51) 

Dual tone (5 dB)  1.05 (0.00, 2.11)  7.54 (6.87, 8.37) 

Dual tone (2 dB)  1.20 (0.06, 2.35)  8.18 (7.45, 9.07) 

Ascending (5dB step)  –0.15 (–1.00, 0.70)  6.05 (5.51, 6.71) 

Ascending (2dB step)  –0.10 (–0.80, 0.60)  5.00 (4.55, 5.54) 

Bekesy (continual)  0.88 (0.19, 1.57)  4.92 (4.48, 5.46) 

Bekesy (modulated)  0.63 (0.09, 1.17)  3.87 (3.52, 4.29) 
Durations of calibration in relation to the calibration methods are presented in
The shortest times were obtained for the modulated signal method and both dual tone methods (5 and 2 dB), which consisted in selfadjusting the volume marker. The mean duration of calibration based on the ascending method with the step of 5 dB was comparable to the duration of calibration using both Bekesy methods (continual and modulated). In the Bekesy methods, the outliers are those examinations that were paused momentarily.
The degree of difficulty of the methods were significantly different (
Calibration durations for all 7 calibration methods in series 13 (N=25). The horizontal line in each box represents the median, top and bottom box borders represent 75th and 25th percentiles, respectively; crosses represent outliers. MOD: modulated signal; 2TONE5: dual tone (5 dB); 2TONE2: dual tone (2 dB); ASC5: ascending (5dB step); ACS2: ascending (2dB step); BEK: Bekesy (continual); BEKM: Bekesy (modulated).
Difficulty ratings of the calibration methods evaluated by 25 participants (0=easiest; 10=hardest). The horizontal line in each box represents the median, top and bottom box borders represent 75th and 25th percentiles, respectively; crosses represent outliers. MOD: modulated signal; 2TONE5: dual tone (5 dB); 2TONE2: dual tone (2 dB); ASC5: ascending (5dB step); ACS2: ascending (2dB step); BEK: Bekesy (continual); BEKM: Bekesy (modulated).
There were 3 methods used to determine the reference sound level. Two were based on the frequency response model of a common sound card and headphones set. Therefore, comparison of methods requires prior evaluation of the model that was conducted using standard deviation of the residual. The mean standard deviation of the residual was calculated on the basis of the differences between the model and the coefficients in series 2 after taking into account the measurement error of coefficients, bilateral hearing threshold of the reference person, and measurement error of this threshold. Measurement error of calibration coefficients and the measurement error of bilateral hearing threshold were calculated from the testretest differences between series 1 and 3. The standard deviation of the residual estimated in this way describes the difference between the actual coefficients and those calculated for the model fitted on their basis. This standard deviation is independent of the measurement method and the hearing threshold of the reference person. Detailed calculations are presented subsequently. A detailed list of all equations can be found in
Let us assume that
where mean(
Let’s assume that random variable
It is worth noting that random variables
variance(
The mean value of the determined coefficient is close to the mean value of the real coefficient mean(
Bearing in mind that
Coefficient
variance(
which, on the basis of equations 5, 7, and 9, allows to estimate variance of the random variable
Following further calculations, a model based on an Aweight filter was assumed [
For each calibration conducted in series 2, variance(
Standard deviation of residual of the model based on Aweight filter estimated by means of measurements at 8 frequencies carried out by 25 participants.
Calibration method  Model residual (dB), SD 
Modulated signal  7.11 
Dual tone (5 dB)  6.58 
Dual tone (2 dB)  6.36 
Ascending (5dB step)  6.50 
Ascending (2dB step)  7.18 
Bekesy (continual)  6.52 
Bekesy (modulated)  5.69 
The model of the frequency response fitted to a sample set of calibration coefficients.
The error of determining the reference sound level was estimated on the basis of intermediate values: the standard deviation of the bilateral hearing threshold in a population of people with normal hearing, the measurement error of calibration coefficients, and, in the case of methods based on the model, previously calculated error of the model expressed by the standard deviation of the residual. The standard deviation of the bilateral hearing threshold was determined from audiograms after eliminating the assessment error on the basis of the testretest examination. Measurement error of calibration coefficients was also calculated from a testretest examination.
The standard deviation of the bilateral hearing threshold measured by the means of puretone audiometry is affected by the population variability and measurement error. Knowing, that measurement error is equal to the standard deviation of the bilateral hearing threshold difference in testretest examination (
(measured bilateral threshold SD)^{2}=(real bilateral threshold SD)^{2}+(bilateral threshold testretest difference SD)^{2}/2 (11)
Standard deviation of the bilateral hearing threshold measured in series 1 by 25 participants, estimated measurement error and standard deviation of the real bilateral hearing threshold after eliminating the measurement error with corresponding confidence intervals at
Frequency  Measured threshold (dB), 
Measurement error (dB) 
Real threshold (dB) 







At125 Hz  5.58 (4.35, 7.76)  3.48 (3.17,3.86)  4.35 (2.98, 6.73) 

At 250 Hz  5.42 (4.23, 7.53) 

4.15 (2.80, 6.47) 

At 500 Hz  4.41 (3.44, 6.13) 

2.70 (1.34, 4.76) 

At 1 kHz  3.82 (2.98, 5.31) 

1.57 (0.00, 3.65) 

At 2 kHz  4.11 (3.21, 5.72) 

2.19 (0.51, 4.22) 

At 4 kHz  5.00 (3.90, 6.96) 

3.59 (2.28, 5.79) 

At 6 kHz  6.61 (5.16, 9.20) 

5.62 (4.08, 8.35) 

At 8 kHz  7.03 (5.49, 9.78) 

6.11 (4.48, 8.98) 

In range 125 Hz8 kHz  5.36 (4.87, 5.95) 

4.07 (3.70, 4.53) 






In range 125 Hz8 kHz  2.62 (2.05, 3.65)  1.23 (1.12,1.37)  2.32 (1.71, 3.38) 
The standard deviation of the bilateral hearing threshold difference in testretest examination was calculated jointly for all frequencies due to lack of significant differences between frequencies in the 1way ANOVA at the level of statistical significance
Analogical computation were carried out for the mean value of bilateral hearing threshold, assuming the measurement error divided by a square root of 8 as the mean was for 8 frequencies (
The error of the independent coefficients method (determining the reference sound level independently for each frequency on the basis of the calibration coefficient at this frequency) depends on the distribution of the bilateral hearing threshold in the population and the measurement error of the calibration coefficient. Measurement error of the calibration coefficient can be easily calculated from the standard deviation of the difference in the testretest examination by dividing its value by the square root of 2. Therefore, the mean error of the independent coefficients method across all frequencies may be expressed in the following equation:
(independent coefficients SD)^{2}=(real bilateral threshold in the range 125 Hz8 kHz SD)^{2}+(calibration method testretest difference SD)^{2}/2 (12)
where bilateral threshold in the range 125 Hz8 kHz SD is the standard deviation of the bilateral hearing threshold calculated jointly for all values reduced by the mean at relevant frequencies (
The modeled coefficients method consists in estimation of the reference sound level on the basis of the model fitted to the mean value of 8 calibration coefficients determined at various frequencies. Therefore, its error is connected with distribution of the mean bilateral threshold, the error of determining the mean of 8 calibration coefficients, and the standard error of the model. Similarly, as for the independent coefficients method, the error of mean of 8 coefficients can be calculated from the standard deviation of the difference in testretest examination by dividing its value by the square root of 2, to obtain the error for single coefficient, and by the square root of 8, to obtain the error for the mean. Thus:
(modeled coefficients SD)^{2}=(real mean bilateral threshold SD)^{2}+(calibration method testretest difference SD)^{2}/16+(model SD)^{2} (13)
Finally, the error of single frequency method consisting in estimating the reference sound level determined on the basis of the model fitted to 1 calibration coefficient at the frequency with the lowest standard deviation will be:
(single frequency SD)^{2}=(real bilateral threshold at 1 kHz SD)^{2}+(calibration method testretest difference SD)^{2}/2+(model SD)^{2} (14)
The standard errors of each method are presented in
The standard error of biological calibration with corresponding confidence intervals at
Method  Reference sound level (dB), SE (95% CI)  

Independent coefficients  Modeled coefficients  Single coefficient 
Modulated signal  5.38 (4.89, 5.98)  7.07 (5.95, 8.38)  7.61 (6.35, 9.24) 
Dual tone (5 dB)  6.71 (6.10, 7.45)  7.21 (6.09, 8.53)  8.60 (7.32, 10.26) 
Dual tone (2 dB)  7.07 (6.43, 7.85)  7.26 (6.13, 8.57)  8.89 (7.60, 10.55) 
Ascending (5dB step)  5.91 (5.37, 6.56)  7.12 (6.00, 8.44)  7.99 (6.73, 9.63) 
Ascending (2dB step)  5.39 (4.90, 5.99)  7.07 (5.95, 8.38)  7.62 (6.36, 9.25) 
Bekesy (continual)  5.35 (4.87, 5.95)  7.07 (5.95, 8.38)  7.59 (6.33, 9.23) 
Bekesy (modulated)  4.90 (4.46, 5.45)  7.03 (5.91, 8.34)  7.28 (6.02, 8.91) 
The standard deviation of the difference in the hearing threshold determined by means of the ascending method between measurements on clinical audiometer and the biologically calibrated personal computer, together with corresponding confidence intervals at
Method  Hearing threshold difference (dB), SD (95% CI)  

Independent coefficients  Modeled coefficients  Single coefficient 
Modulated signal  7.60 (7.01, 8.31)  8.88 (7.79, 10.17)  9.31 (8.09, 10.89) 
Dual tone (5 dB)  8.59 (7.90, 9.42)  8.99 (7.89, 10.29)  10.14 (8.88, 11.77) 
Dual tone (2 dB)  8.88 (8.16, 9.74)  9.03 (7.93, 10.33)  10.38 (9.11, 12.03) 
Ascending (5dB step)  7.98 (7.35, 8.74)  8.92 (7.83, 10.22)  9.63 (8.39, 11.23) 
Ascending (2dB step)  7.61 (7.01, 8.31)  8.88 (7.79, 10.17)  9.32 (8.10, 10.90) 
Bekesy (continual)  7.58 (6.99, 8.29)  8.88 (7.78, 10.17)  9.30 (8.08, 10.88) 
Bekesy (modulated)  7.27 (6.71, 7.93)  8.84 (7.75, 10.14)  9.05 (7.84, 10.61) 
This paper presents methods of biological calibration of a PC for hearing examination by determining the reference sound level on the basis of the hearing threshold of the reference person. Seven methods of measuring calibration coefficients and 3 methods of determining reference sound level on the basis of these coefficients were proposed and analyzed. On the basis of 3 series of measurements conducted by 25 participants, the difference between classical puretone audiometry and audiometry based on biological calibration was estimated. The smallest standard deviation of the difference was obtained for the Bekesy (modulated) method with the independent coefficients method at the level of 7.27 dB (95% CI 6.717.93).
The lowest standard deviation in testretest examination at the level of 3.87 dB (95% CI 3.524.29) was obtained using the Bekesy (modulated) method, which entails assessment of the hearing threshold by means of the amplitudemodulated sound according to the rules of Bekesy’s audiometry. This value is inline with the standard deviation of the testretest examination of Bekesy’s audiometry [
The estimated error of determining reference sound level turned out to be the lowest for the independent coefficients method and higher for the modeled coefficients method (
The standard error of the modeled coefficients method was estimated for the model determined in the frequency range 125 Hz8 kHz. When the range is limited to 250 Hz8 kHz, the standard error of the model decreases from 6.57 dB (95% CI 5.597.54) to 5.98 dB (95% CI 4.457.50). This improves the modeled coefficients method, but the independent coefficients method is still more accurate. However, in this case the relation remained statistically significant only for the Bekesy (modulated) method (
In the single frequency method, only 1 coefficient is needed to fit the model, which indicates calibration time is 8 times shorter at the cost of higher calibration error.
Some of the presented calibration methods have been used in other studies. In Masalski and Kręcicki [
Calibration error strongly depends on the hearing threshold of the reference person. This applies especially to the independent coefficients and single frequency methods, in which the sound reference level at a single frequency is determined on the basis of a single measurement, contrary to modeled coefficients method, which uses mean hearing threshold. To verify the obtained results, the distribution of the hearing threshold of the participants was compared with literature data (
Summary of standard deviations of the hearing threshold in decibels for participants with normal hearing in the literature.
Study  N  Hearing threshold (dB), SD  Mean SD  


125 Hz  250 Hz  500 Hz  1k Hz  2k Hz  4k Hz  6k Hz  8k Hz 















1824 years  46  4.6  4.1  3.9  3.5  3.3  4.1  4.7  4.6  4.1 

2534 years  33  4.8  4.3  3.9  3.8  4.5  4.3  4.8  5.1  4.4 













Men  1636  6.6  6.1  5.6  5.6  6.6  7.8  8.9  9.9  7.1 

Women  1578  6.1  5.6  5.6  5.6  6.1  7.2  8.2  9.8  6.8 
Arlinger, 1982 [ 
10 


7.8  5.2  7.4  6.5  7.4  7.6  7.0  
Arlinger, 1991 [ 
30  5.7  5.2  5.0  4.9  4.6  5.1  6.7  6.1  5.4  
Lutman, Davis, 1994 [ 
241 

4.2  4.4  4.2  4.6  6.9  7.8  7.9  5.7  
Han, Poulsen, 1998 [ 
31 

4.7  4.4  3.5  4.9  6.6  6.3  7.1  5.4  













Men  266  5.7  5.5  5.5  5.4  5.6  6.7  7.0  7.5  6.1 

Women  337  5.5  5.2  4.8  4.5  5.2  7.9  7.4  6.1  5.8 













Men  3587 

7.6  5.7  5.3  7.0  8.9  9.5  8.0  7.4 

Women  1840 

6.3  5.8  5.3  5.7  7.0  9.1  7.6  6.7 
Current study  25  5.9  6.1  5.0  4.2  4.9  5.6  8.0  9.1  6.1 
^{a}Estimated on the basis of the model for the age of 25 years, consistent with ISO 7029, 2000 [
^{b}Estimated on the basis of centiles calculated from the model for the age of 25 years.
^{c}Estimated on the basis of centiles in the age range 2029 years.
The examinations in this study were conducted on young employees and interns of the Otolaryngology Clinic (ie, persons familiar with the subject of hearing examinations). This may have led to better calibration results and shorter duration of the examination than in a population of young people with good hearing without experience with hearing examinations.
In the calculations, it was assumed that the examinations conducted on home computers are not burdened with an error resulting from the presence of background noises other than the fan noise. This assumption was made because during home examinations and in those conducted in the sound booth the fan noise was the loudest and the most disturbing sound. Thus, the estimated calibration error takes into account the fan noise. However, in the case of other background noises, the error may turn out to be bigger.
Calibration methods presented in the paper were implemented as Java applets embedded in browsers. However, their application is not limited only to Webbased tests, but may also be used for offline determination of the reference sound level or on mobile devices. Moreover, in the case of tablets or smartphones, calibration error may turn out to be smaller because of the lack of fan noises.
When conducting examinations on a PC with the use of headphones with very high sensitivity instead of regular ones, interferences of the sound card or other electronic systems may affect the stimulus. During examination at home, such incidents occurred in 2 of 25 cases. As a result, it was impossible to perform the examination. After changing headphones from professional to regular ones, the examination was completed without any problems.
Calibration accuracy may be improved if it is conducted by 2 or more reference persons [
Another method of improving the accuracy is to introduce additional conditions to reject inaccurate calibrations. For example, calibration using the independent coefficients method may be rejected as the difference between coefficients exceeds the predetermined threshold [
The final choice of the calibration method will depend on the desired accuracy of calibration and the time for its performance. If considerable accuracy is required, it is advisable to use the independent coefficients method, whereas when quick calibration is the priority, the single frequency method is preferable. The application of the modeled coefficients method is not justified because of higher calibration error than is in the independent coefficients method at the same duration.
Two of the 7 methods of measuring calibration coefficients seem worth noting: the modulated signal and Bekesy (modulated) methods. The choice of the better of the 2 is not obvious. The Bekesy (modulated) method is the most accurate at moderate duration, whereas the modulated signal method is the fastest at moderate accuracy. Additionally, the modulated signal method is the easiest, and the Bekesy (modulated) method is the second easiest. However, the methods differ significantly in the complexity of implementation with the Bekesy (modulated) method being more complex. On the other hand, in the case of Bekesy (modulated) method, the measurement can be easily verified on the basis of the differences between the intensities at which the stimulus starts or stops being audible.
Therefore, if there are no substantial time limitations, it is advisable to use Bekesy (modulated) method with independent coefficients method, which have the lowest error. When a simple and quick calibration is required, modulated signal method with single frequency method should be chosen.
Translation of the questionnaire on difficulty of the calibration.
All equations used for this paper: (1) the model, (2) the difference between the model and the real calibration coefficient, (3) the determination error of the calibration coefficient, (4) the difference between the model and the determined coefficient, (5) the variance of random variable X, (6) the model estimated on the basis of determined coefficients, (7) the variance of random variable Z, (8) the value of determined coefficient, (9) the variance of random variable Y, (10) the frequency response of the model, (11) the standard deviation of the participants' bilateral hearing threshold measured with ascending method, (12) the standard error of the independent coefficients method, (13) the standard error of the modeled coefficients method, (14) the standard error of the single frequency method.
CONSORTEHEALTH checklist V1.6.2 [
decibel
decibel hearing level
personal computer
The authors of this paper would like to thank the workers and interns of the Otolaryngology Clinic who agreed to take part in the examinations. The research described in this paper was carried out as part of a project (Kluczowy Stażysta no KSW/13/I/2011) cofinanced by the European Social Fund.
The first author (MM) is the owner of an Internet portal (eaudiologia.pl) that offers online hearing tests.