Hugo Fastl Eberhard Zwicker. Psychoacoustics. Facts and Models. With Figures and. 53 Psychoacoustics Demonstrations on CD-ROM. ABC. Psychoacoustics – Facts and Models offers a unique, comprehensive summary of DRM-free; Included format: PDF; ebooks can be used on all reading devices. Hugo Fastl Eberhard Zwicker. Psychoacoustics. Facts and Models. With Figures and. 53 Psychoacoustics Demonstrations an CD-ROM. Springer.
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superior English sources were avail- able to me. There was the wonderful review on valence theory by Van Vleck and Albert Sherman in. Sound quality and psychoacoustics have many aspects in common, since Since psychoacoustic models have been described in detail in the literature . Zwicker, E., Fastl, H. () Psychoacoustics - Facts and Models, 2nd. Ed., Springer. Fastl H., Zwicker E. Psychoacoustics. Facts and Models. Файл формата pdf; размером 11,23 МБ. Добавлен пользователем kba
Following Zwicker and Fastl, sharpness is modeled as a produced by a 1 kHz sine tone with a sound pressure level of 40 weighted centroid of the specific loudness pattern. Its unit is the dB.
Sharpness is a musical term often used to describe a sound with The roughness of auditory stimuli can be manipulated through a pitch slightly higher than a target pitch. This is strongly influences such as loudness and carrier spectral content.
Again, the dependency upon frequency content will have the 2. Fluctuation Strength implication that most displays will use signals of varying sharp- Fluctuation strength describes a sensation caused by relatively slow ness in a fairly uncontrolled way. For harmonic tones, sharpness amplitude modulation within auditory filters with maximum sen- can be roughly controlled through the distribution of the harmonic sitivity at around 4 Hz.
It is easy to appreciate that the perception spectral envelope, although a sharpness model is required for scal- of the degree to which a sound is fluctuating should increase with ing.
As observed by Zwicker and Fastl, fluctuation strength know as critical band rate and g z is a weighting function that appears to be related to speech, since its amplitude modulation emphasises z for high critical band rates. The unit of fluctuation strength is the vacil, 2. Roughness is a sensation caused by quite rapid amplitude modu- The model used by Zwicker and Fastl for calculating the fluc- lation within auditory filters.
This modulation can be caused by tuation strength of tones is summarised by Equation 3. Like the beats between two pure tone components, or by a signal with am- simple roughness model, this fluctuation strength model is based plitude or frequency modulation.
Beating within an auditory filter on the fluctuation of the excitation pattern of the ear. According to Zwicker Zwicker and Fastl also refer to a general model of fluctua- and Fastl, maximum roughness is often achieved for modulation tion strength, structured similarly to the general roughness model frequencies around 70 Hz depending on the carrier frequency. They present as a parameter for auditory alerts. Pulse rate is often used to a set of simple models of roughness associated with a single known indicate levels of urgency in auditory alert systems .
This uses the time-varying excitation pattern of the ear sim- A psychoacoustical pitch ratio scale is an elusive concept because ilar to the specific loudness pattern, except that the magnitude is in of the complexity of pitch perception and cognition.
Even though many fre- Psychoacoustic quencies are present in a harmonic tone, usually the fundamental Parameter 1 frequency dominates as the pitch percept. When the fundamental Psychoacoustic frequency is masked or completely absent, the fundamental as a Parameter 2 pitch percept tends to remain.
Models of pitch perception account normalized so as to reveal and simplify for this phenomenon either explicitly through template matching representation of  or implicitly through autocorrelation . Parncutt has ex- Parameter 1 plained many aspects of musical harmony through this psychoa- Time coustical process .
Psychoacoustic Parameter 1 and In auditory display applications such as auditory graphing, var Psychoacoustic ious approaches can be made to pitch encoding, including the fre- Parameter 2 are used for redundant encoding quency ratio scale also known as logarithmic frequency distri- to increase the robustness bution, exemplified by the musical chromatic scale , the diatonic of the display major scale which has the advantage of musical familiarity , the pentatonic scale which has the advantage of relatively low disso- Time nance for any tone combinations , and the linear frequency scale Psychoacoustic which has the advantage of expressing low order integer ratios Parameter 1 as familiar harmonic intervals.
Unlike the other psychoacoustical Psychoacoustic Parameter 2 could also be scales referred to in this paper, such pitch scales are not necessarily used for encoding a psychological ratio scales, yet they can provide a range and level second data stream simultaneously of precision in data representation unavailable for the other scales.
Time 3. This ubiquity may be a cause of some of the difficulties inherent in the usage of auditory displays. Whilst 4. The algorithms involve several stages and can present iden- the implicit presentation of other sensations. In this situation it is tical results for different sound inputs.
Therefore, they cannot be up to the listener to develop the skills to respond to the perceptual applied in reverse for synthesis, so the use of these models for parameter the sound designer intended to represent the data with, auditory display can present a practical challenge.
A less direct approach is to generate a large matrix of with this problem. In the first instance, we normalise other psy- sounds using traditional digital synthesis techniques, process these choacoustic sensations to control this arbitrary variance, in an at- using psychoacoustical algorithms, and thereby generate a lookup tempt to reduce the confusion caused. In the second instance we table we can use to determine the appropriate digital synthesis manipulate this variance directly in an attempt to reinforce the rep- parameters for any given set of psychoacoustical parameters Fig- resentation parameter with psychoacoustic sensations that move ure 4 a.
Whilst this may seem a relatively trivial process, the in parallel. In the third we use the psychoacoustic sensations to implementation requires great care in preserving the orthogonality represent separate data streams. To generate a set of candidates for this analysis process sim- ply requires a number of sounds that vary sufficiently for each 3. Sound Quality psychoacoustic parameter to be in turn varied. This requires an understanding of to what, and over what range, the models are The use of psychoacoustical models facilitates the prediction of sensitive, as well as an understanding of the unintended effects ma- subjective qualitative response to auditory stimuli.
For example, nipulation of other parameters may induce. For instance, excessive Zwicker and Fastl present models of sensory pleasantness, based frequency modulation may reduce the perception of tonalness in on a combination of psychoacoustical parameters but dominated the produced sound.
The manipulation of amplitude modulation, by sharpness. Such models are context-dependent, but could be frequency modulation, fundamental frequency, spectral slope and developed for an auditory display application.
Many studies in gain allows us a range of control over the psychoacoustic param- the field of sound quality indicate that psychoacoustical scales eters of loudness, sharpness, roughness, fluctuation strength and can better predict human evaluation of sound than physical signal pitch perception.
Table 1 describes possible synthesis parameters measurements . Figure 4: A Method for Implementation not control the psychoacoustic parameters directly, they will only loudspeakers except in very controlled conditions: their frequency be used to vary these parameters significantly enough that a useful response and level at the listener position is heavily dependent on range of psychoacoustic results are produced.
The use The use of headphones with a known and preferably reasonably of amplitude decay envelopes, while popular for creating realistic linear frequency response will provide a degree of insensitivity to sounds, also results in loudness and indeed other variance within listener movement.
However, it is still necessary to calibrate the each representative sound.
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For this particular application this is headphone output level with a known source. Due to the vari- probably not appropriate, or at least it complicates matters to a de- ability of spectral response in different headphone models it is gree not necessary at first.
Therefore in our initial implementation probably better to use a broad-band noise source rather than the the tones do not vary in amplitude over the length of time they more common mid-frequency sine tone. Typically, the ear shows a peak of sensitivity i.
Facts and Models
Equal-loudness contours indicate the sound pressure level dB SPL , over the range of audible frequencies, that are perceived as being of equal loudness. Equal-loudness contours were first measured by Fletcher and Munson at Bell Labs in using pure tones reproduced via headphones, and the data they collected are called Fletcher—Munson curves. Because subjective loudness was difficult to measure, the Fletcher—Munson curves were averaged over many subjects.
Robinson and Dadson refined the process in to obtain a new set of equal-loudness curves for a frontal sound source measured in an anechoic chamber. In , ISO was revised as equal-loudness contour using data collected from 12 international studies.
Main article: Sound localization Sound localization is the process of determining the location of a sound source. The brain utilizes subtle differences in loudness, tone and timing between the two ears to allow us to localize sound sources. Some species of owls have their ears placed asymmetrically, and can detect sound in all three planes, an adaption to hunt small mammals in the dark. Please help improve this section by adding citations to reliable sources. Unsourced material may be challenged and removed.
June Main article: Auditory masking Audio masking graph Suppose a listener cannot hear a given acoustical signal under silent condition. When a signal is playing while another sound is being played a masker , the signal has to be stronger for the listener to hear it.
The masker does not need to have the frequency components of the original signal for masking to happen. A masked signal can be heard even though it is weaker than the masker. Masking happens when a signal and a masker are played together—for instance, when one person whispers while another person shouts—and the listener doesn't hear the weaker signal as it has been masked by the louder masker.
The different kinds of pitch are described in Chap. The last chapter provides examples of applications, which will be of special interest to those engaged in finding practical solutions.
For didactical reasons, the text is not interrupted by the inclusion of references. However, at the end of the volume, the relevant literature published by the Stuttgart and Munich groups is cited, as is the literature dealing with the various applications given in the final chapter. The equations appearing in the book are given as magnitude equations, containing not only symbols but also the units in which the variables are to be expressed.
This should help to avoid mistakes since one can check the units of the calculated quantity.
Some of the figures contain more information than is needed for the immediate discussion. This is simply a device to save space and the additional information is invariably discussed at a later point in the text. We would like to acknowledge the helpful and patient cooperation of Springer-Verlag.
We thank the many individuals who contributed to the realization of this book, notably, Mrs. Angelika Kabierske for drawing the figures, Mrs.This amplitude modulation occurs with a frequency equal to the difference in frequencies of the two tones and is known as beating.
Roughness is a sensation caused by quite rapid amplitude modu- The model used by Zwicker and Fastl for calculating the fluc- lation within auditory filters. Unlike the other psychoacoustical Psychoacoustic Parameter 2 could also be scales referred to in this paper, such pitch scales are not necessarily used for encoding a psychological ratio scales, yet they can provide a range and level second data stream simultaneously of precision in data representation unavailable for the other scales.
Table of contents
With the widespread usage of digital play- ness and sharpness. Other scales have been derived directly from experiments on human hearing perception, such as the mel scale and Bark scale these are used in studying perception, but not usually in musical composition , and these are approximately logarithmic in frequency at the high-frequency end, but nearly linear at the low-frequency end.
Zwicker and Fastl discrete tabulated values, to a visual graph, to quantised MIDI note do not claim that their models are always quantitatively accurate, numbers, to pitches that are audible . Figure 5: Selected portions of a matrix with a total of candidates, which only varies pitch, loudness and sharpness.