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The Display of Visual, Auditory, and Tactual Information
Published in Robert W. Proctor, Van Zandt Trisha, Human Factors in Simple and Complex Systems, 2018
Robert W. Proctor, Van Zandt Trisha
Auditory signals can differ in terms of their distributions of energy across the frequency spectrum, which affects how the signal is perceived (Patterson, 1982). The fundamental frequency of a warning signal should be between 150 and 1000 Hz, because low-frequency tones are less susceptible to masking. Furthermore, the signal should have at least three other harmonic frequency components. This maximizes the number of distinct signals that we can generate and stabilizes the pitch and sound quality under various masking conditions. Signals with harmonically regular frequency components are better than ones with inharmonic components, because their pitches will be perceived as relatively constant in different auditory environments. These additional components should be in the range from 1 to 4 kHz, for which human sensitivity is high. If the signal is dynamic, that is, changing with the state of the environment, then a listener’s attention can be “grabbed” by including rapid glides (changes) in the signal’s fundamental frequency.
The structure of common music technology systems
Published in Kirk Ross, Hunt Andy, Digital Sound Processing for Music and Multimedia, 2013
Consider now the fate of inharmonic components. By definition, if the waveform segment contains an exact integer number of cycles of harmonic components, it must contain a non-integer number of cycles of the inharmonic components. The last cycle of any such inharmonic component in the segment will be incomplete. When this incomplete cycle is looped, there will be a regular discontinuity in the waveform produced, and this will produce a rough-sounding electronic artefact. This will be particularly true if the looped segment is short, containing a small number of cycles. The discontinuity will therefore appear at a relatively high rate on playback, causing a persistent ‘buzzing’ noise.
Sound-Making Techniques
Published in Russ Martin, Sound Synthesis and Sampling, 2012
Hybrid sounds are produced using contrasting or complementary synthesis techniques. Although this often implies the use of physically different synthesizers, some multi-timbral instruments do allow different synthesis techniques to be employed for each part. The range of ‘contrasting and complementary’ techniques is large, but some possibilities include the following: Analogue with digital, where the ‘natural’ sound, variations in timbre and slight tuning often attributed to analogue synthesis can be used to complement the more precise and controlled ‘digital’ sound.Imitative with synthetic, where the resulting sound has some of the characteristics of the real instrument, but with enough artificiality to ensure that it is not mistaken for a purely imitative sound.Familiar with alien, where the final sound has some elements that are familiar to the listener, but which also includes additional elements which are unfamiliar. This can be useful for avoiding the overuse of a lush string sound as a generic pad or backing timbre. Examples include mixing violin samples with slightly pitch-enveloped sawtooth waveforms, or adding munchkinized vocal sounds to conventional choral sounds.Additive with frequency modulation (FM), where FM sounds are used to counter the inharmonic weakness of the additive synthesis technique.Sample with imitative, where the basic sample is enhanced with additional imitative sounds to make it sound more like ‘the real thing’. Curiously, many people prefer sounds which are made hyper-real in this way rather than exact copies.
Effect of wearing hearing protectors on the audibility of railway warning signals – an experimental study
Published in International Journal of Occupational Safety and Ergonomics, 2018
Jean-Pierre Arz, Jean-Pierre Gettliffe, Philippe Delattre
The characteristics of the warning signals are presented in Table 2. A specificity of the warning signals for the drivers is that they are generally different from one railway vehicle type to another (only signal S9 is present in three different railway vehicles). They are used to alert the driver to an event (like a change of the speed limit or an emergency radio call) and require an action from him (like pressing or releasing a driving component). They are of different types, both in time and frequency. In time, the signals are either constant, pseudo-constant (like a mechanical bell), pulsed (signal and silence alternately) or ‘two-tones’ (succession of two different tones). In frequency, the signals are either of type pure tone (one single frequency), almost pure tone (one single frequency plus some weak partials), harmonic or inharmonic.