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Other modulation tools
Published in Roey Izhaki, Mixing Audio, 2017
Chorus can be considered a form of ADT with slightly different settings. Chorus tends to sound richer with stereo delays, where slightly different delay times are set on each channel: Dry/wet—wet set between 20 and 70%; the more wet signal, the clearer the effect.Delay time—between 20 and 80 ms.Modulation depth—around 10%.Modulation rate—can be anywhere between 0.1 and 10 Hz.Feedback—none or very little.
Signal Processors. Toys You Could Play with for Days!
Published in Timothy A. Dittmar, Audio Engineering 101, 2013
Chorus generates a detuned double of the original signal that modulates in pitch slightly over time. Essentially, it is an FX where the original signal is mixed with a modulated delay of itself creating a “chorus” effect. The delay times are generally between 10 and 60 ms. This can happen naturally with groups of strings and vocals. Chorus is often applied to vocals, guitar, bass, keyboards, or strings to make them sound more in tune, thicker, and dreamier than a single sound, while still sounding more or less like a single sound. A chorus FX can come in a pedal form, rack mount, plug-in, or be made naturally by recording multiple takes of a single instrument and mixing them together.
Sound-Making Techniques
Published in Russ Martin, Sound Synthesis and Sampling, 2012
The chorus effect is a cyclic detuning of the sound, mixed with the original sound. This cause the same type of phase cancellations that are associated with several performers playing the same notes on acoustic instruments: the violin section in an orchestra is a good example. Chorus is normally achieved by delaying the audio signal slightly in time by a few tens of milliseconds, and then changing the time delay dynamically. This has the effect of changing the pitch as the delay time is altered, and so produces the detuned chorusing effect. Chorus can also be produced by deliberately detuning two VCOs, oscillators or sounds.
Quantitative effects of cyclotron resonance on the coupling of ULF with VLF and langmuir waves
Published in Waves in Random and Complex Media, 2021
Asif Shah, Shahzad Mahmood, Saeed Ur Rehman
Recently, there has been a great research interest in the wave–wave coupling, leading to nonlinear turbulence [14–32]. The Time History of Events and Macroscale Interactions during Substorms (THEMIS) satellite has found that wave–wave coupling in the lower (having frequency between 10 and 50 % of electron cyclotron frequency) band chorus resulted in the upper band (having frequency between 50 and 80 % of electron cyclotron frequency) chorus waves (which are electromagnetic whistler waves) [14]. Such wave couplings are supported and explained by particle in cell (PIC) simulations [15]. The very oblique whistler waves are thought to be commonly generated through cyclotron resonance with anisotropic electron streams [16]. Nonlinear three-wave resonance coupling in magnetosphere includes quasi-parallel lower band chorus wave interacting with a mildly oblique upper band chorus wave resulting in a highly oblique quasi-electrostatic lower band chorus wave [17]. The density gradients are found to be important for nonlinear wave–wave coupling [18]. Recently, PIC simulations have been employed to explain the rising tone of VLF chorus and parametric decay of whistler waves along the magnetic field [19,20,22]. It is found that wave–wave coupling interactions in the vicinity of Van-Allen radiation belts (inside geomagnetosphere) involve Langmuir and VLF waves [23]. The generation of lower band VLF chorus in the Earth's magnetosphere is strongly dependent on solar wind characteristics and geomagnetic activity [24]. In Ref. [33] a comprehensive mathematical model is developed for quantitatively estimating the strength of turbulent wave–wave coupling processes. The particles fall in cyclotron resonance with waves, when the Doppler shifted wave frequency becomes comparable to the integral multiple of particles cyclotron frequency [34]. The quantitative effects of cyclotron resonance on nonlinear wave–wave coupling has not been studied yet for three-wave coupling involving ULF waves, Langmuir waves and electrons in the cyclotron resonance with VLF waves and therefore studied in this work. The paper is organized as follows, Section 2, presents the mathematical model for electron–cyclotron resonance coupling with nonlinear turbulence. Section 3 describes results and discussion. Section 4 is devoted to summary and conclusions.