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Questions and Answers
What is the primary type of distortion that affects the frequency response of a system?
What is the primary type of distortion that affects the frequency response of a system?
What is the characteristic of a sinusoidal waveform with strong nonlinear distortion?
What is the characteristic of a sinusoidal waveform with strong nonlinear distortion?
What type of distortion is primarily associated with irregularities in the amplitude frequency response?
What type of distortion is primarily associated with irregularities in the amplitude frequency response?
What is the term used for the new oscillations produced due to distortion of a sinusoidal oscillation?
What is the term used for the new oscillations produced due to distortion of a sinusoidal oscillation?
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What is the relationship between the frequency of the original sinusoidal oscillation and the frequencies of the overtones produced by distortion?
What is the relationship between the frequency of the original sinusoidal oscillation and the frequencies of the overtones produced by distortion?
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Which type of overtones are typically considered more pleasant sounding?
Which type of overtones are typically considered more pleasant sounding?
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What is a common characteristic of the amplitude frequency response of analog devices?
What is a common characteristic of the amplitude frequency response of analog devices?
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Which of the following is an example of how nonlinear distortions can be used as a stylistic device?
Which of the following is an example of how nonlinear distortions can be used as a stylistic device?
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What is the primary cause of distortion compression in audio systems?
What is the primary cause of distortion compression in audio systems?
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What is the primary difference between distortion products and intermodulation products?
What is the primary difference between distortion products and intermodulation products?
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What does the term 'saturation' refer to in the context of audio amplification?
What does the term 'saturation' refer to in the context of audio amplification?
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Why are intermodulation products particularly concerning in speakers and power amplifiers?
Why are intermodulation products particularly concerning in speakers and power amplifiers?
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How is the Total Harmonic Distortion (THD) of an audio system measured?
How is the Total Harmonic Distortion (THD) of an audio system measured?
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What is the significance of using RMS values instead of peak values when calculating THD?
What is the significance of using RMS values instead of peak values when calculating THD?
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Which of the following factors can influence the level of distortion compression in an audio system?
Which of the following factors can influence the level of distortion compression in an audio system?
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Which of the following statements regarding harmonic distortion is true?
Which of the following statements regarding harmonic distortion is true?
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Flashcards
Linear Distortion
Linear Distortion
Irregularities in frequency response that affect amplitude.
Nonlinear Distortion
Nonlinear Distortion
Deformations in a signal’s waveform affecting the output sound.
Frequency Response
Frequency Response
The range of frequencies that a system can reproduce effectively.
Harmonics
Harmonics
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Even Harmonics
Even Harmonics
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Odd Harmonics
Odd Harmonics
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Amplitude Frequency Response
Amplitude Frequency Response
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Distortion in Music Effects
Distortion in Music Effects
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Distortion Compression
Distortion Compression
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Saturation
Saturation
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Total Harmonic Distortion (THD)
Total Harmonic Distortion (THD)
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Harmonic Distortion Factor (k)
Harmonic Distortion Factor (k)
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RMS Values
RMS Values
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k2 and k3
k2 and k3
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Intermodulation Distortion
Intermodulation Distortion
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Sensitivity to Intermodulation
Sensitivity to Intermodulation
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Study Notes
Distortions
- Distortions are summarized as different types of signal changes.
- Two main types are linear and nonlinear distortions.
Linear Distortion
- Linear distortion primarily refers to irregularities in the frequency response.
- The human hearing range (20 Hz to 20 kHz) is the basis for observation.
- Almost all real systems have a degree of linear distortion in the amplitude frequency response.
- This distortion is usually more noticeable at the edges of the audio frequency range (upper and lower ends).
- Tape machines are an exception, sometimes showing an increase in amplitude response towards higher frequencies.
- Deviations in phase frequency response are also considered linear distortions.
Nonlinear Distortion
- Nonlinear distortion is a distortion of the transmitted waveform.
- It manifests as a deformation of the input waveform.
- This happens when a transmission element cannot precisely follow the voltage curve.
- Metrologically, these changes are expressed as additional overtones.
Overtone Series
- Distortion of a sinusoidal oscillation (frequency f1) creates new oscillations with frequencies: 2f1, 3f1, 4f1,...
- These oscillations are called harmonics or overtones.
- Harmonics are divided into even (e.g., 2f1, 4f1, 6f1,...) and odd (e.g., 3f1, 5f1, 7f1,...).
- Even overtones often sound more pleasing than odd overtones.
- Odd overtones, especially at higher levels, may become noticeable as a distortion of the signal.
Distortion Compression
- Distortion compression can happen with strong overdriving of an amplifier component (e.g., tubes or transistors) which generates harmonic overtones and compresses the signal.
- The effect is stronger in distortion devices, but also possible with less severe overdrives (e.g. in tube circuits).
- The effect gradually increases when approaching the amplifier saturation point.
- This results in a flattening of the transfer characteristic.
Total Harmonic Distortion (THD)
- Total Harmonic Distortion (THD) measures the proportion of harmonic distortion products in the complete signal.
- The calculation uses root mean square (rms) values, not peak values.
- Typically, only the first two harmonics (k2 and k3) are considered in practical measurements due to the complexity of calculating all harmonics.
- k values are dimensionless and expressed as a percentage.
Intermodulation Distortion
- Intermodulation distortion occurs when a system is driven by more than one sinusoidal input.
- It produces new frequencies that are sums and differences of the original frequencies.
- These new frequencies are not harmonically related to the fundamental frequency.
- Intermodulation distortion is a significant concern in audio systems, especially for high-quality applications.
- Measurements often use two different frequencies, and the rule to follow is: the less the better.
- For professional active speakers, a desirable limit is less than 2% intermodulation distortion, for high-quality speakers the limit is around 0.5%.
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Description
This quiz covers the key concepts of audio distortions, focusing on linear and nonlinear types. It explores how these distortions affect frequency response and the human hearing range. Test your understanding of the nuances between these distortion types and their implications in audio systems.
