1. Sound Quality

2. How to Prevent Distortion
▶ In the first example, the amplitude (strength / height) of the signal falls comfortably within the +/-100 unit range. This is a well-recorded signal.
▶ In the second example, the signal is amplified by 250%. In this case, the recording components can no longer accommodate the dynamic range, and the strongest portions of the signal are cut off. This is where distortion occurs.

3. Minimising Distortion
Distortion can occur at almost any point in the audio pathway, from the microphone to the speaker. The first priority is to find out exactly where the problem is. ……

4. How to Eliminate Feedback
One of the most common feedback situations is shown in the diagram below - a microphone feeds a signal into a sound system, which then amplifies and outputs the signal from a speaker, which is picked up again by the microphone.

5. To eliminate feedback, you must interrupt the feedback loop.
Here are a few suggestions for controlling feedback:
Change the position of the microphone and/or speaker so that the speaker output isn't feeding directly into the mic. Keep speakers further forward (i.e. closer to the audience) than microphones.
Use a more directional microphone.
Speak (or sing) close to the microphone.
Turn the microphone off when not in use.
Equalize the signal, lowering the frequencies which are causing the feedback.
Use a noise gate (automatically shuts off a signal when it gets below a certain threshold) or filter.
Lower the speaker output, so the mic doesn't pick it up.
Avoid aiming speakers directly at reflective surfaces such as walls.
Use direct injection feeds instead of microphones for musical instruments.
Use headset or in-ear monitors instead of speaker monitors.

6. Audio Equalization Shelving EQ Bell EQ Graphic Equalizers
Parametric Equalizers

7. Shelving EQ
In shelving equalization, all frequencies above or below a certain point are boosted or attenuated the same amount. This creates a "shelf" in the frequency spectrum.

8. Bell EQ
Bell equalization boosts or attenuates a range of frequencies centered around a certain point.
The specified point is affected the most, frequencies further from the point are affected less.

9. Graphic Equalizers
Graphic equalizers provide a very intuitive way to work — separate slider controls for different frequencies are laid out in a way which represents the frequency spectrum. Each slider adjusts one frequency band so the more sliders you have, the more control.

10. Parametric Equalizers
Parametric equalizers use bell equalization, usually with knobs for different frequencies, but have the significant advantage of being able to select which frequency is being adjusted. Parametrics are found on sound mixing consoles and some amplifier units (guitar amps, small PA amps, etc).

11. Audio Monitoring & Metering
VU Meter
A VU (volume unit) meter is an audio metering device. It is designed to visually measure the "loudness" of an audio signal.
Peak Program Meter (PPM)
A Peak Program Monitor (PPM), sometimes referred to as a Peak Reading Meter (PRM), is an audio metering device. It's general function is similar to a VU meter but there are some important differences.

12. Audio Processing
Audio Processing means changing the characteristics of an audio
signal in some way. Processing can be used to enhance audio, fix problems,
separate sources, create new sounds, as well as to compress, store and
transmit data.
Compression: Reducing the dynamic range of a signal.
Expansion: Expanding the dynamic range of a signal.
Equalization: Increasing or decreasing the levels of different frequencies in a signal.
Limiting: Constraining the level of a signal to a specified threshold.
Reverb: Adding reverberation to a signal.
Phasing: Creating interesting effects through sound wave phase interaction.
Flanging: A specific type of phasing.
Chorus: An effect which makes a single source sound like multiple sources.

13. Audio Compression

14. Audio Expansion

15. Audio Equalization
Equalization means boosting or reducing (attenuating) the levels of various frequencies in a signal. At it's most basic, equalization can mean turning the bass/treble controls up or down. Advanced equalizers have fine controls for specific frequencies.
Common uses for equalization include correct signals which sound unnatural and reducing feedback.

16. Audio Limiters

17. Audio Reverb (Reverberation)
Reverb is short for reverberation, the effect of many sound reflections occurring in a very short space of time. The familiar sound of clapping in an empty hall is a good example of reverb.
Reverb effects are used to restore the natural ambience to a sound, or to give it more fullness and body.

18. What is Reverb?
Reverberation, or reverb for short, refers to the way sound waves reflect off various surfaces before reaching the listener's ear.
When sound waves reflect off walls, two things happen:
1. They take longer to reach the listener.
2. They lose energy (get quieter) with every bounce.

19. Reverb Effects Adobe Audition
Lexicon PCM 81 Digital Effects Processor

20. Examples of Reverb
Drums – Dry
Drums – Medium Reverb
Drums - Hall

21. Phasing Phase-shifting, AKA phasing, is an audio effect which takes
advantage of the way sound waves interact with each other when
they are out of phase. By splitting an audio signal into two signals and changing the relative phasing between them, a variety of
interesting sweeping effects can be created.
The phasing effect was first made popular by musicians in the
1960s and has remained an important part of audio work ever
since.
Phasing is similar to flanging, except that instead of a simple delay it uses notch and boost filters to phase-shift frequencies over
time.

22. Phase Shifting (Phasing)
The following examples show some of the different types of phasing effects (MP3):
▶ Drums: Dry (original audio with no effect)
▶ Drums: Phased
▶ Drums: Crunchy Phase
▶ Drums: Trebly Phasing
▶ Drums: Bassy Phase
▶ Drums: Tremolo Phasing Left to Right
▶ Drums: Washy Phase Left to Right
▶ Drums: “Bubbles” Phase

23. Phasing Effects Adobe Audition

24. Flanging
Flanging is a type of phase-shifting. It is an effect which mixes the original signal with a varying, slightly delayed version of the signal. The original and delayed signals are mixed more or less equally.
Flanging results in a sweeping sound — see the following example (MP3):
- Drums: Dry (original audio with no effect)
- Drums: Flanged

25. Flanger Adobe Audition

26. Chorus
The chorus effect was originally designed to make a single person's voice sound like multiple voices saying or singing the same thing, i.e. make a soloist into a chorus. It has since become a common effect used with musical instruments as well.
The effect is a type of delay — the original signal is duplicated and played at varying lengths and pitches. This creates the effect of multiple sources, as each source is very slightly out of time and tune (just as in real life). Technically, a chorus is similar to a flanger.
Common parameters include:
▶ Number of Voices: The number of times the source is multiplied.
▶ Delay: The minimum delay length, typically 20 to 30 milliseconds.
▶ Sweep Depth/Width: The maximum delay length.

27. Chorus Adobe Audition

28. Summary, QnA