TECHNOLOGIES

In this section you can learn more about the technologies Sound Temple use. For ease of navigation this guide has been split into multiple pages and you can jump to a topic that interests you by clicking the links below.

• Introduction
• Electronic Signal Generation
• Digital Audio Signal Generation
• Sample Rate
• Bit Depth
• Digital and Analogue Audio Signal Manipulation
• Digital Audio Mastering
• Clip Removal
• Volume Control
• Panning
• Normalisation
• Compression
• Limiting
• Expansion
• Noise Gates

Sample Rate

The sample rate determines the number of times per second to take a snapshot of the audio. Higher sample rates produce higher quality audio, at the expense of requiring more storage space. Frequencies of up to one half the sample rate can be produced effectively. To reproduce a frequency of 10 KHz, a sample rate of at least 20 KHz must be chosen. To reproduce a frequency of 20 KHz, sample rate of at least 40 KHz must be chosen. This observation is referred to as the Nyquist equation.

Bit Depth

The number of bits used in measuring the amplitude of a sample is known as the bit depth. An 8-bit resolution will provide 256 unique "volumes", while choosing a 16-bit resolution will provide 65,536 unique "volumes", for a 96 dB signal-to-noise ratio. Obviously, a much greater dynamic range can be reproduced at 16-bit resolution than at 8-bit resolution, which only has a 48 dB signal-to-noise ratio. Compact disk players have a 16-bit resolution. It has now become widely accepted that the limit of human hearing within the digital domain is at a bit depth of 24 and a sample rate of 96,000 Hz. This provides 194 dB signal-to-noise ratio. A sample value of 32,767 (maximum positive sample value for 16-bit sound) is referred to as having a value of 0 dB. Likewise, a sample value of 16,384 is referred to having a value of -6 dB.

Digital and Analogue Audio Signal Manipulation

An analogue or digital electronic signal may be manipulated in two ways. The signal may be processed or affected via an outboard device. The distinction of process and effect is not based on their creative use, but rather on the signal path. Processors tend to treat the whole of the signal, whereas effects tend to rely on a mix of the original sound and a treated version. Industry standard terminology refers to the original sound as 'dry' and the treated sound as 'wet'. In an analogue domain the outboard device would comprise solely of analogue solid-state electronics. In a digital domain the outboard device would contain digital electronics that contained signal processing algorithms as binary code that map to a model of the analogue environment. In both digital and analogue domains, effects and processes may be chained together, such that the output of one device becomes the input of the next. New effects and processes are evolving constantly.