Audio interconnection 05
Audio signal types - line level 

Level of challenge Easy

Welcome to this tutorial on line level signals.

 

Line level signals are loud and strong and suitable for recording, processing and mixing. All signals must be at line level in order to be mixed together into a stereo or surround sound master. Some sound sources, such as synthesisers, produce line level signals, whilst others such as microphones do not.

 

Caption - Devices which produce line level signals

Devices that produce line level signals include ..

  • microphone pre-amplifiers
  • mixers
  • synthesisers
  • sound modules
  • keyboards
  • drum machines
  • samplers
  • virtual instruments
  • mobile phones

Caption - Devices which work with line level signals

Devices that work with line level signals include ..

  • hardware effect processors such as reverbs and delays
  • hardware compressors
  • hardware noise gates
  • hardware filters and equalisers
  • headphone amplifiers
  • DAWs
  • CD recorders
  • tape machines

Caption - Converting sounds to line level

If a sound that is not at line level is to be added to a mix, it must first be converted. In the case of a mic level signal, this process is carried out by a microphone pre-amplifier, or mic pre-amp.

 

Once a sound is at line level it will usually stay there until it is amplified to loudspeaker or headphone level in order to be monitored.

 

Caption - Line level digital signals

Almost all digital audio signals are encoded versions of line level signals. Digital signals within a computer DAW, such as Logic or ProTools, can be considered to be at line level because they will almost always exit the DAW at line level in order to be monitored processed or mastered.

 

Caption - Digitising analogue line level signals

In almost all situations, a signal must be at line level before being converted to digital. So for example, a signal from a microphone must be amplified to line level by a mic pre-amplifier before being converted to digital and sent to be recorded in a DAW.

 

Caption - Professional and consumer operating levels

There are 2 'flavours' of line level. The 'flavours' differ in their strength, or amplitude, which is expressed in dBs or decibels. Consumer and cost effective equipment operates at -10 dBV and professional equipment operates at +4 dBu. In practice these 'flavours' can easily be combined.

 

Caption - Thanks for watching

The script for this video, with accompanying images, can be found at projectstudiohandbook.com 

 

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