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TPBLeap - Creative Futures

by JJ Vernon

Chapter 3 : The Signal Path

The term “signal path” simply refers to the journey a sound/signal makes from its origin to its final destination.

Let’s imagine a very simple signal path involving a singer, a microphone, a mixing desk, a recording device, an amplifier & a pair of speakers. The origin of the sound is whatever is making it. (Let’s suppose we have a person singing – their vocal chords are vibrating in air & this is producing the sound.) This sound then travels into the microphone & here something interesting happens.

Question - What goes into the microphone?

Answer - A sound.

Question - What comes out of the microphone?

Answer - An electrical signal travelling down a microphone cable.

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In this case, sound energy in the form of the singer’s voice (red) is changed into an electrical signal by the microphone (yellow). This electrical signal is then carried down the mic cable to the mixing desk & on to the recording device. The signal is then captured & stored in some way by the recording device. The recording device might be digital, in which case the electrical signal will be converted into a digital signal that can then be stored onto a disk or CD. (Yellow to blue.)

When it is time to listen back to your recording, you would press “play” on your recording device & this would replay what you had previously recorded. The digital signal would be reproduced, converted back into an electrical signal & sent down a cable to the mixing desk & on to an amplifier & a pair of speakers. Speakers are also transducers – an electrical signal travels to the speakers which causes the speakers to vibrate. These vibrations in turn create sound. This completes this signal path.

As a sound engineer you will have to deal with multiple & often quite complicated signal paths & it is important that you are able to visualise the origin(s) & destination(s) of various sounds/signals. This becomes even more important when learning to deal with mixing desks as we shall see in chapter 5.

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