ACTIVITY, Digital Signal Processing (DSP) Song [HOME]


In this activity, we'll listen to and discuss DSP effects, then take a prepared GarageBand file and transform its sound using some of these effects.

DSP is defined as the manipulation and modification of signals in the digital domain. Today’s DSP enhancements are a carry-over from analog features. A distinction is made between effects and processors. Effects are added to the original signal, while a process changes the original signal. Examples of effects include reverb, echo, delay, chorus, phasing, flanging, and pitch shifting. Examples of processors include equalizers (EQ), gates, compressors. In the digital realm, the distinction between effects and processors is blurred since these alterations can be made “non-destructively”.

DSP EFFECTS can simply color a sound, making it warmer or lusher or brighter, etc. - OR - they can twist and mutilate and sound beyond recognition, making the sound unique, jarring, or bizarre. DSP effects are almost always incorporated into synthesized sound such as that found on a synth keyboard, but they are often applied to recorded sounds (vocals, guitars, drums, etc.) either while recording ("sends") or afterwards.

LISTEN to the following excerpts from recorded music that use DSP effects prominently...
Vocals (Kelly Clarkson)
Vocals, "Welcome Christmas" (GLEE)
Synth Drums, Guitar, & Vocals (Sheryl Crow)
...then, DISCUSS what you hear, referring to the following oft-used DSP effects:
  • Reverb and Echo
  • Compression: CLICK HERE for a great explanation on compression
  • Various Filtering Schemes (Low Pass, High Pass, Band Pass)
  • EQ (equalization): CLICK HERE for explanation of "equalization"
  • Chorus
  • Flange

TUTORIALS:
  1. Using SMART CONTROLS in GarageBand to vary DSP plug-ins. Here's another related video about using Smart Controls and adding DSP plug-ins.
  2. Adding other effects & plug-ins besides those pre-set in Smart Controls.

PROCEDURE:
  1. Using a GB file you create, or a template given to you by your instructor, alter the Smart Control settings for 2-3 tracks.
  2. Note how REVERB, COMPRESSION, and at least one other DSP plug-in modify the sound of these tracks.


EVALUATION: This is a participation grade activity. Making a good faith effort to engage in the activity, and asking questions when you encounter problems, gets you 100% credit!