How do an electric guitar's effects pedals and filters change its timbre?

An effects pedal alters the timbre of an electric guitar by manipulating the electrical signal generated by the instrument before it reaches the amplifier. These devices use analog or digital processing to modify the signal in several ways:1

• Gain and Distortion: Overdrive and distortion pedals increase the gain, which alters the harmonic content of the signal to create a grittier, more compressed sound.1
• Filtering: Pedals like the wah-wah filter the tone by emphasizing or suppressing specific frequency ranges, creating a vocal-like quality.1
• Modulation: Effects such as chorus and flanging combine the original signal with delayed versions of itself, creating complex, shifting textures.1
• Dynamics: Compressor pedals manage the loudness and sustain of notes, smoothing out the signal's envelope.1
• Pitch: Pitch-shifter pedals modulate the frequency of the input signal to create harmonies or altered intervals.1

By arranging these pedals in a chain, musicians can extensively personalize their sound, moving far beyond the guitar's raw electrical output.1