1. Amplifier Distortion:
An amplifier’s main job is to take a weak electrical signal (like from an instrument, microphone, etc.) and make it stronger. But sometimes, the amplifier doesn’t just make the signal louder – it can also change or distort the sound. This is what we call distortion.
Distortion can happen when:
- The signal is too strong for the amplifier to handle (it “overdrives”).
- The amplifier is intentionally designed to add a certain kind of “gritty” or “fuzzy” sound (like in electric guitar amps for that classic rock tone).
There are two types of distortion:
- Clean distortion (also known as “clipping”) happens when the amplifier starts to push the signal too hard, causing the waveform to flatten out. This results in harsh, gritty sound.
- Overdrive/distortion effects are actually designed to create that sound, which is why guitarists use them to get that edgy, crunchy tone.
2. Feedback:
Now, let’s talk about feedback in the context of amplifiers. Feedback is when the sound from the speaker (or output) gets picked up by a microphone (or input), goes through the amplifier again, and starts creating a loop. This can cause the amplifier to keep amplifying the sound, which leads to a loud, often high-pitched “squeal” or “howl.”
Positive Feedback:
- In a negative feedback system, the amplifier tries to reduce distortion and keep the sound clean. But positive feedback happens when the output (the sound) keeps getting amplified in a loop. This is what happens in cases of loud ringing or howling sounds from a microphone near a speaker.
- You may hear this as the classic “feedback” sound, especially in concerts when a mic is too close to a speaker.
Some amplifiers are designed to use controlled feedback to intentionally modify sound. For example, guitarists may use feedback to get that sustained, screaming note.
Summary:
- Distortion happens when an amplifier overdrives a signal, either by accident (overloading) or on purpose (like in guitars for a specific sound).
- Feedback is when the sound from the speaker gets picked up by the mic and creates a looping effect that can lead to loud squeals.
