ELI5 : Why do guitar amplifiers give off bad feedback? guitars in giant rock concerts don’t normally do this, how they can be so loud without feedback?
In: Technology
The guitar amps/setup at rock concerts are different to your typical bedroom 30watt fender amp.
Firstly, at most large concerts, amps are ethier mic’d up on stage, or off stage in an Isolation Cabinet. The musicians will probably have ‘in ear monitors’ (head phones essentially) for listening to all the audio they need to hear. This essentially means that its much harder for a feedback loop to occur as any amp noise isn’t being directed to the guitar.
Secondly, a lot of feedback is caused by noise, a few things can remedy this.
1) A noise suppressor – This acts as a gate where low-level noise such as power-hum isn’t let through to the amp, as soon as anything louder is detected (for example playing the guitar) the gate is opened and sound is let through to the amp. This makes feedback harder to occur (in simple circumstances)
2) Power conditioners – These help prevent ‘noise’. Which i think is commonly referred to as ‘ground hum’ ?
Any large concert will have (high end) noise gates and power conditioners to help prevent unwanted noise/feedback.
Note : A lot of musicians will have their ‘rig’ off stage, however they’ll have an amp or speaker on-stage so they can intentionally trigger feedback by walking up to said amp/speaker and dry-humping it with the guitar. This is a very intentional setup which prevents feedback in 99% of the regular performance.
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