A very concise page. If you are going to build circuits firmly in the audio frequency range, a lot of this is still good to be aware of. Or even things that a

A very concise page. If you are going to build circuits firmly in the audio frequency range, a lot of this is still good to be aware of. Or even things that are not listenable, like temperature controllers. In that case you want your electronics layout not to pass radio frequencies. Which aren't really that difficult to filter out, although it's possible for the part of the circuit doing the filtering to be ineffective against RF generated or received inadvertently in other parts of the circuit. Plus, people don't always realize that audio frequencies "broadcast" too. Just not very effectively nor very far. But the more power, the more boldly either way. Sometimes if you're not careful, a high-current wire or PCB trace will serve as a broadcast antenna, and other structures nearby within the same chassis may just happen to pick it up and you can get quite a bit of positive or negative feedback being amplified. This can be a serious compromise to the design goals, and may just be a matter of physical layout of the circuitry with a few of these things in mind.