The layman's explanation of overdrive is that a signal is radically boosted in either the instrument, preamp, power amp, or speaker stage of the signal path (or any combination). The boosted signal is so strong that it overloads the following stage. This creates a compressed effect (sustain), and also emphasizes various overtones, thus "thickening" the sound.
The problem, however, is that when a signal is boosted like that, it is prone to feeding back... especially when you are playing at gig volume. The phenomenon of feedback may sound cool occasionally, but when it unintentionally sneaks in between the notes of your lead, it can be irritating.
If this is a problem for you, the obvious solution is not to use so much distortion. It's important to note that the distortion setting that sounds right in your bedroom is probably too much on stage. The reason for this is that when you play loud, the power tubes and even the speaker itself may be distorting. Therefore, you don't need to dial in so much at the pedal and/or preamp stage. Besides, extremely saturated tones may sound muddy in the context of a full band.
É exactamente este tipo de feedback que me acontece.
As minhas cordas também já estão mais para lá do que para cá. Será que isso contribui igualmente?
The first step is to turn down your treble on your amplifier. Too much treble invites feedback so don't have too much treble in your amplifier settings.
The second step is to turn the volume on your guitar up only 3/4. Don't turn your volume up full as this is invites huge feedback! Always leave a little room on your volume, so don't turn it up all the way. Only 3/4 and I guarantee you will reduce feedback at least 80% with this trick.
One other trick is to turn down the gain or distortion on your amp. When you play softly, you can turn your gain or distortion full. But when you start playing with some serious volume, turn your gain only 50%.
Não sei se esse truque do volume knob da guitarra ou não funciona, mas tenho uma ligeira ideia de que a "gritaria" é mais evidente quando tenho o knob no máximo.