Yo guys, just a quick question to see if any of you can help me on power chords, i can do them fine on any strings with just downstroke but if im doing down and up stroke for like a fast song or whatever i tend to for example if the chord is on strings A, D and G i will more or less always hit the top string with it and make it sound strange, any ideas how i can restrict the movement of hand to the 3 strings?

Cheers x
Mute the other strings with your left hand.
I'm currently working on a system to generate MIDI from the motion of a guitar. More info coming soon.
Just more practice. But you should also be fret hand muting. Mute the low E with the tip of your index, and all strings higher than what you're playing with the underside of your index.
Mute them with your fretting hand.

But you should also slow it down and work on your accuracy.
Yeah fair enough with the muting but it still sounds different when plugged into an amp and okay will try slowing it down
What do you mean when you say it "sounds different when plugged into an amp"? Perhaps you're not muting the other strings enough, or are pressing down on them too hard so they form unwanted notes.
I'm not sure this will work as well for power chords played on 3 strings, but for the 2 string variety, I'll use more wrist when alt picking them (similarly to if you were playing a single note) rather than strumming with them. That keeps the picking action in a smaller area, and keeps them sounding tight and chunky. Note, I do use a bit more elbow than I would on one string, so it's more of a hybrid between how you'd play a full chord and a single note.
Sometimes yes - I often feel lazy and it's easier than straight downpicking
Actually called Mark!

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