Does marijuana ruin your singing voice?
Singing actually requires a lot of oxygen to have a clearer, and not just louder voice. This is why when you're singing, you're often recommended to being able to practice taking deep breaths, so you can last longer and have wider range. This is also why you're often told to widen your mouth when annunciating a lot of words when singing, and the smoke just makes that a lot harder.
It leaves behind residue in your lungs that can give you shorter breath, sometimes it makes it harder hit higher notes.
Not so much the marijuana, itself, but the smoking of it...just like smoking cigarettes.
Any type of smoking can ruin your voice. So yes, marijuana can.
maybe, I think marijuana ruins a lot of stuff though