We are gonna do one song at a studio recording live. Our singer wont be there. How much time will we need to do this 2 hours?
Depends entirely how well you know the song.
All I want is for everyone to go to hell...
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Quote by DisarmGoliath
You can be the deputy llamma of the recordings forum!
If the drums are perfectly tuned & you have your guitar & bass tones properly EQ'd (collaboratively) so that it won't sound like a muddy mess on a recording (which is very different to setting an amp for a gig), and any other instruments are up to a similar level of preparation BEFORE you get to the session, depending on how long the engineer wants to spend getting mic positioning right & experimenting to get the best results, you may get a take or two in two hours, but it's unlikely, unless your engineer is a numpty.

Obviously you all have to know every single part of the song inside out (your own parts, how they fit with other instruments, section lengths, tempo, changes), and your drummer has to be completely comfortable with playing to a click track.
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become a circumsizer, you get like £60,000 a year + tips.

Quote by Flying Couch
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Could I get some more talent in the monitors, please?

I know it sounds crazy, but try to learn to inhale your voice. www.thebelcantotechnique.com

Chris is the king of relating music things to other objects in real life.