So we are working on a Christmas song last night. The band leader had worked out to sit on an Em chord for the turnaround. I felt like I should be playing a C. Band leader decides he likes the C better than the Em, so when he starts playing the C chord with me the piece looses all of its power. Him playing the Em with me playing C makes it part of a C maj7 chord. When he plays the C it just becomes a simple C chord with a lot less separation sonically between the bass and guitars. Will your guitarist let you play the root while they only play the upper notes of a Chord? Why do they feel a need to hear the chord only on their instrument?
My guitarist doesn't 'let' met do anything, I don't need to ask permission. I'm actually an equal member of the band.
If I ever play guitar now with a bass accompanying me if a chord has extra extensions to it, I will stay off the root to let my bass player shine AND because it often makes it easier to finger the chord. That's what I meant by "let".
My music theory-fu is incredibly weak, but if you want a Cmaj7 and he's playing a simple C chord on the guitar, can't you just play the B to make it a Cmaj7? You end up with the same notes as him playing Em and you playing C; maybe that sounds too different than the other way, though.
I started on bass then played guitar for about 10 years before realizing my mistake. I always made sure that everyone had plenty of opportunity to shine and provided an atmosphere where everyone felt free to speak up if they didn't like something. I wouldn't play in a band where I couldn't just say, "hey, it feels like you're stepping on the bass there, what would you think about playing ..." If that ruffles someone's feathers, then they really won't like what I'd say next.
simple solution -- tell the guitar player to lay out for the turn around,or play a fill, if he can't figure out why he is muddying it up. I will guess that the guitar player is playing the chord in the same range as the keys player, and that is creating the mud. There is no reason why you have to have two instruments playing the same chord at the same time in a song. If guitar player wants to play a chord then have him voice it up the neck above the keyboard's chord. A simple little C / E / A triad would work, or if he wants to use extensions, then C / E / A / D... You don't say what key the song is in - but if it is in C and you play an E, that won't resolve - you're on the third of the key sig (C). Play a C then sneak in a G on the last beat. The keys played is hearing his voicing, and I will bet he is voicing a C chord with the third on the bottom- probably E below middle C, and you have to play the root - C, 3rd fret A string. If he is playing anything under that E it will make more mud...
From your description, it sounds like the issue is not so much that the guitarist is playing the C, but that he isn't playing the B.
Of course that gets closer to the sound, how ever dropping the root on the Guitar gives you a much more open expanded Chord.
My drummer does that a lot. But he's very good at drums and most of his advice is solid. That said, if I want to play something I'll play that and he'll usually respect that.
It's all a matter of context, it might sound incredibly hip or incredibly awful. Or maybe both. Maj 7 note in the bass is correct, but a gamble. Your ear will probably hear this as a weird altered/sus chord built on the B which will be heard as the root, and the melody as some chord tension. You can get all theoretical and sciencey about building chords and leading notes/voices from one chord to the next, but you ear will tell you pretty fast if the voicing is wacked out or actually a neat change of scenery.
I appreciate the insight and expansion. Real-world experience beats book learning. Did I mention my grasp of theory is incredibly weak?
Sometimes my guitar will stay off the root and let me have that, other times he will stay right on top of it. Usually when there is a disagreement like this, we (the band) will try the part both ways and discuss and vote on it. Sometimes I win, sometimes I don't, sometimes we find a compromise. Either way I get what you are saying, but I would question is the E or the C the root? Neither answer is wrong, and it isn't wrong for the bass player to not play the root, and play something that creates a chord, which I think is what you are trying to do. Either way, if your guitar player insists on playing the root, and it's muddying things up, ask him to play an inverted chord or play the chord at a higher position.