...hope no one minds me digressing slightly since this has arisen, but can someone once and for all explain in simple terms (to someone with zero musical ability or particular interest in/knowledge of instruments) what IS the difference between guitar and bass? I always knew it as "bass guitar" but nowadays everyone seems to shorten that to "bass" as if it's not really a guitar (which just happens to sound deeper?). They look the same instrument to me, and players hold them in the same manner - it's not like you'd adopt a different style of playing like you would if switching between a mouth organ and a xylophone, for example.
If bass is so different from guitar, why isn't rhythm? Why don't we still call them "bass guitars"? or do we? I'm not being obtuse, honestly.
Bass guitars are still Bass guitars, some people shorten it to just Bass (maybe a throwback to the days of Double Basses)
Rhythm Guitar plays essentially chords throughout a song (groups of notes played together, strumming technique)
Lead Guitar plays single or sometimes double note melodies when there are no vocals ie " a Lead break" think of Georges great lead guitar break in his song 'Something'..........to play a good lead break a guitarist has to be quite skillfull at things like bending strings (to change the pitch)
Sometimes a lead guitarist will play chords but usually different/complimentary chords to what the Rhythm guitarist is playing.
A Bass guitarist play basically Root notes of the chords to the song, so if the chords to a song are C,F & G the bass will play these but the Bass is tuned an octave lower than the other guitars so gives a sort of foundation to the overall sound of the band. A very basic Bass player will pretty much play C F & G.
A good Bassist will play notes inbetween the root notes of C F & G (embellishments), but sometimes these in between notes can be too many or too frequent so it can be said 'he's playing Bass like a lead guitarist'
Paul was very good at coming up with his own little melodies on Bass that seem to fit perfectly with the song, this was more common on later Beatle stuff like Bulldog, I Want You and a lot of Pepper songs, He constructed a wonderfull Bass line on George's Something, listen to the Bass on headphones, he concocts a brilliant melodic Bassline.
Thats probably clear as mud