How much common ground is there between applied theory on guitar vs bass guitar?

Question

I'm currently just getting into playing bass, as a guitarist. I've noticed that a lot of the online lessons I see are very similar to guitar lessons e.g:

• You MUST know all the notes on your fretboard inside out
• Triads and scales

Improving my musical theory knowledge and how it directly applies to guitar playing is another thing I want to do so I wondered just how much overlap there is here between the two instruments. Clearly music theory is music theory but I'm talking the subset which is crucially important to each instrument.

Is it exactly the same things for a lead guitarist and a bass player and the only difference is how you implement this in terms of rhythm/speed/feel? Or are there some bits of theory which are far more fundamental to bass playing than guitar or vice versa... i.e. if you're creating a "theory syllabus" for someone learning each instrument how would they differ which things you did in which order?

(yes I know they are very different instruments in terms of what they do and should be approached)

Answer 1

Firstly, I'm going to disagree a little with the first statement. Others will disagree with that, I'm sure. If you're going to play from dots all the time, then I'll partially agree with knowing ALL the notes. However, even that isn't necessarily necessary, as sight reading often involves reading the next note from what the last one was. Not reading a C#, playing it, reading a D, playing it, but thinking D is one fret higher than C#, etc. The former is far too slow, and takes up too much brain power.

Knowing what notes are relatively positioned to others is more important. As in, you're on an A, D string, 7th fret. Next to play is a D (4th up from A,5th down). It's either on the next higher string, same fret, or next lower string, two frets down. I'm addressing beginner/intermediate here, and speaking generally.

On to the question, of which all I've said is relevant - guitar or bass. The scales and arpeggios are a given - for any instrument! Except that a lot of playing expected from a bassist is similar patterns - ostinati, if you like, which change with each chord change. Root and 3 and 5 figure a lot,as these notes arpeggiate the chord being played. Hence the need to know where a G# or a Bb is - although knowing their addresses on E and A strings will often be enough to start the arps going. It's patterns after that.

Rhythms and note value knowledge are very important, too, as the bass is part of the rhythm section - part of a team, generally, and as such keeps the others together, on track, in time, along with the drummer. That stuff isn't so important for a lead player - although it's paramount for the rhythm guitarist in any situation.

I suggest for more insight into an answer to this specific question, look at RGT exams for electric guitar and bass. You'll see there is a lot of similarity, but more and less emphasis on some facets.

And, of course, the tuning of the lower 4 guitar strings mirrors the 4 strings on a standard bass, albeit an octave higher, so any theory relating to that phenomenon will be shared.

Answer 2

Some things to keep in mind:

1.) "The bottom strings are the same." Yes, on a standard tuned 6 string guitar and a standard tuned bass, the bottom strings are G, D, A, E. However, bass maintains the interval of the fourth when adding strings while guitar uses the interval of the 3rd between the G and B strings for the purposes of chord fingering and tonal modality. So, a standard 6 string guitar is tuned: E, B, G, D, A, E. Where as, a standard 6 string bass is tuned: C, G, D, A, E, B.

2.) "You can't strum a bass." You certainly can but, the application is very different - Can you strum a bass guitar?

3.) "How are you engaging the strings?" With a pick or your fingers? There are arguments for both (I can't stand picks.) Beginners, and converted guitar players, tend to like using picks - using a pick is fine (I like the tone and there are great bassists that have used picks; Phil Lesh, for example,) but, you may miss out on other interesting bass techniques, like slapping or tapping.

Finally, "how you implement this in terms of rhythm/speed/feel," as you say, isn't the only difference when performing the respective instruments but, it is a major one - for example, if you take a tasty guitar solo from the bottom 4 strings and simply pick-up a bass and play it there, it'll likely just sound like a guitar solo on a bass. :P