Improvisation/scale question

[Depth_Charge]

I play in a jam band with a few older guys from work, who have all played a lot longer than me. The lead guitarist has been playing for 30 years and spent a year learning guitar in the US, so even though I feel way out of my depth and my "strength" as a bass player is in regurgitating covers, I just had to take the opportunity to jam with these guys!

Anyway, after we finished jamming, the lead guitarist comes up to me and starts telling me that if I'm improvising a line or supporting his solo, I can "play the 3rd or the 7th to really add some colour to those lines".

He didn't elaborate much more than that and I was rushing to leave so I didn't get much chance to chat with him about it indepth, but I'm assuming he means I can play the 3rd and 7th notes from the scale the song is built on rather than just pump the root notes with an occassional fifth.

Probably a dumb question, but how do I know which scale a song is built on/from?

Is it just a matter of practicing the various scales until I can pick the correct scale, or is there a formula I can apply to find it out?

Any other advice on successfully contributing in a jam/improvising band most welcome

Thanks in advance,

Andy

[Poop-Loops]

Ask.

I don't know if it gets any easier to distinguish which scale it's in, because I sure as hell can't do it just by ear.

[HardTech]

most songs have a chord progression. For example, a lot of songs use the I-IV-V progression. In chord terms, this would be a G, C, and D.

What he's saying is that you can play a 3rd or a 7th of those notes when playing those chords.

[hova9018]

i think what he means, is the 3rd and 7th of the chord. So if he's playing a Cmaj7 chord, he's telling you to play the 3rd or 7th which would be E(3rd) and B(7th). If he was playing a Dmaj7 chord, you would play the 3rd or 7th which would be F# and C#. however, chances are he's not playing all major chords, so you just need to kno ur fingering to find ur notes for the diff. chords (i.e min, dim, aug....), since the fingering is the same no matter what the tonic(root). Hope i didnt confuse you and i hope im not wrong. Wouldn't be suprised if i was wrong, i'm new at this stuff, but this is what i think he means. please somebody correct me if i'm wrong.

[WillBuckingham]

Originally Posted by hova9018

i think what he means, is the 3rd and 7th of the chord. So if he's playing a Cmaj7 chord, he's telling you to play the 3rd or 7th which would be E(3rd) and B(7th). If he was playing a Dmaj7 chord, you would play the 3rd or 7th which would be F# and C#. however, chances are he's not playing all major chords, so you just need to kno ur fingering to find ur notes for the diff. chords (i.e min, dim, aug....), since the fingering is the same no matter what the tonic(root). Hope i didnt confuse you and i hope im not wrong. Wouldn't be suprised if i was wrong, i'm new at this stuff, but this is what i think he means. please somebody correct me if i'm wrong.

A good start. But if it's a "jam band" everything will be minor 7 chords.