Hi kaeote and welcome to BAIB and the forum. No better topic around here than cipherin' chords. If this is your biggest newbie problem, you're doing pretty good. First, to be clear, I suggest you spell out exactly what you want. I think by Bb7/13 you want Bb D F Ab G (no 9th or 11th). It looks like the chord builder does not have that explicit spelling, and when I play Bb D F Ab G on my keyboard and ask BIAB wghat I played, it says Bb13. And when I play Bb D F Ab C G ist says the same. So if that is what you want, you may have to take the 9th with it. Do check out the chord builder so see all the variations.

I think it is not the case that a Bb7/13 indicates you want a Bb7 chord with the 13th in the base . We (and BIAB) use what are called slash chords, and if you wanted the 13 in the base you specify Bb7/G. That could be called a Gm7b9. A Bb13 would technically be Bb D F Ab C Eb G, although the Eb (11th) is usually omitted.

So - spell out your chord for us and someone will give you best BIAB answer.

Regards,

kelso

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