Can't understand why any harp would have 'all keys only' on it. Blues harps come in many keys, and decent blues players will have an armoury of at least half a dozen.

Reason being - blues harp works best using one that is not in the same key as the song. Song's in C - use an F harp. Song's in A - use a D harp. basically, count forward to the fourth note in the song's key. A-B-C(#)- D.

So if you play with a band which plays blues in different keys, you will need those appropriate harps. I used to do a particular open mic, and one guy would keep trying to make his one and only harp fit in every song, till somebody explained where the problem lay. Went out, bought several, can now play along in several keys!

The harmonicas which can be played in any key are those with a push button. But even they won't work as blues harps, unless the song's in F. That's because a lot of chromonicas are basically in C.

Can't understand why any harp would have 'all keys only' on it. Blues harps come in many keys, and decent blues players will have an armoury of at least half a dozen.

Reason being - blues harp works best using one that is not in the same key as the song. Song's in C - use an F harp. Song's in A - use a D harp. basically, count forward to the fourth note in the song's key. A-B-C(#)- D.

So if you play with a band which plays blues in different keys, you will need those appropriate harps. I used to do a particular open mic, and one guy would keep trying to make his one and only harp fit in every song, till somebody explained where the problem lay. Went out, bought several, can now play along in several keys!

The harmonicas which can be played in any key are those with a push button. But even they won't work as blues harps, unless the song's in G. That's because a lot of chromonicas are basically in C.