m7b5 is pronounced as 'minor seventh flat five'.
'Cm7b5' represents the chord C minor seventh flat five.
Remember that in chord naming, a small letter 'm' indicates minor and caps 'M' indicates a Major. 'b' (or more correctly '♭') is the symbol for flat.
Now, how do we find the notes to play the chord 'minor 7th flat five'?
Start with a minor 7th chord.
Minor 7th chord has the following spelling : Root – minor 3rd – fifth – minor 7th
Now flatten the fifth of the chord to get 'minor 7th flat fifth' chord.
Minor 7th flat five : root – minor 3rd – flat fifth – minor 7th
We play the flat five note instead of the fifth note.
Let us take the example of C minor 7th flat 5th :
C minor 7th chord = root – minor 3rd – fifth – minor 7th = C Eb G Bb
C minor 7th flat fifth chord = root – minor 3rd – flat fifth – minor 7th = C Eb Gb Bb
Minor 7 flat five chord is also known as the half diminished chord. Here is a video on playing 5 related chords on the guitar, knowing the relationship between the chords which makes it easier when playing.
Playing minor 7th flat five on the guitar
Try the following chords on the guitar. Here the chords are given with D as the root – 3rd string 7th fret. Change it to 3rd string 5th fret, keep the pattern intact – the relative position of the notes – and you have all the chords with C root. Similarly by changing the root position while playing the notes in the same relative position from each other, you can find chords for each of the 12 roots on the 3rd string.
D minor 7th
D minor 7th flat five
D diminished 7th
Notice how you can change just one note of each of the chord and get the other. Learning to play and see chords in relation to each other makes guitar playing more practical and applicable to different situations.