minor key
minor mode

When it's in minor key, you can hear the man talking to God.

He began to play, finger picking in a minor key.

One of those building blocks, for instance, is the difference between major and minor keys.

Each group covers the eight major and seven minor keys.

The second movement is written in the relative minor key.

Each minor key has the same signature as its relative major.

As expected, the evening moved along in a minor key.

The melody this time was not that light air in a minor key which she had played before.

The music was nostalgic, most effective in a minor key.

Quite often the music is not in a major or minor key.