The major scale is the major scale. If it was altered, then it wouldn't be the major scale anymore.
A melodic minor scale is a minor scale where the sixth and seventh are raised by a half step as the scale ascends; however, the melodic minor scale is played exactly the same as a natural minor scale as it descends.
Harmonic minor scale has a raised 7th in both ascending and descending scales. Melodic minor has raised 6th and 7th in ascending scale. It is similar to natural minor in descending scale.
There are a few types of scales for EACH key: major natural minor harmonic minor melodic minor The major is the one that you typically learn first, natural minor next, etc. The harmonic minor scale is a scale that is similar to the natural minor, only the 7th tone is raised by a half step. For the melodic, it is similar to the harmonic only its 6th tone is ALSO raised. NOTE: when you are coming down on a melodic scale, play the natural minor scale for that key. There are as many of each type of scale as there are scales, which, in total is 48. Including all of the 4 types listed above.
C minor melodic
The difference between a melodic minor scale and a harmonic minor scale is that in a melodic minor scale, the sixth and seventh scale degrees are raised on the way up, and on the way down they are the same as they would be in natural minor. In a harmonic minor scale, only the seventh scale degree is raised and stays the same on the way down.
B melodic minor is the relative melodic minor of D major, and therefore consists of the sharps of D major, with a raised sixth and seventh on the ascending scale, and with a flattened sixth and seventh on the descending scale. Therefore the scale's notes (ascending and descending) are as follows: B C# D E F# G# A# B A G F# E D C# B
6th and 7th are sharped.
When ascending, the melodic minor scale has a raised 6th and 7th scale degree, but those two notes are lowered when descending.
There are three varients of a minor scale: natural, harmonic and melodic.
It is called the supertonic (Latin super=above. Thus, "above the tonic"). This is the same for the major scale as well as the 3 minor scales of Western music (natural, melodic and harmonic).
pure (natural), harmonic, and melodic pure minor-none of the scale degrees are altered harmonic minor-7th scale degree raised a half step melodic minor- 6th and 7th scale degrees raised ascending and pure minor descending
In B harmonic Minor, you lower the third and sixth scale degree from the B major scale. So your notes will be B, C#, D, E, F#, G, A#, B There are three forms of minor: Harmonic, Melodic, and Natural.