Both hands playing uses wrong octave

[Jarzka]

Hi again

When playing the attached song with only left or right hand, everything works ok. However, when I switch to play with both hands, synthesia moves both tracks one octave higher. I can still play it with my physical keyboard, but it sounds wrong since I'm really playing it one octave higher. Why does this switch happen?

More detailed explanation:
In the file correct.png, I'm playing with right hand track only. I'm pressing the middle-D key on my keyboards and it works as as I expect.
In the "wrong with both hands", I play the same song with both hands. I'm pressing the same middle-D key on my keyboard, but for some reason Synthesia expects me to play it one octave higher. This sounds wrong.

[Jarzka]

I think I realised the problem. There is one extra low note on the left hand track that I'm unable to play with my current keyboard. That's the reason why Synthesia moves everything one octave right to make it possible to play this song. But it still sounds wrong.

Anyway, I removed that one low note and now I can play the song just fine.

[Nicholas]

Another way to prevent Synthesia's "helpful" behavior in this case is by changing Settings --> Gameplay --> Keyboard Octave --> Manual Only.