Specific chords have distinct ring that may distract from exercise

[vitalash1]

I really don't know whether this is what users are intended to learn to hear, but it seems like it makes it very easy.
Some chord have a distinct ring that others do not (with the "Piano" instrument).
In the following picture, I circled the ones that have the ring. When playing a circled chord against one that is not circled, it is very very easy for me to know which is which by virtue of the ring alone.

Using the "Piano (old)" instrument and playing Yellow sounds far better than with the "Piano" instrument.

This happens for me with Windows 10/FireFox and iOS/Safari.