I'm not shure, but maybe you are using a midi keyboard or software
sequenser that has assigned the 'mute' keys to other functions than
notes. Like 'stop', 'play' etc. Once a key has other assignments, you
can't hear the note.

Some midi keyboards have templates for sequensers with these other
functions.

Succes from the Netherlands,

Jos

--- In XL-1@yahoogroups.com, "plaisirpw2006" <patrick@...> wrote:

> When i play the lowest C key, i heard the sound. When i play the
next note (D) i heard
> nothing until i reach the E one octave upper, and nothing from there
to the C again octave
> upper. After that all notes are responding well.