I believe that synths will typically give priority to the most recent note (or notes). When you reach the voice limit, the result is usually a note being cut off abrubtly rather than a note failing to play at all.
The oldest note will be shut off to free up the voice for the newest note. So typically you will hear each new note begin at least.

Even in a case where the bass channel has only one voice allocated, you should always here the most recent bass note.