Thank you for your very quick reply. Wow, I haven't used a default aircraft for 12 or 15 years!!! However, I loaded the default Baron 58 and opened the original Baron 58 checklist that came with FDC Live Cockpit when first installed. The result was the same - asterisked items were silent.
I am aware the interactive items do not work with third party aircraft (or at best they work sometimes) however the asterisked items, which are the ones that are the problematic ones, "are only available when using one of FDC's 'Extended' Voice Sets". I have been using FDC for many years with third party aircraft from different vendors without any problem - I am not aware of anything that has changed in my system, with FSX or FDC installations - the missing voice problem just mysteriously happened a couple of months ago.
I am not sure what the "Extended Voice Sets" are or if the are allocated to any particular voice set, so I tried each and every voice set but the problem was the same with each of them.
I look forward to your reply..........