Голоса их были слышны, но нельзя бы

Голоса их были слышны, но нельзя было разобрать, о чем они говорят.

Results (English) 1:

Their voices were heard, but it was impossible to make out what they are talking about.

Results (English) 2:

Their voices were heard, but could not make out what they say.

Results (English) 3:

Their voices were heard, but they should not have been disassembled, what they are talking about.