Had exactly the same experience with a p2 decoder last week. Changed speaker twice, no joy. Bought a replacement... works fine. It is no doubt a faulty batch. Your experience mirrors mine to the letter. I understand your frustration - poor quality control. Added to which, fitting the decoder and a mini sugar cube speaker in my dcc ready p2 (in the loco not tender) was an exercise in patience and tedium. Since they did not leave any room to comfortably fit the decoder and speaker. I absolutely love the brand and most products, but this was a pain from start to finish. And for what it’s worth Hornby, please start supplying sugar cube speakers by default instead of the huge round frisbees which no doubt most people cut off and discard since they fit very few locos. Rant over.