All of the replacement candidates tested are not as loud as the original part. The design of the original part is a bit different - and the video below shows what I'm up against.
If anyone has ideas on ways to solve this, please email me at "rwb134" using Google's fine e-mail service. I really want to get more of these made, especially so I can have them ready in time for TagFest 2015 this year. Keep your fingers crossed.