I'm building THE B-25 Apache Princess EPO Twin. I'm looking to add a sound module with speakers and a battery with just start-up and full power engine sound.
I did found one site...but they wanted about $500.00 for the complete set.....that's a lot of money.
Is there a cheaper way building this sound module with speakers and a battery or another site you may know?

Thanks,
bobbart

The sound systems I've experienced are not loud enough to be heard clearly while the plane is in the air. You can only hear anything at all if it's perfectly calm and everyone holds their breath, and then it's just a muffled rumble or annoying buzz.

Sounds cool up close, but you simply can't fit a big enough speaker into a typical model airplane to get good sound at a distance.

These folks have this down pat:

http://www.benedini.de/

I've seen/heard videos of models implementing their equipment and I am impressed.