I think the problem you'll find with the RAM sound units is that they're way underpowered. They typically come with a little 2" speaker and an output power of maybe 2-3 watts. That may sound loud on the bench, indoors, but get your model out in the open and on the lake 20- 30Ft away and you definitely won't hear anything. SPL (sound pressure level) decreases as the square of the distance from the source so get any reasonable distance between you and a RAM sound module, and you won't hear it. Plus they're voice quality only which means they have high distortion and can sound muffled.

They are cheap - but then, as with most things in life, you get what you pay for.

Regards,
David