Hello everybody.
I always had my Edge 130 mounted in the stem, and I could clearly hear the alerts, even with a lot of traffic. But I recently bought the Varia UT800 and mounted my Edge in the Garmin out-front mount. I didn't know why, but the audio alerts became very, very low. With traffic the alerts can't be heard. Then I decided to mount the Edge 130 again in the stem, and the volume sound increased! What is my conclusion? Is that the edge sound "reflects" in the stem, and "don't go away", but "stay there"! That's why the alert sounds can be heard. Please try with your gear. Hope my (bad) english was good enough to be understood... Thanks.