Originally Posted by ahorsewithnoname

My guess is that your motor exhaust is louder when air temperature is colder and denser rather than a noise velocity consideration from your exhaust to the alarm. You are probably making more power in cold temps. If the alarms are set at some threshold, it wouldn't take more than a few db's louder exhaust. I wonder how the specs for motorcycle noise are measured at what temperature, atmos. pressure and humidity are taken.
Greatgrandpop FXDB (not decibels)