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Old Nov 5, 2011 | 07:21 PM
  #11  
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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)
 
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Old Nov 5, 2011 | 07:58 PM
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I don't know how newer models without carbs work, but I have to use more choke when starting in colder temps (higher revs) to keep from stalling.
 
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Old Nov 5, 2011 | 09:01 PM
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Originally Posted by fardept
I asked my wife, who`s a Harley rider and a physics teacher (brains and beauty, believe me) and she says, "USMAMule has his physics right, but it seems that those changes in wave speed and dissipation -- loosing less oomph -- wouldn't be significant over such a short range. (You can definitely hear far-away things better when it's very cold. There are also fewer competing noises outside on a cold night.) I wonder if it isn't in the car's sensors. Most are designed to detect vibrations, and in the cold, whatever spring is in the sensor would be more rigid and might trigger more easily. Awesome question! I'm going to toss it out to my students on Monday."

I think my high school physics teacher would have gotten a kick out of knowing one of his students remembers the lessons he taught 35 years later. :-) I wish Dr. Katman was still alive. I guess it is really true that teachers effect the future in ways they never imagined and achieve a kind of immortality.

Please tell your wife he's made an old physics student happy.

USMAMule
 
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Old Nov 5, 2011 | 09:10 PM
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just ordered pizza. its cold out. lets see what happens
 
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Old Nov 6, 2011 | 01:45 AM
  #15  
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warm air rises and cold air sinks. so when its cold out the sound waves travel on the ground rather than rise with the warm air.
 
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Old Nov 6, 2011 | 06:30 AM
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Originally Posted by gartec81
just ordered pizza. its cold out. lets see what happens

Did Ya get your Pizza yet? Or are you still waiting?
Remember cold-fast pizza, will warm up in your belly causing it to heat up and the gasses will expand rapidly and cause the expulsion to be loud and odoriferous................
 
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Old Nov 6, 2011 | 06:35 AM
  #17  
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Originally Posted by gartec81
just ordered pizza. its cold out. lets see what happens

Did Ya get your Pizza yet? Or are you still waiting?

Remember eating fast-cold pizza, will warm up in your belly causing it to heat up and the gasses will expand rapidly and cause the expulsion to be loud and odoriferous................
 
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Old Nov 6, 2011 | 07:58 AM
  #18  
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Originally Posted by gartec81
so what your saying is: if i call in pizza when its cold out I will get it to my house faster than if i ordered and it is hot out. due to sound traveling faster and all?

Too funny!!!
 
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Old Nov 6, 2011 | 03:11 PM
  #19  
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Gartec how'd the pizza turn out. Or better yet, how quickly did it arrive?
 
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Old Nov 6, 2011 | 03:44 PM
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test, test
 
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