NEW GOVERNOR FOR THE STATE????

[Kreutz]

Sirens are audible as they approach because they actually emit waves, a simple deer whistler strapped to the front of a vehicle does not.

Uh, no. If the deer whistle makes any sound at all, it is emitting sound waves too. Doesn't matter if it is powered by wind or by electricity or compressed air. Now, we could shift (get it? shift? ) the discussion to whether or not the passive whistles make any sound at all (questionable), but if they do they don't just make sound pointing rearward...

As the air moves into it nothing is propelled out/forward. Any air currents entering into it to generate sound would go back/towards the driver and thus not doing a thing to deter deer in front of the car.

If this were true, you couldn't hear a referee blow a whistle if his back were to you, and you wouldn't hear a gun's report if it weren't pointed in your direction (just to get us back to guns!)... That Doppler Effeeeeeeccctttt is mighty powerful!

Want to make sure we're on the same page here, we are talking about these kind right?



This is not analogous to a whistle or a gun. Try and picture the above device meaningfully projecting soundwaves, from a moving car (this is a key difference between hearing a whistle or gun from a stationary source) in a forward direction, while working against the friction of the very air it needs to make sound.

Not gonna happen.

Any sound waves would be incidentally produced from bouncing back off the car. They would be weak and all over the place. I've seen the ads for these things, they draw in a line like this is propelling a beam of sound straight ahead; total BS.

A powered whistler would be able to project sound to an appreciable, like a police siren. I'm only discussing the cheapies you stick on the car.

Whether or not those really work, who knows? My philosophy is I have collision insurance so if I hit a deer I get a new car.

[meak99]

Those are what I'm talking about. They are the same as a whistle, except instead of you blowing in them, they use the oncoming wind to generate the sound. How does that magically mean the sound only travels rearward? Forget any claims made by the manufacturer of what they do. I don't think they simply project sound forward. Sound waves go out in all directions.

[dorminWS]

I get it, and it makes a lot of sense as to why the consensus out here in the hills is that those things are worse than nothing. To put it in simple terms, the thing is unlikely to be very audible in front of your car because it is blowing backwards. (And as you brake to avoid a collision, it would become less audible as the wind of motion that blows it diminishes) And if it is heard, as someone has already observed, it is most likely to cause a deer to freeze - not get out of the road.

Please shut up for a while, Kreutz.............. All this agreeing with you is scaring the hell out of me.

[WRW]

This is not analogous to a whistle or a gun. Try and picture the above device meaningfully projecting soundwaves, from a moving car (this is a key difference between hearing a whistle or gun from a stationary source) in a forward direction, while working against the friction of the very air it needs to make sound.

I think this is where you are going off course. For this example, wind speed and friction of the wind has no effect on sound. Whether 70db of mechanical sound (at x frequency) or 70db of passive sound (at x frequency), the sound will spread in all directions. If the whistle or the mechanical sound generator is at the rear of the megaphone, the sound will be projected forward, wind speeds be damned.

[BW1911]

For this example, wind speed and friction of the wind has no effect on sound.

Exactly!

Whether 70db of mechanical sound (at x frequency) or 70db of passive sound (at x frequency), the sound will spread in all directions.

Right again!

If the whistle or the mechanical sound generator is at the rear of the megaphone, the sound will be projected forward, wind speeds be damned.

Three for three!

Doppler Effect affects frequency but not propagation, and sound is sound, whether it is a deer whistle, a ref's whistle, or a gun shot. The report posted says the whistles are heard forward, but that they're not always in the best frequency range and that they don't always elicit the desired response from the animal.

Now, we should transform this conversation into why suppressors work, just to return to our roots

[dorminWS]

Doppler Effect affects frequency but not propagation, and sound is sound, whether it is a deer whistle, a ref's whistle, or a gun shot. The report posted says the whistles are heard forward, but that they're not always in the best frequency range and that they don't always elicit the desired response from the animal.

Now, we should transform this conversation into why suppressors work, just to return to our roots

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Experience will tell you that sound does not propogate (at least not well, at least not most of the time) against a strong wind. A car moving at 60mph makes it's own strong wind (assuming, of course, that it doesn't have a 60mph tailwind), and so common sense would seem to dictate that the whistle would be much less able to be heard in front of than behind the car. On the other hand, deer can hear a mouse break wind at 500 yards, so we're right back to WHO THE HELL KNOWS?, right?

The other little thing that bugs me about this is that I've never known anybody that had one of these doodads that thought it worked. Maybe that's because the deer are getting hit when they stick their heads out in front of the car to get a better look at whatever is making that gawd-awful sound?

[BW1911]

Experience will tell you that sound does not propogate (at least not well, at least not most of the time) against a strong wind.

Okay so far... but we're not talking about a wind field that is blowing at 60 mph everywhere. We're talking a car that is moving at 60 mph... that's a whole different critter since the observer is not in the car, but is in front of the car.

A car moving at 60mph makes it's own strong wind (assuming, of course, that it doesn't have a 60mph tailwind)

Okaaayy.... kinda.... but recall that a car moving at 60 mph only experiences a free stream velocity very near the body of the car due to its own velocity. The car doesn't make a 60 mph wind EVERYWHERE, it only experiences a relative (to the car) wind in very close (within a few feet) proximity to the car. A car approaching at 60 mph from anything more than a car length away does not create a wind where the observer is standing.

So... if you're standing on a roadway in still air, and a car is approaching at 60 mph, will you hear it arriving before it passes you? Of course! If the driver is leaning on the horn as the car approaches, will you hear that before the car arrives? Of course you will! You can hear the whistle on an approaching train. You can hear a siren on an approaching ambulance. Why, then, would you not expect to hear a whistle located on the car? (Rhetorical question, only)

[grumpyMSG]

Since everybody seems hung up on the silly little deer whistles and the direction of sound. I'll throw my $ .02 in on it. Sound can be directional. the wind blowing through the whistles indeed would project most of the sound through the whistle and it may or may not bounce off the car or be absorbed by the material behind it (it would bounce off a headlight or piece of sheet metal but be absorbed when it is in front of the radiator). The Doppler affect is why the siren changes sound as the Police car or Fire truck passes you. Using a firearm analogy, think of being on a firing line at a range, have you ever shot next to a muzzle brake that redirects muzzle blast to reduce recoil? It is a lot louder (sometimes uncomfortably so) to the left or right than for the shooter.

If you are indeed trying to avoid hitting a deer, you have to understand them. They actually have three responses to threats, flight, freeze or fight. Most people forget about freeze and it gets them when the perceived threat gets close enough and it changes to flight. I can't guarantee that you won't hit one, but know how to help reduce the risk. Most deer are nocturnal, coming out late in the evening to and disappearing early in the morning. So chances are, you are going to hit the deer in the dark not daylight. One of the worst places I know for deer/car accidents are on I-64 west of Charlottesville to the top of Afton mountain, an 18 mile stretch that I can't remember not seeing evidence of a deer strike every time I go through. The biggest thing you can do to avoid a deer strike or hitting a suitcase/box that fell off a car in front of you is to slow down. Let the weather/ terrain dictate how fast you go, not necessarily the speed limit. If you are running along at night and can't stop in the distance your headlights allow you to identify threats, you are an accident waiting to happen. The same can be said for driving in fog or rain or on a windy country road. If you can't stop in all the distance you can see, you are going too fast. Too many people are hurt popping over a hill and hitting a stopped car, truck or bus or a slow moving piece of farm equipment. The other thing you can do to help with deer is to trigger the flight reaction sooner. If you are driving along and see the deer freeze, honk the horn or flash the headlights, at least slow down, they will know you have seen them and take off rather than waiting until you are right on top of them and then trying to run.

[Tweaker]

I have had deer whistles on all my vehicles and have never hit one. I have seen on many occasions:
- deer locked on my vehicle as I approached, they heard me before I came around the curve
- deer who froze in place off to the side of the road, rather than run off or run into the road
- deer actually walk backwards slowly off the roadway while locked on my car

I don't know if they work or not, but my small sample of personal experience says yes. If not they are $5 each and don't look too bad.

I drove in the rural areas all around Charlibsville, and I did it at night and hauling ass most often.

[BW1911]

IIRC, there has been a lot of past concern that the passive whistles don't really work and, in response, a powered whistle or two (or 50) have been marketed. I know someone who bought one for a motorcycle and claimed they had no apparent effect on deer on the edges of the Colonial Parkway, but they startled dogs in his neighborhood and horses visibly shied away, too. I believe he said it was switchable "on" and "off" for that reason. I never rode with him, though, so this is just a bit of heresay...

I vote for the "PA System" approach. If you see a deer on the side of the road, grab your mic and yell at it "FREEZE!! DO...NOT...MOVE!"

or if you see one in the middle of the road in front of you, grab the mic and yell at it "HEY!! YEAH, YOU!! GET THE HELL OUTTA THE ROAD BEFORE YOU GET KILLED!!"

+1! I bet this would work for brain-dead pedestrians, too! You ought to see people jump when you start talking to them from a motorcycle! Things like, "I'm RIGHT here, so get BACK in your own dang lane!"