Unitrol 480K?

[Shinkansen]

What does that siren sound like? I saw one at the fair on Rockwell Fire Dpt's Heay Rescue Truck, but they couldn't turn it on. Any clips/Vids? Thanks

[q2bman]

The basic tones (yelp and wail) sound like this model. I love, abolutely love Unitrol siren tones.


http://www.youtube.com/watch?v=UYqgBITv_DA

[Shinkansen]

Ok, thanks. Those Unitrols sound great.

[Robert Gift]

480K is my favorite.
Switchable from one speaker to almost 200 watts into two speakers.
Nice compact headesign by Unitrol. (Dunbar Nunn)

A tiny dislike is that it slightly holds the peak before descent.
(Or is this just our 480K.)

Seen in the link above is NOT a 480K.
Notice how the ridiculous gimmick sounds are less loud than Wail and Yelp?
They should be banned from emergency vehicle sirens.
An EV siren should be unmistakable and convey that an EV is near.
Not cause motorists to wonder what is happening or who has their Gameboy turned up too loud.

[q2bman]

That's why I like the siren. That peak hold you're talking about. And I agree. The "traffic clearing" tones are worthless on the unitrol sirens. They sound like half the output of the wail.

[Robert Gift]

Would be nice to measure the amplitudes of the gimmick sounds.
Surely they are the same output as the Wail and Yelp.

Many people may wonder whathe gimmick sound is instead of recognizing it as an EV for which they may need to pull over.

In Aurora, CO a there is a Rural/Metro Ambulance which has TWO electronic sirens -or sounds that way.
How ridiculous.
Is no louder than one siren, but all the more annoying.

Imagine drivers becoming used to two sirens per ambulance.
A driver hears two sirens, pulls over, then when thEV passes, pulls out into the path of a second responding EV, having assumed the second siren was that of the FIRST EV!

It isometimes amazing that drivers are so impatient noto simply check before proceeding.

Scene:
1 lefturn lane, 3 through-lanes SB.
Recently I witnessed a near collision when a SB ambulance used the left turn lane to pass SB traffic which had stopped. (He was turning right athe intersection when a fronthrough-vehicle began to proceed. Apparently the driver assumed the ambulance was either turning left or heading straight.

Scene:
2 lanes with center turn lane WB
WB backed-up traffic stopped for several hundred yards due to congestion from road construction ahead.
I have video of a WB guy pulling from lane one into the turn lane, no signal, as I was WB silent in the turn lane. We had just received the call to proceed emergent and, checking behind and using left turn signal, I had just pulled into the turn lane. Was a little close.

[q2bman]

I like the two siren tones. It seems you have the best of both worlds. The wail is good for distance warning and the yelp good for close up warning. Since cars may be traveling fast the frequency spectrum is covered in a shorter time allowing any "blocked" frequencies to enter the vehicle. This is my theory.

[Robert Gift]

One Wail from two speakers is louder then wail from a one 100w speaker
and Yelp from the other speaker.

Wail is percieved by the human ear.lier than Yelp.
So even at the same volume, Wail is "heard" first.

Both are equally affected by the doppler effect.

Also, Yelp tends to panic people.

Wail is the better sound for distance and also intersections.

For most runs I keep in Wail holding microphone button to silence the siren. Then open the button to sound Wail only enough as needed.
Then depress the button for instant silence - not even the 4 second run-down.

[q2bman]

For most runs I keep in Wail holding microphone button to silence the siren. Then open the button to sound Wail only enough as needed.
Then depress the button for instant silence - not even the 4 second run-down.

WHILE YOUR DRIVING? It's not bad enough that you are not sounding the siren, you're not even keeping you hands on the wheel!? Man you scare me. I agree about the panic, all loud noises panic people. Just seeing an EV panics people. Yelp, i'm saying, would be picked up faster by a fast moving vehicle. All you hear when you pass wail at high speeds is a beep sound. Yelp at least has varies the freaq faster so that a siren sound is heard by people approaching the intersection at a high rate of speed. In my opinion, I hear the low end of the yelp frequency "punching" through other noises. The woo woo seems to get my attention faster than the boreing wooooooooooooooooooooooooooooo-ooooooooooooooooooooooow. Also, I agree that if I can hear an ambulance in the distance it's almost always the wail I can hear. But the Yelp is better for intersections in my opinion. The wail blends in music and road noise to easy.

[Robert Gift]

Good point Q.

I can keep the microphone in my R hand with both hands on the wheel.
If making a sharp turn I must hand-over-hand.

I was thinking of making a smaller button device, like that of a hospital nurse call button, which would beasier to hold.

But better would be depressing a floor button with left foot.

You're right abouthe Yelp doing more changes faster.
But still, Wail is perceived earlier and better, so I rarely use Yelp unless Wail seems ineffective. Then we try everything, including obnoxious horn.
But horn also seems less loud than Wail.