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Re: What is your favorite siren port ratio/interval?

Fri Aug 09, 2013 3:06 am

I think the only difference is that a 10/12 is an octave higher, and slightly lower volume. A model 2 has a port ratio of 4/5

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PugetSoundStormWatch
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Re: What is your favorite siren port ratio/interval?

Fri Aug 09, 2013 3:09 am

Liquid_Pooterbear wrote:I think the only difference is that a 10/12 is an octave higher, and slightly lower volume. A model 2 has a port ratio of 4/5
A 10/12 Port 3T22A spins at 3450 RPM, a 5/6 Port Thunderbolt 1000AT on Chopper Level 5 spins somewhere around 6960 RPM, so they're actually nearly the same pitch.

To answer Captain Dynamite's question: You can have a 2:3 Ratio for an 8/12 Port Siren, and a 3:4 Ratio for a 9:12 Port Siren.
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Re: What is your favorite siren port ratio/interval?

Fri Aug 09, 2013 7:43 am

PugetSoundStormWatch wrote:
To answer Captain Dynamite's question: You can have a 2:3 Ratio for an 8/12 Port Siren, and a 3:4 Ratio for a 9:12 Port Siren.
Okay thankyou PugnetSoundStormWatch for answering my question.

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Re: What is your favorite siren port ratio/interval?

Fri Aug 09, 2013 8:15 am

My favorites are 8/12, 4/5, and 10/15.

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Re: What is your favorite siren port ratio/interval?

Fri Aug 09, 2013 4:53 pm

Mine would have to be either a 4/5 t-bolt on level 4 in attack or a 9 or 5 port siren in attack! ( model 2/ HOR Super Sirex)
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Re: What is your favorite siren port ratio/interval?

Fri Aug 09, 2013 5:27 pm

1st: 10/12 (or 5/6)
2nd: 8/12 (or 2/3)
3rd: 8/10 (or 4/5)
4th: 9/12 (or 15/20)
5th: 7/10
6th: 8/16

The first three are my most favorite because 1st classic, 2nd makes the hairs stand up on my back, and 3rd is very creepy and unique sounding.
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Re: What is your favorite siren port ratio/interval?

Fri Aug 09, 2013 8:37 pm

PugetSoundStormWatch wrote:
Liquid_Pooterbear wrote:I think the only difference is that a 10/12 is an octave higher, and slightly lower volume. A model 2 has a port ratio of 4/5
A 10/12 Port 3T22A spins at 3450 RPM, a 5/6 Port Thunderbolt 1000AT on Chopper Level 5 spins somewhere around 6960 RPM, so they're actually nearly the same pitch.

To answer Captain Dynamite's question: You can have a 2:3 Ratio for an 8/12 Port Siren, and a 3:4 Ratio for a 9:12 Port Siren.
If you ran a 10/12 and 5/6 at the same speed, would the 5/6 be the same volume, but an octave lower?

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Re: What is your favorite siren port ratio/interval?

Fri Aug 09, 2013 9:50 pm

Liquid_Pooterbear wrote:
PugetSoundStormWatch wrote:
Liquid_Pooterbear wrote:I think the only difference is that a 10/12 is an octave higher, and slightly lower volume. A model 2 has a port ratio of 4/5
A 10/12 Port 3T22A spins at 3450 RPM, a 5/6 Port Thunderbolt 1000AT on Chopper Level 5 spins somewhere around 6960 RPM, so they're actually nearly the same pitch.

To answer Captain Dynamite's question: You can have a 2:3 Ratio for an 8/12 Port Siren, and a 3:4 Ratio for a 9:12 Port Siren.
If you ran a 10/12 and 5/6 at the same speed, would the 5/6 be the same volume, but an octave lower?
They wouldn't be the same volume, lower frequencies have longer sinusoidal wavelengths than those of higher frequencies, therefore they can carry farther than high pitched sirens, but high pitched sirens can penetrate objects better than longer wavelengths. This is why the attack signal is more effective than alert, peak RPM allows better penetration, then the wind downs allow the sound to carry farther.

So no, the 5/6 port siren would be a bit more effective than a 10/12 port siren, and yes it is an octave lower.

Hope this helped! :D
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I like DJ equipment, Weather Radios (23 in my collection), Fire Alarms, and Sirens.
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Re: What is your favorite siren port ratio/interval?

Fri Aug 09, 2013 11:00 pm

Since i'm planning a wooden air raid siren I'm making soon, I'm not sure if it's better to make it 9/12, or 6/8, or even 3/4. I would do a low one since it wouldn't take as long to cut out all the blades, and this siren is hard to make. The motor i'm using can't be more than 4000 RPM or the wood will fly apart. So do I have to use 9/12 for a slow motor, and what if I used 6/8 or 3/4? I prefer low pitched sirens but I want it to be loud too.

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Re: What is your favorite siren port ratio/interval?

Fri Aug 09, 2013 11:08 pm

10/12 port or 5/6 port on the Thunderbolt at chopper level 5.
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