Sentry's New Horns For 8 and 16 Port Sirens

[DJ2226]

Quick question: What's the point in the different length horns again?

The longer horns project the sound out farther. That's why the 7V8 gets less range than the 10V. Drop the horns all together, 5V, and you get less range.

[uncommonsense]

Quick question: What's the point in the different length horns again?

The longer horns project the sound out farther. That's why the 7V8 gets less range than the 10V. Drop the horns all together, 5V, and you get less range.

Or it could be the 7V8 is a smaller and less powerful siren than the 10V. That's like saying the Model 2 gets less range than the Model 5 because the housing is smaller.

[DJ2226]

Quick question: What's the point in the different length horns again?

The longer horns project the sound out farther. That's why the 7V8 gets less range than the 10V. Drop the horns all together, 5V, and you get less range.

Or it could be the 7V8 is a smaller and less powerful siren than the 10V. That's like saying the Model 2 gets less range than the Model 5 because the housing is smaller.

IIRC they use the same chopper. All of their sirens from the 5V to 20V1/2T and Defender use the same 8 or 16 port choppers from the Sterling M/N sirens. The 10V2T, 15V2T, 16V2T-B, and 20V2T are the same sirens with different motors coupled to the choppers with the 10V2T using short and long horns. The 10V2T is a Sterling M10 on its side with horns attached.

[uncommonsense]

IIRC they use the same chopper. All of their sirens from the 5V to 20V1/2T and Defender use the same 8 or 16 port choppers from the Sterling M/N sirens. The 10V2T, 15V2T, 16V2T-B, and 20V2T are the same sirens with different motors coupled to the choppers with the 10V2T using short and long horns. The 10V2T is a Sterling M10 on its side with horns attached.

That may or may not be true--I can't honestly speak to that. My point is your original argument says the horn length alone affects range. All these sirens also vary in motor size, ergo, different power. Your argument is invalid.

[Mark N]

On the topic of Sentry; what exactly does the "V" stand for? I never understood that...

[Sirenguy02]

Quick question: What's the point in the different length horns again?

Let me rephrase it, What's the point in the different horn lengths on one siren?

[uncommonsense]

The 10V utilizes staged horn projectors, 4 long and 4 short. This design helps to spread the sound from this mid-sized outdoor warning siren over the coverage area more evenly, balancing the need for short distance penetration with long distance throw.

http://www.sentrysiren.com/warning-sire ... siren-10v/

[DJ2226]

That may or may not be true--I can't honestly speak to that. My point is your original argument says the horn length alone affects range. All these sirens also vary in motor size, ergo, different power. Your argument is invalid.

How would motor sizing effect the output from the chopper? If two sirens use the same choppers but different motors that are rated for the same speed they'd produce the same amount of sound granted the motor with the lower HP can drive the chopper at the same speeds. This is like the P-10 and P-15. If both have the same choppers and the motors are able to spin them up at the same speed they'd have the same output. Compare their 16V1T-B and 15V1T, since they are pretty much the same sirens, just with AC or DC motors. They rate the 16V1T-B to get 5 dB more than the 15V1T (129dB vs 124 dB), but they advertise them both to run at 460 Hz. Same deal with the 7V8 and 7V8-B where the 7V8-B gets 9 more dB than it's AC counterpart (121 dB vs 112 dB), both being advertised to run at 460 Hz. I understand that DC motors spin up to different speeds depending on the voltage they take in, but here they'd have to be spinning at the same 3450 RPM to produce the same pitches. If they use the same choppers that spin at the same speed, then they should equal out.

[sirendude2012]

That may or may not be true--I can't honestly speak to that. My point is your original argument says the horn length alone affects range. All these sirens also vary in motor size, ergo, different power. Your argument is invalid.

How would motor sizing effect the output from the chopper? If two sirens use the same choppers but different motors that are rated for the same speed they'd produce the same amount of sound granted the motor with the lower HP can drive the chopper at the same speeds. This is like the P-10 and P-15. If both have the same choppers and the motors are able to spin them up at the same speed they'd have the same output. Compare their 16V1T-B and 15V1T, since they are pretty much the same sirens, just with AC or DC motors. They rate the 16V1T-B to get 5 dB more than the 15V1T (129dB vs 124 dB), but they advertise them both to run at 460 Hz. Same deal with the 7V8 and 7V8-B where the 7V8-B gets 9 more dB than it's AC counterpart (121 dB vs 112 dB), both being advertised to run at 460 Hz. I understand that DC motors spin up to different speeds depending on the voltage they take in, but here they'd have to be spinning at the same 3450 RPM to produce the same pitches. If they use the same choppers that spin at the same speed, then they should equal out.

It's all in the money. If they advertised them to be equal, why pay extra for a battery powered version when you can get the 3-phase version that covers the same area for cheaper? They have to bring more to the plate to sell the DC ones because otherwise, they wouldn't sell nearly as much as they do.

[uncommonsense]

How would motor sizing effect the output from the chopper? If two sirens use the same choppers but different motors that are rated for the same speed they'd produce the same amount of sound granted the motor with the lower HP can drive the chopper at the same speeds.

There you go. Using an apples to apples comparison, the 7V8-B uses an 8 hp DC motor, the 7V8 a 7.5 HP AP motor. Granted, I can't say what RPMs those are rated for. However, I'm missing info I'd need from the motor tag (current) to calculate theoretical torque at 100% efficiency. Of course, don't forget, AC and DC motors vary in efficiency, so that matters in performance, too. If someone (Ed Wise?) has some info from motor tags--or knows where I can find photos from the 7V8 and 7V8-B, let me know. Of course, I say this under the assumption the 7V8 and 7V8B use the same noisemaking parts and just differ by motor.

This is like the P-10 and P-15. If both have the same choppers and the motors are able to spin them up at the same speed they'd have the same output.

That single toned beast burned up 10 hp motors because they couldn't handle that big chopper + rotating the thing. Hence the need for the 15 hp motor. Besides, do we know single toned P-10s, of what few there were, were performing at the rate of the P-15?

Compare their 16V1T-B and 15V1T, since they are pretty much the same sirens, just with AC or DC motors. They rate the 16V1T-B to get 5 dB more than the 15V1T (129dB vs 124 dB), but they advertise them both to run at 460 Hz.

They're really not. The 15V1T uses on 15 hp AC motor to drive the noisemaking parts. The 16V1T-B uses two independent 8 hp DC motors. Its not a combined 16 hp DC. And are we certain they're using the same noisemaking parts? Besides, what Sentry quotes is the dB rating for the dual toned siren, which will always take a slight dB hit compared to a single toned brethren due to noise cancellation.

P.S. The 16V1T-B is quoted at 125 when running on batteries as opposed to 129 when not. That's also something--if minor and nitpicky--to consider. The 15VT2B gets 124. The single toned 15V is likely to meet the 16V1T-B or get darn close.

Same deal with the 7V8 and 7V8-B where the 7V8-B gets 9 more dB than it's AC counterpart (121 dB vs 112 dB), both being advertised to run at 460 Hz.

Addressed above.

I understand that DC motors spin up to different speeds depending on the voltage they take in, but here they'd have to be spinning at the same 3450 RPM to produce the same pitches. If they use the same choppers that spin at the same speed, then they should equal out.

I guess at the end of the day I'm not convinced there's also not another factor in here we're not considering. And I don't have the numbers I need to do the math. Its not this simple and that much I can assure you.