The Sentry 3V8-H-B

[SuperBanshee]

I suppose certain designs of fans might accommodate tolerance slop better than others - angled blades come to mind, such as those used by Decot and ACA. They are more efficient than non-angled blades since they pump out more air than non-angled blades, but only when spun in the right direction. The difference in volume when it's spun in one direction versus the other is quite notable. I was going to make a much longer post on the topic of siren chopper design, tolerance slop, field observations, and all else, however Sentry's decibel ratings came up so I thought I'd mention it here first.

Here's an interesting idea for anyone with several sirens on hand: take a few common production sirens of the same type (Model 2 would be an ideal choice, but take your pick) and individually test them, recording the decibel rating as each siren is run up. As each siren couldn't possibly be machined to the same tolerances (unless you got really lucky) then each siren should give a different total sound output. That would give more perspective in regards to how much tolerance slop matters. Perhaps there's little difference as you suggest, or there's a greater difference as I mentioned - at the very least I still feel it is one factor that should be considered in regards to a siren's volume.

As for Sentry I wanted to clarify that my original post was not supposed to be viewed as any form of attack. I was simply intrigued by how they claimed such high average decibel ratings from sirens that, from an acoustic engineering standpoint, are rudimentary at best. Unless there's some trick with Sentry's sirens that I've missed, I'm just not convinced. I welcome feedback from Ed Wise or Sentry in hopes that everything will eventually be cleared up.

[archangel_cpj]

Ill jump in here bit first a disclaimer THE OPINIONS BELOW ARE THOSE OF ME AND IM NOT SPEAKING FOR ANY COMPANY THEY ARE FOR INFORMATIONAL AND DISCUSSION PURPOSES ONLY... There now my thoughts for what they are worth first full disclosure Ive been selling sirens since 1999... IF anyone disagrees with me great Im not going to have hurt feelings... First the decible ratings from the Sentry cut sheets are as Ed said bare minimums and use the OLD FEMA guidlines for sound propagation which are more stringent than the current guidelines... So there is no exaggeration of sound propagation in the cut sheets quite the opposite in fact there are many times where a competitors map model has 12k feet coverage from a 5HP siren and Im like can we bump up our DB rating and the answer is always NEVER even though the lab numbers are there... The rating change between a DC siren of the same HP is due to the torque available in a DC motor vs AC the exact AC replacement for a 16v1t - B for example is the 20V2T which kinda answers a question someone had up above in another thread about the 20v2t still being popular... Interesting trivia the only time Ive ever heard of a fan in R and D ever cavitating was with a DC motor... They are torque machines and HP vs HP do more work than AC but nothing is free and AC power is more efficient than DC (see the Edison vs Tesela current war) Running the AC current through a rectifier does get a bit wastful but its a siren that runs for 3 minutes so the power tradeoff is worth it... So after the brief history lesson the story is a 3HP DC motor probably can do the work or a 5 or 6HP AC motor in the siren world... The fan (stator rotor) clerances play an important role as stated in this as does bearing condition... If your tolerances are poor then the sound generation is also poor Im not sure the numbers i.e if the tollerance changes say by 50 thousanths in shrinkage what sound level drop is there but I do know if the parts expand at different rates they will bind and fail which is why the single ingot forging and casting process is important... So is bearing reliability tight bearings rob power lower the sound generation... Sentry hand builds their sirens there is no big warehouse of parts so all the parts in the siren are origional to that siren... In a car comparisson its like a Chevy Malibu vs a Corvette the Malibus are built on an assembly line where vettes are almost hand built... An assembly line can produce a quality product but not usually as good as hand built... This also leads to another benefit in my mind the ability to customize a unit to the clients specific needs be it skirting a large siren something like 50 colors and almost unlimited color schemes custom graphics and I think the only vendor with the option of a Stainless Steel Siren... A mass produced siren has a hard time matching this... Its almost an apples oranges comparison... Just like the age old rotating vs omni argument its like comparing a flash light to a large lamp to light a room... The flashlight with a couple D batteries can light up part of that room with a concentrated beam of light or for a siren sound but the 110 volt 100 watt bulb can light up the whole room at once... In my eyes you cant compare the two they are different critters... Anyway interesting topic and thesecare my generalized thoughts...

[2Fly333]

I was directed to this post by a colleague who said I might find it interesting. Needless to say, I did. I’m a VP at Sentry and one of the members of the ownership family. I don’t often post things and I don’t have any social media accounts, but after reading this, I felt I should respond.

Mr. Super Banshee made some pretty bold claims. These claims seem to imply that he has a unique and “behind the scenes” look at our production, R&D, and testing processes and procedures. Let me assure all of you, he does NOT.

He also later clarified that his post “was not supposed to be viewed as any form of attack”. I think all of us here saw that his intent, most certainly was to degrade our business, our abilities, and our products. Not sure how you can call a company’s products “rudimentary at best”, and not be seen as insulting or attacking. Same goes for “crazywarriorman” claiming we “BS our dB ratings”.

So to best respond, I believe I’ll take the individual statements one at a time and retort with simple bullets.

"The specifications posted by Sentry do not give the siren's average decibel rating at 100 feet. Instead they show the peak rating: the absolute maximum sound any siren will give. Peak ratings are not consistent because no two sirens are machined identically at the factory: some sirens have finer tolerances while others are sloppier and produce less sound."

• Correct, we do not post the average. We post the MINIMUM. No, they are NOT peak dB measurements. Only the underhanded members of our industry (and yes, there are a few) post peak measurements. Every one of our sirens is tested prior to shipping for proper functioning and for dB measurements. If one does not meet the minimum, it is taken out of production and examined. Only those that meet the MINIMUM measurements are shipped. Most far exceed our published ratings.

And as CDV777-1 said: "I guess my point is that if you make 100 rotors this way and 100 stators this way and have two piles of parts then you can pull any parts and they will fit and they are all manufactured to the same "refinement" or tolerances."

• We machine fans and stators as matched pairs. Some manufacturers build 100 fans and 100 stators to a predetermined specification and all must be interchangeable. This is the cheap method and as you can imagine, this does create larger tolerances and less efficient sound production. Not us. Our tolerances are the tightest in the industry. Through single ingot casting and matched pairs, we can be more efficient and have monumentally tighter tolerances. We have produced sirens in this manner since 1980.

"While it is nice to see Sentry try out a more competitive DC battery backup siren, their methods of measuring specifications and subsequent advertisement of specifications leave something to be desired."

• If you’re going to make a claim of that magnitude, at least have some kind of evidence to back it up. This approaches libel and angers me. You are calling into question my character and my family’s long legacy of honesty and sound business practices. I’ll get to this later.

• Not all of us can afford our own anechoic chamber, so we make due with 3rd party testing laboratories and our own field testing. When a new model is undergoing testing, a testing lab or engineer performs routine tests when a major change to the design is made. Often, 3-5 times per development phase. At $7,500 per shot, this adds up quickly. A final series of tests is performed on 5 different versions of the same model to determine the final db Rating. The 3V8-H-B does use a new and slightly different fan/stator design and in testing, its peak was 121.4 dB. Its minimum over the 5 tested models was 116.3 dB. The 14V’s tested last spring reached a peak of 128.9 but a minimum of 127.8

• Again, after each model is built, it is field tested at the factory (5,000 feet in altitude and very little humidity) to ensure it meets our minimum requirements. All sirens that leave our doors meet or exceed the minimum.

Now, to answer the question about our character; we are a family company. We have been in business for 100+ years CONTINUOUSLY (44 years under the current family). My father has been our leader for all of those 44 years and he has personally built/sold/installed/tested/troubleshot/etc. more sirens than anyone in this industry. I have been in my current job for 19 years and I’ve done my fair share in this industry as well. We tell the truth and we stand behind our products. We strive to under promise and over deliver. We don’t do $50 million in sales per year and we don’t want to. We like being small, flexible and family oriented and I like bringing my dog to work.

The SINGLE most important thing on a day to day basis for us is helping protect our customers and the residents they protect. That means making sirens that work, every time and are heard by as many people as possible. Our clients often become members of our family and we form long lasting personal relationships with many of them. We don’t gain market share by tearing down our competitors or questioning their products or methods. We just make our products as good as we can and our price as low as we can. Also, we don’t lie as to what our products can and can’t do. If we “BS” our ratings, our customers would put us out of business, quickly.

My personal goal is to make people safer, make enough money to put food on the table, and have some fun in between. I believe that we, along with the folks at Federal, American, and Whelen are all good people deep down and are all striving for the same goals. To that end, none of us deserve to have neither our, nor our family’s character or business/technological acumen questioned.

If Mr. Super Banshee, or anyone else for that matter, wants to discuss this further, here’s the direct line to my office. 719-275-8691 ext. 114.

W. Scott Yarberry
Sentry Siren, Inc.

[Crazywarriorman]

Maybe I made a mistake in my earlier post. What was changed in the design of the 40V2T that increased the decibel rating by 3 db?

[Bryan]

I would love to hear some more about Sentry's designs and back story. I find it interesting.

[SuperBanshee]

To Mr. Yarberry and associates,

While I appreciate all the responses posted over the past weekend, the comment posted by Mr. Yarberry is a first for me. Over the years we have had many posts critiquing modern sirens yet up to this point I don't believe any company officials have responded directly to criticism. I really don't understand the claim of damaging the Yarberry family name - if any form of criticism really hurts the company on such a level, then I just don't know. You have so many glowing reviews on your website (which I am going to hope are all in the majority and were not cherry-picked), yet my one criticism was enough to set off this debate. It just doesn't make sense.
Criticism is supposed to help one learn and grow - you're supposed to see why your product (in this case, a siren) got a negative review in the first place, research and invest in ways legitimate improvements can be made, and then ultimately win over critics with your improved product. Accusing critics of libel and attempting to sweep everything under the rug is the exact opposite of what I thought any responsible company was supposed to do.

I never implied I saw factory level testing, or have been to the factory myself. Many of my observations were done personally, on the field with whatever sirens I was studying that day. I don't have much fancy equipment besides the camera, but I always took notes of each siren's characteristics. Harmonic dual tone, non-harmonic dual tone, single tone, smooth sound, raspy sound, and then I proceed to study each siren's profile to find out *why* it sounds and works the way it does. Chopper design, exponential horn curves, there's so much you can learn through observation and studying. In regards to what I've observed with Sentry, their sirens give a very raspy sound and the two I've observed were not particularly loud. The fact that it's been previously asserted that Sentry's decibel ratings were somewhat off simply solidified the observation that something was wrong here.

Furthermore, none of Sentry's sirens show any form of acoustic engineering - they are quite rudimentary which makes it difficult to believe they really live up to their advertised sound ratings. The horns and skirts are not exponential, nor do they appear to be tuned to accommodate the siren's output frequency. In fact on many of the dual tone models there appear to be fewer horns than there are fan blades ("ports"). This seems very inefficient and I don't understand how this works. Some models also have staggered horns while others don't, which make things even more confusing. Even with peak and average decibel ratings in mind, I still don't see how these sirens live up to their advertised sound ratings. There are simply too many unanswered questions in regards to Sentry's acoustic engineering. I'm open to any answers but I'm not open to any personal attacks.

I am also intrigued by the presence of the "Defender". Your company touts non-rotating sirens as the way, yet here was a rotating siren amid all the criticism your own company gives to such a class of sirens. No explanation, no justification, just a rotating siren that I presume was supposed to fight off the T-128 and 2001-SRNB. It just seems hypocritical.

Finally comes the topic of "family name". I understand you, Mr. Yarberry and your family, own and operate Sentry Siren. What you don't make clear is when you began Sentry and how - I realize it is somehow linked to the old Sterling Siren & Fire Alarm Company of Rochester, New York however nothing on your own website gives much detail in regards to this. While many old members might recognize you, there are many new members who don't know you so well - perhaps you would like to take a chance to introduce yourself and your company to us all.

[holler]

Here's my .02:

Mr. Yarberry is the VP of sentry siren, the VP. Sentry has been the only manufacturer to have anything to do with this board, and now we have the VP on here talking to us even if it's under not so ideal circumstances. For years Sentry ran ads on the board and helped keep this place going, and you have two Sentry dealers on here also.

Some of y'all have the finesse and tact of a bull in a china shop. Quit attacking the man's sirens, be thankful they actually acknowledge the fact that we exist and are willing to talk to us, instead of trying to track down who made the comments and sue them for libel and slander.

IMO Sentry is the only manufacturer left that makes a "true" siren. They are only one left that makes a dual tone siren, the only one that makes a CONTINUOUS DUTY siren, and the only one left that makes a three phase omnidirectional, which is the most reliable and robust siren design in history, no ifs, ands, or buts.

[Busgeek71]

To Mr. Yarberry and associates,

While I appreciate all the responses posted over the past weekend, the comment posted by Mr. Yarberry is a first for me. Over the years we have had many posts critiquing modern sirens yet up to this point I don't believe any company officials have responded directly to criticism. I really don't understand the claim of damaging the Yarberry family name - if any form of criticism really hurts the company on such a level, then I just don't know. You have so many glowing reviews on your website (which I am going to hope are all in the majority and were not cherry-picked), yet my one criticism was enough to set off this debate. It just doesn't make sense.

Making assumptions as to how Sentry records their data and then proceeding to call their products "rudimentary at best" is pretty far-reaching. Telling others an incorrect statement and giving unjustified reviews of a company's product line would likely offend a business exec with a company of Sentry's size. It is offensive to make such bold claims against people who have first-hand experience building sirens for decades. Aside from that, a co-worker happened to see this thread and directed Mr. Yarberry to it. Mr. Yarberry had a great opportunity to speak to a community that is wanting to learn anything about sirens, and he took it. Him responding was a chance event. It wasn't like he was angrily ranting, or anything like that, anyway. He was just clearing the air.

Criticism is supposed to help one learn and grow - you're supposed to see why your product (in this case, a siren) got a negative review in the first place, research and invest in ways legitimate improvements can be made, and then ultimately win over critics with your improved product. Accusing critics of libel and attempting to sweep everything under the rug is the exact opposite of what I thought any responsible company was supposed to do.

Give an example of a customer that was dissatisfied with a Sentry system that didn't get the problem solved. There was no accusation of libel, only that a statement is approaching libel. What was swept under the rug?

I never implied I saw factory level testing, or have been to the factory myself. Many of my observations were done personally, on the field with whatever sirens I was studying that day. I don't have much fancy equipment besides the camera, but I always took notes of each siren's characteristics.

...

In regards to what I've observed with Sentry, their sirens give a very raspy sound and the two I've observed were not particularly loud. The fact that it's been previously asserted that Sentry's decibel ratings were somewhat off simply solidified the observation that something was wrong here.

Perception gives no justification of anything. Measurements made with acoustical equipment and hard evidence of incorrect documented dB ratings are what give the truth, not one person saying a few sirens aren't very loud in variable conditions. Where are assertions of ratings being off, anyhow? Were they based on evidence?

Furthermore, none of Sentry's sirens show any form of acoustic engineering - they are quite rudimentary which makes it difficult to believe they really live up to their advertised sound ratings.

The sirens are the result of advanced acoustical engineering. Nothing more needs to be said here.

I am also intrigued by the presence of the "Defender". Your company touts non-rotating sirens as the way, yet here was a rotating siren amid all the criticism your own company gives to such a class of sirens. No explanation, no justification, just a rotating siren that I presume was supposed to fight off the T-128 and 2001-SRNB. It just seems hypocritical.

Choices for the customer. That's all. Doesn't negate the fact that omni sirens are objectively more effective and efficient. Even FEMA makes this clear. Some customers want rotating sirens. Sentry made them due to that fact and to compete. They can still say, "yes, option x is better, but if you want option y, here you go". Of course the Defender fell through, but still. It was to compete and give customers choices without going to other companies for a solution to their siren wants/needs.

[gman 1]

I figured that while we had the VP of sentry with us I might as well ask, is it possible Sentry might try to make an electronic siren? I know you guys don't like them, but they do offer more options such as voice, and more signals than a mechanical siren. Do you think that maybe a "coded" model could be manufactured?

[holler]

Give an example of a customer that was dissatisfied with a Sentry system that didn't get the problem solved.

^This^

Sentry is known for customer satisfaction, if something isn't right they make it right and they have a very tight relationship with the customer as a result.

Sentry is the only manufacturer who will refurbish one of their older sirens if you send it back to them. Everybody else wants you to buy a new siren, and makes existing models obsolete after 10 years and quits making parts for them soon after. Not so with Sentry.