Safety Whistles | Decibel Testing

Safety Whistles Compared

A few months ago I wrote a mini review of the UST JetScream whistle which, if you recall, I was a little disappointed with. As part of that review, I performed a very unscientific comparison of the loudness of the JetScream to other whistles that I own. By unscientific I mean, just how it sounded to my ears.

After that review I wanted to do a slightly more scientific and accurate test of several whistles that I own to see if my ears were right and what whistles really were the loudest, but I would need a decibel meter. One of the great things about being a self-confessed geek, is that you have lots of other geeky friends. So when asked my geek friends if any of them had a decibel meter – and more than one responded saying that they did. LOL!

So I created a short video to document my attempt to test the loudness of half a dozen of the most popular safety/emergency whistles used by backpackers. I used two video cameras, one to film me testing each of the whistles and the other to film the decibel meter readings. I tested the following six popular whistles:

What surprised me was not only which whistle came out on top as the loudest, but how far off all of the whistles were from the decibel level stated in their product descriptions. Not one of the six whistles I tested was able to break the 100 decibel mark, yet most, if not all, of them state they they do – very interesting.

Below the video is a table showing the results of the testing. If you want to watch the video without spoiling it by seeing the results ahead of time, don’t scroll below the video just yet!

Here are the results of the testing in a table format ranked loudest to quietest.

Safety Whistles Decibel Testing

I was very surprised to see that a $0.99 Harbor Freight Aluminum whistle beat all of the other whistles I tested. As I said earlier, not one of the whistles were able to break the 100 decibel level despite product specifications stating they could, which bothers me a great deal. Of course I’m not an expert, but I did use a professional-grade decibel meter in as much of a controlled manner as possible.

I hope this was as interesting for you to read and watch as it was for me to conduct. What whistle do you carry on the trail and did the results of my testing surprise/concern you?

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  • http://www.blogger.com/profile/02784130095157180086 Jolly Green Giant

    Funny, I have nearly the exact same collection and I’ve asked myself why I spent so much money money on so many different options that really aren’t all that different. Ultimately I decided to just stick with my ACR. It’s small, lightweight, flat, orange, pealess, inexpensive….what’s not to like.

  • http://blog.dankim.com/ adriftatsea

    Did you try the Storm Whistle. It’s a bit larger than most of the ones you’ve mentioned, and worth a shot.

  • http://www.blogger.com/profile/09628095804170935682 Brian

    Jolly, I agree completely. The ACR is an awesome whistle with an almost perfect size/weight profile. I recently had one crack/split on me and break, I think it was because of the type of plastic used – it is somewhat brittle. Because of that I had bought a couple of Fox 40 Micros to play with and found that they were made of a slightly different material that is a little bit more forgiving than the ACRs. Of course this is nitpicking at a nano level – both are superb lightweight whistles.

    Dan! Are you referring to this Storm Whistle? The specs say it is 130dB which is outrageous if true. As I said in my post, several of the whistles I tested claimed to be over 100dB, but I was unable to get any of them to break that mark. Great – now I have to get a Storm Whistle to test it too :-)

  • http://www.blogger.com/profile/13192655115298965527 treeswing

    Nice! Love seeing this kind of real testing in a blog :)

    If you’re planning another round of tests, may I suggest doing some distance metering as well? 5-15-25-50 yds, or the like… do you think pure dB will always be better as opposed to frequency?

  • http://www.blogger.com/profile/09628095804170935682 Brian

    treeswing, glad you liked it – I’m a big geek so I love this stuff. I agree that the distance metering would have been useful element of testing to add to it, but I didn’t have a whole lot of time and completely didn’t think of it.

    You know, I see whistles listed/rated online in both dB and frequency/mhz. I’ll admit that I’m too much of a noob to know what the difference or benefits of testing in either one really is. I was able to get my hands on the decibel meter and that seemed sufficient to put the issue to rest as far as I was concerned.

    You sound like you have a lot more experience in this field than I do. So, if I were to do something like this again, what would you suggest?

  • http://www.blogger.com/profile/09364636677279037964 Mattexian

    I’ve got one of those Storm Whistles, and I can attest to it being ear-splitting loud, tho I have no instruments for gauging it in decibels. It’s only drawback is it’s bulkiness, tho it wasn’t a problem when I wore ACUs, I could drop it in the lowest leg pocket without worrying about it. I much preferred keeping the AMK pocket kit with it’s whistle, tho I recently found one of those cheap flat keychain whistles, with a sheriff dept’s boating safety slogan on it. I’d say smaller is definitely better, as it’s more likely to be carried it with you if it’s not bulky.

  • http://www.blogger.com/profile/09628095804170935682 Brian

    Matt, you and Dan are trying to shame me into getting a Storm Whistle now aren’t you? Ha! I’ve been reading reviews online and it does sound good (no pun intended).

    I wanted to do the decibel test mostly for my own gratification because I couldn’t easily determine what whistle was loudest. As it turned out they were all within 1 dB of each other and nowhere near as loud as the claimed to be.

    I’m very pleased with the super slim ACR WW3 whistle and the super durable Fox 40 Micro.

    As and when I get a few more whistles (let’s face it, it’s inevitable) I’ll post an update. Are there any other whistles that are potential candidates?

  • Anonymous

    Yes, repeating this at distances of 50, 100 meters would be very interesting!

  • Anonymous

    Fox 40 Sonik Blast (possibly the CMG version). Reported to require relatively small air volume to produce loud sound and its sound is “shrill” to get noticed.
    The sound meter may give different reading for different frequencies and thus whistles that produce the same output loudness but different pitches may result in different readings.
    Suggest repeating your blowing each whistle at least three times to check for variations, especially since such a small variation was measured from whistle to whistle. i.e. is that variation due to variation in your blowing them or in the whistle itself ?
    The 120 dB spec is probably at some specific distance and maybe closer than your 8 or 9 feet.

  • http://blog.dankim.com/ adriftatsea

    Did you try the Storm Whistle. It’s a bit larger than most of the ones you’ve mentioned, and worth a shot.

  • jbrett14

    I just did a real world distance test tonight with 7 different whistles. These “decibel” tests with meters are NOT representative of real world distance tests with wind, birds, hills, etc.. They are misleading.

    These are the 7 whistles I tested at 1/4 mile distance, over a hill and with general outdoor noise present (birds, wind, etc.):
    1) Cheap aluminum whistle exactly like the Harbor Freight model.
    2) Cheap $1.50 whistlecompassthermometer from DealExtreme
    3) Fox 40 Sharx – on paper, their loudest whistle in decibels
    4) Fox 40 Classic
    5) Acme Tornado
    6) Acme Tornado 2000 – the “loudest whistle in the world”
    7) Storm

    I did my test two different ways and then compared the results. First I had my 90 lb. son blow each whistle 3 times while I listened from 1/4 mile away, over a small hill. We could not see each other, but we used walkie talkies to communicate. Then we traded places and repeated the testing. We both wrote down our scores which were based on how loud we perceived each whistle, and we did not show them to each other until all testing was done. Here were the results:

    We both rated the Storm to be the loudest, easily.
    We both rated the Fox 40 CLASSIC to be the second loudest.
    We both rated the Acme Tornado 2000 to be the third loudest.
    The remaining 4 whistles were not significantly different from one another and none of these 4 were even close to the top 3, with the exception of the Acme Tornado which, to my ears, was rated the fourth loudest. Not surprisingly, both the cheap whistles were barely heard, but VERY surprisingly, the Fox 40 Sharx was no louder. In fact, my son actually rated the cheap aluminum whistle to be just a bit louder than the Sharx. I rated them the same.

    The biggest surprise was the Fox 40 Sharx, which was among the quietest of the bunch. And here is the irony. Up close, the Sharx was, by far, the most ear-piercing, even more than the Storm. Hence the reason you can’t do close up tests for whistles. The pitch of the whistle is just too misleading up close, and they simply do not carry over a distance the way you would think.

    Conclusion: If you want a real “life saver” from a distance, choose the Storm. If it’s too big for your taste, choose the Fox 40 Classic. The Acme 2000 would be a runner-up. Throw the rest away or give them to your little children to play with. At 1/4 mile they are barely heard.

    I hope this was helpful to somebody.

    • http://www.briangreen.net Brian Green

      Wow! That’s a great response in follow up to what now seems a very unscientific test that I did :-) I’m convinced that I need to perform the test again but from a much further distance using the decibel meter. I recently received a Storm whistle so I will be able to include that.

      Thanks again, good stuff.

  • jbrett14

    I just did a real world distance test tonight with 7 different whistles. These “decibel” tests with meters are NOT representative of real world distance tests with wind, birds, hills, etc.. They are misleading.

    These are the 7 whistles I tested at 1/4 mile distance, over a hill and with general outdoor noise present (birds, wind, etc.):
    1) Cheap aluminum whistle exactly like the Harbor Freight model.
    2) Cheap $1.50 whistle\compass\thermometer from DealExtreme
    3) Fox 40 Sharx – on paper, their loudest whistle in decibels
    4) Fox 40 Classic
    5) Acme Tornado
    6) Acme Tornado 2000 – the “loudest whistle in the world”
    7) Storm

    I did my test two different ways and then compared the results. First I had my 90 lb. son blow each whistle 3 times while I listened from 1/4 mile away, over a small hill. We could not see each other, but we used walkie talkies to communicate. Then we traded places and repeated the testing. We both wrote down our scores which were based on how loud we perceived each whistle, and we did not show them to each other until all testing was done. Here were the results:

    We both rated the Storm to be the loudest, easily.
    We both rated the Fox 40 CLASSIC to be the second loudest.
    We both rated the Acme Tornado 2000 to be the third loudest.
    The remaining 4 whistles were not significantly different from one another and none of these 4 were even close to the top 3, with the exception of the Acme Tornado which, to my ears, was rated the fourth loudest. Not surprisingly, both the cheap whistles were barely heard, but VERY surprisingly, the Fox 40 Sharx was no louder. In fact, my son actually rated the cheap aluminum whistle to be just a bit louder than the Sharx. I rated them the same.

    The biggest surprise was the Fox 40 Sharx, which was among the quietest of the bunch. And here is the irony. Up close, the Sharx was, by far, the most ear-piercing, even more than the Storm. Hence the reason you can’t do close up tests for whistles. The pitch of the whistle is just too misleading up close, and they simply do not carry over a distance the way you would think.

    Conclusion: If you want a real “life saver” from a distance, choose the Storm. If it’s too big for your taste, choose the Fox 40 Classic. The Acme 2000 would be a runner-up. Throw the rest away or give them to your little children to play with. At 1/4 mile they are barely heard.

    I hope this was helpful to somebody.

  • bfgreen

    Wow! That’s a great response in follow up to what now seems a very unscientific test that I did :-) I’m convinced that I need to perform the test again but from a much further distance using the decibel meter. I recently received a Storm whistle so I will be able to include that.

    Thanks again, good stuff.

  • Peter

    The most common distance for sound pressure level testing is one meter, and the most common configuration is to place the meter to the side of the sound source rather than directly in front of it. Following these guidelines allows your results to be compared more directly with those from other tests, but as long as you test consistently, your results for each whistle may be compared against each other, which is probably good enough.

    I agree that you should test at some longer distance, however, because the purpose of these whistles is to be heard at a distance and different frequencies are absorbed and reflected differently by ground cover, vegetation, and other local objects.

    I don’t know of any standard for this kind of distant testing, but if I had to come up with one, I think I’d try 100 meters directly in front. That should still be close enough to get good readings. If not, try 50 meters.

    • http://www.briangreen.net Brian Green

       Peter, thanks for the feedback. Several others have given the same advice and I think that once I can get the decibel meter back I’m going to give this another try. I also have two new whistles to test, so I’m excited.

      • ChemE

        I too prefer the ACR WWW-3 above other whistles and I’m a hardcore gram weenie.  Here is a link for cutting the weight of this whistle in half without impacting performance one iota.
        http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=33706

        • Bryce

          I just came across the same BPL post, haha.  Brian, what are the weights of all the whistles you have tested? (w/out lanyard or D-rings)  Thx.

          • http://www.briangreen.net Brian Green

            Did I not include that information? Shame on me :-) I know I have it somewhere, so I’ll add it as soon as I can. If I forget feel free to bug me.

          • Bryce

            *bump* But turns out I have an ACR anyway from a long time ago.  I’ll try modding it.

          • http://www.briangreen.net Brian Green

            Ha, I saw the modification on BPL. How much weight does it shave off? I have to admit that I prefer how the modified whistle looks compared ot the original.

  • Peter

    The most common distance for sound pressure level testing is one meter, and the most common configuration is to place the meter to the side of the sound source rather than directly in front of it. Following these guidelines allows your results to be compared more directly with those from other tests, but as long as you test consistently, your results for each whistle may be compared against each other, which is probably good enough.

    I agree that you should test at some longer distance, however, because the purpose of these whistles is to be heard at a distance and different frequencies are absorbed and reflected differently by ground cover, vegetation, and other local objects.

    I don’t know of any standard for this kind of distant testing, but if I had to come up with one, I think I’d try 100 meters directly in front. That should still be close enough to get good readings. If not, try 50 meters.

  • bfgreen

     Peter, thanks for the feedback. Several others have given the same advice and I think that once I can get the decibel meter back I’m going to give this another try. I also have two new whistles to test, so I’m excited.

  • ChemE

    I too prefer the ACR WWW-3 above other whistles and I’m a hardcore gram weenie.  Here is a link for cutting the weight of this whistle in half without impacting performance one iota.
    http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=33706

  • Bryce

    I just came across the same BPL post, haha.  Brian, what are the weights of all the whistles you have tested? (w/out lanyard or D-rings)  Thx.

  • http://www.briangreen.net/ Brian Green

    Did I not include that information? Shame on me :-) I know I have it somewhere, so I’ll add it as soon as I can. If I forget feel free to bug me.

  • Bryce

    *bump* But turns out I have an ACR anyway from a long time ago.  I’ll try modding it.

  • http://www.briangreen.net/ Brian Green

    Ha, I saw the modification on BPL. How much weight does it shave off? I have to admit that I prefer how the modified whistle looks compared ot the original.

  • Tom Harris

    if you do another test could you please test the acme tornado 2000 its supposedly the most powerful whistle ever and it is only £1.80. if this is true then surely its the best whistle ever?

    • http://www.briangreen.net Brian Green

      If that is true. Is the Acme tornado the same thing as the Storm whistle, just re-branded for the UK market? Just asking without having looked up the Acme whistle. You can reference the storm whistle here.

      Update: I just looked online and the Acme Tornado 2000 is not the same as the storm whistle, so this is a new one to me. Does anyone have any experience with it?

  • Tom Harris

    if you do another test could you please test the acme tornado 2000 its supposedly the most powerful whistle ever and it is only £1.80. if this is true then surely its the best whistle ever?

  • http://www.briangreen.net/ Brian Green

    If that is true. Is the Acme tornado the same thing as the Storm whistle, just re-branded for the UK market? Just asking without having looked up the Acme whistle. You can reference the storm whistle here.

  • BBC

    Brian,,, watched the whisle test.. interesting ,, i also thought of how comparison too a referee whisle would had tested in this also whisle of one using his own fingers for tring too be loud… agian thanks for the test interesting blog    C

    • http://www.briangreen.net Brian Green

      A referee whistle typically has a pea in it. The purpose of my test was to compare emergency whistles which are usually pea-less. I have no doubt that a referee whistle would be loud, but I don’t carry one because of the bulky size and weight.

  • http://www.briangreen.net/ Brian Green

    A referee whistle typically has a pea in it. The purpose of my test was to compare emergency whistles which are usually pea-less. I have no doubt that a referee whistle would be loud, but I don’t carry one because of the bulky size and weight.

  • BBC

    Brian,,, watched the whisle test.. interesting ,, i also thought of how comparison too a referee whisle would had tested in this also whisle of one using his own fingers for tring too be loud… agian thanks for the test interesting blog    C

  • http://www.noisekiller.co.uk/ Noisekiller

    94.1 – 93.7: Not a lot between them really. But in the dark cold night on a mountain, you’s want that loudest one!

    • http://www.briangreen.net Brian Green

      Yeah it’s pretty much all a wash, or I was doing something terribly wrong. I was just surprised by the results, especially from the Harbor Freight whistle! BTW, the ACR is my whistle of choice 9 times out of ten.

  • http://www.noisekiller.co.uk/ jason_soundproofing

    94.1 – 93.7: Not a lot between them really. But in the dark cold night on a mountain, you’s want that loudest one!

  • http://www.briangreen.net/ Brian Green

    Yeah it’s pretty much all a wash, or I was doing something terribly wrong. I was just surprised by the results, especially from the Harbor Freight whistle! BTW, the ACR is my whistle of choice 9 times out of ten.

  • Rick

    Brian,
     There are at least 2 things to consider in choosing a “Noise Maker” for calling for help.
    1. Sound distance. I would like to see a srudy done on how far these can be heard.
    2. If they can be MASKED by natural sounds. Birds, wind thru the trees, and rushing water.
    I carry 2 kinds
    1. is like the “Normal” type like you tested. This is for short distance use like Rope work and river work.
    2. is for calling SAR victims It is Very Un Natural.
    it is a StowMaster Marine Distress Horn.
    It fits in my pack only being about the sixe of my fist and is reported to produce 125 Db of sound. It is Very well made and at $9.00 a good value.
    It is not too good for rope or swift water use mainly because of it’s size.
     
    Another one like it is the
    The whistle

    Everyone in the outdoors needs a signalling device. It’s surprising how little a voice carries when you have the sound of running water from a river in the background – or even the wind. We found that on a quiet night a whistle can be heard distinctly up to 600M – we didn’t have anywhere to try at further distances. What surprised me was that the light from a cigarette lighter or match can be seen clearly at that distance too. An old referee’s whistle actually beat out the Fox 40 being of lower pitch and more distinct – well for a couple of old guys it was. Later, in testing of a Fox40 against a Scotty Lifesaver #1, and in a further test of a Fox40 against an Acme 649, young people believed the Fox to be much louder. Being old I didn’t hear it that way..
    Alberta Ed has the warning that some of the high pitched wavering tone whistles might act as a varmint call to bring in bears. That is a distinct possibility as I have had them come to varmint calls. Just the idea of using a whistle that has a similar sound to a varmint call while lying injured with the smell of blood in the air – well that’s not pleasant to contemplate!
    The work to see how far the whistle sounds carry with regard to background noise – and to find some observable predators is waiting until late in the year since we don’t want to bring out search and rescue to find the cause of whistle sounds… Note This had to be put off as I had delays getting a gun license. I wasn’t too confident on standing down bears at close range without a gun.
    For most purposes a whistle should be loud, work after being wet (OK – dumped in the river!), and cheap. It should be cheap so that you can have a few handy – otherwise it’ll always be at home when you want it. After a quarter of a century of teaching I have a neat collection of whistles, some plastic some nice chromed metal. None are that loud, certainly not waterproof, and with strong lanyards as likely to strangle me as help. Proper refs’ whistles might not have these shortcomings – as with the one we tested of 25 years’ vintage.
    I had put off getting a good whistle because I couldn’t find one locally, and because of shipping charges in getting one from the US. The signal whistles in the camping section of stores were worse than I already had. Eventually I found that the whistles I was looking for were in the hockey section of Canadian Tire since they are used for refereeing. The Scottie and Acme were found in the local hardware store.

    The Fox 40 Whistle
    This comes in 3 colors here, (red, orange and yellow) that have good visibility – many other colors are available. The whistle sells for $4.40 CA so you can afford a bunch. It’s extremely loud, and we’ll try some tests to see just how far it can be heard under various conditions. Most important it comes with a landyard that has a plastic “break-free” clip so that you won’t get strangled by it. The whistle is pea-less and works well after being soaked. Yep it even works under water, though you’d probably want to save your breath there.
    The Fox 40 Webpage A Review
    The Scottie Lifesaver
    As you can see above, this is a pretty bulky whistle. It has synthetic peas but seems to work under all conditions and is durable. It’s Coast Guard approved as are the others.
    the Acme 649
    This is a pretty decent whistle, sounding much the same in tone (single lower tone) as the Scottie. The advatage of this one is the flat profile – being much the same size and shape as a bic lighter, so it fits easily into pockets. Same story – old people will hear this as being louder and so hear it further than a Fox40. Opposite with young people. Mine didn’t come with lanyard or snaps, but the price was only $5.00 CA.

    Others
    Marion David Poff sent me some whistles to test a while back. More on them later as I get chance to test further. For now the Storm really does sound 50% louder at half a kilometre, but all the whistles work at that distance.
    Here’s a picture for comparison of sizes. From left to right, Acme 200, Acme 649, ACR, Storm and Fox40. (Naturally I’m missing some he sent as they were in my other jacket!!!!

    Here’s a comparison between the Acme 2000 and Storm

    And here a closer look at sizes comparing Storm to Fox 40

    I’ll fix this up in a little while – Marion!
    Here’s an interesting piece of information I got from Phil:
    ” I have numerous FOX40′s and the one I have found that works the best and seems to have a slightly lower audible range then any of the rest is one that FOX40 produces for animals handlers! It’s basically made for people with pets to use to either help train their dogs and/or warn others of the dog. It seems to produce a tone that either carries further or is heard slightly easier by our ears. I’m not sure if there is any other info on the whistle around, but it came in a blister package, and out of the 10 they had(Local Pet store) they were all a black/purple mixture. The only diff I could see as far as the structure of the whistle was that it was missing the lower chamber(did not have part of the chamber where the bump on the bottom is). It also has a VERY distinctive sound verses any other whistle on the market, such as a policeman’s whistle, ref’s, fox40, storm…etc. It has what sounds like a lower-wavering tone and pitch, although the decibel range still appears the same.”

    Conclusions:
    Since whistles are excellent signalling devices and a $5 whistle will last many years – a whistle is a pretty good deal. Getting two of different pitch might be a good signalling strategy too. I wouldn’t make too much of what I found – for the cost involved I recommend you get a few and run your own tests with the people you are in the outdoors with. Any of the whistles shown so far are excellent value, durable and really work.

     

  • Ribuhite

    Brian,
     There are at least 4 things to consider when looking for a emergency SAR whistle.
    1. What does it sound like? Does it sound like birds,wind thru the trees, or other NATURAL sounds.

    2. How loud is it. Can it be heard over long distances.

    3. Is is small enought to carry and use. A seemingly dumb point but you could carry a Trumpet that would work Great BUT it is a lot to carry.

    4. Does it use your breath to work. This sounds (pun) like another dumb point but there AIR horns that fall into the last 3 points but when the air is gone it’s done.

    In my case I carry 2.
    1. One is a normal small one like the ones you tested. I use them for Rope and litter work where a fellow SAR member recognizes the sound and it is mostly over shorter distances. I also use it with Swift Water opperations for the same reasons

    2. This one, The StowMaster Marine & Distress Horn, is the Best Loudest (125 Dc) lightest, mouth blown horn I have found. It doesn’t sound like anything in Nature and the sound carries a Long distance.
    It is about the size of my fist.
    At $9.00 is a great bargin.
    Marine Horn | Shop | StowMaster® Folding Fishing Nets by Norsemen Outdoors

    There is another one like it but is thinner plastic and can Break.

    Amazon.com: Shoreline Marine Horn Safety Blaster (Small): Sports & Outdoors
    The diaphram can be rebuilt with any thin plastic bag, like the one it comes psckaged in if you “Blow it out” .
     You can remove or slide part of the “Horn” end to change the pitch of the sound.

    Down side: it is larger than “Whistles”  BUT the Up side It can be heard far off and the sound is Un Natural.

    Check them out and do a test on the #2s

    Be safe out there and remember…
     “It is not Nature we must control, but Ourselves”
    Rick

  • drielok

    From your test results I question your decibel meter as they are all the same. You need to have know standards for the test to be valid. I’m guessing your meter maxes out at 94 decibels which is why they all stopped there.