markshan
Sir Thrift a Lot
So we do agree on something. I'm out.
Digital audio explained (even I grasped some of it!)
- Thread starter RobInONT
- Start date
So we do agree on something. I'm out.
rifftrax
mix-meister
This is the exact same kind of response I got in another thread on another forum when I talked about people (of ages up to 40 and beyond) readily hearing devices like a Dazer (it got especially crazy when I mentioned what that frequency actually is, lol). It's like, everyone freaked on me. It's starting to become this legitimately funny thing. People called me names who were otherwise relatively rational posters and generally just shot back that I was daft. I tend to consider myself one of the most absurdly calculated and pragmatic people I know... to the point where it gets annoying (maybe that is the whole problem here). Ah, good times.
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PAGS
Super Member
Nice tech talk. And when a narrator sports a beard like that, it's going to be about science
Or shoofly pie.
c.coyle
Fighting the Dunning-Kruger effect.
rifftrax
mix-meister
Where did they publish that at? I'm not seeing it on any of the websites I've reviewed information for that device from.
I don't make anything from K-II enterprises. I don't work for them. I actually helped build a competing product, so being a shill for the Dazer is the last thing on my roster of primary interests. Here, you can even buy one of these, works the same way at a very similar frequency:
http://www.amazon.com/Lentek-BF03-Koolatron-Dog-Off/dp/B000CEFOSW
Anyway, just seems odd that people seem so disinterested in the actual point I was making about hearing limitations.
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RobInONT
Active Member
Hi rifftrax,
Is this the same product?
http://www.tesco-shopping.com/Dazer.htm
I dont think people are disinterested...it just that you are wanting us to believe that the pretty much universally accepted hearing range of humans is actually wrong. Thats a big claim...needs to have big evidence.
I gotta ask the obvious question about this dog whistle: How are we to know it only emits 25khz?(and not some incidental lower frequencies as well) I know I dont have any way to measure it.
Is this the same product?
http://www.tesco-shopping.com/Dazer.htm
I dont think people are disinterested...it just that you are wanting us to believe that the pretty much universally accepted hearing range of humans is actually wrong. Thats a big claim...needs to have big evidence.
I gotta ask the obvious question about this dog whistle: How are we to know it only emits 25khz?(and not some incidental lower frequencies as well) I know I dont have any way to measure it.
rifftrax
mix-meister
That's understandable
I guess I can see how some might be incredulous over it. Hence why the test is so easy.Yes, the product you've linked to is the same. Interesting that they actually advertise the 25khz metric (that's exactly what they measure). I've taken extensive spectrograms of the device, the output waveform is a totally pure sine wave, harmonic content of any kind is below -40db (vs. the fundamental), easily testable with any DSO with an FFT function by probing the transducer output. There are no sub-harmonics produced, these ultrasonic transducers are extremely narrowband output emitters and wouldn't support a sub-harmonic regardless. You can also tell because the signal requires an very specific positioning in relation to the ear-drum to hear (it has to be totally on-axis or at least very close), a sub-harmonic would be far less directional and could be heard from a much wider range of incident angles.
As to why people have gotten the whole "hearing limitation" thing wrong for so long? Beats the hell out of me. Like most things, it was probably just a metric that someone introduced at a certain point and after it "stuck", no-one simply bothered to actually question it and test to really see if it held up. I can tell you right now the "estimated" area of the normal equal-loudness contours charts that everyone is familiar with is absolute rubbish.
Of course, you have similar BS that exists all over established audio regimes, like the dependence on a-weighting filters as a standard measurement method, when using any weighting at all only makes sense at a static volume level, and of course the algorithm itself could never be a dynamic function (how the hell would you do that for an analog meter for instance). Even more than that, it's senseless because a-weighting doesn't even inversely match any established contour at any phon level. Anyway, I digress.
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Dmannnnn
Up Late
I don't think anyone should attempt this. Even if you can't 'hear' it, it will likely cause damage to your hearing apparatus.
.
tppc
Dogs know best
Ah yes. This guy certainly knows his stuff.
Though, the fact is that humans can quite easily hear up to around 28khz (potentially above that). Ask me how I know
Does the presence of ultrasonic frequencies in music really benefit the listening experience? I could see bats and dolphins jamming on it.
RobInONT
Active Member
Well, this is definitely not my area of expertise, though it is interesting. I still think you may be hearing subharmonics, apparently they're pretty common manifestations from ultrasonic cleaning equipment as well...
I did find an interesting paper form a fellow in Virginia who claims we sense ultrasonic content in music through our eyes!?
Looks like a legit paper...idk?
I need to reread Monty's article, but wasn't one of his arguments that allowing ultrasonic content to be recorded and replayed would also cause considerable increase in intermodulation distortion because of the resultant subharmonic content? The old amplifier design axiom "the bigger the window, the more sh*t that flies in".
I did find an interesting paper form a fellow in Virginia who claims we sense ultrasonic content in music through our eyes!?
Looks like a legit paper...idk?
I need to reread Monty's article, but wasn't one of his arguments that allowing ultrasonic content to be recorded and replayed would also cause considerable increase in intermodulation distortion because of the resultant subharmonic content? The old amplifier design axiom "the bigger the window, the more sh*t that flies in".
bshorey
Super Member
25,000 hz. What do I win?
What's the highest frequency produced by a musical instrument? Understanding that noise and harmonics above those frequencies are important to the reproduction process, I think pretty much anything over 20khz is in the area of fourth order harmonics of the highest frequencies of any instrument, no?
bs
Dmannnnn
Up Late
Speaking of limitations, if your device were to emit a 50db signal instead of 115db and you were able to hear it at 10ft, then I would agree that you can indeed hear at 25khz.
Unless our hearing stops dead at a specific frequency, I would assume there is a rolloff, similar to a speakers response curve. Turn it up loud enough and, yes, you will hear it. It still does not fall into the functional range of human hearing.
Quote:
Originally Posted by kcbluesman
How much do you make on each Dazer sale?
Note: According to the manufacturer, the Dazer II emits a 25kHz signal (+/- 2kHz) at 115dB, measured at .5 meter.
Well, perhaps one reason that people seem to be disinterested is that you appear to be hijacking the thread (taking it off course from its original topic). Another reason might be that you seem to be disputing not just conventional wisdom, but information regarding the range of human hearing which appears in scores of textbooks, government publications, research documents, etc. This doesn't make you wrong, but if you are right and can easily prove it, it would seem that you would do so within the related scientific, academic and interest-group communities...rather than try to do so by convincing AK member to purchase an ultrasonic dog-deterrent (which, by the way, based on its reviews, appears to be of very questionable usefullness). And yet another reason might be that I would expect an expert on sound and hearing to be able to cite other experts who support his findings...again, rather than trying to prove his point by having us purchase electronic dog deterrents. If we've got a little extra money to spend, we're going to use it on some high-end speaker cables or other proven technology...not dog radar.
Originally Posted by kcbluesman
How much do you make on each Dazer sale?
Note: According to the manufacturer, the Dazer II emits a 25kHz signal (+/- 2kHz) at 115dB, measured at .5 meter.
Well, perhaps one reason that people seem to be disinterested is that you appear to be hijacking the thread (taking it off course from its original topic). Another reason might be that you seem to be disputing not just conventional wisdom, but information regarding the range of human hearing which appears in scores of textbooks, government publications, research documents, etc. This doesn't make you wrong, but if you are right and can easily prove it, it would seem that you would do so within the related scientific, academic and interest-group communities...rather than try to do so by convincing AK member to purchase an ultrasonic dog-deterrent (which, by the way, based on its reviews, appears to be of very questionable usefullness). And yet another reason might be that I would expect an expert on sound and hearing to be able to cite other experts who support his findings...again, rather than trying to prove his point by having us purchase electronic dog deterrents. If we've got a little extra money to spend, we're going to use it on some high-end speaker cables or other proven technology...not dog radar.
rifftrax
mix-meister
If that were the case, I'd be completely deaf by now. I ear test tones at over 100db @ 1 meter (from 20 - 30khz) on literally a daily basis. The dazer's claim is also sliiiightly inflated.
It's not dangerous by any means, but I also don't sit there and trigger tones for more than a half-second or so at a time (believe me, a typical person just wouldn't be able to take it, it does get a little excruciating). I can tell you just by ear testing a typical 20 - 30khz tone how loud it is within a few db I've had to do it so much at this point.
See Ooashi's white paper:
http://jn.physiology.org/content/83/6/3548.full
But the answer would appear to be, yes absolutely. This makes tons of sense. I've been able to detect tones as low in amplitude as 79db readily in the range of 25khz, and that is in a typical room... not even an anechoic chamber or something abnormally quiet. There is actually a surprising amount of sound sources that produce a large degree of content past 20khz, specifically with brass, bells, pitched and non pitched percussion and of course let's not forget pretty much every synthesized signal at all that's not a pure or low-frequency sine tone.
An organ can produce fundamentals into around 7khz. Depends on what you're defining as a musical instrument. Why is this getting restricted to music? I'm just talking about recording and playback period.
I get what you're saying but even then we're getting a little past the point of what my argument even was. But there is this:
http://www.overgrownpath.com/2013/08/how-classical-music-was-covertly-dumbed.html
Well, I'm not purporting that 192khz is necessary. Just bump the existent window up a bit. Of course there are always intermodulation concerns.
I've tried pointing ultrasonic sound sources at my eyes (i'm familiar with the "bone conduction" and "eye resonance" ideas). No such luck in seeing any validity there with my anecdotal evidence however.
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True story...in the early 90's when I lived in Boise, I noticed that when spending any extended period of time at the back of my house that I'd get these terrible headaches. I also noticed that, when orienting myself 'just right', I was sort-of 'hearing' something...a weird pressure on the eardrums that was difficult to describe. I thought I was going nuts.
Weeks later, in the backyard clearing brush and pulling weeds, all the while 'hearing' this noise, I noticed some metallic box over the fence and in the garden of the elderly lady who lived next door. I immediately realized that this device was the source of the noise and headaches...some sort of animal deterrent thingamajig. I thought it very odd that I was hearing it, but relieved that I had found the source of my misery. I went to my neighbor and told her about my experience, and after looking at her documentation on the device and seeing that it was very directional, we simply rotated the thing 90° so it wasn't pointing my direction. Problem solved.
I do not know what frequency this thing was emitting...I had 'tested' my own ears some years earlier and determined that my own hearing dropped rapidly after about 16KHz. If we assume that the device was emitting in the band somewhere above 20KHz, I have no explanation as to why it caused me such misery, except to assume that the SPL level emitted must have been huge.
Anyway, this whole 'dog whistle' thing is detracting from what is otherwise a good OP and discussion. I suggest that if we'd like to discuss such tangent subjects, that a separate thread be created. My own thoughts are that ultrasonic energy is a waste of sampling bits and amplifier power.
Weeks later, in the backyard clearing brush and pulling weeds, all the while 'hearing' this noise, I noticed some metallic box over the fence and in the garden of the elderly lady who lived next door. I immediately realized that this device was the source of the noise and headaches...some sort of animal deterrent thingamajig. I thought it very odd that I was hearing it, but relieved that I had found the source of my misery. I went to my neighbor and told her about my experience, and after looking at her documentation on the device and seeing that it was very directional, we simply rotated the thing 90° so it wasn't pointing my direction. Problem solved.
I do not know what frequency this thing was emitting...I had 'tested' my own ears some years earlier and determined that my own hearing dropped rapidly after about 16KHz. If we assume that the device was emitting in the band somewhere above 20KHz, I have no explanation as to why it caused me such misery, except to assume that the SPL level emitted must have been huge.
Anyway, this whole 'dog whistle' thing is detracting from what is otherwise a good OP and discussion. I suggest that if we'd like to discuss such tangent subjects, that a separate thread be created. My own thoughts are that ultrasonic energy is a waste of sampling bits and amplifier power.
rifftrax
mix-meister
That's throwing out the baby with the bath water. Why is what you're proposing in any way the proper litmus test of hearing?
What I'm saying is that the limitations of human hearing as proposed by so many agencies and "science" (oooohh) sources were a piss-poor badly researched set of "metrics" (think how many books and the like just says "human hearing ends at 20khz. The end. Moving on"... what?!) that's is now the direct reasoning behind so many malformed takes on how human hearing works.
Yes, human hearing rolls-off slightly at a certain point, and then probably more steeply at some point after that. But I'd be lying if I told you that in listening to pitches of 25khz and 27.5khz (that I verified to be the exact same db level) I heard any actual difference in how loud they seemed. So my problem is why isn't this being presented in such a way?
Saying it doesn't fall into the functional range of human hearing is just another "i'd like to go ahead and dismiss this issue without actually qualifying if it matters" kind of response. You basically just told me you don't care. That's fair I suppose. Really this specific area does need it's own thread.
I stated that Monty reference's the 192khz article he writes in the video. Realistically, sample-rate is integrally related to the whole demonstration he was doing (and why). You're other points are red herrings. I would love to tell you that I've seen anything in writing that supports my testing, but (and believe me, besides the Oohashi white paper... I've found nothing, ever. In my life) I'll admit that there is not. Again, that's why I stated the test was so simple to rather quickly show how readily a normal person can hear an ultrasonic tone.
It's fair if no-one wants to try it. Not my loss. It's amusing to me at this point that such "rudimentary knowledge" of the limitation of human hearing is rather a non-researched load of bunk. I'm wondering if you can point me to a white paper that actually "proves" the limitations of human hearing? You'll find that is also in short supply...
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rifftrax
mix-meister
tppc
Dogs know best
To quote from the paper:
"Psychological evaluation indicated that the subjects felt the sound containing an HFC to be more pleasant than the same sound lacking an HFC."
The qualifier needs to be much stronger than just "more pleasant" to cause a new standard to be established in audio production and playback.
Bob Stuart of Meridian is generally acknowledged as one of the experts on digital audio and audio perception.