Dave
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Post by Dave on Jan 9, 2014 11:16:43 GMT
Hi Guys, I was thinking that my hearing was worse than it should be for my age (73+) and then I saw this: - www.pinkfishmedia.net/forum/showthread.php?t=149857My interpretation of some of the posts on there is that hearing loss above 12 to 15kHz is quite common in people much younger than me and I am not so unfortunate after all. How do you guys fare? Dave.
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Rabbit
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Post by Rabbit on Jan 9, 2014 17:18:06 GMT
I think my hearing drops off at 16KHz or 17. I'm not entirely sure, since in order to determine that, you need something to play all the frequencies at the same volume. At 17 KHz, I am 'aware' that something is starting and stopping but don't hear a proper pitch. More like a hiss.
I had my ears checked when I had a moulding taken and the guy that did it was very surprised at what I was hearing for my age. In fact, he didn't believe me and continued testing until he became convinced that I wasn't just guessing right. He expected my hearing to be tailing off much sooner due to my job, but then again, I've always been fairly careful and blotted noise out with plugs and turned the volume down for my ears.
I don't hear evenly though. ie - my hearing isn't flat. 15KHz is pretty high in any case in terms of musical instruments.
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Post by jhelms on Jan 15, 2014 2:24:43 GMT
I am in about the same boat Ian, mine seems to drop off considerably at 18K. I tested myself a few weeks ago using my function gen. I can tell something is there but cannot perceive it as a frequency, just something starting and stopping. Below that I do not have an issue with. I was pretty happy with that considering I fly at least 80K miles a year - it is hell on hearing from the noise, drone and pressure changes.
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solderdude
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Post by solderdude on Jan 15, 2014 7:17:57 GMT
When I was young I could not 'hear' above 18kHz either. I just felt a 'pressure' when listening to it at HIGH levels well upto 19kHz in those days. In music there are no high levels of those frequencies present, instead they are very low in amplitude even when playing music loud. Those that have played with tone generators will understand why 20kHz is considered the max frequency needed. Also when recording double that frequency will be needed in order to end up with a good 20kHz BW recording. I can still hear up to 16kHz but above it I don't 'percieve' much of that pressure.
What's also fun to test is your dynamic range ! There are tests for that as well. It'll show 16 bits is enough for reproduction but again for recording you will at least need 20 bits and if you have a DAC and digital volume control more than 16 bits is needed as well.
On the other hand... show me a DAC that can actually produce a 20 bit RESOLUTION (there are plenty that can handle 24 ro even 32 bits but NONE can resolve it)
And yes... there is some research that shows one can perceive a difference when related harmonics above the 20khz threshold are present BUT only when playing a single signal. This cannot be shown with complex music so seems quite irrelevant.
Thing is that an FR with a roll-off of -0.5dB around 20kHz vs flat at 20kHz can be perceived in a (blind) test that is level matched. It does not maifest in the sense of loss of highs, ambient air or anything. Rather it has the effect of sounding 'fuller' with a mild roll-off. It is not possible to reliably detect this 'subjectively' with statistical relevance. The differences could be because of phase shifts rather than the level roll-off... at 20kHz.
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Rabbit
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Post by Rabbit on Jan 15, 2014 16:57:37 GMT
Many hi fi people take it as a matter of 'pride' in describing how high up they can hear. I'm not certain that they always tell the truth since not only is 20KHz extremely high, but most headphones and speakers tail off up there as well so they are also being played quieter. What with your hearing rolling off and the headphone, it all becomes a bit difficult.
there is some research that shows one can perceive a difference when related harmonics above the 20khz threshold are present BUT only when playing a single signal. This cannot be shown with complex music so seems quite irrelevant.
Well, there is also a possible 50% 'hit' rate perhaps by guessing? It could also be that headphones can distort up there - I have heard some weird anomalies in the very top register with some headphones, where the sound is kind of 'disjointed and not playing a proper tone. (ie - it's cracking up!!)
As far as harmonics go, I don't normally hear the actual harmonics, but the addition of harmonics (or making them stronger) has the effect of changing the timbre of the sound rather than me hearing the actual harmonic notes themselves. I find that very same thing with tubes. The strength of the harmonics change and so each tube has a different timbre, but I don't 'hear' the actual harmonics.
If you heard harmonics singly, then you would perceive music as an awful noise (like a dog) where each note consists of loads of notes (where they don't gel harmonically the further up you go) so you would hear a cacophony of sound. (A bit like dropping a piano from a height, so that all the strings vibrate at the same time to lesser or greater degrees)
One note consists of loads, superimposed on top of the fundamental and in the early days of synths, the harmonic content would be electronically altered through what was called 'additive' methods, where you combined a pitch played with sine, square and sawtooth waveforms and by altering the strength of each 'superimposed' waveform, you added harmonics since some were reinforced more (or cancelled) by changing the amplitude of each wave form. This is the way that the early Yamaha DX synthesisers worked and loads of groups in the 80's were using Yamaha DX7's in their bands so all bands tended to sound the same.
Then along came a 'subtractive' method which was more 'analogue' sounding and less clangy. (The Rolands and in particular the Roland D10) They had wonderful fat, round sounds.
However, the whole principle revolves around harmonic content and no one heard individual harmonics right up high the frequency spectrum!!!
Nowadays - everyone uses presets and samples!!!!
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solderdude
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Post by solderdude on Jan 15, 2014 17:11:49 GMT
Most membranes start to break up above 5kHz which can create frequencies that aren't there in the applied signal.
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Rabbit
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Post by Rabbit on Jan 15, 2014 17:20:08 GMT
Sorry Frans, I was editing my post while you replied.
Yes, that's what I think people 'really' hear not the sound. They hear the nasty combinations and claim to have hearing that is not normal!!!! The creation of those frequencies due to break up is kind of similar to early synths except they were controlled and not breaking up!!
Some techniques in singing and even in electronics even tries on purpose to create really strong harmonies via the use of harmonics. Live, you hear them, (Like a whistling sound above the real note) but they can be very hard to hear on speakers or headphones and sometimes need to be 'enhanced'.
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