How’s your hearing?
Dec 8, 2005 at 12:46 AM Thread Starter Post #1 of 35

GotNoRice

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The range of human hearing is generally considered to be 20Hz to 20,000Hz. Starting at about age 20, human hearing begins to naturally decline by about 1Hz per day. For example, while a child may be able to hear sounds all the way up to 20,000Hz, someone in their mid 40’s may not be able to hear anything above 14,000Hz or so.

I have made a small torrent of custom generated test tones ranging from 10,000Hz to 20,000Hz, in 500Hz increments starting at 13,000Hz. I also included a test tone of 15700Hz, as that is the frequency of the high pitched whine that a NTSC CRT television gives off (a common indicator that you can use for easy comparison).

I’ve noticed that at lower bitrates, many compression algorithms (MP3, WMA, etc) tend to discard any information above 16000Hz or so, presumably due to the assumption that most people can’t hear it anyway so it is insignificant.

http://home.comcast.net/~gotnorice/Audiotest.torrent

As for me, my hearing rolls off pretty hard above 19,000. I can just barely hear 19,500, and I can’t hear 20,000 at all.

Also, try to keep the volume constant during the tests. If you have to turn the volume up in order to hear a tone, chances are you’re not actually hearing the tone at all, but rather you’re hearing this:

testtone.JPG


You can see that as the tone approaches the noise floor, it becomes less precise, sometimes including information up to 1000hz below the frequency of the actual tone. This should not be an issue, but if you are not hearing anything else, and you turn up the volume, this could easily become faintly audible, and would essentially defeat or at least diminish the accuracy of the results.
 
Dec 8, 2005 at 2:12 AM Post #5 of 35

GotNoRice

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The files use the WMA Lossless codec and are 16-bit, 48Khz. Windows media player should be able to play them at least, but WMA in general is pretty widely supported.
 
Dec 8, 2005 at 2:14 AM Post #6 of 35

discord

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Quote:

Originally Posted by GotNoRice
The files use the WMA Lossless codec and are 16-bit, 48Khz. Windows media player should be able to play them at least, but WMA in general is pretty widely supported.


Yeah it wasn't that. I'm just a bittorrent noob.
 
Dec 8, 2005 at 2:38 AM Post #10 of 35

chych

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No .wav files? A little better supported than WMA... (especially for non-windows users).

Also I'd be curious as to how our respective sound systems shift the actual frequencies of the sounds.
 
Dec 8, 2005 at 3:36 AM Post #15 of 35

AdamWill

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Could we please have .flac or at least .shn for cross-platform compatibility? I'm hoping my Linux system will be able to play these, but I'm not optimistic.
 

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