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Frequency Range ( 5Hz vs. 15Hz) - Page 3

post #31 of 35
Quote:
Originally Posted by AzN1337c0d3r View Post


First of all, the Fletcher-Munson Wikipedia Page, suggests that the ISO standards were affected in the LF region due to several factors. Anyways, notwithstanding that, those tests were made using speakers and here's what the Equal-loudness contour page said:

 

Sorry, the page you reference doesn't say that at all. It is pointing out the difference between Fletcher-Munson and ISO standards at LF and theorizes on what caused the differences, but doesn't reach any conclusion.
post #32 of 35
I should note that one could hit a table with a chopstick twenty times per second (or once per second, for that matter) and you would be able to easily "count the beats" without hearing anything resembling a 20Hz fundamental...

That said, many dynamic driver IEMs have been measured by Rin Choi to have very low distortion even at 20Hz, including some cheap bass heavy models. With an airtight seal one should have no problem hearing 20Hz with one of those?
post #33 of 35

I personally don't doubt the ability to notice each individual cycle, but I do doubt the ability to count to 20 in one second. That's some superhuman stuff right there.

 

I can easily hear 20Hz with my headphones. They have relatively low distortion and extend just about flat out to it. But I can't count to 20 in one second. Not even close.

post #34 of 35
Quote:
Originally Posted by Joe Bloggs View Post

I should note that one could hit a table with a chopstick twenty times per second (or once per second, for that matter) and you would be able to easily "count the beats" without hearing anything resembling a 20Hz fundamental...

Here's as close as I could come to a 20Hz chopstick, the zip contains a high-rate mp3, and a spectrum plot.  It's a filtered pulse, peaked at 3KHz, rolled off below 500Hz.  Two things you might try: first, look at the spectrum, noting the 20Hz fundamental.  Second, without opening it in an editor or timing it, someone post how many taps (pulses) there are by counting only.

 

One technical note, the spectrum plot was done on the original 96KHz 32-bit floating file, and to get enough data for good low frequency FFT resolution the original file was several minutes long.  The clip in the zip sounds nearly identical to the original, just shorter.

 

 

 

 

chopstick.zip 46k .zip file
post #35 of 35
Quote:
Originally Posted by Joe Bloggs View Post

That said, many dynamic driver IEMs have been measured by Rin Choi to have very low distortion even at 20Hz, including some cheap bass heavy models. With an airtight seal one should have no problem hearing 20Hz with one of those?

If the distortion is much lower than 10% at high enough SPL you should totally be able to hear the 20 Hz fundamental (plus some harmonics depending on the amount of distortion).


Edited by xnor - 3/13/13 at 7:18am
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