16.5k it it for me now. Almost not worth it. But I want everyone to hear this at its best. When I was a kid I could tell if someone's tv was on the second I came in a house. Kinda miss that.
Yes but...
I can hear the difference in texture (or whatever) between a 10k sine wave and square wave, even though if we do a Fourier analysis the main difference is the first harmonic at 20k which I can't hear. I don't know what is going on with my ears and brain but it doesn't seem to be Fourier!
The point that I hope that I have made is that frequencies that we can't hear by themselves affect our perception of the character of sounds.
Pete
The first harmonic of 10kHz is 10kHz, and square waves consist of odd harmonics, 30kHz, 50kHz etc..
What a speaker produces when presented with a square wave seldom looks anything like a square wave..
Yes, good point. I probably shouldn't post while watching the football game!
More fully fleshed out, a 6k sine wave sounds quite different from a square wave even though the first Fourier term at 18k is beyond my hearing.
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The first time I really became aware of the true high harmonics was on a Robert's tape recorder in 60s. At that time the Japanese thought they had best disguise all their products with "America/ Anglesized" names. Robert later became Akai. Inside the highly compliant 4" or 5" was a whizzer cone. The speaker was probably a Fostex unit and not bad. Well..... my 14 or 15 year old ears were opened to a whole new world of musical harmonics Before that I thought there was only one high harmonic. It was 15.5 k or so came from the rear of a TV and regularly knocked me on my ***! Later I found out it was called flyback transformer. I had assumed it was named for its ability to make me fly back across the room from it (-: but yeah..15k or higher. (-:
In the USA, the NTSC flyback transformer frequency is 15.750 kHz for black and white TV and 15.734 kHz for color.
I can remember what those sounded like, it would be interesting to measure the level at 1 meter to find out how sensitive our hearing was.
That said, the construction and position of the flyback transformers in CRT TVs makes a huge difference in their SPL- some could be heard all through a room, others barely audible only when within inches, probably at least -60dB less than the more noisy ones.
I can remember what those sounded like, it would be interesting to measure the level at 1 meter to find out how sensitive our hearing was.
That said, the construction and position of the flyback transformers in CRT TVs makes a huge difference in their SPL- some could be heard all through a room, others barely audible only when within inches, probably at least -60dB less than the more noisy ones.
Especially the sound rebounding off of hard cheap wood paneling...and if the back was off and the cord removed from the Masonite cover re-plugged in and horizontal linearity was adjusted while sitting in front.......man that cage with a 1b something or other , if you too close got zapped hard!!!!
1953 to spring 1969 I hated to walk by the television department of the department store. An awful screech. Covers did not have to be off. Summer 69 the US Army had me fire the 8" howitzer at ROTC camp. No more problem in the TV department. Fifty years later my hearing still fades into tinitis at 14 khz, due to aggressive use of earplugs in noisy areas.