Sure, find me a CD where there is a 19kHz signal at -30dB throughout the entire CD and, for bonus points, someone who slept next to it with their hifi at full volume for 2 days without going deaf
It is not at -30dBFS but at -78dBFS. Please recheck your files. Even your post shows something below -70dB.
There are many recordings with standard high frequency (signal, not interference) content well above -70dB!!
Do you know George Orwell, 1984?
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You missed the point I made about the fact that the high frequency signal is only 30 or 40dB below the audio content. The absolute level is irrelevant, it's the volume that it will be played at which is significant when determining if it will be damaging.
I have read 1984 a couple of times but both over 20 years ago. I don't get your point but it's probably OT anyway so perhaps best left unsaid.
Sure, find me a CD where there is a 19kHz signal at -30dB throughout the entire CD and, for bonus points, someone who slept next to it with their hifi at full volume for 2 days without going deaf
Hehehe I believe heb1001 on this. I listened the file on very low volume but I could feel it. I wouldn't be able to stand a full volume
Fatigue due to peaks above 20kh is commonly perceived by people including me.FM stereo pilot tone is 19kHz at -20dB, and de-emphasis will reduce this (and the HF end of the signal) by about another 20dB. Stereo tuners will usually filter or null this out but mono ones might not. Most people never noticed it except when harmonics caused beats with a tape recorder bias oscillator. Possibly tweeters were not so good in the 1950s and 60s?
Very sorry to say that but you are wrong again. Level of the 'audio content' is summed from spectral components. So the 'level' is much higher than you are expecting. On the other hand, 19.2kHz was the only and isolated spectral line so its 'level' was correct. To see what is 'level of the audio content' please check the attached file. Do not forget that FFT is a narrow band tool and shows only amplitudes at the selected frequency, it is like narrow band filtering. In the image attached, the level is -15dB though no component is above some -50dB.
Attachments
Possibly. Amplifiers would have been lower power too. I think the point has now been made about the signal. People can make up their own minds about what volume they want to listen at and how long for.
I think assertions that it's perfectly safe are unfounded but also I agree that it won't blow your ears off.
Just be aware and be careful.
To understand the potential damage, you'd need to work out how the power was transferred to the fragile structures in the ear. I was imagining that the cochlea is tuned to resonate at particular frequencies along it's length and that that signal would deliver disproportionate power to a localised section. I also thought that the delivered power was a function of frequency as well as amplitude.
There is probably a reason that people lose their high frequency hearing first right?
Well none of you lot told me I could look at an FFT plot even in Audacity
I can see it for myself now. I must try this on the Dell at some point.
It might be an idea to wind this up later today. Have any of you any idea what you might be listening to ?
Mainly the fault in your sound card I think
You can change the scale in Audacity to 0 - -160dB and the FFT size. The analyze feature supports 1M sample FFTs. It's much better than most of the FFT plots people as to be posting here.
Mainly the fault in your sound card I think
You can change the scale in Audacity to 0 - -160dB and the FFT size. The analyze feature supports 1M sample FFTs. It's much better than most of the FFT plots people as to be posting here.
Thanks. Yep, its the sound card in the Acer doing it.
Anyhow, what do you think you were listening to ?
The fault in your sound card was mainly what I thought I was listening to. That and a low pass filter of some kind. Possibly a long cable or a simple RC network in opal.
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