What Happens To Your Recording?

Jay2U

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A few years ago I performed a quick test to find out about the playback quality of MP3 and YouTube. In order to keep things simple, I generated a 600 Hz square wave. Square waves consist of the fundamental frequency plus all odd harmonics. The amplitude of each harmonic with regard to the amplitude of fundamental wave, is the reciprocal value of the number of the harmonic. So the amplitude of the third harmonic is 1/3, of the fifth harmonic 1/5 and so on. If all harmonics (say up to 20 kHz) are present, a neat square wave will be the result. If some harmonics are left out or have an incorrect amplitude, the wave will look distorted.

I recorded the 600 Hz signal with a digital recorder which produces a 16 bit uncompressed wav-file. Then I converted this to a high quality 320 kB/sec MP3 file. I also uploaded the original signal to my YouTube account and downloaded it from there. Hereunder the results can be seen, as captured with Audacity. The difference can be heard, even with speakers or headphones of lesser quality.

BlockwavesThree.jpg
 

DiMarco

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Yep. Anything denoted as HQ on Youtube never actually is HQ.
Especially treble always sounds distorded as f**k.

Nice post!
 

Jay2U

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Yep. Anything denoted as HQ on Youtube never actually is HQ.
Especially treble always sounds distorded as f**k.

Nice post!
I just don't understand people who say they don't hear any difference...
 

jester

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Excellent post, I'm assuming your knowledge of signal theory is quite impressive. :)
To be honest I didn't expect so severe artifacts from the 320Kbps mp3!
 

DiMarco

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Question is how important is it to the listener.
In my youth I used to listen to radio Luxemburg, on the AM band which is very low-fi. It never bothered me, I just listened to the songs without ever paying attention to the soundquality.
 

Jay2U

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Question is how important is it to the listener.
In my youth I used to listen to radio Luxemburg, on the AM band which is very low-fi. It never bothered me, I just listened to the songs without ever paying attention to the soundquality.
I also listened to Radio Luxemburg a lot. I loved their programs, but hated the lack of quality and the ever fading and phase shifting signal. I think AM radio is part of the reason why the P-Bass got so popular. Those basses produce notably more second harmonics, so they were more suitable for the limited spectrum of AM radio transmissions and the small speakers in most radios used back then.
 

Florin

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Also the reasons rock basslines were mostly 8ths. Anything else was lost in the mix
 

Hardy

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All our stuff, actually I most of the vids don’t have any more stored. But the quality was not high def at any time:

Channel SiKS
 
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