![]() ![]() Not only does an ‘a’ string have a fundamental note of 110hz (in 440hz tuning), but many harmonic overtones accompany it in order to create the guitar sound we’re familiar with, including 220hz, 440hz etc. With pure sine waves, we are dealing with very basic forms of audio, specifically the fundamental frequencies which provide a base tone for more complex waveforms, such as those found in musical instruments.įor example, with a violin, it is the addition of harmonics and overtones which give a violin its signature sound.Ĭompare the above spectral graphs to this one of an acoustic guitar ‘A’ string being plucked: Let’s hammer home the point a little further… The spectral analyser shows the exact same response curve. And guess what? The same resultwas achieved by uploading an already compressed MP3 file to Youtube, including one featuring isochronic tones. Yes that’s right, there is absolutely no vital frequency loss and the audio is once again identical to the one which passed through the initial render process. Let’s take it a step further and upload that uncompressed WAV file to Youtube before once again analysing the frequency content… The frequency response graph is pretty much identical, with any difference being aurally and visually undetectable. Uncompressed WAV Exported from Audacity (BEFORE YOUTUBE CONVERSION):Ĭompressed MP3 Exported From Audacity (BEFORE YOUTUBE CONVERSION):Īs you can see, the fundamental frequencies (200-210hz) of the MP3 are still intact. The spectral graphs below will show the WAV and MP3 files’ frequency content before and after conversion by Youtube’s servers. For this to occur, the tones must be panned hard left and right respectively. We would never upload an MP3 to Youtube but the following experiment will show how commonly used data compression does not inhibit an entrainment session.īinaural beats work by combining these two tones, the difference of which is used to create a third ‘ghost’ beat inside the head. We’ll then load these into a spectral analyser. In this experiment we’ll render two identical binaural beat tracks – one in uncompressed WAV format, and the other as an MP3 file (41,000 Sample Rate, 320kbps Bit Rate). We can take these away and the difference will be unnoticeable.Īt The Brainwave Hub, we send uncompressed PCM audio to Youtube’s converters just for the sake of presentability, but what if you were to upload an already-compressed MP3 file for further transcoding? Well, when listening to CD quality audio, or uncompressed FLAC files for example, not all frequencies are perceivable to the human ear, particularly those on the extremes of the spectrum. How is it determined exactly which frequencies to remove? Encoders work by removing certain frequency content in order to reduce file size. The range of human hearing is approximately between 20hz – 20khz. Youtube transcodes uploaded content in order to make it suitable for streaming, and readily available to a wide audience on devices such as mobile phones, tablets, notebooks and PCs. ![]() During this stage, the audio can remain uncompressed, leaving this task to Youtube’s automated encoding process. First there is the initial rendering process, where the video file is compressed down to a size that won’t take days to upload. ![]() There are two stages to encoding a track to be uploaded to Youtube. Let’s put this claim to the test shall we? With the sudden proliferation of brainwave entrainment audios on Youtube, certain companies, in an attempt to compensate for diminished traffic to their web stores have attempted to discredit channels like ours, claiming that once uploaded and subjugated to the process of audio compression, Youtube audios are no longer effective. ![]()
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