Digital Audio: The Basics

Comparing Different Audio Formats:

I have a second channel:

[johnwhyte]

Hi Mark,

I enjoyed your video, it took me back.

The derivation of the 44.1KHz sampling rate is based on the following:

The original experiment was to store the digitised audio on 2 inch video
tapes, as that was all they had and was the mest medium.

In the Uk the number of TV lines was 625, this is made up of two 'fields';
one odd, one even, and 'flyback'. The odd and even lines are interlaced.

Flyback is the time taken for the scanning beam to get from the bottom of
the screen back to the top to start the scan again and it equates to 37
lines.

So we must subtract 37 from 625 = 558 lines (total of both odd and even
fields).

Next we seperate the odd and even fields (call it left and right)

588/2 = 294

It was assessed at the time that three samples could be stored on each
line, thus:

294 x 3 = 882

The electrical mains frequency in the UK is 50Hz (used for timing), so;

882 x 50 = 44100Hz, 44.1KHz.

Hope this helps.

Kind regards,

John.

[slxth]

im not into sound engineering or math and physics at all but i still understood everything, you are a great teacher !

[MegaGraham]

Excellent. Good structure and a nice delivery style. Many thanks.

[ninetailscosmicfox]

It is rare to hear above the 24khz level, but there are those who can, myself included can even hear bats. My hearing tests showed that I barely detect up to 30khz but apparently that means I’m also more susceptible to high frequency noise damaging my ear

[llamafromspace]

Soo useful, really like the Segways, like why telephones sound the way they do. Very useful and hard to find. It helped me understand the other stuff.

[athishankaranarayananv]

Fantastic!👌 Very well explained. Thanks for making such a fantastic video…

[victorcoss]

Hey Mark! Thanks for this. I was just headed off to bed and saw this notification. Will watch tomorrow. Thanks a lot!! :) Love your content.

[garnet]

Learned a lot from this video, great information and presentation. Found it easy to follow thank you

[JoshuaKisb]

Awesome tutorial. very informative. well explained. Thank you

[akarimsiddiqui]

I love this video. Please do more of these!

[user_just.com]

الحمدلله فهمت ال ساعتين ادور على فيد عشان افهم
One of best 👌 video

[DeadlyNinja]

Hey Mark, I know this is a bit unrelated to this video but, I just finished watching your pfSense series and god it was awesome, I have learnt so much from it, I love it!!! Is there any chance that you are going to continue it though? Such a good series would be complemented with a continuation!!!

[mikethebeginner]

This was great, exactly what I needed, but...I really need you to GO ON and explain more about digital audio as music for ignorant consumers (i.e., me)...what are high resolution formats, what are the various options for buying and storing digital music, how do you access it, etc., etc....this is a great FIRST video but it just doesn't go far enough for me to get me where I need to go. I want to understand the options for digital music so I can make intelligent decisions as to how to move into the present era.



Not that YOU have to provide this, just saying it's what I need.

[CasualCheetah]

Awesome video, man! Thanks for the info!

[ninetailscosmicfox]

I thought of a way to increase resolution to a greater degree with a minimal increase in sample rate. If you sample four points, with the peaks and troughs acting as a trigger reset (I feel like opamp summers would work best here) then the mid-wave sample points could serve as slope checks - if the voltage is rising or falling faster/slower than the previous slope, we can discern a derivative change in frequency, shift the stored bits accordingly and maybe use ASP to reduce the delay that would be reflected in the data (hearing the 20khz just a few nanoseconds sooner). I don’t know if this is already done but it’s an idea I just had 👍

[obsoletepowercorrupts]

Would you ever make a video to show how to go from say, calculus (diff/int) to impossible numbers (i of SquareRoot), then Fourier anaysis to separate a signal into its harmonic series (like an audio CD graphic equaliser), then Fourier Transforms (like FFT for digital audio) and end by hinting at video compression via the Discrete Cosine Transform (Cooley Tukey), Bit Twiddling?

[lucafrondoni]

good tutorial :D if you have more time now, we would greatly appreciate if you could continue with the pfsense tutorials. thanks :)

[Guust_Flater]

24:00. Increase 3dB = 10 times the amplitude = sounds (for human ear) twice as 'hard'. So each increase of 3dB makes is sounds dubble as loud. Human hearing is based on log10 and that why 10 times amplitude is 'only' 2 times louder.

[nathantcampbell]

Correction: 3db is a doubling in power, 10db is 10x in power. Human's experience a 10db gain as a doubling in perceived volume.

[amnesiacsardine]

All that trouble when you could just stick to analog all along ;)