Silly high resolution downloads
In yesterday's post we learned that sample rates are a term coined from the A/D process rather than what most people assume: the D/A process. So named because we take a sample of the incoming music 44,100 times each second in a standard CD. Once the sample is taken we convert that number to a digital equivalent, store it on a CD and then, when we play it back, we get the same single point sample at the output of our DAC. String all those single point samples, or steps, together and what comes out looks identical to what went in. Voila! Audio.
One of our more technically informed readers scolded me (nicely) for having propagated the myth that what comes out of a DAC looks like a stair step with each of the samples connected together to form what looks like a quasi sine wave, stepped, but the shape is intact which, he pointed out, is inaccurate. While he is absolutely correct I struggled with even bringing this to your attention because I was afraid it might veer us off course and perhaps even worse, confuse some of you with information details not essential to gaining a broad understanding of the subject.
I changed my mind when I thought about it. It cannot be that offering greater depth to information is bad. I have to reject that and accept it is only my failing as a communicator if our community doesn't get it. We're all in this together, so let's march forward and learn all we can. Together.
And to help prove my point about learning and stretching out, along comes one of the best video eye openers I've seen in a while, compliments of the same poster! But I digress. This gets juicy but we need to move forward at a reasonable pace.
First, the output of a DAC using PCM looks more like a series of lollipops than it is typically shown - as a stair step waveform. Here's more accurately what it looks like.
Note how there are the individual samples and nothing connecting the samples? This is right, the connecting of the dots handled later (and we'll discuss that). So, the next time you go to a magazine of anyone's website and see the stair step waveform we're all familiar with, you'll know it's not accurate - and this is.
Now for the juice. Along with this note I was asked to view a video on the same subject. The video is excellent and presented by Monty Montgomery of the non-profit XIPH Foundation an organization dedicated to making sure online media stays open and free and not swallowed up by the monopolies and oligarchies that seem to always wrest control from communities like ours. An excellent group and purpose if ever there was one.
If you have a few minutes, watch the first half of this video "24/192 downloads are silly indeed" because it explains a lot I am trying to cover and is very well done. Worth the watch.
The other reason I find this fascinating and juicy is because of the title. Here's yet another example of a wonderfully bright, well purposed Flat Earth Society member explaining to us why what we hear isn't real! It's great!
Watch the video - remember everything he is telling you is absolutely true. Tomorrow I'll explain why he's FOS about his conclusion despite the fact his info is correct.
Cheers.
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