New video! The rise of Digital Sound
Added 2018-07-24 16:08:50 +0000 UTCRemember how I started this channel and never finished the story arc of sound reproduction? Time to fix that.
As a note of future concern: you may have noticed that my upload "schedule" has been very, um, unschedule-like. My target has been three videos a month at least, and with this video I've now reached it for July. For the next week, I'm pretty much unable to do any of the YouTube business due to other stupid real-life deadlines that I need to focus on, so although you might see something simple pop up on TC2, there won't be a main channel video until probably the second week of August.
This will happen at least once more around December, but I'm hoping I can work ahead and by that point be making something like weekly videos.
Anyway, cards, captions, and the endscreen are in-progress. But feel free to watch now!
Comments
The highest frequency that a PCM digital signal can reproduce is half the sampling frequency, and since the theoretical limit of human hearing is around 20kHz it's going to be around twice that value. I believe the 44.1 kHz (rather than 40kHz) arose because modified VCRs were originally used to master digital audio and the 44.1KHz relates to the frame and line frequencies. Digital video was using 48kHz as a sample rate when CD was developed, but legend has it that the 700MB disc which Sony was developing in cahoots with Philips wouldn't have held Beehoven's 9th symphony in its entirety, and the CEO of Sony, a big Beethover fan, wasn't having it. Well, that's the urban legend, probably a load of codswallop, not that my ageing grey matter can remember all the details from that far back.
Gordo
2018-07-26 22:24:50 +0000 UTCPlease explain why 44.1 kHz was chosen, and if it still makes sense today. Great channel as always.
Tim Skloss
2018-07-26 01:32:34 +0000 UTCfantastic video!!! When you get into talking about CDs, make sure you cover reed-solomon code!!!
s3v
2018-07-25 17:36:36 +0000 UTCNice video and as someone commented on YouTube it's great that the displayed sound-waves match the voice-over. But I think the statement about analogue = always flawed and digital = always perfect simplifies things a bit too much. It's also debatable if 44.1khz 16bit is really capable of being a lossless capture of the source.
Robert
2018-07-25 08:27:29 +0000 UTCThe comment on the relative size of 64Kb of digital sound reminded me of something interesting I had just read the other day... Many of us in the 35-40yo range in particular can probably remember the "SEGA"! voice that played when you inserted a Sonic cartridge into the Sega Genesis. But it only existed on the Sonic games. Why just a few games? Because just little tiny bit of sound took fully 1/8th of the ENTIRE memory on the cartridge. But, at the time, it was so cool to actually hear something approaching a voice in a game (which is why it's still so memorable to gamers today, despite being about 2-seconds of sound) and Sega really wanted to show off the level of sound their console was capable of producing.
2018-07-24 22:07:30 +0000 UTCreally struggled with this video. The audio appears a fraction behind the video, and was making me "seasick" viewed on different devices and got the same result. Have you changed your audio sync program?
mark barratt
2018-07-24 21:10:39 +0000 UTC"A virtual stylus in a virtual groove" never thought of it that way before. Nice.
Stephen Bell
2018-07-24 20:46:01 +0000 UTCI think the development of the T-carrier system by Bell/AT&T was probably a really important step in the development of digital sound. The ability to flawlessly repeat/regenerate the digital signal allowed phone trunks of unlimited length to be feasible. Ah, the good old days of 8000 Hz 8-bit sound, using µ-law companding to compensate for the really limited bit-depth! Still in use in phone systems everywhere.
Peter Jerde
2018-07-24 18:17:45 +0000 UTCWhen I first became a projectionist in my teens, I was fascinated how a light shining through the film onto a photocell reproduced the audio and how the Dolby system took a stereo signal and made it into LCRS signals. But when we got our digital systems in the mid 90s oh boy could you tell a difference in quality.
Jason McMillon
2018-07-24 17:37:04 +0000 UTCIf you ever go into detail on CD technology, be sure to point out the difference between data capacity and audio capacity. Due to error correction, data CDs can hold 650/703 MB data, but 765/827 MB (74/80 minutes) of audio. :)
Quinton Wilson
2018-07-24 17:36:14 +0000 UTC
