Explanation of 44.1 kHz CD sampling rate
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Explanation of 44.1 kHz CD sampling rate
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Re: Explanation of 44.1 kHz CD sampling rate
#2Also, the fact that 44,100 can be factored as 2^2 * 3^2 * 5^2 * 7^2 makes it very efficient to do Fast Fourrier Transforms on moving windows. Which we do a lot in Speech Recognition and DSP in general.
Re: Explanation of 44.1 kHz CD sampling rate
#3Also, the fact that 44,100 can be factored as 2^2 * 3^2 * 5^2 * 7^2 makes it very efficient to do Fast Fourrier Transforms on moving windows. Which we do a lot in Speech Recognition and DSP in general.
Yep. But understanding Fourier Transforms takes some effort. Luckily,
HN user 'bsilvereagle' posted this earlier today:
"Linear Systems and Optimization | The Fourier Transform and its Applications"
https://news.ycombinator.com/item?id=7789767
http://see.stanford.edu/see/courseInfo.aspx?coll=84d174c2-d7...
Re: Explanation of 44.1 kHz CD sampling rate
#4Also, the fact that 44,100 can be factored as 2^2 * 3^2 * 5^2 * 7^2 makes it very efficient to do Fast Fourrier Transforms on moving windows. Which we do a lot in Speech Recognition and DSP in general.
What you say actually makes no sense whatsoever. What is forcing you to consider 1 second windows?
Also, 48kHz is 2^7 * 3 * 5^3 so it actually avoids the larger prime factor of 7. Not that anyone cares: just use an actual power of two as your window size to begin with!
Re: Explanation of 44.1 kHz CD sampling rate
#5It seems strange to me that they would be re-purposing video tape for digital audio, given that digital tape technology was used in computers since UNIVAC in the 1950's [1].
Re: Explanation of 44.1 kHz CD sampling rate
#6It seems strange to me that they would be re-purposing video tape for digital audio, given that digital tape technology was used in computers since UNIVAC in the 1950's [1]. [1] http://en.wikipedia.org/wiki/Tape_storage
Tape is tape, and VHS was a popular platform. I do remember people wanting "higher grade" Super VHS for some digital audio recording platforms, but for the most part you could even use regular VHS in a pinch.
Re: Explanation of 44.1 kHz CD sampling rate
#7It seems strange to me that they would be re-purposing video tape for digital audio, given that digital tape technology was used in computers since UNIVAC in the 1950's [1]. [1] http://en.wikipedia.org/wiki/Tape_storage
The key innovation is 'helical scan':
http://en.wikipedia.org/wiki/Helical_scan
This came along for video applications. Up until then the idea of tapes for audio or data was to put as many linear tracks on them as possible. With video some new thinking was needed, hence the helical scan. As it turned out helical scan was the future for data and audio storage too.
Re: Explanation of 44.1 kHz CD sampling rate
#8This confuses me because the vertical rate is not 60 Hz, it's 3579545 Hz / (525/2 * 455/2) = 59.94 Hz. In other words it's odd that they would have chosen to be compatible with black and white instead of color.. instead of 44.1 KHz, it would be 44.056 KHz.
Edit:
Well it turns out that 44.056 KHz was used for the "EIAJ digital-audio-on-videotape standard"
http://recordingtheworld.infopop.cc/eve/forums/a/tpc/f/22260...
Re: Explanation of 44.1 kHz CD sampling rate
#9This has already been posted to HN before, but its the best explanation of digital audio I have seen: http://xiph.org/video/vid2.shtml
Re: Explanation of 44.1 kHz CD sampling rate
#10It seems strange to me that they would be re-purposing video tape for digital audio, given that digital tape technology was used in computers since UNIVAC in the 1950's [1]. [1] http://en.wikipedia.org/wiki/Tape_storage
I used to use VHS set on 6-hour EP recording speed along with dbx noise reduction (compression/expansion, really). I used dbx because the bandwidth & sound quality was so bad on the slower speeds -- until the HiFi audio technology was introduced later on.
I'd get the play time of a reel-to-reel in a device that I already owned, and so no additional space was needed on my shelf.