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Re: [ARSCLIST] Audio History In a Nutshell?



The Math:


78 RPM, 10 Inch Record


This type of record has 9.5 inches on its outer most edge and 4.5 inches on its inner most edge (by inspection).

Using an elliptical 2.7 x 1.2 mil phono stylus, the frequency response will be as follows:

Theoretical Starting Frequency Response: 16.25 KHz
Theoretical Ending Frequency Response: 7.7 KHz
Response Variance: 8.55 KHz
Average Response: 11.97 KHz

Likewise the generally accepted 16KHz high frequency limit of higher resolution mp3 encoding is a decent match.

AA


Steven C. Barr(x) wrote:
----- Original Message ----- From: "Howard Friedman" <hsf318@xxxxxxxxxxx>
Mike,

MEA CULPA! I assumed KB, but that makes it even 1,000 times more difficult to
stuff 6MB or more of information into a CDA file! How do they point? How can
one produce a CDA file from an MP3 file, for example? If I put an audio CD
with 21 tracks into my drive, my file program tells me that there are 924 bytes
on the CD. Doesn't really make much sense, does it, unless you're an audio
engineer!
Howard

I'm not the expert here, by any means...but it seems to me that if you
are speaking of putting the musical content of an MP3 file onto a CD
as its content...the CD content would be a much-expanded set of bits/
bytes which actually contain the same sonic content as did the MP3
(since you can't recreate anything lost during the "MP3-ization" of
the audio...?!).

A CDA "file" (or, more accurately, the digital content of a CD prior
to its being algorithmically converted to sound...) can contain anything
from NO sound (simply don't provide any sonic content while the disc
is being recorded...just like a 78 can in theory contain three minutes
of silence...!), to the sound of a full symphony orchestra...! Each
one will result in a specific set of bits being placed on the disk's
surface...which, when processed, will replay whatever (if anything?)
was recorded...!

If one records an acoustic 78 onto a stereo LP, for example...the
groove track on the LP will contain a representation of the sonic
content of the 78...and nothing more...!

OTOH, if you play the LP and use a Recordio to create a 78rpm
reproduction (which is, of course, mono...!), you will get a
mono, "limited -fi" version of the sonic content of the LP!

Note that one could also use one's computer to copy the acoustic
78 onto a CD-R or CD-RW...but doing so will NOT upgrade the sound
on the 78 to CD quality...! Nevertheless, the three-minute content
of the old 78 will take up the same amount of space as a 3-minute
full-fidelity stereo recording...

Steven C. Barr



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