[78-L] World 1920s Records

[neechevoneeznayou at gmail.com]

DCart would be the solution for this I believe.

joe salerno


Michael Biel wrote:
> 
> 
>>> Does anyone know the cordinnates formular to play the variable speed
>>> 1920s World and Vocalion record recordings at the correct speed on
>>> the computer? I would like to transfere some of the dance band tracks
>>> to CD. I've played around with Adobe and Soundofrge with no luck so far.
>>> Jamie
> From: Jeff Lichtman <jeff at swazoo.com>
>> I don't know what you mean by "co-ordinates formula." Sound Forge
>>> has a pitch shifting tool (under the Effects menu select "Pitch"
>>> followed by the "Shift" sub-menu). You can set the number of
>>> cents by which to adjust the pitch - one cent is a hundredth
>>> of a semi-tone, or one twelve-hundredth of an octave.
> 
> The terminology you and many computer programs and pieces of equipment
> use sometimes really confuses the situation because they are sometimes
> used incorrectly and I can't tell if you are or are not.  What Jamie is
> discussing are the records which run at constant linear velocity, which
> means that the groove speed is constant while the rotational speed
> changes as the reproducer location moves inward or outward.  The
> rotation is faster at the center than at the rim.  What he means by
> "co-ordinates formula" is the ratio of the starting and ending
> rotational speeds so that he can restore the recording which is being
> played at constant rotational velocity to its original constant linear
> velocity status.
> 
> In analog the pitch and tempo remain in coordination with each other. 
> Raise the tempo and you raise the pitch.  Slow down the tempo and you
> lower the pitch.  THIS IS NOT PITCH SHIFTING, although many turntables
> and computer programs call it by this name because they are designed by
> IDIOTS, or Computer Geeks.  In digital (as well as some advanced analog
> devices such as the Whirling Dervish or the Eventide) you can change the
> pitch while keeping the tempo constant, or vary the tempo while keeping
> the pitch constant.  THIS IS PITCH SHIFTING, and is not what Jamie
> needs.  
> 
> Jeff, what do you and Sound Forge mean?  From the daze of numbers below
> it sounds like you are shifting the pitch, and then making an adjustment
> to the mechanical rotational speed of the record.  That louses things
> up.  What Jamie needs is some way to play the record at constant
> rotational speed and vary the pitch and tempo TOGETHER in the computer. 
>  
> 
> Mike Biel  mbiel at mbiel.com 
> 
>> There's a simple formula to convert a frequency ratio to cents. 
>> Suppose you have a signal of 430 Hz, and you want to speed up the 
>> recording to where the signal is 440 Hz (concert A). The formula is:
>> cents = 1200 * (log(desired frequency / current frequency) / log(2))
>> In this case, it would be:
>> cents = 1200 * (log(440 / 430) / log(2))
>> The base of the logarithm doesn't matter as long as it's the same
>> in both the numerator and denominator. Using the natural log, we get:
>> cents = 1200 * (0.022989518224698739423565307535635 / 
>> 0.69314718055994530941723212145818) cents
>> = 1200 * 0.033166863935199317315221406257726 cents
>> = 39.800236722239180778265687509271
>> Rounding to one place after the decimal point, we see that we
>> need to speed up the recording by 39.8 cents. - Jeff Lichtman
> 
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