Yahoo Groups archive

The Logic Off Topic list

Index last updated: 2026-04-28 23:27 UTC

Message

Re: Re: [L-OT] Digital signal

2001-11-08 by GAmoore@aol.com

>"All" you have to do is find some way of, for example, representing pi 
>accurately in a digital filter ... which by its very definition is going to 
>be somewhat limited in its capabilities given that the synthesizer with the 
>ability to represent pi accurately has yet to be created (far as I know 
>none of them have the infinite memory required to represent pi with the 
>required degree of accuracy).

Thats what double precision floating point is for. 64 bits or 128 bits 
will get you pretty accurate estimate - certainly good enough so no one 
can hear any difference. I have the Maple program on my computer and I 
can give you as many digits of Pi as you like. You want 1,000 digits of 
Pi? (it only takes a second) - if you want 5 or 10,000 digits, just le me 
know
 
Pi == 
3.1415926535897932384626433832795028841971693993751058209749445923078164062
862089986280348253421170679821480865132823066470938446095505822317253594081
284811174502841027019385211055596446229489549303819644288109756659334461284
756482337867831652712019091456485669234603486104543266482133936072602491412
737245870066063155881748815209209628292540917153643678925903600113305305488
204665213841469519415116094330572703657595919530921861173819326117931051185
480744623799627495673518857527248912279381830119491298336733624406566430860
213949463952247371907021798609437027705392171762931767523846748184676694051
320005681271452635608277857713427577896091736371787214684409012249534301465
495853710507922796892589235420199561121290219608640344181598136297747713099
605187072113499999983729780499510597317328160963185950244594553469083026425
223082533446850352619311881710100031378387528865875332083814206171776691473
035982534904287554687311595628638823537875937519577818577805321712268066130
01927876611195909216420199

>>Real analog devices are pretty noisy actually.
>So are digital ones. Lots of squealing and stuff. Then you've got all that 
>Nyquist palaver. Etc etc etc. No Shangri-La there, sadly. Pretty good though.

There is a simple point which you keep avoiding.

Case 1.
Peter Gabriel sings 
 ----> mic -> preamp -> A/D converter -> digital file

Play back 
digital file ---> D/A converter ---> amplifier ---> speakers


Case 2
Mathematical numbers are used to create a sound
 .......  digital file

Play back 
digital file ---> D/A converter ---> amplifier ---> speakers

There may be noise going out in both cases, but there is bunch of noise 
going on the first case only. And analog synths produce a lot of noise!!!




>>The digital analog synths sound source was
>>purely mathematical.
>And ... so was the sample purely mathematical. A sample is not a real 
>recording, it is merely a collection of numbers that is supposed to 
>represent a wave form. But ... so also is 'a sine wave', within the same 
>digital domain, merely a collection of numbers that is supposed to 
>represent a waveform. Both are thrown at converters in order to produce a 
>sound. Can't see the difference myself. But I accept that you do.


Do you like to argue just for the sake of arguing or do you actually 
believe this?

Attachments

Move to quarantaine

This moves the raw source file on disk only. The archive index is not changed automatically, so you still need to run a manual refresh afterward.