[PD] New user question: How to create simple audio delay?

Benjamin Freidlin benjamin at allthecraze.com
Wed Oct 15 16:48:27 CEST 2003

Thanks for the extra explanation. I am guessing dac is digital audio converter or something like that? i am not from the audio world unfortunately, in fact i'm from the real-time 3d dev world so a lot of this stuff is new to me. 

but again thanks for the hand holding. if i still have trouble after trying to modify the sample and reading the docs, i'll post back.

---------- Original Message ----------------------------------
From: "matthew jones" <M.Jones at signal.qinetiq.com>
Date:  Wed, 15 Oct 2003 15:35:36 +0100

I'm sure you'll get a few other replies but I thought I'd send it anyways...
ADC stands for Analogue-to-Digital Converter, the circuitry in your sound
card that every few nanoseconds looks at the voltage it's being sent via the
line-in socket (yes, all audio signals will be in the form of a fluctuating
voltage in the Analogue domain) which is clearly an analogue signal, and
sends a corresponding number to the computer.  The higher the number the
higher the voltage at that particular instant. the output number is clearly
a digital number, since there is finite precision in this circuitry.

Hence this is called sampling - every N nanoseconds it samples the input to
find out its value, and sends a corresponding number, called a 'sample'.
you then get a long series of numbers into the computer, which you can save
to hard disc in the form of a wav file, or PD can read them via the [adc~]
object.  So from the outlet of this object comes a fast stream of numbers
between 0 and 1 (1 corresponding to the maximum input voltage on your
soundcard), which you can then stream to a [dac~] object for instance... can
you guess what this stands for? (ha, joke.  me? patronising??!)

the [delwrite~] object is just being told to send out the sample that was
read M miliseconds ago.

sorry if all this is way below your level, but it's hard to know where to
start sometimes.
have fun with pd! see what else can be done!


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