Hi,
Yeah, unfortunately audio experts do like to use a lot of graphics to
demonstrate concepts, the GoldWave manual is very much the same. I think the
expression evaluator manual plays host to no less, maybe even more, than
five diagrams.
Unfortunately, looks like the audacity diagrams are just as useless as the
GoldWave ones. Whereas GoldWave diagrams at least have an albeit extremely
small and useless ALT text, this seems to have nothing except the image
filename!
Also this tutorial doesn't seem to go into exactly how samples work. I knew
about the various audio attributes (sample rates, bit depths etc, aliasing
and clipping, and also quantisation noise which it doesn't even seem to
mention).
To be able to make plugins or expressions or any kind of tools that work
directly with the audio, adding effects like pitch shifting, time
stretching, reverb, delay, reverse, filters, compressers, mixing,
overdrive/rock distortion, flanging etc, it's the audio data itself that
needs changing, and that's the tutorial that needs creating - how audio data
is represented, I.E. what each "bit" of a sample represents (I'm guessing 1
means on and 0 means off like anything else), and what each "sample" as a
whole represents (Of course audio isn't a case of on and off - hence the 8,
16, 24 or 32 bits). What samples represent which channels? What samples
represent the pitch, what represents volume, etc. Audio is just such a
complicated spectrum that no matter how much maths you do, whether decimally
or binarily, it just doesn't make sense what goes where.
Cheers.
Damien.
-----Original Message-----
From: Steve the Fiddle
Sent: Monday, August 14, 2017 9:58 AM
To: audacity4blind@xxxxxxxxxxxxx
Subject: [audacity4blind] Re: Manuals and tutorials (Re: nyquist little
manual)
There is an article in the manual called "Digital Audio Fundamentals",
which you may find helpful. Unfortunately it uses quite a few
graphical illustrations, so I'm not sure how accessible it is, but
nevertheless it is here:
http://manual.audacityteam.org/man/digital_audio.html
Steve
On 14 August 2017 at 09:16, Damien Sykes-Lindley
<damien@xxxxxxxxxxxxxxxxxxxx> wrote:
Hi,
I don't know why, but Nyquist kind of reminds me of the GoldWave expression
evaluator. Not sure if it's because the common upshot was I couldn't
understand either one of them, despite having a programming background. Lol.
Seriously though, I may be mistaken but they both may have this weird caveat
that you need a working knowledge of both programming, and digital audio
structure. The latter I have no experience with whatsoever, so when people
talk about adding signals to increase volume or multiplying signals to mix
or multiplying/dividing individual samples to manipulate speed...I haven't a
clue how that works in practice. I was always taught that 2*2=4, not
chipmunk. *Grin*.
At least making an attempt to be serious again, I think it's more a theory
behind digital audio processing is more what's needed. Everything I have
seen so far has either been very technical, or doesn't make sense. For
instance, I read somewhere, or at least understood it as, that an audio
sample is a number between -1 and 1. If that were the case, that could
easily be stored in 2 bits, yet audio is generally saved as 16, mixed at 32
bit, which I calculate as providing ranges of -32768 to 32767 and
-2147483648 to 2147483647 respectively.
Additionally, I can't seem to find anything regarding a logical explanation
as to what the numbers mean. The simplest explanation used most often, which
I understand to a degree, is that each number represents either an
amplitude, or a speaker position. I've seen both explanations, not sure how
they link together but I guess they do. But nothing explains why doing
something to one number and something else to another can change the output
in a way that makes me think that adding would logically change the volume,
multiplying would logically change the speed, using a square root of the
inverse sign might apply a filter, or raising to the power of 16, dividing
by Pi and adding the number of miles between NASA's latest rocket and the
sun would cause a flange. In case those weird formulas start a form of
interesting debate, let me clarify for those that didn't pick up on it that
those last ones are completely made up garbage...I've no idea what would
cause those effects and I've no idea what using those formulas might do -
knowing my luck probably cause a lot of distortion and unwanted hiss.
But as you can see. I personally think that's the kind of tutorial that is
needed.
I've always wanted to make a convolution plugin since neither GoldWave or
Audacity seems to have one - Wondering if Nyquist is up to such a task once
I can get all this theory learned first.
Cheers.
Damien.
-----Original Message----- From: Steve the Fiddle
Sent: Monday, August 14, 2017 8:48 AM
To: audacity4blind@xxxxxxxxxxxxx
Subject: [audacity4blind] Re: nyquist little manual
There is this page in the Audacity wiki that covers much of the
Audacity specific Nyquist information:
http://wiki.audacityteam.org/wiki/Nyquist_Plug-ins_Reference
The complete reference for Nyquist functions is in the full Nyquist
manual: http://www.cs.cmu.edu/~rbd/doc/nyquist/indx.html
and detailed information about LISP in Nyquist (with examples) can be
found here:
http://www.audacity-forum.de/download/edgar/nyquist/nyquist-doc/xlisp/xlisp-index.htm
Steve
On 14 August 2017 at 08:39, Paolo Giacomoni <paolgiac@xxxxxxxxxx> wrote:
Hi listers.
I.m looking for a little nyquist manual, specially for audacity
applications.
Thanks you
Paolo
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