Re: [LAU] from 4 to 400 Hz

> On 07/17/2011 10:41 AM, Rustom Mody wrote:
>> On Sun, Jul 17, 2011 at 1:21 PM, Philipp Überbacher
>> <hollunder@email-addr-hiddenwrote:
>>
>>> Excerpts from Rustom Mody's message of 2011-07-17 05:33:44 +0200:
>>>> I am preparing to give a talk on the wider ramifications of music.
>>>> One of the things I wish to demonstrate is that things that look
>>> different
>>>> are merely analogs but at different scales.
>>>>
>>>> eg if something vibrates at 400Hz we hear a sound of A-flat. If it
>>>> 'vibrates' at 4 Hz we hear a beat.
>>>> In the same analogy a 2 vs 3 poly-rhythm (should?) change to a do-so
>>> chord.
>>>> And so on.
>>>
>>> I suggest you do some experiments before you give a talk. At 4 Hz you
>>> won't be able to hear anything, you won't even be able to reproduce a
>>> 4 Hz sound with common speakers.
>>>
>>
>> You took me quite literally, [I did put the vibrate into quotes :-) ]
>> Let me spell out the experiment in more detail:
>> Say I have a rhythm in 4/4 time -- 4 even quarter notes, bar repeating
>> every
>> second played by say a click. [What kind of click I am not very sure;
>> sharp
>> with few harmonics would be best I expect]
>
> Exactly. Just take a short audio-sample (aka grain) and trigger it
> repeatedly. Increase the trigger freq. (aka grain-speed) from 4 Hz ->
> 400Hz.
>
> Search the net for granular-synthesis. Your use-case is not the typical
> grain-synth application, but the principle is the same.
>
>> Now if there were some (realtime) way of sliding the tempo from 1 sec to
>> millisec I expect the separate clicks would vanish into a hum at some
>> stage.
>>
>> This (and other such experiments) is what I want to demo.
>> Ive started looking at chuck.
>> How does it compare with puredata?
>>
>
> It's a bit of an apples vs oranges question.
>
> the main difference: Chuck you program in text, pure-data you
> graphically connect "objects" (if you know Max/MSP: pure-data is similar).
>
> AFAIK, Chuck does not offer GUI elements - you'll need to implement the
> slider via OSC or use a "text slider".
>
>>>> Is there some kind of software where I can make a 4 Hz beat and pull a
>>>> slider or a freq text box entry until it sound like a A-flat note?
>>>
>>> puredata springs to mind, it's easy to use and has everything you need.
>
> Indeed. Though chuck, supercollider, csound,... could all do the trick.
>
> If you know neither of those. Pure-data is probably the easiest to get
> started with.
>
> http://www.timvets.net/video/grains.php will do what you want with Pd.
>

I'm not sure that does what he wants. He asked for a tool that takes an
existing signal/tone and then down tunes it. What you are suggesting
creates an emulation of that process but generates a completely new
signal/tone.

It would achieve a similar sound but is functionally quite a different
process.

--
Patrick Shirkey
Boost Hardware Ltd
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