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Topology of Sound
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lady seals
Started Topics :
5
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76
Posted : Mar 15, 2010 19:37:00
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If topology applies to objects, it surely applies to sound. Like, in my aftertaste of a psytrance night, I hear “psy” sounds everywhere. Busses driving by... whooobumbumbum. Birds chirping.. .twdtwdtwdee.
It's like the music has always been there.
If you are unfamiliar with it, topology would say that a pattern of sound can be molded and bended in many ways, but it will still be the same “soundshape.”
When you place your face underwater and make a nice natural breath, tiny bursts of air interchange with nonbursts of air continuously at an exponentially slower rate. IOI O I O I O I O Is that pulsating wave in breath not the same “soundshape” as so many natural earth sounds and musical sounds?
Share thoughts because I have many, and others should express theirs.
Humbly,
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konvndrvm
IsraTrance Junior Member
Started Topics :
33
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1398
Posted : Mar 15, 2010 20:24
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Quite the erudite post lady seals!
Reminds me of the movie Pi, when the protagonist discovers the 'pattern' within everyday life.
which is ironic considering yesterday was 3-14.
Certainly, I will have to try the underwater experiment next time I'm singing the rubby ducky song in the tub.
Thanks for stretching my mind 
11:24
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lady seals
Started Topics :
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76
Posted : Mar 16, 2010 01:41
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hehe rubby dub dub, golden ratios in da tub! enjoy thinking about it.
(yes, why, it was pi day!)
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Moonclear
IsraTrance Junior Member
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48
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162
Posted : Mar 20, 2010 22:10
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Hazrat Inayat Khan writes that vibrations of sound are, to paraphrase, the source of all existence. peace |
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ASom
Started Topics :
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45
Posted : Mar 21, 2010 01:41
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Maybe we should ask 'under what transformations is sonic topology preserved?' In your example of hearing psy sounds everywhere, I think you are referencing perceptual topology--that is, psytrance music, filtered through your experience, emerges transformed in everyday sound. But in this case, we are talking about a specific instance of sound (psy music), and specific instance of topological preservation. Don't be tempted by this observation to assert that this somehow relates to other sounds, or (yet worse) all sounds, because such a relationship will be quite difficult to prove logically. However, despite the fact that this observation relates a particular kind of music to your private experience with the world, I think it's clear enough through this that there is indeed a topology of sounds (plural).
But what does this mean in the general sense? Let's move away from abstractions and look at a concrete example: the time stretch operation. Through the use of granular synthesis or phase-vocoding it is possible (as any sound engineer knows), to alter the duration of a sound without altering it's pitch content (I say 'pitch content' rather than 'frequency content' because sonic artifacts are added to the resulting sound, but in most cases the perceptually significant aspects of the frequency content [the pitches] are preserved). If you time stretch the sound of a bird chirping it may end up sounding like a person singing, or a baby crying, or something else. But the 'soundshape' is preserved, and with enough training we can learn to identify the output sound as a processed version of input sound.
Now, consider the underlying operation that enables the time stretch as a system which takes an input sound and linearly maps the temporal characteristics of the sound to a new timeline. The mapping in the case of the time stretch is simply a constant [y = c], where y is the output time scale and c is the time-stretch factor. But what if the mapping in instead a function [y = f(x)] where x is the input time scale. Setting [f(x) = mx] gives us a linear variation of the time-stretch factor over time (a speedup in the sound for [m > 0] and a slowdown for [m < 0]). Is the topology of say, a drum loop, preserved under these conditions? Does the sound of a drummer slowing down the tempo have the same 'soundshape' as the drummer playing at a constant tempo. For that example I'd say yes, but is psytrance music still psytrance music at 80 BPM? (this question alone can be debated, I am sure.) So in general I think the answer to a slowdown preserving topology is 'it depends'.
But let's take it a step further. What if the time-stretch system (let's now call it the temporal mapping unit) is fed a non-linear input, say a sine wave [f(x) = cos(2*pi*f + phi)] or a frequency modulated sine wave [f(x) = cos(2*pi*fc + cos(2*pi*fm))]. Depending on the parameters of the modulation, the temporal characteristics of the input sound are now varying wildly, perhaps even with new frequency content due to side-bands (if the modulation frequencies are in the audio range). I'd say at this point that the resulting sound has taken on a completely different form. In other words, there is no way to 'decode' the new sound to the original--topology is lost.
So I think this shows that there is no inherent topology of sound, but perhaps sounds have a natural morphology. If you look at just psytrance, you'll see a homogeneous mush of sound that can be rearranged in just about any way to create yet more psytrance. The same is true for just about any genre of music (indeed even a computer can perform genre classification these days http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.107.2530&rep=rep1&type=pdf ). But I believe that when genres are pushed to their limits they may start to resemble other genres (punk -> thrash, metal -> noise, dub -> drum & bass), or perhaps they take on an entirely new form never yet heard (psy -> ???).
So, perhaps it's best not to obsess over anything, because you will inevitably start to see it everywhere. I think it's safer to conclude:
Psytrance everywhere? no.
MUSIC everywhere? YES! |
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lady seals
Started Topics :
5
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76
Posted : Mar 21, 2010 06:19
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So, anything beyond a time-stretch creates an irreversible (or in-decodable) change? I am unfamiliar with those sine functions related to frequency. So, once the variable has gone through the function, it can't be "solved backwards" to figure out the original sound?
If it truly can't, then many variables (or sounds) could produce the same output in their topological destruction. Is that correct?
If it is, that means any sound can be manipulated into... any sound.
Which brings us almost back to where we started, and as we read Khan's words paraphrased by Moonclear, we think..... Om...
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.:DRAGON:.
Dragon
Started Topics :
18
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432
Posted : Mar 21, 2010 06:47
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Colin OOOD
OOOD/Voice of Cod
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95
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5380
Posted : Mar 21, 2010 17:19
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Scatter
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142
Posted : Mar 21, 2010 18:52
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ASom
Started Topics :
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45
Posted : Mar 21, 2010 22:26
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Quote:
| On 2010-03-21 06:19, lady seals wrote:
f it is, that means any sound can be manipulated into... any sound. |
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Yeah! Fourier theory tells us any sound can be decomposed into a set of sine waves and reconstructed exactly. We can instead modify the sine waves prior to reconstruction, or build sounds by combining the fundamental building blocks (sine waves) in various ways and sculpting them over time (this is called additive synthesis) to create any sound.
To turn a familiar sound into another familiar sound is difficult, but "any sound" includes the set of unfamiliar sounds (which is infinitely larger than the set of familiar sounds). The psy kik was once an unfamiliar sound, as were all those synth tweaks you hear in almost every track. Why, then is psytrance today so obsessed with familiar sounds when there is a universe of unfamiliar sounds at every producer's fingertips? Another question worth debating, but in the mean time everyone should try to make new sounds out of familiar ones with Tapestrea http://taps.cs.princeton.edu/ |
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lady seals
Started Topics :
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76
Posted : Mar 28, 2010 08:34
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this is the greatest reason to live. infinity. praise life. |
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Omega
Started Topics :
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61
Posted : Mar 28, 2010 08:59
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Quote:
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On 2010-03-21 17:19, Colin OOOD wrote:
Quote:
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On 2010-03-21 01:41, ASom wrote:
So, perhaps it's best not to obsess over anything, because you will inevitably start to see it everywhere.
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YES
To my mind this is the one true shape of belief. Best not to have any, if you can help it.
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couldn't agree more!!
 Original Tracks and Remixes:
http://soundcloud.com/omegadubstep
http://omegadubstep.com |
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lady seals
Started Topics :
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76
Posted : Mar 29, 2010 06:24
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Go there. |
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Whr
Started Topics :
2
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130
Posted : Mar 29, 2010 18:52
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very very interesting... !
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psymonk
Started Topics :
2
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152
Posted : Apr 1, 2010 23:40
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Found my post. Now, I'm gonna stay here till the end of time...stretch. |
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