adaptive convolution

Adaptive Convolution, it turns out that this exists in image processing and in live audio, convolution is used to mask predictable noise patterns. I will need to read up on these.

The reason that I start with this word is that I have been playing around with different Convolution paradigms in my imagination. One that I have imagined is, adaptive convolution, where the convolution IR adapts over time. In this way two sounds can be crossed. Tom Erbe implemented something close to this in SoundHack with "Mutation." I was not able to get the wide variety of results or precision that I imagined with this tool though. He describes it as thus

Cross-synthesis between two soundfiles with soundfile convolution, ring
modulation or spectral mutation.

This is what ges1 sounds like when made with SoundHack



So I began to play today with convolution of two signals in order to see what I could arrive at. I choose to use this audio file as the Impulse Response.

I chopped it up by hand into it's constituent sounds. (Looking back I think there are some things that I would change now, as the 7 files don't account for the entirety of the sound).

Then I combined these IR's with 3 different sound files and also some pink noise. Here is what I came up with.
ges1


ges2


ges3


mix1n2


mix1n3


mix3n2


Here it is with just Pink Noise

noise


And now with the original audio file
orig


Ok, this worked out fairly well. So it occurred to me that I could granulated the IR file in real time and perform the convolution on an ongoing basis. Basically the whole thing happens in real time. The windowing of the grain determines the type of window on the IR. I found that through changing grain density and windowing type there is a wide variety of options in sound. Also, I was able to slow down the playback of the IR file without distorting the pitch material, hence theses are slower. Here a couple of examples.
grain1

grain2

grain3

grain4

grain5

grain6


Working on this and a couple of other projects which are similar, I realized that when I do things by hand there is a certain precision and necessity of decision. The more that I automate, the further from my expected results I get. Both results have their place and I happily use both. I generally find the difference striking though. The irony of course is that in stating "adaptive convolution" I am imagining something that is not hand made, but rather more automated.

Luc Ferrarri made this statement about listening which I find very profound.

The wise and poetic French composer Luc Ferrari (Ferrari, 1991), while walking in the streets of Paris, reminded me that "one has to learn to recognise sounds on top of each other. In relation to each other, that it to say in layers and this can be learned by the sensitivity that we develop and by awareness."

from Schryer 1998


This statement resonates on a compositional, listening and life level for me. I can begin to identify the layers that are intertwined and woven to construct my reality. Identifying each thread of a Persian rug... an intriguing metaphor.


A great quote form Schryer in this same text is,

I want to use the wind as a verb, water as a noun, the beep of a truck as an adjective and silence as a comma. I want to conjugate noise in the future and in the past and bring the listener inside a story, space, experience or sensation, with or without words and perhaps also, with or without music.

When I first read this I thought he meant a the wind as a reverb. Interesting notion. But upon rereading I changed my understanding and rather like this notion of articulation with and about sound.

Nebraska Day 10

The final day was a festival of food. We were invited over for a serious steak dinner and had a wonderful evening.

I had the pleasure of watching the sun rise as I drove the length of Iowa and reflected on the time and lessons.

I will miss Dinty Moore, where I learned...
"Beer has food value, but food has no beer value."

Nebraska Day 9

I am entirely thrilled that I am making the "Day 9" entry on 9.19.09 (I even started the entry at 9:09PM, that part was planned). As if that weren't enough today and past couple of days have been amazing.

Two days ago I stayed up until 4AM working and then recording ideas for the following day. Yesterday I awoke and implemented most of those ideas and it turned out to all be pretty good.

I went out last night to a bar/restaurant that is located in a former train station. There we met a really interesting and intelligent guy. Eric, has spent a good time away from and decidedly returned to Nebraska in order to raise a family. Yesterday was his day out golfing and then a beer and burger at The Depot. We all had a great time contrasting our perception of the world with what we projected would his children's view at our age, as well as people who had never left Nebraska, a thoroughly interesting and enjoyable evening. The Depot is owned by Dave, who is from Buffalo, nice guy and a real fun place. There was a possum outside eating the cat food when I got home, terrible pic, but still kind of interesting.

Today had a bit of a slow start (go figure), but has been really productive since sitting down. About an hour ago I was interrupted in my work by amazing light and a distant thunder storm. I hope that the storm comes our way in the evening, but even if it doesn't get close enough to feel, I can hear and see it. Oh and the light had me take 250 pictures in a half hour. Along with two double rainbows. The end of the rainbow, it turns out, is here Kimmel Harding Nelson Center for the Arts, go figure.

Here are some recent sounds for your listening pleasure. The first is an example of the sounds that I was making this evening.

Here is a screen shot of the session that bore the sound.



This is the first version of the electronics for the 14th section of my viola and electronics piece (that is what I have been working on here in Nebraska and for the past year). Still needs some work, but getting close.

Nebraska Day 8

Eagles Club. (I actually wrote Eagles Nest, published it and then read the photo again). Is that sort of like the Boar's Nest? (20 bonus points if you know that reference, one hint Waylon Jennings).

Today I sat down to work on the viola piece and realized that I only have two more sections to complete! I was so swamped in the minutia that I lost site of fact that this piece is actually very close to completion.

If that wasn't enough, out on a walk tonight while looking for the marina (the pictures of clouds below are taken from the dock in Missouri river) there was a table with vegetables on it and a sign that read "Free." One large cucumber salad later, a realization of what wondrous time and place summer is.

I was listening back to a section of the viola piece that I made on Saturday and I realized that it sounds conspicuously like the crickets and cicadas that I have been listening to . Well maybe not entirely, but then again, I tend to listen in a pretty particular way.