Wednesday, June 15, 2011

Review of Alchemy II - the mysteries of the attack transient

While I may get some keyboard players upset, I have always found being both a guitar player and a keyboard player very complementary although I always have to smile when the latest distorted electric guitar preset comes out and everyone thinks their Jimmy Hendrix on a keyboard. Truth is that what I have always loved about a guitar is how subtle and beautiful a guitar sounds when played by a talented artist. I would not classify myself as one but I can tell you that years of playing have given me a sonic pallet that can't be duplicated by cleverly placed samples. I can place my thumb behind a pick a certain way and get harmonics but I can't really tell you how. You have to feel it and hear it. I did not read a guitar for dummies book. I had to teach my brain by doing it over and over again until it became natural.

So what does all this have to do with Alchemy? Simple. Often, that quintessential aspect of how a musician plays, their style, is much more dictated by that short universe of the attack transient. Much (not all) of the magic seem to lie in that fraction of a second. Now enter the additive world. Additive synthesis is what we call linear. Put simply, it's made of parts that can be added together. Now for the interesting part. A guitar transient is what is called non linear which means that all those partials do a complicated little dance. In fact, I believe that grains are far more applicable than partial in the world of the transient. If the transient is a bunch of partials dancing, the dance does not easily reveal it's secrets. Partials dance in and out like the particles of sub atomic physics. In short, the additive model does not work to well.

The solution of the Akai K5000, a little known but powerful additive synth, was to use both samples and additive models. The transient was created with samples. Alchemy works much the same way and can mix or cross fade a sampled transient. This adds realism.

But here is another problem. One of the benefits of additive synthesis is that one can morph between one sound and another and explore that wonderful sonic universe in between. So far so good right. Well, sort of but to do this one has to connect the partials and if we are talking about transients it's a bit like trying to do a tango on a dollar coaster. Trust me, I gave done a lot of modeling and believe me, you can get some bizarre artifacts when trying to morph sounds and they don't always sound that good. I have re-synthesized many sounds and have reacted as if eating spoiled food, yuck, phooey. I have often felt as if my sonic pallet was assaulted. The secret is to start off with some good material. I always felt that was lacking in Cube. In fact, I always felt it was a collection of samples from experiments rather than an effective library. Alchemy has what seems to me a solid library and of course, one can always use ones own samples but be forewarned, some models just don't mix.

Try morphing a bell into a guitar and you will see what I am talking about. Bottom line this will confuse the re-synthesis engine. Also using AM will do the same thing. Re-synthesize a sin wave modulated by a sub audio LFO and then move it into the audible range. The re-sythesis engine will first interpret it as amplitude modulation and then see it as partials. First they are not there and then they are there like Schrodenger's famed cat or the Cheshire cat of Lewis Carol and said Alice. Here, we have the sonic looking glass. A thought experiment like this will show you that the world of additive synthesis gets stranger and stranger when you take it places it may not want to go.

I will have to have a part III soon. I will be working again with Alchemy soon and I will continue to investigate.

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