"Ascending" Super Saw
(1). Select the Default Program 999 and press EDIT button.
(2). Open ALG page and select algorithm 5.
(3). Open the AMPENV page and switch to USER, otherwise you would use the piano's envelope.
(4). Open DSPMOD page and assign a negative value to Saw Pch and then assign the same value in cents, but positive, as Src1 Depth. Select ENV2 as Src1. For example: Saw Pch: -7ST / Src1: ENV2 / Depth: +700ct.
(5). In the ENV2 page, assign to Att1 the value you need.

http://www.youtube.com/watch?feature=player_embedded&v=Kh4EKK6yd_c

Noise + filters
(1). Select Default Program 999 and press EDIT button.
(2). Open the KEYMAP page and select Noise as PlayBackMode, so White Noise will be reproduced.
(3). Switch the parameter in AMPENV page form NORMAL to USER.
(4). Select the algorithm 6 in ALG page; select 2POLE HIPASS in the first block and 2POLE LOWPASS in the second.
(5). Open DSPMOD page and choose the right frequencies for the hipass; select the lowpass and assign the maximum value to LP Freq, then go to the right side and set Src1: ENV2 / Depth: 10800ct
(6). Open the ENV2 page and set Att1 and Dec1 to -100%, then adjust the Att1 time and add some LP resonance to make the filter self oscillate

Super Saw "Ascendente"
(1). Selezionare il program 999 - Default Program; premere il tasto EDIT.
(2). Aprire la pagina ALG e selezionare l'algoritmo 5; selezionare la forma d'onda SUPER SAW.
(3). Cambiare da NATURAL a USER il parametro che si trova nella pagina AMPENV; questo perchè l'envelope fa ancora riferimento alla keymap di pianoforte, stroncando lentamente il suono con un decay lento, mentre, impostando su USER, può essere personalizzato.
(4). Nella pagina DSPMOD, portare ad un valore negativo il parametro Saw Pch ed usare lo stesso valore in centesimi e positivo per il parametro Depth di Src1. Selezionare come Src1 il parametro ENV2. Esempio: Saw Pch: -7ST / Src1: ENV2 / Depth: +700ct. In questo modo la forma d'onda partirà con un pitch inferiore al normale di 7 semitoni e tornerà alla normale tonalità grazie all'ENV2. Attenzione: bisogna modificare Saw Pch e non Pitch perchè quest'ultimo si riferisce al pitch della keymap, ma in questo caso stiamo utilizzando una forma d'onda generata dal virtual analog e quindi non avrebbe alcun effetto.
(5). Regolare l'attack dell'ENV2 nell'apposita pagina in base alle proprie esigenze.

http://www.youtube.com/watch?feature=player_embedded&v=Kh4EKK6yd_c

Noise + Filtri
(1). Selezionare il program 999 - Default Program; premere il tasto EDIT.
(2). Nella pagina KEYMAP, selezionare in PlayBackMode il parametro Noise. In questo modo verrà riprodotto rumore bianco (utile per effetti come vento o attack percussivo) indipendentemente dalla keymap.
(3). Cambiare da NORMAL a USER il parametro che si trova nella pagina AMPENV.
(4). Selezionare l'algoritmo 6 nella pagina ALG, impostando nel primo blocco un 2POLE HIPASS e nel secondo blocco un 2POLE LOWPASS: l'effetto finale sarà dato da un envelope che controlla solamente il lowpass, ma prima è bene tagliare le frequenze basse inutili tramite l'hipass.
(5). Nella pagina DSPMOD, scegliere a proprio gusto l'apertura dell'hipass; selezionare ora il lowpass aprendolo al massimo e, sulla destra, impostare come Src1 il solito ENV2 e come Depth il valore massimo positivo (10800ct).
(6). Aprire la pagina ENV2 e impostare Att1 e Dec1 a -100%; regolare l'attacco in base alle proprie esigenze. Aggiungere un po' di risonanza al filtro lowpass per ottenere il classico effetto "autoscilazione".

Last time we talked about the simple sound and its features.

The sound we usually hear is not a simple one (sinusoidal oscillation), but a complex sound.

In order to treat this issue, it is necessary to clarify the concept of envelope (we will study this argument in deep later) and harmonics.

The sound envelope is the variation of its amplitude over time.

Let's consider now an instrumental sound: his complexity is evident. If you listen to just a single note, you will find out how the sound is made up, not only of an oscillation, but also of a changeable number of "elements". Those elements are the harmonics we are talking about.

Harmonics show well defined relationship between themselves, and with the fundamental oscillation.

Our definition of a complex sound will thus be:

A periodic oscillation constituted by a fundamental frequency and a series of other frequencies which are integer multiples of the fundamental, and are named higher order harmonics.

This definition naturally leads to the Fourier theorem: “Every periodic function, anyhow complex, can be represented as a (weighted) sum of simple sinusoidal functions whose frequencies are integer multiples of a fundamental frequency”.

So, every harmonics has its own frequency, but also its own amplitude and phase, which are completely independent with respect to the fundamental component. It's indeed the number of harmonics and the parameters of each of them which determines the character of a complex sound that is its timbre.

Complex sounds may be composed of a varying number and kind of harmonics. They can have more or less, even and/or odd harmonics.

Let's look at the harmonics series starting from C2 (about 66Hz). As one can see from the example, the harmonics which are generated have well defined frequency intervals. Starting from 66Hz (C2) we find 132Hz (C3 - octave), 198Hz (G3), 264Hz (C4) and so on.

We may now define the interval which is mainly a musical concept, but may be defined also in a physical framework. The interval is the pitch difference between two sounds, whose value is represented by a ratio between their frequencies.

We may say, at this point, that both the kind and the number of harmonics contained in an instrumental sound depend on the shape of the instrument and the materials it is built of: thus we may give a first definition of a sound TIMBRE as depending (from a physical point of view) on the kind and number of harmonics added to the fundamental one, on their amplitude and phase.

Let's see now some practical examples of complex sounds. 

The Hammond organ works exactly in this way, by generating a fundamental sound plus even and odd harmonics which can be managed through the Drawbars.

The "classical" waves of our synthesizers (triangle, sawtooth, pulse) are nothing else than complex sounds formed by different harmonics. Let's look at them one at the time:

Square Wave

Only odd harmonics are present, whose amplitude is proportional to their order, so the second component (third harmonics) has an amplitude which is one third of the fundamental, and so on. They are all in phase.

Triangle Wave

Only odd harmonics are present, and they are in counter-phase. Their amplitude is proportional to the square of their order. This means that the second component (third harmonics) has an amplitude which is one ninth of the fundamental, and so on.

Sawtooth Wave

There are both even and odd harmonics, they are in phase and their amplitude is proportional to the harmonics order, so that the second harmonics has an amplitude which is half the amplitude of the fundamental and so on.

In order to obtain a reversed sawtooth one should simply change the harmonics phase (counter-phase)

This seems very complex, but one simply has to sum up all the components and the fundamental to obtain the resulting wave.

The acoustic instruments sound is a complex sound itself. But, compared to the sounds seen above, they also show a number of inharmonic components, due to the instrument features. For example, the noise of a grand piano hammer beating up a string, or that of a bow sliding on a violin strings are examples od inharmonic components.

We will treat all these things in the next issues.