Surface Filter Tools

The selection tools are accessed with a click on the second item of the palette located at the top of the AS window.

• Surface : draw rectangular surfaces with a click and drag

• Region : draw free polygons with successive clicks, or with a click and drag

• Pencil : draw free lines of various thickness, for the selection of partials for instance, or any other type of item.

• Harmonic pencil : the pencil stroke is copied and translated with a constant harmonic relationship.

The surface tool is selected by default. Select an item in the menu with a click. The selected tool will be displayed in the palette.

Each tool can also be selected pressing a specific key.

A number of parameters can be set via the menu. Click on the area tool icon and select the Harmonic Pencil Settings menu item.

• Pencil Gain : filter gain, which can be subsequently modified

• Pencil Stroke Size in pixels : this graphic parameter has an influence upon the frequential precision of the selection.

• Bandwidth Compensation : when a pencil stroke is done, its thickness in pixels results into a given bandwidth. This bandwidth is then translated to the superior harmonics according to their rank, and to a compensation factor. For instance, with a 100 % compensation, if a stroke for the F₀ covers a range from 100 to 110 Hz, the thickness of the upper harmonics will be increased on either sides of a central frequency, in order to covers 20, 30, 40 Hz bandwidth, from 200 to 220 Hz, 300 to 330 Hz, 400 to 440 Hz, and so on. With a 10% compensation, ranges will be restricted to 2, 3, 4 Hz...

• Number of Harmonics : the global number of harmonics to be represented, be they odd or even or both.

• Harmonics Parity : odd harmonics are the produce of the F0 by an odd integer, even harmonics by an even integer

• Harmonic Number : pencil stroke's harmonic rank. The full series is always represented, so that harmonics of inferior rank are automatically added by AS.

• Harmonics List : harmonics respective rank in a list with commas and parenthesis, such as (1, 3, 4, 5, 8). The choice of this option prevails over the preceeding ones.