Generate Menu

OK, so are we settled then on the style of these menu pages? We have both an image with quick summary text as a table (and sort out screen reader issues later, or avoid them some other way with CSS) and a more detailed, headered explanation below with examples, maybe including why you might want to use this etc.? I think that is OK with me, it lets the reader skip away quickly if they are not interested (a bit like the "Intro" idea on our main Wiki, which might be useful on some pages). Incidentally, DB has said screenreaders don't read the "legend" tag in these tables so we may as well not bother...

The image ideally ought to include Risset Drum as this is in source code and we are currently intending to include it in release builds as users often ask for a quick Drum Generator. Gale

Yes, I think we're settled on this style, quick version, then detail. If we want to try variations on styling (widths, borders, colours, TOC enabled/disabled), let's use this page, Generate, as the prototype for the family, and if we agree we like a chnage apply it to the others later. - James

Menu

Description

Chirp... Sound that smoothly increases (or decreases) in pitch and volume. DTMF Tones... Sound used in tone-dialing on telephones. Noise... Hisses and crackles... Silence... Genuine silence. Tone... A sound of constant frequency - a pure sine wave, or more "rasping" buzzes. This section has generate effects provided by Nyquist or LADSPA plug-ins. Some possibilities include: Click Track... Like a digital metronome. Pluck... Inspired by a guitar string (though can be made to sound very different). Risset Drum... Drum sound.

Audio Generation

The items in Generate menu are for creating a new section of audio, including different types of tones and noise, or silence. The audio you create can be placed into the project in three distinct ways:

• If there is no audio track already on screen, or no tracks on the screen are selected, a new track is created of the duration you specify.
• If there is already a selected track or tracks on screen, but no selection of audio, your specified duration of audio is inserted into those tracks at the cursor point, thus extending the length of the selected track(s).
• If there is already a selected track or tracks on screen, with an area of audio track selected, then that selected area is replaced with your chosen type of audio, such as a tone or noise. The total length of the selected tracks thus remains the same.

If there is no selected area of audio, the length of the created audio defaults to 30 seconds unless you specify another length. However some of the generators such as Noise always remember the last length entered, so that last length becomes their default.

Examples

Example 1: Insert two seconds of silence at the start of the track as a "lead-in":

1. Click the "Skip to Start" button or press HOME to place the cursor at the start of the track
2. Choose Silence from the Generate Menu
3. Specify the two seconds silence. This works by the highlighted digit being overtyped with the figure you enter, then the highlight moving to the next digit. So if the value is showing at 30 seconds with "3" highlighted, simply type "02". To change the digit that is highlighted, click on the one you want to highlight or use the left or right arrow keys on your keyboard
4. Click OK or hit ENTER on your keyboard

Example 2: Replace a 30 second section of audio starting at 1 minute 15 seconds with a tone:

1. Click in the track at 1 minute 15 seconds (underneath "1:15" in the timeline above the track).
2. Drag your mouse to the right to select 30 seconds of audio, then release the mouse button
3. Choose Tone from the Generate menu.
4. Specify your Waveform, Frequency and Amplitude in the dialogue (see explanation in the Tone section below)
5. Click OK or hit ENTER on your keyboard

The different types of generator are described below. All generators which have a choice of amplitude allow a value between 0 (silence) and 1 (the maximum possible volume without distortion).

Chirp...

Produces four varieties of pure tone like the Tone Generator, but allows you additionally to set the starting and ending amplitude and frequency. Short tones can thus be made to sound very much like a bird-call. As with Tone, created frequencies can be in a range from 1 Hz to 20000 Hz (these outer limits are beyond the hearing range of most humans).

DTMF Tones...

Generates dual-tone multi-frequency (DTMF) tones like those produced by the keypad on telephones. Enter numbers from 0 to 9, lower case letters from a to z, and the * and # characters. You can also type the four "priority" tones used by the US Military (upper case A, B, C and D). As with most of the generators, you can choose the amplitude and overall duration of the sequence. Use the slider to select the ratio between the length of each tone in the series and the length of the silences between them. This ratio is displayed underneath the slider as the "duty cycle", along with the resulting duration of each tone and silence. For example, if you create four tones in a sequence lasting four seconds, with a duty cycle of 50%, the four tones and the three silences between them will all be the same length (571 milliseconds).

Noise...

Choose amplitude and one of three different "colours" of noise. White noise is that which has the greatest ability to mask other sounds, as it has similar energy at all frequency levels. Pink noise and brown noise both have more energy at lower frequencies, especially brown noise, which has the most muffled, low pitched sound of the three types.

Silence...

Creates audio of zero amplitude, the only configurable setting being duration. When applied to an audio selection, the result is identical to Edit > Silence.

Tone...

Choose amplitude and one of four different pure tones: Sine, Square, Sawtooth or Square (no alias), with a frequency of 1 Hz to 20000 Hz.

Plug-in Generators

Any additional generators which appear underneath the menu divider are Nyquist or LADSPA plug-ins. Audacity includes the following three Nyquist generators, but more are available on our Nyquist download page.

Note: Nyquist generators do not take the length of any selected audio as the length of the audio to be generated: specify the length required in the appropriate input field(s) of the plug-in. Any selected audio will be replaced by the length of audio specified in the plug-in, but the total length of the track(s) will change unless the selected and specified lengths are identical.

Click Track...

Generates a track with regularly spaced sounds at a specified tempo and number of beats per measure (bar). This can be used like a metronome for setting a pulse to record against. To do this, enable "Play other tracks while recording new one" in the Audio I/O Preferences. Any length of track can be created by adjusting "number of measures" accordingly, and the type and pitch of the sound can be customized. Once created, the track can be edited (for example, its volume changed) like any audio track. Note: When exporting your finished recording, either close or mute the Click Track so that it's not audible in the recording - see Audio Tracks.

Pluck...

A synthesized pluck tone with abrupt or gradual fade-out, and selectable pitch corresponding to a MIDI note.

Risset Drum...

Produces a realistic drum sound consisting of a sine wave ring-modulated by narrow band noise, an enharmonic tone and a relatively strong sine wave at the fundamental. The length of the drum sound is determined by the "Decay" field.