Generate Menu

Peter 24Nov12: Plan for revising this page (based on discussions in ednote below and in the email thread); three options are offered:

• Strawman-4 all the generators moved to their own page plus Usage and Examples moved to their own page.
• Strawman-5 just the Plug-in generators moved to their own page - and with the Usage and Examples split to a separate page.
• Strawman-6 just the Plug-in generators moved to their own page and the Usage&Examples placed immediately below the built-in generators.

Following some suggestions from Gale in the email thread which was discussing this I created Strawman-5 and Strawman-6 and I revised Strawman-4. I don't like #6 as I find the Usage & Examples section really gets in the way of the reader easily seeing the Plug-in generators section and thus impedes readability. I could live with Strawman-5, but I still prefer Strawman-4 not least because it provides consistency with the recently reworked Effect Menu and Analyze Menu.
For me "Strawman-0" the "do-nothing-plan" is not really a viable option as I really don't like the Usage section at the top of the page as it gets in the way of the user seeing the reference documentation of the commands first - and I don't like the Usage section and Examples sections slpit, they really belong together (I think Ed commented on this too).

• My voting:
  • 1 Strawman-4
  • 0.5 Strawman-5
  • -0.5 Strawman-6

Peter 15Nov12: Recent discussion on the Manual list after the work on the Effects documentation it was proposed that we leave the documentation of the Generators in-line in this page; Gale commented"Possibly the flow of the Generate page would be harmed by making separate pages?".

• ToDo Assuming that is the case then I think this page's navigability could be improved with a table of contents - either a TOC or a manually created contents list. Thoughts?
• Though personally I still think it would read better with each generator split off onto its own page (as is the case now with Effect Menu and planned for Analyze Menu, in which case a contents list or TOC would not be required.
  • Steve 15Nov12: I'm inclined to be in favour of separate pages for the Generate effects. I think that some of the effects (in particular "Click Track") are inadequately documented at present
  • Ed 15Nov12: philosophically, I lean toward separate pages but in this instance since all the entries are very short I give the nod to Gale. One problem I see is the example section being at the very bottom of the page is not very discoverable. If we stick with the current format I think it should be moved to the top of the page just underneath the "Usage" section. I do agree that if we keep the current page we need some form of index.
    • Gale:15Nov12: Steve wrote "I'm inclined to be in favour of separate pages for the Generate effects.I think that some of the effects (in particular "Click Track") are inadequately documented at present". I agree about the Click Track comment. My concern is that the built in generators should be kept together. And even if they are kept together on their own page they lose association with the text above unless the text goes with it. I think I'm becoming +1 on leaving the built-in generators as now.

      I agree the examples are about built-in generators so should be above the Nyquist Generators (if they stay here).

• Peter 16Nov12: So how about this as a compromise plan: leave the five built in effects in-line on this page but move the Plug-in ones to separate pages of their own with enhanced documentation for these plugins along the lines of the effects documentation.
  • I agree that the "Usage" stuff belongs with the "Examples" but I would not like to see that much text at the top before the reader's eye gets to the documented built-in generators. Either it should go at the bottom - or my preference would be to place "Usage & Examples" on a page of their own (possible title "Usage of Generators") with a link to it from this page; in which case the link could be at the top of this page to aid discoverability - and it would not delay too much the eye seeing the documented generators.
  • Gale: I can't think any other place where we split the "examples" to a new page, and in this case such a new page would be too short. So I would say, just put the examples underneath the current text for "Tone", if we only split out the plug-in generators.

    By all means Peter can try (in his own user space) a) splitting the individual built-in generators to a single page for them, or b) even to a page for each generator - as long as very clear links to those pages are kept here. I don't see that really helps user understanding, unless understanding is being limited by length here. On reflection, if we do split the built-in generators out, I think b) makes more sense as it might be easier to keep tight links and mini descriptions of each generator on this page. But I'd want to see it first.

• Peter 20Nov12: OK, as Gale suggested I have created some strawmen in my user-space for ToDo consideration (the command titles would, of course, be links to the individual pages documenting each generator):
  • Strawman-1 just the Plug-in generators moved to their own page
  • Strawman-2 all the generators moved to their own page
  • Strawman-3 all the generators moved to their own page and with the usage notes moved to the end
  • Strawman-4 Strawman-3 plus Usage and Examples moved to their own page.
    • Personally I have a preference for the versions with all the generators moved to their own pages and none in-line. And I have a more than marginal preference for the Strawman-4 version with Usage and Examples set off on their own page. I find the page swith all the generators spun off to be clean, readable and esay to assess at a glance or so just what is available (and with minimal scrolling) - plus this would maintain consistency with Effect Menu and Analyze Menu which consistency is important for me. Furthermore there would be no need for a contents list with a compact layout like this.
• Steve wrote in email thread 20Nov12: strawman-4 looks clearest to me. Most browsers these days support tabbed browsing, so it is easy to flit between a specific effect and the general usage notes. Would you want a TOC ?

The items in the Generate menu create new audio containing tones, noise or silence. Generate at a cursor position to insert the new audio and extend the track, or in a selection to replace that selection with the new audio. Although by default, no keyboard shortcuts are provided for the generators, it is possible to set up your own shortcut for any Generate command. For instructions on how to do this please see Keyboard Preferences.

Usage

• To generate into a new track: If there are no existing tracks, choose the required generator. If there are existing tracks, click outside the tracks in the gray background to deselect them, then Generate. To deselect tracks using the keyboard, press <enter>, then to deselect any further tracks, use up or down arrow and <enter> as needed.
• To insert generated audio at the cursor position: Place the cursor in the track, then Generate. The specified duration of audio will be inserted into the selected tracks at the cursor position, thus extending the length of the selected track(s).
• To replace an existing selection with generated audio: Select the region, then Generate. The selected region(s) will be replaced with the generated audio. The total length of the selected tracks will remain the same, unless you change the length in the generator to replace the selection with a longer or shorter one. You can select an exact region to replace using Selection Toolbar.

Having placed the cursor or selected the region, there are several ways to select extra tracks so as to generate into those at the same time. The simplest method is to hold down SHIFT then use up or down arrow on the keyboard. See Audacity Selection for more details.

Duration: Type (or use the keyboard arrows) to enter the required Duration. If the first digit you want is highlighted, just type the whole number. If the required first digit is not highlighted, use LEFT or RIGHT arrow on your keyboard to move to the first digit, then type. You can also increment a highlighted digit with keyboard UP or DOWN arrow instead of typing.

• If there is no audio selection, Duration initializes to 30.000 seconds (except 1.000 second for the DTMF and Noise generators) as in most of the images on this page. However, your last entered Duration is always remembered.
• If there is selected audio, the generator always displays the exact duration of that selection to the nearest audio sample, as in the Silence Generator image below.

Selection Format: Whether generating in a selection or not, you can change the Selection Format to another unit of Duration so that the generation will be in those units. To do this, open the context menu by clicking the triangle to right of the digits. You can also open the menu by hovering over or selecting in the Duration digits, then right-clicking or using a keyboard equivalent.

Amplitude: All generators (except of course Silence) let you type in an amplitude value to set the loudness of the generated audio. Permitted values are between 0 (silence) and 1 (the maximum possible volume without clipping), with a default of 0.8.

See the examples at the bottom of the page for a couple of common audio generation scenarios.

Built-in Generators

Chirp...

Produces four different types of tone waveform like the Tone Generator, but additionally allows setting of the starting and ending amplitude and frequency. Short tones can thus be made to sound very much like a bird-call. As with Tone, frequencies can be specified anywhere between 1 Hz and half the current project rate, as shown in the Selection Toolbar.

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 "colors" 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 > Remove Audio > Silence Audio.

Steve 15Nov12: Is the default "units" for "Generate > Silence" hh:mm:ss_milliseconds? The image shows hh:mm:ss+samples.

• Peter 15Nov12: Certainly the other examples shown on this page use hh:mm:ss_milliseconds for their units.
• Gale15Nov12: You are not RTFM :=) "If there is selected audio, the generator always displays the exact duration of that selection to the nearest audio sample, as in the Silence Generator image below." I've tried putting that in a note div now. This information is also in the image hover text.

Tone...

Choose amplitude, one of four different tone waveforms: Sine, Square, Sawtooth or Square (no alias), and a frequency between 1 Hz and half the current project rate (as shown in the Selection Toolbar). One half is chosen because a given sample rate can only carry frequencies up to half that rate. Although frequencies above 20000 Hz cannot be heard by most humans, generating at up to half the sample rate (22050 Hz at Audacity's default 44100 Hz) can have scientific uses, for example in measuring impulse responses. Note that creating tones at or close to half a given sample rate may (correctly) generate either silence or a pulsing rather than steady tone, according to the type of waveform chosen.

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 Download Nyquist Plug-ins on our Wiki.

Nyquist generators do not take the length of any selected audio as the length of the audio to be generated. Instead, 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, thus 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 Recording 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, use the Track Control Panel to either close or mute the Click Track, so that it's not audible in the recording.

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.

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 30.000 seconds with "3" highlighted, type "02". To change the digit that is highlighted, click on the one you want to highlight or move the highlighted digit using the LEFT or RIGHT arrow keys on your keyboard.
4. Click OK or press 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. If you selected a little too much or not quite enough audio, move the highlighted digit as required using the LEFT or RIGHT arrow keys on your keyboard, then type over that digit.
5. Specify the Waveform, Frequency and Amplitude in the dialog
6. Click OK or press ENTER on your keyboard.