30. Selection of track

Figure 30.1
Click on thumbnail for full size image.

Figure 30.1 shows track 7 being selected by a mouse click in the Edit pane E7, which causes the black vertical line near the start of Edit pane E7, and properties for track 7, to appear. If a Sequence box were added to Edit pane E7 now, it would be placed at the location of this black vertical line.

The properties of the track are as follows:

• Description A free format text field that describes what this track contains; for example, Guitar bass chords.
• Start time Start time (in seconds) of the track in the composition.
• Duration Maximum duration (in seconds) of the track in the composition; no computation takes place before Start time or after Start time + Duration.
• Left channel ext./mult. If a Left channel graph has been specified, this field indicates the range of y-values, corresponding to amplitudes, to which the Left channel graph is scaled; for example, if a value of 3 is specified, then the maximum y-value that will be returned from the graph is 3. If a Left channel graph has not been specified, this field value represents a multiplier which is applied uniformly to left-channel amplitudes. Use smaller values of this parameter to make the sound of this track quieter on the left channel or speaker, or use larger values to make it louder.
• Left channel graph Use this graph to effect a change to how loud or quiet this track is on the left channel or speaker over time. Higher graph y-values will make it louder, whereas smaller y-values will make it quieter.
• Left channel graph invert-X Inverts the y-values of the Left channel graph relative to the x-axis. For example, with a Left channel ext. of 1, a y-value of 0 would be mapped to 1; a y-value of 0.25 would be mapped to 0.75; 0.5 → 0.5; 0.75 → 0.25 and 1 → 0. If the same graph is used for both left and right channels but only one has its invert-X set, then at any moment, the track values on one channel will be the exact inverse of the other. This can be used to create the effect of a sound 'moving' from the left speaker to the right one, or vice versa.
• Left channel graph invert-Y Inverts the x-values of the Left channel graph relative to the y-axis. For example, with a Left channel ext. of 1, a graph that starts at 1 and decays to 0, would, when inverted about the y-axis, start at 0 and then sharply rise to 1 at the end.
• Right channel ext./mult. If a Right channel graph has been specified, this field indicates the range of y-values, corresponding to amplitudes, to which the Right channel graph is scaled; for example, if a value of 3 is specified, then the maximum y-value that will be returned from the graph is 3. If a Right channel graph has not been specified, this field value represents a multiplier which is applied uniformly to right-channel amplitudes. Use smaller values of this parameter to make the sound of this track quieter on the right channel or speaker, or use larger values to make it louder.
• Right channel graph Use this graph to effect a change to how loud or quiet this track is on the right channel or speaker over time. Higher graph y-values will make it louder, whereas smaller y-values will make it quieter.
• Right channel graph invert-X Inverts the y-values of the Right channel graph relative to the x-axis. For example, with a Right channel ext. of 1, a y-value of 0 would be mapped to 1; a y-value of 0.25 would be mapped to 0.75; 0.5 → 0.5; 0.75 → 0.25 and 1 → 0. If the same graph is used for both left and right channels but only one has its invert-X set, then at any moment, the track values on one channel will be the exact inverse of the other. This can be used to create the effect of a sound 'moving' from the left speaker to the right one, or vice versa.
• Right channel graph invert-Y Inverts the x-values of the Right channel graph relative to the y-axis. For example, with a Right channel ext. of 1, a graph that starts at 1 and decays to 0, would, when inverted about the y-axis, start at 0 and then sharply rise to 1 at the end.
• Left channel delay secs This field allows a delay of up to one second on the left channel (destined for the left speaker). The idea is to simulate sound from a source reaching your left ear slightly after it reaches your right ear. The value in this field is used when generating the stereo files from the intermediate (mono) file for the track, and it effectively inserts a pause, or silence, at the start of the left channel portion of the stereo files, while shifting the rest of the track by the delay value in order to accommodate the pause. You can see this effect in the left channel views (which need the Keep left intermediate file checkbox to be checked in order to view).
• Right channel delay secs This field allows a delay of up to one second on the right channel (destined for the right speaker). The idea is to simulate sound from a source reaching your right ear slightly after it reaches your left ear. The value in this field is used when generating the stereo files from the intermediate (mono) file for the track, and it effectively inserts a pause, or silence, at the start of the right channel portion of the stereo files, while shifting the rest of the track by the delay value in order to accommodate the pause. You can see this effect in the right channel views (which need the Keep right intermediate file checkbox to be checked in order to view).
• Enable channel limits This checkbox field can be used to enable or disable the following four channel limit fields. When unchecked, the channel limit fields are ignored; when checked, all the channel limit fields will be used so need to be set appropriately.
• Left channel limit hi This field is used in conjunction with the Waveform and Channel >> Left >> Waveform views and the Compute Stereo button. Any amplitude values in the Waveform view that exceed this limit are set to it in the Channel >> Left >> Waveform view, and underlying stereo files, when stereo is computed. This effectively chops the sound wave, and it may produce a distorting effect.
• Left channel limit lo This field is used in conjunction with the Waveform and Channel >> Left >> Waveform views and the Compute Stereo button. Any amplitude values in the Waveform view that are less than (usually more negative than) this limit are set to it in the Channel >> Left >> Waveform view, and underlying stereo files, when stereo is computed. This effectively chops the sound wave, and it may produce a distorting effect.
• Right channel limit hi This field is used in conjunction with the Waveform and Channel >> Right >> Waveform views and the Compute Stereo button. Any amplitude values in the Waveform view that exceed this limit are set to it in the Channel >> Right >> Waveform view, and underlying stereo files, when stereo is computed. This effectively chops the sound wave, and it may produce a distorting effect.
• Right channel limit lo This field is used in conjunction with the Waveform and Channel >> Right >> Waveform views and the Compute Stereo button. Any amplitude values in the Waveform view that are less than (usually more negative than) this limit are set to it in the Channel >> Right >> Waveform view, and underlying stereo files, when stereo is computed. This effectively chops the sound wave, and it may produce a distorting effect.
• Keep left intermediate file Indicates whether an intermediate file for the left channel should be kept. It is necessary to check this checkbox if you want the left channel to be included in track 0 (i.e. the overall composition), if you want to visualize the sound using the Channel >> Left views, or if you are having memory problems (using the intermediate file is more efficient with internal memory, although Compute Stereo will be a little slower).
• Keep right intermediate file Indicates whether an intermediate file for the right channel should be kept. It is necessary to check this checkbox if you want the right channel to be included in track 0 (i.e. the overall composition), if you want to visualize the sound using the Channel >> Right views, or if you are having memory problems (using the intermediate file is more efficient with internal memory, although Compute Stereo will be a little slower).
• Keep intermediate file Indicates whether an intermediate file for this track should be kept. It is necessary to check this checkbox if you want to compute stereo for this track and subsequently include it in track 0 (i.e. the overall composition). You will also need to set it in order to visualize the sound using the Waveform, Amplitude and Pitch views. The advantage of un-setting it is it saves disk space and computation time if you don't intend to compute stereo or include this track in the final composition.
• Include in track 0 Indicates whether this track should be included in track 0 (i.e. the overall composition). More precisely, it is whether the left or right intermediate files (or both) should be included in the composition, which means that one or both must have been computed; this can be done by clicking Compute Stereo with the Keep left intermediate file and/or the Keep right intermediate file checkboxes checked, and the aforementioned checkbox(es) should still be set when computing track 0 by choosing Track 0 >> Fast compute.

The Compute kwik button behaves the same as the Compute button unless there are existing intermediate files that have already been computed for descendants of the track, such as Sequence boxes and Chord Groups. For example, if an intermediate file is found for a given Sequence box this gets used and no thorough computation for that Sequence box and its descendants takes place. This has the advantage of speed, but could result in an unexpected result if any property values of the Sequence box or its descendants have been altered, but without the Sequence box intermediate file having being recomputed. If the Sequence box does NOT have an intermediate file, then the Compute kwik function will look for any intermediate files used by the descendants of the Sequence box (Chord Group, Repetition Group, Sound box etc.); intermediate files at lower nesting levels take priority over intermediate files at higher nesting levels; for example, an intermediate file associated with a Chord Group would be used if found, ignoring any intermediate files associated with descendants of the Chord Group such as Harmonic boxes.