Audio (waveform) editor

MitSyn audio (waveform) file play-edit-record

The MitSyn Audio Editor supports the viewing/editing of waveform stream files. All the usual viewing (zooming), playing, recording, and editing (cropping, splicing, fading in or out, applying effects such as adding reverberation and filtering) operations are supported. Several types of spectral and spectrograph analysis views are available.

The main window view is of channel waveforms (viewing a list of selected channels), and the view is usually set to use fixed scaling (for audio, although not for process simulations), so that the scale will stay constant while paging through a waveform stream file. See the ViewWaveform View Options dialog for setting scaling. A position in the waveform stream called the “cursor” is updated or used by many of the commands. The cursor is shown by a yellow vertical bar in all time views whose current scope encompass that time. The cursor can be set by clicking the left mouse button (i.e., its usual “select” function). The current Selection is shown as highlighted in the main window.


waved-view-optionsWaveform channel signals are displayed in a time-compressed format, using one of the available forms of decimation such as Range, First, Max, Mean, or RMS. The current decimation types for the various displays may be set using the “Wave View Options” dialog.

Another window (called snapshot) may be used to show a snapshot of the current waveform selection. This is very useful when you wish to closely compare two different segments of the file, i.e., select the first segment, take a snapshot of that, and then move the selection to show the second segment of interest in the main windoiw.

Additional floating windows may be shown to view the spectrum of the waveform at the cursor, and a spectrogram of the current selection. The showing of these data windows windows may be turned on/off from the Show menu or toolbar buttons.

Spectral analyses may be viewed in both single spectrum and spectrogram format, with adjustable analysis parameters such as window size (transform length) and spectral smoothing options. Spectrogram views may be either gray scale, or colored.

Playing options

Many different play (real time audio output) options are available. Most of these may be invoked from buttons on the Play toolbar, and also from the Play menu.

Editing operations

Many editing functions operate on the “currently selected segment”. The easiest way to select a segment is to click and then drag through the desired range, exactly as you would select a segment of text in your word processor. Other common selection actions include the dragging of either end of the selection, and the Select » Select All command (shortcut key Ctrl+A).  The currently selected segment is shown with a light blue shading.

Some editing operations can be applied to either the “current channel” or to all channels. The current channel is the channel viewed at the top of the top pane, and is selected clicking one of the first buttons on the View toolbar . Clicking the Some button drops down a menu which allows you to select arbitrary channels for viewing, and in any specified order so that you may specify the “current channel” by putting its number first in the list.

Trimming (cropping), deleting, reordering segments, etc. (cut and paste)

waved-splice-barSingle segment at a time cut and paste, i.e., splice, types of operation may be requested using the usual cut and paste commands such as Edit » Trim, Delete, Copy, Paste which bring up the Splice (cut and paste) toolbar window shown here. You can quickly cut out segments (to be deleted or copied), repeat segments, reorder segments using these features. This window stays open during priview plays, so you can tweak segment boundaries (using the main window) by listening and then saving. These activities are very useful for extracting and cleaning up small segments from longer sound files for use with Web pages.

Another (less used) action is to time shift one channel in a multi-channel file with respect to other channels. This action is supported, using the Array Editor.

Audio effects – clearing, fading, scaling, etc

waved-common-effects-dlgThe Audio Editor’s Effects menu supports tasks such as fading, clearing, and amplfying segments. These effects may be applied equally to all the channels, or to each channel independently. The effect is applied over the domain of the current selection, so in order to apply to the entire file, first select the whole file using the Select ► Select All command (Ctrl+A). The More Common Effects menu item supports additional effects such as filling with noise and adding offsets.

Audio recording

waved-recorder-barThe Wave Editor has built-in support for direct recording into any of the supported waveform file format files. Clicking on the Record button, or the menu command File » Record new wave, brings up the Recording toolbar shown at the right.

The Tooltips for the controls across the top of this toolbar describe their function. While recording the channel level indicators show the current levels of the signals being recorded. If at any time a level is so high that overflow (saturation) occurs the main view background changes from green to red for the remainder of the recording run. The saturation level is a function of the destination file format. .WAV files containing 8 or 16 bit samples are limited to peak signal values of less than 1.0, while no such limitation occurs with 32 bit floating samples.

Recording parameters such as the number of channels, and the sampling rate, are initially set to that of the currently open file, but may be changed by clicking on the Change wave properties button, which brings up a dialog box where these parameters may be changed.

Playlists (reordering segments, including multiple files, etc.)

More complex multiple-segment splicing tasks (i.e., more than simple cut and paste), e.g., including segments from different wave files or inserting a gap of silence for time shifting, may be expedited using “Playlists”, which are simply lists of segments from the same or different waveform files. In the example shown here segments from three different wave files are referenced by the playlist. Be sure to check the playlist menu for additional options not shown by the playlist toolbar command buttons. Choosing the Playlist » Show Playlist toolbar menu command (or the Playlist toolbar button) brings up the playlist toolbar shown here.

Spectral analysis

The Audio Editor also supports the display of waveform data in several spectral analysis formats. Spectra at a single time and spectrograms over a selected segment may be viewed.

spectrogramwaved-spectral-analysis-optionsThis sample spectrogram is of human speech recorded by the Audio Editor. Such spectrograms are clickable, i.e.,the cursor position may be set by clicking at a position in exactly as clicking on a waveform view. Such is often a quick way to navigate over waveform data since global features are quickly seen by eye. Spectrograms and spectra are displayed in separate windows, so a click on a spectrogram will immediately show the spectrum at that point and also show the position with the cursor in a waveform display window.

Other types of waveform editing/transformation

Segments of waveform files selected using the Waveform Editor may also be edited using the MITSYN Numeric Array Editor (Edit » Edit selection using Array Editor). Sample values may be drawn in with the mouse, individual sample values may be easily changed. Also such segments may be saved as “wavetable” files.