The Linux Soundfile Editor Roundup

With its colorful interface and excellent organization, Davy Durham's ReZound is a pleasure to see as well to use. But eye candy is the least of ReZound's features; the program also provides a complete suite of editing tools, excellent transport controls, some impressive native filters, support for LADSPA plugins and a unique audio remastering/burn-to-CD facility.

Figure 7 illustrates ReZound with three soundfiles loaded and the Curved Balance tool at work on the active file. Curved Balance is one of ReZound's remastering utilities; others include a noise gate, a dynamics compressor and gain and normalization controls. These tools, along with ReZound's other editing amenities, let you massage your sounds to perfection before burning them to CD. ReZound even provides a simple dialog for burning the CD (by way of the cdrdao program) directly from ReZound's File menu.

ReZound's LADSPA support extends to good basic support of the LADSPA VST host plugin (vst.so) from Kjetil Matheussen. This plugin to support plugins provides a usable interface based on WINE for running VST/VSTi plugins under Linux. The vst.so plugin currently is in its early stages, and its degree of harmony with the hosting application varies considerably. Figure 8 shows ReZound employing a VST plugin to apply an effect to the active soundfile.

The most recent version of ReZound supports the JACK audio server, connecting ReZound to the JACK network of intercommunicating audio applications. More JACK enhancements are planned, along with effects previewing, noise removal tools, native time/pitch scaling and many other features and improvements.

Figure 7. ReZound

Figure 8. ReZound with LADSPA/VST Support

At first look, Conrad Parker's Sweep seems much like the other newer editors profiled here. It's ALSA-aware, provides a good basic editing suite, supports LADSPA plugins and shows off a nice modern GTK interface. Sweep offers two unusual tools, though, that give it special value. One is the ability to define multiple regions for nonlinear editing; the other is an interesting little tool named Scrubby.

Defining a selection in a soundfile typically is achieved by placing the cursor at the selection start, then left-clicking and holding as you sweep the cursor to the selection end. This selection method is a common practice employed by all the editors reviewed here. That's how it's done in Sweep too, but Sweep also lets you define multiple selections. Hold down the Ctrl key while making your selections, and voilà, you have multiple-defined selections available for further processing.

An Invert Selection function provides a neat way to create a dialog of effects over a soundfile. Figure 9 illustrates the aftermath of this series of alterations: define multiple selections; apply reverse effect to those selections; invert selection areas (non-selected becomes selected, and vice versa); and apply LADSPA effect to new selections. This is fun stuff and a powerful and creative feature.

Scrubby is Sweep's virtual stylus, essentially functioning as a freely movable playback head with features more typically associated with a DJ's turntable system. Scrubby transforms Sweep into a performance tool, an unusual characteristic for a soundfile editor. A screenshot can't possibly do justice to Scrubby; you have to use the software to see and hear it in action.

Figure 9. Sweep

The soundfont format (SF2) is a complex soundfile format that includes not only audio data but also data regarding various effects and performance controls. Soundfonts have become ubiquitous in the audio world, finding employment in applications such as Csound, jMax, Pd, Fluidsynth and many others.

If you want to work with soundfonts, you definitely want Josh Green's excellent Swami in your toolkit. Swami is a soundfont-only editor with a well-designed GUI and a wealth of useful features. You can edit existing soundfonts and create your own from the level of individual samples up to the composite instrument. You also can edit and design your own soundfont banks. Other tools are available for setting an instrument's velocity response curves, keyboard zoning (mapping) and modulator routing. Because of Swami's strict focus, I don't have much more to say about it; it is first-rate and is highly recommended Linux audio software.

Figure 10. Swami