From the release notes:

New Features

• Ready for Leopard!
• Reading/Writing FLAC files.
• Reading OGG/Vorbis files.
• Saving CAF files.
• It is possible to choose the sample size, bit rate and codec when saving a file.
• Added the cursor position and (optional) selection length in the toolbar.
• Added two dialogs for editing the cursor position and selection.
• Added the ability to reorder the channels.
• The file duration is displayed in the status bar.
• Added support for splitted multichannel files.
• Double click to select a whole channel, triple click to select all.
• Added the ‘Invert Polarity’ effect.
• It is possible to change the timeline font size.

Fixes and Improvements

• Recording would crash if the sound file and input device didn’t have the same number of channels.
• Previewing the “Change Speed” effect could crash.
• The check for updates should pass through proxies.
• The help buttons would not always open the documentation at the right page.
• Shift-clicking will select everything between the cursor and the mouse pointer.
• Improved the way TwistedWave follows the wave when recording.

Here’s a few comments on the main new features:

Cursor Position and Selection in the Toolbar

The Toolbar can now show the current cursor position, and the length
of the selection. Only the cursor position is included in the default
Toolbar. You can add the selection length by right-clicking the
toolbar, and selecting “Customize Toolbar…”.

If you had already used TwistedWave 1.0 or 1.1, the old toolbar was
saved in your preferences, and the cursor position will not show up.
You can customize the toolbar, and select the default toolbar.

Clicking on any of these two new items opens a dialog that allows you
to enter a precise position for the cursor, or the start and end
positions for the current selection.

Cursor position editor

The cursor position editor allows you to enter a numerical value for
the time you want to move the cursor to. This dialog allows a number
of formats for specifying the time, such as 10s for 10 seconds, or
1m25 for 1 minute and 25 seconds.

Selection editor

Exactly as with the cursor position editor, the selection editor
allows you to enter the precise duration of the selection, or specify
the start or end time.

An interesting feature of this dialog is the list of checkboxes on the
right hand side. They allow you to have a selection active only for a
selected number of channels. This can be useful if you want to have an
effect apply only on a subset of the channels. Some Audio Units, for
instance, are only able to work on stereo documents. You can now
easily select two channels, and apply the effect on these.

Reordering channels

In the Edit menu, you will now find this useful tool that allows you
to reorder the channels in a document.

With this tool, you can:

• Reorder the channels by drag and dropping them.
• Remove selected channels by pressing the delete key.
• Add channels by duplicating already existing ones.

Splitted multichannel files

Many audio file formats support more than two channels. These files
are already pretty well handled by TwistedWave.

Some applications, however, produce multichannel samples as a group of
mono files, one for each channel. These files are identified by a
.L/.R/.C/.LFE/.Ls/.Rs in the file name to indicate which channel they
represent.

When opening one of these files, TwistedWave automatically recognizes
that it is in fact a multichannel document, and opens all the other
similarly named files, one per channel.

Maybe the files you need to load don’t use the naming convention
described above. In that case, you can still manually select all the
files you want to open from the open panel, and check the option to
merge the channels from multiple files. If the channels don’t come up
in the right order, you can reorder them with the tool described just
above.