freqtweak - Realtime audio frequency spectral manipulation
freqtweak [-h] [ -c <num> ] [ -i <str> ] [ -o <str> ] [ -n <str> ] [ -D
<str> ] [ -p <str> ] [ -r <str> ]
freqtweak is a graphical tool for realtime audio spectral manipulation
and display. It provides several algorithms for processing audio data
in the frequency domain and a highly interactive GUI to manipulate each
associated filter. It also provides high-resolution spectral displays
in the form of scrolling-raster spectrograms and energy vs frequency
plots displaying both pre and post-processed spectra.
Freqtweak is a jack client. You need to have jackd running in order to
get sound input and output with freqtweak.
The processing filters are controlled through mouse operations on each
filter GUI window. The possible operations are:
Left button click/drag to draw filters. If Control is down, the y-axis
is fixed at the last cursor location (to draw nice horizontal lines).
If Control and Alt are down you can draw nice arbitrary straight lines.
Right button drag to move filters around in space. The filters wrap
around the left/right edges unless you hold down Control. Dragging
with both left and right buttons down on the GUI for the Gate processor
moves both the primary and the alternate filter together.
Holding Shift modifies the alternate filter (on double filter graphs
like Gate) for the previous operations.
Middle-button pops up frequency axis menu.
Ctrl-Alt right-click resets a filter to default values.
Shift-Ctrl-Alt left-drag zooms in on the y axis. Look at the status
bar to see the values for the cursor itself and the values of the
filter at the cursor’s frequency.
Shift-Ctrl-Alt right-click release resets the Y-zoom to full.
The B and BA buttons mean Bypass and Bypass All respectively.
The L and LA buttons mean Link and Link All respectively.
The G and GS buttons mean Toggle Grid and Toggle Grid Snap
This program follows the usual GNU command line syntax, with long
options starting with two dashes (‘-’). A summary of options is
Show summary of options.
-c <num>, --channels=<num>
Processing channels (1-4). Default is 2.
-i <str>, --inputs=<str>
Connect inputs from these jack ports (separate each channel with
commas). Defaults to ’alsa_pcm:capture_1,...’
-o <str>, --outputs=<str>
Connect outputs to these jack ports (separate each channel with
commas). Defaults to ’alsa_pcm:playback_1,...’
-n <str>, --jack-name=<str>
Jack name. Default is freqtweak_1.
-D <str>, --tmpdir=<str>
Jack server tmp directory (should match jackd --tmpdir).
-p <str>, --preset=<str>
Load the given preset initially.
-r <str>, --rc-dir=<str>
Specifies what directory to use for run-control state. Default
Here is an example of using freqtweak with an alsaplayer feeding it and
output going to speakers (alsa_pcm:out_?) without using a JACK
Start freqtweak first with this command line:
freqtweak -n ft &
Then start alsaplayer like so:
alsaplayer -o jack -d ft:in_1,ft:in_2 &
jackd(1), jack_connect(1), jack_lsp(1)
Freqtweak was written and is maintained by Jesse Chappell
This manual page was created by Enrique Robledo Arnuncio
<email@example.com> for the Debian GNU/Linux system, using text from the
README file by Jesse Chappell.
February 11, 2003