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- Committer: Bazaar Package Importer
- Author(s): Anand Kumria
- Date: 2005-10-31 18:45:50 UTC
- Revision ID: james.westby@ubuntu.com-20051031184550-80syq495jzgad34r
Tags: 0.7.0-2
* Include documentation (Closes: #303230)
* Revert change to biquad_run function (Closes: #315575)
* Revert change to biquad_run function (Closes: #315575)
- files added:
- doc/README
- doc/ladspa
- doc/reverbed
- files modified:
- debian/changelog
added
removed
doc/reverbed/manual.html
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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
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"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
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<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
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<head>
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<title>TAP-plugins</title>
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<meta name="generator" content="GNU Emacs 21.2.1">
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<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
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<meta name="description" content="Tom's Audio Processing plugins for
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audio engineering on the Linux platform.">
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<meta name="keywords" content="TAP-plugins TAP Reverb Editor
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Reverberator Equalizer EQ Vibrato Tremolo Echo Tom Szilagyi LADSPA
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JACK Plugin Linux Audio">
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<meta name="author" content="Tom Szilagyi">
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</head>
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<body bgcolor=#ffffff>
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<table cellpadding="5" cellspacing="0" border="0" bgcolor=#ffffc0 width="100%">
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<tr><td>
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<font size="+2" color=#004060><b>TAP</b>-plugins</font><br>
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<font color=#004060>Tom's Audio Processing plugins</font><br>
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<font size="-1" color=#004060><i>for audio engineering on the Linux platform</i></font>
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</td><td>
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<center>
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<a href="../index.html">[ Home ]</a>
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<a href="../ladspa.html">[ LADSPA plugins ]</a>
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<a href="../reverbed.html">[ TAP Reverb Editor ]</a>
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</center>
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<hr>
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<center>
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<a href="install.html">[ Compiling & installing ]</a>
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<a href="manual.html">[ User Manual ]</a>
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</center>
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</td></tr>
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</table>
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<br><br>
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<font size="5">TAP Reverb Editor</font><br>
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<font size="6"><b>User Manual</b></font>
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<h2>Starting the program</h2>
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<p>
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If the program is <a href="install.html">correctly installed</a> on
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your system, all you have to do is type
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<code>reverbed</code>. However, there are a few command-line
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parameters that are worth mentioning:
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</p>
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<ul>
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<li><b>-a</b>: by default, the program does not connect its inputs and
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outputs to any JACK port. When this option is used, the program will
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try to connect its inputs to the first two hardware capture ports, and
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its outputs to the first two hardware playback ports.</li>
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<li><b>-i</b>: same as <b>-a</b>, but connect only the inputs to
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hardware capture ports.</li>
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<li><b>-o</b>: same as <b>-a</b>, but connect only the outputs to
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hardware playback ports.</li>
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<li><b>-c <i><client_name></i></b>: use
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<i><client_name></i> instead of the default 'reverbED' when
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registering to JACK. You need this option if you want to run more than
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one instance of the program at the same time, since JACK client
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programs must have unique client names.</li>
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</ul>
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<h2>The main window</h2>
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<img src="editor1.png" alt="Editor window (1)">
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<p>
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The main window (as shown above) lets you do most of the work. It
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consists of three areas: the top part provides controls for adjusting
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global parameters of the reverberation unit, as well as three buttons
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to launch additional windows (<i>Port Setup</i>, <i>Save / Export</i>,
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<i>About</i>). The middle part (with the combo box and the <i>New</i>,
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<i>Copy</i>, <i>Rename</i>, <i>Del</i> buttons) lets you manage your
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Reverb Types by creating new ones from scratch or from an existing
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one, as well as renaming and deleting them. Finally, the notebook
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provides controls to adjust internal parameters of a chosen Reverb
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Type. So let's describe them in detail.
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</p>
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<h2>Global parameters</h2>
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<ul>
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<li><b>Comb filters</b>: this toggle button switches processing of
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comb filters on/off, the default being switched on. Comb filters
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simulate the early reflections part of the reverb sound.</li>
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<li><b>Allpass filters</b>: switches processing of allpass filters
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on/off, the default being switched on. Allpass filters simulate the
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dense 'tail' of the reverb; they add more depth to the reverberated
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sound.</li>
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<li><b>Bandpass filter</b>: switches the bandpass filter on/off, the
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default being switched on. The bandpass filter has a low and high
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cutoff frequency; the spectral content that falls outside this range
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is attenuated. It processes the sound coming from the comb and allpass
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filters, and makes the effect more natural by filtering out those
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frequencies that normally do not occur in natural reverberation.</li>
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<li><b>Enhanced Stereo</b>: adds spatial spread to the reverb sound,
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largely adding to its depth and dimension. It sounds so great, it's
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best to always leave this on. It does not consume extra CPU, just
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changes the way internal parameters are calculated.</li>
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</ul>
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<p>
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The <a href="../ladspa/reverb.html">TAP Reverberator</a> manual has
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detailed advice about setting the following plugin parameters.
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</p>
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<ul>
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<li><b>Decay</b>: adjusts a mostly important global parameter of the
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whole effect. Larger values create depth, while smaller ones create
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the feel of tighter, smaller spaces.</li>
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<li><b>Dry Level</b>: adjusts the amount of the incoming dry signal in
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the output signal.</li>
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<li><b>Wet Level</b>: adjusts the amount of processed signal in the
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output signal.</li>
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</ul>
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<p>
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Some people will agree that the <b>BYPASS</b> button provides the most
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useful feature of the program. ;-)
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</p>
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<h2>Managing Reverb Types</h2>
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<p>
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It's all about creating the perfect sounding reverb for your own use!
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TAP Reverb Editor comes with a set of Reverb Types, but the whole
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point is that you can create your own ones. Let's see what the program
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provides to this end.
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</p>
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<ul>
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<li>The <b>Reverb Type</b> selector combo box holds the name of all
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currently available Reverb Types. Use it to select a Reverb Type to
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listen to, or operate on.</li>
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</ul>
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<p>
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These buttons provide functions for Reverb Type management:
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</p>
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<ul>
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<li><b>New</b>: create a new Reverb Type from scratch. After you enter
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the new name in the dialog that pops up when you press this button, an
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'empty' Reverb Type with that name is created and inserted into the
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list, so it will show up in the combo box. The new Reverb Type is not
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completely empty: it has one comb filter and one allpass filter, with
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their parameters set to default values. The bandpass low and high
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cutoff frequencies are also set to default values.</li>
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<li><b>Copy</b>: create a new Reverb Type, starting out as a copy of
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the currently selected Reverb Type. Use this to enhance existing
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Reverb Types while keeping the old version as well. Or create a
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working copy of an already satisfactory Reverb Type for random
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experimentations without spoiling the original.</li>
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<li><b>Rename</b>: change the name of the currently selected Reverb
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Type.</li>
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<li><b>Delete</b>: remove a Reverb Type that you don't like.</li>
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</ul>
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<p>
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Any changes you make to any Reverb Type (including creating, renaming
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and deleting them) remains in memory until you explicitly tell the
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program to save Reverb Types to file (more on saving later). So if you
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mess something up, just exit the program without using the <i>Save /
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Export</i> button, and all your changes will be gone.
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</p>
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<h2>Editing a Reverb Type</h2>
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<p>
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Reverberation is modelled by a set of comb filters, allpass filters
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and a bandpass filter. The maximum number of comb filters is 20, and
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the same limit applies to allpass filters. (It's easy to heighten this
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limit in the source code, but that is beyond the scope of this
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manual.)
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</p>
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<h3>Mastering the filters</h3>
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<p>
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The notebook pages <i>Comb Filters</i> and
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<i>Allpass Filters</i> consist of a graphical display representing
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each comb/allpass filter with a vertical line. There are controls to
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cycle through all filters (<i>Next</i> and <i>Prev</i> buttons),
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add/remove filters (<i>New</i>, <i>Del</i>) and adjust the parameters
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of the currently selected filter (spin/slider controls at the bottom
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of the page). The currently selected filter is highlighted in the
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graphical display.
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</p>
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<p>
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The reverb sound will immediately follow the changes you make to
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filter settings. It is possible to set filters so hot that they start
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operating as oscillators instead of filters (usually at extreme high
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feedback <i>and</i> extreme low delay time settings). If this happens
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while you are editing a Reverb Type, <b>don't panic</b>. Just hit the
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BYPASS button -- that will zero out all internal buffers so everything
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will cool down. While the effect is bypassed, move the filter
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parameters that caused trouble back to the 'safe area', then re-enable
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the plugin.
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</p>
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<h4>Comb filters</h4>
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<p>
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Comb filters are responsible for creating early reflections. They have
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three parameters: <i>Delay</i>, <i>Feedback</i> and
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<i>Freq. Response</i>. The delay time is proportional to the distance
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the sound travels before it reaches your ear as an early
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reflection. As each comb filter simulates a certain area where
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acoustic reflection occurs (a wall or the ceiling for example, but
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possibly other objects as well), the delay time you set determines the
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virtual distance of this object from the sound source and the
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listener. In the graphical display, the horizontal position of the
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line representing the filter depends on this parameter.
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</p>
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<p>
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Various kinds of materials reflect and absorb acoustic energy in
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various degrees. The feedback parameter provides control of this
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effect. For something that is a very good reflector (a flat brick-wall
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for example) a reasonably high feedback value should be used. In the
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graphical display, the length of the line representing the filter
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depends on this parameter.
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</p>
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<p>
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There is a secondary effect taken into account when simulating early
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reflections: not only does the reflection ratio of acoustic surfaces
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vary from one to another, but the reflection ratio of surfaces is also
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frequency-dependent. Higher frequencies are attenuated more, thus high
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frequency components decay in a shorter time. The <i>Frequency
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Response</i> slider sets the amount of high attenuation for a given
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comb filter. There is nearly no extra attenuation of high frequencies
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when it is set to zero. In the graphical display, the color of the
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line representing the filter depends on this parameter. Filters with
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lower Freq. Response values (which mean smaller extra attenuation of
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high frequencies) will be plot with a 'hotter' shade.
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</p>
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<h4>Allpass filters</h4>
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<p>
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Allpass filters are responsible for creating a reverb tail that makes
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the reverberation thicker and more natural sounding. They have two
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parameters, identical to the first two parameters of comb filters.
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Note, however, that the maximum delay time of allpass filters is about
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an order of magnitude lower than of comb filters. The graphical
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representation of allpass filters is done in the same way as comb
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filters, but here each line has the same color.
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</p>
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<h4>Bandpass filter</h4>
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<p>
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This notebook page provides two sliders to set the low and high cutoff
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frequencies of the bandpass filter.
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</p>
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<h3>Impulse Response: a visual aid</h3>
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<img src="editor2.png" alt="Editor window (2)">
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<p>
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A cornerstone of linear systems theory is that any linear system (such
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as a complex digital filter like this reverb) is unequivocally
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determined by its impulse response. Apart from this theoretical
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curiosity, it may be useful to take a look at the impulse response of
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a Reverb Type while inspecting or modifying it.
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</p>
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<p>
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The <i>Length</i> slider below the plot lets you choose the end time
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of the simulation (with the start point being at time zero). The time
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needed to finish plotting is proportional to the time simulated. As
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this is quite a CPU-demanding operation, it is never performed
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automatically: you have to press the <i>Recalculate</i> button every
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time you want to see a new plot of the currently active Reverb Type.
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</p>
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<p>
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Please note that the simulation shows the impulse response of the
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'clean' reverb: the settings of the dry and wet levels as well as the
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BYPASS button are irrelevant. The decay time setting and the global
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switches (Comb Filters, Allpass Filters, Bandpass Filter, Enhanced
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Stereo) do affect the plot, though.
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</p>
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<h2>Port Setup</h2>
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<img src="ports.png" alt="Port Setup dialog">
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<p>
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When you press the <i>Port Setup</i> button, a dialog similar to the
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above pops up. It is very much like the input/output connections
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dialog of a mixer-strip in Ardour, the only difference being that here
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the input and output ports setup is performed in one dialog.
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</p>
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<p>
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The upper half of the window handles connections to the input
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ports. On the left, each input port has a list of its current
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connections. By clicking on any list item, that connection will be
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removed. The <i>Clear connections</i> button removes all connections
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from the input ports.
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</p>
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<p>
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The notebook on the right has a page for all client programs and
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hardware devices available to the JACK server. By selecting a page,
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you will see a list of that client's output ports. Clicking on a list
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item connects the port to the currently selected input port (which has
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a blue header). You can change the selected input port by clicking on
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the unselected (grey) list header. When you add connections to the
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input ports, the selection alters between the two inputs.
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</p>
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<p>
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Connecting the outputs can be performed in the same manner. If you
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start up another JACK client while the dialog is open, you may press
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the <i>Rescan</i> button to make it appear in the notebooks on the
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right. Closing and re-opening the dialog has the same effect, since
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JACK ports are re-read and a new dialog instance is built every time.
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</p>
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<h2>Save / Export</h2>
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<img src="export.png" alt="Save / Export dialog">
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<h3>Saving your work</h3>
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<p>
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After you have had a good time messing around with Reverb Types, you
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may want to leave everything as it was. In this case, just exit the
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program and every change you made will be lost. However, there may be
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times when you do have something to save: in this case, you will want
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to make the changes permanent. So press the <i>Save / Export</i>
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button, and the above dialog will appear.
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</p>
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<p>
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Since there is quite a lengthy explanation included in this dialog,
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things are pretty straightforward. The program stores everything there
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is to Reverb Types in one file, and reads it every time you start the
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program. The file read on program startup is always
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<code>~/.reverbed</code> (a file called <code>.reverbed</code> in your
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home directory), but you have the option to write to another file in
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case you want to maintain different versions of the file.
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</p>
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<blockquote>
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<h4><u>A request to all users</u></h4>
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<i>The author of this program kindly asks you that if you develop any
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new Reverb Type that you think would be of general interest, please
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send him your </i><code>.reverbed </code> <i>file via e-mail, along
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with your name (if your mail headers don't tell it all). Good Reverb
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Types will be included in the next release (with due credit given to
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the original author, that's why I need your name). This is a perfect
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way to give something back for this software, and other users will
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benefit from it as well. Thank you.</i> </blockquote>
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<h3>Exporting to TAP Reverberator</h3>
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<p>
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Since this program is a JACK client, it cannot be automated from
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within powerful hosts such as Ardour. However, if you created a good
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Reverb Type, the program supports transferring its data into <a
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href="../ladspa/reverb.html">TAP Reverberator</a>, which is a LADSPA
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plugin for the same reverberation algorithm. It has the advantage of
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being automatable on Ardour mixes, but it has no capabilities for
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editing Reverb Types (that's why TAP Reverb Editor was created, after
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all).
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</p>
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<p>
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Exporting is the process of making the set of Reverb Types in TAP
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Reverberator be identical to the set of Reverb Types in this
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program. To do this, you have to export two files named
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<code>tap_reverb_presets.h</code> and <code>tap_reverb.rdf</code> to
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an arbitrary place on your computer storage. In the source code
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directory of the TAP-plugins LADSPA plugin package you will find two
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files with these names. Overwrite them with the newly exported ones,
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and re-compile and re-install the TAP-plugins package. That's all, you
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will have the same Reverb Types available in TAP Reverberator after
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that. Pretty cool, eh?
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</p>
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<br><hr>
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<center>
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$Id: manual.html,v 1.2 2004/06/22 13:36:36 tszilagyi Exp $
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</center>
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</body></html>
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