Hi, thanks for filing this. We're going to work in conjunction with the Debian
Multimedia team on these, but in the meanwhile, have a look at [0] for the
already-existing LADSPA plugins in Debian, and file a sync request bug for the
upcoming 12.10 development cycle. If you're comfortable with terminal, you can
use the `requestsync' tool.

I do see some vocoder plugins in the archive already, like these:

$ apt-cache show mda-lv2
Package: mda-lv2
Priority: optional
Section: universe/sound
Installed-Size: 2153
Maintainer: Ubuntu Developers <email address hidden>
Original-Maintainer: Debian Multimedia Maintainers
<email address hidden>
Architecture: amd64
Version: 0~svn3620+dfsg0-1
Provides: lv2-plugin
Depends: libc6 (>= 2.4), libgcc1 (>= 1:4.1.1), libstdc++6 (>= 4.1.1)
Filename: pool/universe/m/mda-lv2/mda-lv2_0~svn3620+dfsg0-1_amd64.deb
Size: 1345158
MD5sum: f86436a343504a0e6e481f614766fa92
SHA1: 757b6001fb8b6fb44d8c803ffcca040c09d2a06a
SHA256: 2b2c5bc4e61f8efaa58c0645377685144d1c5b3ed9cec0caae13f2101c1a1b37
Description-en: Paul Kellett's MDA plugins ported to LV2
 This package provides Paul Kellett's MDA plugins ported to the
 LV2 specification.
 .
 LV2 (LADSPA version 2) is an open standard for plugins and matching
 host applications, mainly targeted at audio processing and generation.
 .
 This package provides the following synths and effects:
  * Ambience - Reverb effect
  * Bandisto - Multi-band distortion
  * BeatBox - Drum replacer
  * Combo - Amp & speaker simulation
  * De-ess - High frequency dynamics processor
  * Degrade - Sample quality reduction
  * Delay - Simple stereo delay with feedback tone control
  * Detune - Simple up/down pitch shifting thickener
  * Dither - Range of dither types including noise shaping
  * DubDelay - Delay with feedback saturation and time/pitch modulation
  * Dynamics - Compressor / Limiter / Gate
  * DX10 - FM Synthesizer
  * Envelope - Envelope follower / VCA
  * EPiano - Acoustic piano
  * Image - Stereo image adjustment and M-S matrix
  * JX10 - 2-Oscillator analog synthesizer
  * Leslie - Rotary speaker simulator
  * Limiter - Opto-electronic style limiter
  * Looplex - Looping plugin
  * Loudness - Equal loudness contours for bass EQ and mix correction
  * Multiband - Multi-band compressor with M-S processing modes
  * Overdrive - Soft distortion
  * RePsycho - Drum loop pitch changer
  * RezFilter - Resonant filter with LFO and envelope follower
  * RingMod - Ring modulator with sine-wave oscillator
  * Round Panner - 3D panner
  * Shepard - Continuously rising/falling tone generator
  * SpecMeter - VU-meter
  * Splitter - Frequency / level crossover for setting up dynamic
    processing
  * Stereo Simulator - Haas delay and comb filtering
  * Sub-Bass Synthesizer - Several low frequency enhancement methods
  * Talkbox - High resolution vocoder
  * TestTone - Signal generator with pink and white noise, impulses
    and sweeps
  * Thru-Zero Flanger - Classic tape-flanging simulation
  * Tracker - Pitch tracking oscillator, or pitch tracking EQ
  * Transient - Transient shaper
  * Vocoder - Switchable 8 or 16 band vocoder
  * VocInput - Pitch tracking oscillator for generating vocoder
    carrier input
 .
 These plugins make no claim of compatibility, or any other relation,
 to VST. This code does not require the VST SDK, or any other non-free
 software, and it has never come into contact with any part of the VST
 SDK.
Homepage: http://dev.drobilla.net/browser/trunk/plugins/mdala.lv2/
Description-md5: 1be12f735bb9c5dd0834bcad9abad0e7
Bugs: https://bugs.launchpad.net/ubuntu/+filebug
Origin: Ubuntu
Task: ubuntustudio-audio-plugins

$ apt-cache show pd-bsaylor
Package: pd-bsaylor
Priority: optional
Section: universe/sound
Installed-Size: 268
Maintainer: Ubuntu Developers <email address hidden>
Original-Maintainer: Debian Multimedia Maintainers
<email address hidden>
Architecture: amd64
Version: 0.1-2
Depends: libc6 (>= 2.4), libfftw3-3, pd, pd-libdir
Filename: pool/universe/p/pd-bsaylor/pd-bsaylor_0.1-2_amd64.deb
Size: 74742
MD5sum: 3b35e6771e49e9e5bf06368d25448dcc
SHA1: 9cf9e5eed435afed0ece4c42fa12d45a9ad40c1c
SHA256: 997cb900cb1294e026c68cb6e4a5151c0409b61b7d396ed13d99e403812957d3
Description-en: a library of FFT-based Pd objects by Ben Saylor
 bsaylor is a library of Pure Data objects by Benjamin Saylor:
 .
 pvoc~ is a phase vocoder based on Pd's 09.pvoc.pd example patch. Advantages
 over the abstraction include (reportedly) faster execution, instantaneous
 response to input, and adjustable phase locking. It requires FFTW3.
 .
 susloop~: sample player with various loop methods (ping-pong, ... ) think
 tracker. svf~ This is a signal-controlled port of Steve Harris' state
 variable filter LADSPA plugin.
 .
 svf~: a signal-controlled port of Steve Harris' state variable filter
 LADSPA plugin (http://plugin.org.uk).
 .
 zhzhx~: Turns the input signal into a staticky, distorted mess. Comes with
 tone control
Homepage: http://puredata.info
Description-md5: da6d888b46f1e3cbc6f1f970680af9af
Bugs: https://bugs.launchpad.net/ubuntu/+filebug
Origin: Ubuntu

 status confirmed