Albert Gräf [email protected]
Computer Music Research Group
Johannes Gutenberg University (JGU) Mainz, Germany
The Raptors.pd patch implements an experimental algorithmic composition arpeggiator program with 3 parts (i.e., 3 Raptor instances running in parallel, each with their own set of parameters). A few sample presets are included in the presets folder, and you can use the raptor-preset subpatch (in the lower left corner of the main patch) to switch between these. This subpatch also has some controls to change meter and tempo.
The patch accepts MIDI note input, as well as controller and system realtime messages for the most important controls as detailed below. The controller assignments should be convenient to use with popular modern MIDI controllers featuring keys, pads and rotary controllers, such as the Akai MPK mini, or more "classic" equipment like the Behringer controllers.
The actual algorithmic core of Raptor is implemented as a Pd external written in Pure, see the raptor.pure program. Thus in addition to Miller Puckette's Pd you'll also need the author's Pure plugin loader for Pd (pd-pure) to run it. Any recent version and flavour of Pd will do; see http://puredata.info/. The author's Pure programming language and the pd-pure plugin loader can be found at https://agraef.github.io/pure-lang/. We also provide ready-made packages of pd-pure for Linux (Arch, Ubuntu and derivatives) and macOS (via MacPorts), please refer to the link above for details. Mac users may also want to check the Pure on Mac OS X wiki page for detailed instructions.
Copyright (c) 2005-2018 by Albert Gräf.
Raptor is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
Raptor is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with this program. If not, see http://www.gnu.org/licenses/.
The main Raptors patch has a raptor-preset subpatch offering controls to change presets, meter and tempo in a convenient fashion.
The preset-changing control is the radio button strip in the right upper corner of the subpatch. Simply click on one of the radio buttons to change the preset. This will affect all three parts. Note that currently the preset names for the different parts are hard-wired, so in order to change these you'll have to open the subpatch and edit the patch accordingly. Also note that once the patch and the initial presets have been loaded, subsequently switching presets will not affect the tempo and meter any more, so that these can be changed freely with the other controls in the subpatch, see below. However, it is possible to force tempo and meter settings to be loaded from a preset. To do this, press and hold the Ctrl key (or click the red button in the lower right corner of the subpatch) and then choose the preset you want to load by clicking on the corresponding radio button as usual.
The remaining controls in the subpatch provide a way to set tempo and meter in a convenient fashion that will be familiar to musicians.
The tempo (in BPM a.k.a. beats per minute) can be changed using the slider or the number entry widget in the bottom row of the subpatch. By default, in tempo calculations a "beat" is taken to mean a quarter note. The actual frequency of base pulses in the chosen meter then is m/4 times the BPM value, where m is the denominator of the meter (see below).
The meter can be changed with the three strips of radio buttons in the middle of the subpatch. The green strip changes the numerator (number of base pulses), the red strip the denominator (unit of the base pulses) and the white strip the subdivision of the meter (tuplets). The latter setting applies a heuristic which lets you play tuplets of the given kind (1 indicating no subdivision, 2 duplets, 3 triplets, etc., up to 7-tuplets) without changing the basic meter and tempo.
NB: Raptor's tuplet heuristic isn't perfect and in some corner cases only calculates a rough approximation which is expressible as a Raptor meter in the format discussed below. In particular, you should make sure that the tuplet's real length (which is 3 in the case of duplets and quadruplets, 2 in the case of triplets and 4 in the case of 5-, 6- and 7-tuplets) divides the number of base pulses, otherwise the numerator of the resulting meter will be rounded down to the nearest integer. For complicated meters it is often easier to get what you want by adjusting tempo and meter directly, using the input format for meters discussed below.
In any case, the resulting meter is displayed in the symbol entry widget above the white strip of radio buttons. The symbol box can also be used to just directly enter the desired meter. The format used by Raptor allows you to specify a meter using the customary n/m notation where n denotes the numerator (the number of base pulses making up a measure) and m the denominator (unit of the base pulse) of the meter. The latter is usually a power of 2, but Raptor allows you to use any positive integer there, which is useful when tuplets are the base pulse of the meter. Moreover, the numerator n can also be specified in stratified form by explicitly listing the decomposition of the meter into different levels separated by dashes. E.g., 12/16 can also be specified as 4-3/16 or 2-2-3/16. Or you could write 6-2/16 or 2-3-2/16 to denote a 6/8 meter subdivided into 16th notes. Likewise, a 6/8 meter subdivided into triplets would be specified as 18/24, 6-3/24 or 2-3-3/24.
If you don't specify a stratified meter, Raptor does the stratification internally anyway, by decomposing the numerator into its prime factors in ascending order. Finally, if the denominator m is omitted, Raptor chooses the power of 2 which is closest to the numerator as a reasonable default, so that in most cases you can also just specify the (unstratified or stratified) numerator of the meter. E.g., 2 becomes 2/2, 3 becomes 3/4, 9 becomes 3-3/8, 12 becomes 2-2-3/16, 2-3-2 becomes 2-3-2/16, etc.
One important limitation to keep in mind is that Raptor only supports integer (non-fractional) components in both the numerator and denominator of the meter right now. As already mentioned, this affects, in particular, the tuplet heuristic. The default meter shown initially in the raptor-preset patch is 4/4 (common time) a.k.a. 2-2/4, but note that this may be overridden by the preset loaded at startup. The raptor-preset patch always changes tempo and meter for all Raptor parts simultaneously. However, it is also possible to change meter and tempo (and even the definition of a "beat") by changing the corresponding fields in each individual Raptor part. This makes things much more complicated and will only be needed in special situations; in particular, it allows you to configure polyrhythms in Raptor, which isn't possible possible with just the raptor-preset patch.
You can click the Edit button in each of the three Raptor parts to open the corresponding subpatch, which will give you a bunch of additional control parameters which can be changed to affect Raptor's operation. (A more detailed description of the parameters is beyond the scope of this document, so we refer the reader to the raptor.pure script instead.)
Once you have changed the parameters to your liking, you can close the subpatch and click the Save button to write your changes to the corresponding preset file. You can also use the SaveAs button if you want to save the settings in a new preset file instead, or use the Load button to load a different preset file.
In addition, each Raptor part also has a few special toggles visible in the main patch which are typically used in real-time during performance:
-
"Mute" (abbreviated "M") silences one part, i.e., it suppresses note output from that part (but not the metronome clicks, see "Metronome" below).
-
"Hold" ("H") provides a kind of ostinato effect in which input notes are kept indefinitely. Raptor will then loop playing the same notes and chords at random until "Hold" is switched off again.
-
"Pause" ("P") pauses a part until it is switched off again, at which point the part resumes with the next pulse it was about to play when paused. Parameter changes such as meter and tempo are still registered and will take effect when the part resumes. This is typically applied to all parts simultaneously, but if your timing is exact enough, you can also use this with individual parts to achieve some interesting polyrhythmic effects.
Muting individual parts can also be done with the F1, F2 and F3 keys, and you can hold or pause all parts with the F5 and F6 keys, respectively. All these functions can also be controlled using various MIDI controllers. In particular, the sustain pedal is by default assigned to the "Hold" function, but can also be switched to "Pause" by pressing the F7 key (see "Keyboard Shortcuts", "Switches" and "Other Controllers" below).
The "controls" subpatch in the upper right corner of the main patch has "Start" and "Stop" buttons which let you start and stop Raptor manually. There's also a "Reset" button to reset all parts and have them reload their current presets, as well as "Hold" and "Pause" toggles which control the corresponding switches of all parts simultaneously (see above).
Raptor can also be started and stopped remotely by sending it the appropriate system realtime messages (see "Sequencer Messages" below). However, the most convenient option for remote control and automation is through Jack transport. Raptor then also picks up the current tempo and meter (if the host DAW provides that information). The "jack-transport" patch in the bottom right corner of the main patch lets you connect to Jack transport (red toggle), as well as start and stop Jack transport and rewind to the initial Jack transport location. This requires the author's pd-jacktime external to work. Two suitable DAWs which have full support for Jack transport are Ardour (available on Linux, Mac and Windows) and Qtractor (Linux-only).
The "harm-sweep" subpatch gives you direct access to various parameters controlling Raptor's note generation process. A discussion of these parameters is beyond the scope of this document, but in a nutshell, they are used to control the degree of harmonicity in the generated notes. If the (minimum) harmonicity is high, the generated notes and chords will match the chords you play on Raptor's MIDI input. Lowering the harmonicity gives the algorithm more leeway (for very low values you'll get complete atonality).
In addition, there's a preference parameter which controls how much Raptor will prefer notes with a high degree of harmonicity (this works best if the minimum harmonicity is not too high, giving Raptor more freedom to choose disharmonious notes). The preference value can also be negative, in which case Raptor will favor disharmonious rather than harmonious notes. Moreover, all these parameters are also varied automatically according to pulse strengths, using associated "bias" parameters (these aren't shown in the "harm-sweep" subpatch, but can be edited in the different Raptor parts and are also accessible using corresponding MIDI controls, see below).
The subpatch also offers some controls to initiate automatic "sweeps" of the harmonicity and preference parameters, using the radio button strips at the bottom. All changes done in this subpatch apply only to the active part(s) (all, upper, lower or lead) set in the radio button strip on the right.
Raptor provides some keyboard shortcuts (mostly function keys) to control the most important functions of the patch. Note that to make these work, the patch must have keyboard focus. F1, F2 and F3 will mute/unmute the corresponding part, F4 toggles the metronome clicks, F5 and F6 toggle the "Hold" and "Pause" controls of all parts, F7 switches the assignment of the sustain pedal (see "Other Controllers" below) between "Hold" and "Pause", F8 changes presets by cycling through them, and F9 starts and stops playback. Also, the cursor keys on the numeric keypad let you control the harmonicity sweep functions in the "harm-sweep" subpatch.
(e.g., K1-8 on Akai MPK mini)
- CC1/CC5: Harmonicity/Bias
- CC2/CC6: Preference/Bias
- CC7: Volume
- CC4/CC8: Density/Bias
Note that Harmonicity/Preference/Density and the corresponding Bias controls apply to the active part(s) set in the "harm-sweep" subpatch, see above. The Volume controller sets the corresponding controls in all parts and is also passed through to MIDI output. Also note that all these controls are reset when switching presets (see below).
FCB 1010 users: The FCB 1010 has its right continuous controller pedal assigned to CC7 by default and can thus be used to control the Volume setting of all Raptor parts. You may want change this to match your preferences and playing style. E.g., I have the FCB's left and right continuous controller pedals (CC27 and CC7) assigned to CC1 and CC2, respectively, so that I can control both the Harmonicity and Preference parameters of the active part(s) while playing. The controls can be remapped most conveniently by using some appropriate MIDI plugin inside a DAW (like pizmidi's midiConverter3), or a stand-alone MIDI filter/mapping software (like qmidiroute on Linux, MidiPipe on the Mac,or MidiOx on Windows).
(PAD1-8 on Akai MPK mini in CC mode)
- CC20: Start/Stop
- CC21: Metronome
- CC22: Hold/Pause
- CC23: Preset-
- CC24: Mute 1
- CC25: Mute 2
- CC26: Mute 3
- CC27: Preset+
CC23 and CC27 work like push buttons (only react to "on" values), the others are toggles. Note that in contrast to standard MIDI semantics, any value >0 means "on" here; so velocity-sensitive buttons like on customary pad controllers should work fine. A suitable Akai MPK mini II configuration is included (Raptors.mk2).
FCB 1010 users: The FCB 1010 has its left continuous controller pedal assigned to CC27 by default, which will wreak havoc with Raptor's preset setting when you operate this controller. Thus you'll want to to reassign the pedal to a different CC number (such as CC1, see above).
The presets #0-#4 can also be accessed directly through program changes (PC) 1-5, which correspond to Pads 1-5 on Akai MPK mini in PROG CHANGE mode, and to foot switches 1-5 on a Behringer FCB 1010 foot controller.
PC changes will be taken modulo 5, i.e., they wrap around after PC 5, so they will also work with the higher banks on the FCB 1010. To make this more useful, Raptor actually implements four "sets" with different variations of the presets, which are identical to the original presets #0-#4 but with some parts muted, as follows:
- Set #0 (PC 1-5): all parts playing
- Set #1 (PC 6-10): lead part ("piano") muted
- Set #2 (PC 11-15): upper part ("guitar") muted
- Set #3 (PC 16-20): lead and upper part muted ("bass" solo)
- Set #4 (PC 21-25): all parts muted (no output from Raptor)
Again, these wrap around after set #4, so that higher banks of the FCB 1010 (second row of FCB bank 02 and beyond) will simply cycle through Raptor sets #0-#4. Note that all this assumes the FCB 1010 default setup which has PC 1-10 mapped out over its ten banks accessible with the Up/Down pedals.
-
CC16 (0-4): Preset #0-#4 (alternative way to change presets, mainly useful for automation)
-
CC64: Hold/Pause (sustain pedal)
-
CC80: Start/Stop (alternative way to control transport state, see below)
Note that CC64 (the sustain pedal) and CC80 (general purpose button #1) are interpreted using standard MIDI button semantics, so a value >=64 means "on", <64 "off".
Also note that all these settings are just examples tailored to the external MIDI gear and software applications that I use; you can customize these to your heart's content (have a look at the midi-in subpatch of the controls subpatch in the Raptors main patch).
If you don't have Jack transport as a sync option available in your DAW, then Raptor's playback state can also be controlled through the usual system realtime messages start/cont/stop. This should work with most popular DAWs. (Bitwig Studio and Reaper have been tested. Tracktion's system realtime implementation seems to be broken, so you'll have to use the CC80 workaround described below. YMMV, though.)
To synchronize Raptor with your DAW, it's usually sufficient to turn on MIDI clock sync in the DAW and make sure that the transport messages are delivered to Raptor (but see Limitations/TODO below for some caveats).
If your DAW doesn't support MIDI clock sync then you can also start/stop Raptor explicitly through a special controller message (CC80, see above). Use a CC80 value >= 64 to start, <64 to stop Raptor.
Note that in any case Raptor keeps its own internal time, so it only interprets system realtime messages controlling the transport state. Thus you have to make sure that the DAW starts out at the beginning of a measure and tempo/meter settings match up with Raptor (or use Jack transport with a DAW that emits real-time tempo and meter messages, such as Ardour).
In addition to MIDI, Raptor can also be controlled through OSC (including parameter feedback). This is bidirectional, so Raptor will feed control data back to the connected OSC device(s). A corresponding TouchOSC layout is included (Raptors.touchosc). The main patch also includes an OSC browser subpatch which lets you detect and connect to OSC devices on the local network (either manually or through Zeroconf). Using Zeroconf, the Raptor patch is visible to OSC devices as "Raptor".
Raptor supports OSC natively (if you have the requisite mrpeach externals installed), so no MIDI bridge is needed. The Zeroconf support requires that you have a corresponding system service running, usually Avahi on Linux, or Bonjour on Mac OS X or Windows. Also note that in order to make OSC communication work, your local network must have the OSC UDP input and output ports open, so you might have to configure the firewall on your local router accordingly.
For convenience, Raptor always connects to OSC (on the local UDP port given as the argument of the oscbrowser abstraction) and starts browsing for possible OSC clients during startup (i.e., patch load time). The default input port is 8000 which matches TouchOSC's default. If this interferes with other OSC receiving software (such as OSCulator on the Mac) then you may want to change the argument of oscbrowser to a different port number and reconfigure your OSC devices accordingly.
Also, oscbrowser will auto-connect to the first available OSC client on the local network as soon as it finds one. If this isn't desired then you can turn oscbrowser off and disconnect it by clicking the corresponding message in the main patch. You can also use oscbrowser's next and prev controls to cycle through the list of all known OSC clients, or enter an IP address and port number and then push the conn button to connect Raptor to the given client. Finally, by clicking the "connect 255.255.255.255" message in the main window you can have Raptor broadcast outgoing OSC messages to the local network, so that any connected OSC client receives them. This is useful if you're running multiple OSC devices on the same network. (You can adjust the outgoing port number in the message as needed. The default is 9000 which matches TouchOSC's default.)
Raptor optionally outputs a kind of metronome click in the chosen tempo and meter, if you specify the number of clicks to emit per measure in the metronome field of one of the parts (the sample presets all have this setting in the upper part). In the future we may turn this facility into a separate Raptor part providing a full-blown automatic drum sequencer, but for the time being the metronome is there mostly for the traditional purpose: to help you keep the right tempo and rhythm while you play.
The metronome always outputs MIDI note 37 (Side Stick) with varying velocities on MIDI channel 10 (the drum channel on GM devices) while Raptor is running, no matter whether the emitting part is currently muted or not. The velocities of the notes are set from Raptor's internal pulse strengths computed from the chosen meter, which are also used to determine the most prominent pulses at which the clicks should occur. All this happens automatically. To quickly toggle the metronome click you can use one of the available controls (CC21 or function key F4 in Raptor's main window). To completely suppress the metronome clicks just filter out MIDI channel 10 in your DAW, or reset the metronome value to zero in the presets that you use.
If you change meters on the fly using the corresponding controls in the raptor-preset subpatch then the metronome field will be adjusted automatically as well (only in parts where it's nonzero already). Raptor picks a default which works reasonably well (half the number of base pulses in the meter plus one in the current implementation).
Bug reports and comments/suggestions are always appreciated, please mail me at [email protected], submit an issue or drop me a pull request at Github.
Here are some known issues and items on my wishlist:
-
At present you have to edit the raptor-preset subpatch in the main Raptor patch to change the definitions of the presets. This really needs to be replaced with a more generic system which allows switching between different "banks" of preset collections (maybe also through a MIDI controller).
-
A MIDI mapping for the meter and tempo controls in the raptor-preset subpatch is in order. (The TouchOSC layout already has some controls for these parameters on its third page, though.)
-
Raptor's MIDI mapping is somewhat idiosyncratic, as it matches the specific MIDI gear that I often use (most notably the AKAI MPKmini2 and the FCB 1010), so you may have to edit this in the "midi-in" subpatch inside the "controls" subpatch. A MIDI learn capability would be nice to have in order to simplify these kinds of adjustments.
-
SPP (song position pointer) and tempo sync through MIDI clock messages aren't supported right now. Use Jack transport instead if you need that kind of functionality.
-
Raptor keeps its own internal time, so there's the potential of Raptor's and your DAW's time drifting away from each other. Pd's internal timing is rock-solid, however, so normally this shouldn't be an issue if Jack transport is used and your DAW properly communicates tempo and meter changes (Ardour does).
-
While Raptor should be stable enough for stage usage, there are some obscure situations in which its timing still goes bonkers and/or the different parts fall out of sync. In particular, it's usually not a good idea to use "Reset" or high-frequency tempo/meter changes during a live performance. Another recipe for disaster is to use "Pause" when Raptor is driven by Jack transport, unless you can keep time very accurately. If you avoid these pitfalls then you should (mostly) be safe from such mishaps. If all else fails, stop and reset Raptor, take a deep breath, and start over. :)