SA and SA2: Is Motif up to the task?

Every now and again, the subject of Super Articulation and Super Articulation 2 voices come up on the Motifator site. Here are some rather lengthy comments that I posted in response to a recent inquiry.

First, here is some background information from the S950 and Tyros 5 manual. The descriptions of Super Articulation (SA) and Super Articulation 2 (SA2) are quoted from the Tyros 5 manual. The voice descriptions (e.g., JazzArtist guitar voice) are taken from the PSR-S950 itself — when you press [INFO] in the voice selection screen, the S950 displays a description of the selected voice. These descriptions show the kind of SA effects supported by the S950. The S950 does not have front panel articulation buttons; a foot pedal can be assigned to trigger SA effects.

The description of Articulation Element Modeling (AEM) is from the Tyros 5 manual. It is a pretty good concise description of what AEM (SA2) does, but is a gross simplification WRT Yamaha’s patents. AEM does a lot of cross-fading and sample whacking. Plus, the concise description downplays the timing analysis in order to avoid unwanted latency effects and to detect releases.

Super Articulation voices

These Voices provide many benefits with great playability and expressive control in real time. For example, with the Saxophone Voice, if you play a C and then a D in a very legato way, you will hear the note change seamlessly, as though a saxophone player played it in a single breath. Similarly with the Concert Guitar Voice and play the D note strongly, the D note would sound as a “hammer on,” without the string being plucked again. Depending on how you play, other effects such as “shaking” or breath noises (for the Trumpet Voice), or finger noises (for the Guitar Voice) are produced.

JazzArtist: Super Articulation provides realistic guitar phrasing: Legato notes played within an interval of a 4th sound as a hammer on, pull off or slide. The last note has a release noise. fret noise is added randomly and the Foot pedal 2 [controller] adds a cutting noise.

NylonGuitar: Play normally and the voice is expressive and dynamic. The Foot pedal 2 [controller] changes the sounds to harmonics.

SmoothBrass: When brass instruments play legato, there is no attack sound on the legato notes. Super Articulation recreates this. Play legato and the notes join together, changing with velocity.

ConcertStrings: Strings can play legato, where each phrase is one continuous sound. Play legato and Super Articulation strings work in the same way. There are also three dynamic levels.

TrumpetFall: Jazz Trumpeters often use a fall or doit. Super Articulation recreates this with a velocity switch: Play harder to create the effect, change between fall and doit with the Modulation wheel. (Pushing forward changes to a doit.) Use the Foot pedal 2 [controller] to add breath noise.

Super Articulation 2 voices

For wind instrument Voices and Violin Voices, a special technology called AEM (see below) has been used, which features detailed samples of special expressive techniques used on those specific instruments — to bend or slide into notes, to “join” different notes together, or to add expressive nuances at the end of a note, etc. You can add these articulations by playing legato or non-legato, or by jumping in pitch by around an octave. For example, using the Clarinet Voice, if you hold a C note and play the Bb above, you’ll hear a glissando up to the Bb. Some “note off” effects are also produced automatically when you hold a note for over a certain time. Each S.Art2! Voice has its own default vibrato setting, so that when you select a S.Art2! Voice, the appropriate vibrato is applied regardless of the Modulation wheel position. You can adjust the vibrato by moving the Modulation wheel.

AEM Technology

When you play the piano, pressing a “C” key produces a definite and relatively fixed C note. When you play a wind instrument, however, a single fingering may produce several different sounds depending on the breath strength, the note length, the adding of trills or bend effects, and other performance techniques. Also, when playing two notes continuously — for example “C” and “D” these two notes will be smoothly joined, and not sound independent as they would on a piano.

AEM (Articulation Element Modeling) is the technology for simulating this characteristic of instruments. During performance, the most appropriate sound samples are selected in sequence in real time, from huge quantities of sampled data. They are smoothly joined and sounded — as would naturally occur on an actual acoustic instrument.

This technology to smoothly join different samples enables the application of realistic vibrato. Conventionally on electronic musical instruments, vibrato is applied by moving the pitch periodically. AEM technology goes much further by analyzing and disaggregating the sampled vibrato waves, and smoothly joins the disaggregated data in real time during your performance. If you move the Modulation wheel when you play the S.Art2! Voice (using AEM technology), you can also control the depth of the vibrato, and still maintain remarkable realism.

Motif and MOX

Starting with the Motif XS, Yamaha added Expanded Articulation (XA). Without diving into too much detail, XA allows control over articulations using the assignable function buttons. XA also detects and triggers samples to handle legato technique. The Motif/MOX player has precise control over when an articulation is sounded and the Motif/MOX programmer can construct new voices using XA (or tweak existing voices).

The S950 (and Tyros) monitor and analyze the notes played by the musician. The Tyros, in addition, has two panel buttons to control articulation. The workstation software determines which articulation to sound and when based upon what the musician has played on the keyboard or (optional) controllers.

Both the S950 and Tyros implement Super Articulation (SA) voices. SA voices and XA voices use roughly comparable sample playback technology (AWM). New samples can only be installed onto an S950 through an expansion pack (proprietary format). Yamaha has not released an expansion pack editor. S950 voice editing is limited to “quick edit” envelope tweaks; you cannot get to the element level on the S950. Motif/MOX voice editing is vastly deeper.

Super Articulation 2 (SA2) voices on the Tyros are a whole other beast. SA2 uses Articulation Element Modeling (AEM) to “stitch” samples together in real-time in response to what the musician plays. The Motif XS (and later) do not have the software to analyze the musicians playing/gestures and it does not have the AEM sound engine. SA2 is not implemented on the S950. SA2 is a very complicated critter because it takes note timing into consideration. (See Yamaha’s patents on AEM.)

So, voices/samples cannot simply be ported from S950 (or Tyros) to Motif. You can, however, use XA to make your own SA-style voices without any of the front-end analysis of musical gestures/control.

Thoughts and speculation

Sometimes, I think SA is a different front-end for Mega Voices. A guitar Mega Voice, for example, uses velocity switching to trigger (one of) an open soft, open medium, open hard, dead soft, dead hard, hammer on or slide waveform for a given MIDI note played on the keyboard. Effects such as strum noise and fret noise are triggered by MIDI note numbers above C6 and c8, respectively.

An SA voice based upon the same waveforms might use velocity switching for open soft, open medium, open hard, dead soft and dead hard, while using legato notes within an interval of a fourth to trigger hammer on and slide. An articulation control button or pedal trigger strum noise. Fret noise is added randomly. Thus, the SA voice uses the same basic waveforms as the Mega Voice, but the SA voice uses different means and analysis to select, enable and render the waveforms.

Motif XS (and later) have Mega Voices. The MOX Mega Nylon voice, for example, uses seven elements:

       Elem#  Waveform                Low  High Velocity
       -----  ----------------------  ---  ---- --------
       Elem1  Nylon Open Sw St        C-2  B5   1-60
       Elem2  Nylon Dead Notes St     C-2  B5   61-75
       Elem3  Nylon Mute St           C-2  B5   76-90
       Elem4  Nylon Hammer St         C-2  B5   91-105
       Elem5  Nylon Slide St          C-2  B5   106-120
       Elem6  Nylon Harmonics St      C-2  B5   121-127
       Elem7  Nylon FX St             C6   G8   1-127

that select and play an internal waveform based upon MIDI note number and velocity. One could build a different voice that triggers the same waveforms under different conditions such as AF1 ON, AF2 ON, etc. Indeed, some of the other Mega Voices respond to AF1/2 and AS1/2. Thus, I believe that a stock Motif/MOX with XA could emulate an SA voice within certain limitations. Specific conditions like “legato within an interval of a fourth” are not supported in Motif/MOX. XA detects legato without regard for interval.

SA2 voices are based on AEM and I believe that the AWM tone generation model in the stock Motif/MOX is not enough. In AWM, each note is independent and follows the familiar attack, decay, sustain and release life-cycle. Legato based on XA merely changes the waveform that is used to render the attack of an independent note. An AEM note, on the other hand, evolves and morphs into the next note. The AEM tone generator behaves more like physical modeling than AWM’s ADSR note life-cycle. As mentioned in Yamaha’s description of AEM, the AEM tone generator does some fancy computation to correctly render vibrato through note transitions. Further, a stock Motif/MOX does not perform the timing analysis and control functions that drive AEM tone generation.

I would love to see Yamaha add AEM-based voices to future members of the Motif family!