We get plucky with Ableton Live’s Tension instrument.
Like Collision and Corpus, covered in the May 2014 Live column, Tension is a physical-modelling-based instrument developed in collaboration with Applied Acoustic Systems (AAS). Based on the AAS synth String Studio, Tension’s purpose is to emulate stringed instruments while providing lots of tools to take you beyond the sounds of acoustic instruments, be they sampled or real. Tension is included in Live Suite and available for €79$99 as an add-on for other versions. If you like Tension, String Studio VS2 is worth a look for its added features and extensive preset library. I’ll start with some Tension basics and then explore how to use them to create your own sounds.
Stringed instruments start, of course, with strings under tension; you tune each note by twisting tuning pegs to adjust the tension on the strings. To play the instrument you pluck, strike or bow a string with an ‘excitator’, which starts the string vibrating. The length and tension of the string determine the rate of vibration, and therefore the pitch, of the sound. For stringed instruments such as guitar and violin you change the length (and pitch) of the vibrating part of the string by pressing it against a fingerboard, whereas for others (stringed keyboards for example), you have one or more strings for each note. Other important factors also affect the sound. The thickness, shape and material of the string influence both timbre and decay. How, where and with what you start the string vibrating influence timbre as well as volume. Damping (how you stop the string from vibrating) determines how the sound decays. The body of an acoustic instrument, or pickup design and placement, for an electric instrument affect timbre.
Tension’s interface has two panels: String and Filter/Global. The rather crowded String panel controls each of the aforementioned factors. The Filter/Global panel adds a multi-mode filter with dedicated envelope and LFO. It also houses controls for how Tension reacts to your MIDI keyboard, along with global settings for voice management (count, detuning, transpose, unison and portamento). I’ll start with that panel because it provides a quick way to subtly or radically alter the sound of factory presets — always a good place to start exploring a new instrument.
Insert Tension on an empty MIDI track and take a quick look at the String panel. The default patch uses the Excitator section’s Plectrum (pick) setting and the String section in the middle of the panel controls various string parameters. The other sections are disabled. Play a note and you’ll hear a decent emulation of a plucked string that decays slowly as long as the key is held, and dies out quickly when you release the key. Lowering the String section’s Ratio setting increases the release time — try 30 percent to add a little tail to the sound.
Switch to the Filter/Global panel and you’ll see the Filter, Envelope and LFO controls lined up on the left with the keyboard and global settings on the right. Only the filter is turned on, and that doesn’t have any effect because it is a low-pass filter with its cutoff frequency all the way up. Playing around with the Freq and Res controls or dragging the round cursor in the display works just as you would expect from using other Live filters. For something a bit unusual try the two formant filter types at the bottom of the drop-down list. The Envelope and LFO are mostly typical of Live instruments, but notice that you get separate Vel(ocity) controls for Attack and Sustain and that there are separate filter cutoff and resonance modulation-amount controls for the envelope, LFO and key number. Enable these sections and try the settings from screen 1, which uses a formant filter to produce a kind of auto-wah effect. You can defeat the effect by deactivating the Filter section, and that’s a good target for toggling with a footswitch or a MIDI note.
One of the advantages physical modelling offers over sample-based instruments is that you can change the characteristics of the instrument; you’re not stuck with the sound of a specific piano or guitar or what have you. Be careful of your ears and speakers, though, because small changes in physical-modelled parameters will sometimes push levels way over the top.
There are many ways to get to grips with complex control panels like Tension’s, but one of the quickest is to compare similar presets modifying the controls of one and auditioning the difference until all settings match. For example, insert the default preset in one track and the Blues Guitar preset from the Guitars & Plucked folder in another track. The settings of the Blues Guitar preset yield a quite different and more authentic guitar sound. Notably, the Damper, Pickup and Body sections are used and the Excitator and String sections have different settings. Change the default settings one by one to the Blues Guitar settings and you’ll find that some are more influential than others (see screen 2).
As another approach, load any of the individual Tension presets (avoid the racks so you hear just what Tension is doing), figure out what’s causing the most audible features of the sound and then try some modifications. Here are three examples:
- Mallets/Big Kalimba: the Perfect Fifth interval you hear results from the enigmatically calibrated Global Detune setting of 92 percent in the Unison section of the Filter/Global panel. Try different Voices and Delay settings — Delay is a good target for MIDI mapping or automation. Use Detune settings of 88, 84 and 80 to dial in intervals of a Perfect Fourth, Major Third and Minor Third respectively, but beware that there are several increments for each numerical value, so hold the Command/Control key for fine tuning.
- Bass/Slap Bass: try changing the Mass, Stiffness, Position and Damping settings in the Excitator section to change the character of the slap.
- Pianos & Keys/Mellow Wurly: try lowering the Position in the Pickup section and the Damping amount in the String section. Also experiment with the Excitator Mass and Stiffness knobs.
Some judicious effects processing can do wonders for raw Tension patches. An obvious example is inserting Amp and Cabinet effects after any guitar sound. Try the Blues Drive Amp preset followed by the Slight Reflections Cabinet for the Blues Guitar preset in screen 2. Inserting Auto Pan after an electric piano for the classic Rhodes tremolo effect is another obvious example.
Corpus, which embodies the resonator section of Collision, is particularly well suited for use with Tension. You can use it in addition to or instead of the Body section of Tension; I usually disable Tension’s Body section. For example, load Tension’s Bass/Acoustic Synth Bass preset, disable the Body section, insert Corpus after Tension and try different Corpus presets. Don’t be too concerned about the Corpus preset names — for example, most of the drum-category presets work well with any acoustic-instrument-modelled Tension sound. The presets with Loop in the name work more like special effects, and a little goes a long way, so try MIDI mapping the mod wheel to Corpus’ Dry/Wet knob and using the low end of its range. Many Corpus presets have strong resonances at some frequencies, so you may want to use Corpus’ Side-chain section to track the MIDI notes playing Tension.
Tension can produce special effects that have an acoustic flavour while being unlike any real-world acoustic instrument, and Live’s more exotic Audio Effect racks can often take those to the next level. For example, try following the Tension preset Effects/Ambient Drops Hold with the Audio Effect rack Space/Chamber Trio Delay. Ambient Drops Hold is a mono preset that uses the Hammer (bouncing) excitator with extreme Damping to generate a series of repeats. That’s interesting in its own right, but a bit repetitive. Chamber Trio Delay takes care of that with a couple of Grain Delay and Resonator chains along with chains for reverb and the dry signal. Automate or MIDI map the rack’s Dry/Wet macro knob to keep the effect under control. Slowly playing staccato notes with a low Dry/Wet setting produces an interesting alternative to the bouncing hammer. Another bouncing-hammer Tension preset, Ambient & Evolving/Moving Stringpad, becomes much more dynamic when followed by the Audio Effect rack Space/Ambient Space Delay. Here again, modulating the rack’s Dry/Wet macro knob tames the effect.