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AAS String Studio

Modelled String Instrument
Published August 2005
By Martin Walker

Panel B contains the various modules that make up this unique physical string model and allow you to interact with its various parameters.Panel B contains the various modules that make up this unique physical string model and allow you to interact with its various parameters.

String Studio uses Applied Acoustics' physical modelling expertise to (in theory) generate the sound of any string instrument. Good or bad vibrations? We find out...

Imagine a magic guitar which can be restrung with anything from two to 64 strings and played with a plectrum, bow, or bouncing hammers at any position along the strings. You can pitch the strings with fingers or add frets, damp them, or shrink or expand the soundboard. You can listen to it acoustically or via a modelled magnetic pickup, and it has built-in multi-effects. You need imagine no longer, since I've been playing this instrument a lot over the last few weeks — it's String Studio, from Applied Acoustic Systems.

When you've experienced the many and varied sounds that it encompasses, 'String Studio' does seem the perfect moniker. However, it's led some musicians to assume that this product was designed to create hyper-realistic orchestral strings to compete with the various vast multisampled libraries now available. In fact, it's a far more versatile synthesizer that physically models a wide range of sounds generated by strings, such as the hammered strings of acoustic pianos, bouncing hammers of instruments like the dulcimer, the bowed strings of the violin family, and the plucked strings of guitar and pizzicato violin. And that's not all — this new AAS engine is also capable of a wide range of ethereal pads, unusual textures, and out-and-out weirdness.

Overview

Applied Acoustics Systems have championed physical modelling for some years now, ever since the first release of their Tassman software synth in 2000, but with String Studio, they've unveiled a completely new acoustic 'engine'. As with their Lounge Lizard electric piano, processor overhead remains comparatively low compared to modular designs like Tassman, and there's plenty of opportunity to allow the user to interact with the engine in real time using MIDI controllers.

String Studio will run on Mac OS X 10.2 or later with a minimum 733MHz G4 processor, while PC users can use Windows 98SE, 2000, or XP with an 800MHz Pentium III or faster. As usual, if you want to run your sequencer and other software synths alongside, the more powerful your processor is, the better. Installation is easy, but unfortunately you have to enter your serial number and go through the now familiar challenge/response routine on the AAS web site before you can play a single note. String Studio can be run in stand-alone mode, or as a plug-in in VSTi, DXi, Audio Units, and RTAS formats inside a suitable host application.

The main display will be familiar to existing AAS customers. There's a strip across the top with options for loading/saving and importing/exporting of presets and preferences, editing functions, and MIDI Link options (more on these later), while the Toolbar beneath it shows the current preset name and MIDI link, maximum polyphony, active MIDI channel, the value of the currently selected control, plus a CPU meter and MIDI activity 'LED'.

The main area is split between the Preset Browser (which can be hidden if preferred) and the main control area. String Studio has a lot of controls in this area, but AAS have managed to pack the majority into two very manageable areas labelled Panel A and B, which you switch between by clicking on one of the three illuminated buttons on the main title bar (the third is Compare, which lets you make comparisons to the original sound when editing presets, and there's also a master level control with stereo level meters). Panel A is the default view, and houses two horizontal rows of modules, mostly featuring fairly traditional-looking rotary knobs (see the box on the right for more details on this panel).

The Bundled Library

In the final couple of months before shipping String Studio, a huge amount of effort has gone into the bundled sound library, and it shows. Compared with the embryonic sounds that some SOS staff heard at trade shows, the vastly improved presets the software now contains reflect both further refinements in the PM engine, and the increasing adeptness of the designers in using the engine parameters to recreate existing acoustic instruments — and to dream up new ones.

The presets have been carefully organised into folders to make finding a suitable sound easier. As always with AAS products, the Imports folder is at the top, so you can add downloaded presets to the library, while the instruments are contained within a further 17 folders. The first of these, Guided Tour, contains 57 highlights from the other categories, while the others include guitars, basses, clavinets, pianos, harps, and pad and bowed sounds, as well as sound effects. I estimate that there must be about 500 presets in all, covering a lot of sonic ground.

Many of the guitars and basses are truly excellent, and String Studio excels at clavinet, clavichord, and harpsichord sounds, complete with the characteristic mute 'choking' as the notes are released. Not surprisingly for an Applied Acoustics product, there are quite a few electric pianos of note, although Lounge Lizard is the real expert in this department, but the acoustic pianos are rather weak. However, some of the bowed strings are superb, as are the selection of ethnic instruments such as the Japanese koto and the Middle Eastern dulcimer. The synths are a mixed bunch, but some of the pads and ambient sounds are wonderful. Overall, there are loads of real gems on offer, some highly expressive.

You can select any String Studio preset by double-clicking on its name in the browser, but since there are far more on offer than could be chosen from the 128 available MIDI program changes, AAS also provide a Program Change Map to which you can allocate your choice of presets and then switch between them remotely via MIDI program change commands from a keyboard or sequencer.

Here are a few of my favourites, some of which you can hear on this month's free covermount SOS DVD.

  • 'Jazz Guitar': A touch-sensitive clean sound that's ideal for jazz, country, and 'My Sweet Lord' impersonations.
  • 'Hold and Hammer Lead': A screaming lead with hammer-on harmonics, offering a wide expressive range.
  • 'Mute Bass': A very expressive instrument, offering a range of tones from round and smooth to hard and 'clicky'.
  • 'Pop-Rock Clavinet': If you're feeling funky, a quick burst on this will surely satisfy you.
  • 'Violin 4': You can really hear the bite of the bow being scraped across the strings here, and each note sounds slightly different, just like on a real instrument.
  • 'Dulci Delicate': An authentic-sounding hammered dulcimer, with distant bouncing repeats.
  • 'Soft Pad 1': An unusual cross between a brass sound and that of a bowed string, with rosin scrapes on top notes.
  • 'Cosmos Soundscape': A unique and haunting combination of bowed string and resonant enveloped filter.

String Things

The more interesting low-level design of your instruments goes on in Panel B, where there are six main modules. Some of their controls are multi-functional and context-sensitive — in other words, the labels below some of the knobs change as you go along, but thankfully this feels quite natural. The most important module is the virtual String, which is permanently 'in circuit'. Its Damp and Decay controls let you adjust the high-frequency content and decay time of the string respectively, to mimic different materials such as nylon or metal, while the Inharm control lets you detune the upper partials, as though you were changing the 'width' of the string.

Additional grey rotary knobs beneath the main controls let you alter the amounts of various modulation signals related to the main controls, and each knob may control and display the values of up to three sources, selected by clicking on one of the green routing 'LEDs' to their right. The modulation signals can also be inverted by clicking on the LED above each knob. For the String Module, the sources are Keyboard (which alters the Damp and Decay values so that the high notes have a shorter decays and more damping), and Ratio, which allows you to adjust decay times for note on and note off, to reproduce the action of dampers on a string.

The string is set into motion by the 'Excitator' module to its left, and this is where you can choose a plectrum, hammer, bow, or bouncing hammer (like those used to play a dulcimer, for instance). This is also where you use the Geometry controls to determine at what position you'll 'play' the string, where the string will be damped (if anywhere), and whether or not its sound will be heard naturally or via the modelled magnetic pickup. The latter is movable along the string so you can achieve bridge or neck sounds.

The remainder of the modules are all optional, and are activated by clicking on the LEDs alongside their title. Beneath the string module is Termination, which models the finger or fret pitching contributions, while above it is the Damper, which adds features for 'stopping' the sound, like virtual felt dampers (as on a piano) or a performer's finger (as on a guitar). The string signal can then pass through the Filter section, where you can add modulation courtesy of the ADSR filter envelope, or put it through a wide variety of more traditional 'analogue' swept filter treatments from subtle to extreme. There are low-pass, band-pass, notch, and high-pass options, a very handy three-peak formant filter for throaty vocal-like sounds, plus a dedicated LFO with a variety of waveforms and sync options.

Next in the signal chain is the Body module, where you can mix in the unique resonances of a range of soundboards ranging from that of a tiny violin to a huge piano, and fine-tune the resonance mix and decay to simulate different materials. This module can add a lot of character. If you want to add a little grit, you can also switch in the Distortion module, which contains a choice of algorithms from mellow to metal. The final module in Panel A is EQ, where you can fine-tune your instruments using a three-band design with low- and high-shelving sections, and a parametric mid section.

Panel A

There are quite a few controls in the seven modules of Panel A, but it doesn't take too long to get the hang of them all. The Vibrato module provides pitch modulation via a dedicated LFO with Rate and Amount controls. Vibrato can be delayed and faded in using two further controls, or added in real time with the mod wheel. However, the highlight of this section for me is the Error control, which lets you add a varying amount of randomness to the Vibrato controls for each voice. It's great for adding slightly differing vibrato to each 'player' in a string section to enrich the ensemble effect, for instance!

Panel A contains the more traditional controls for fine-tuning your sounds, including multi-effects.Panel A contains the more traditional controls for fine-tuning your sounds, including multi-effects.

The Keyboard module contains a set of master controls covering overall tuning in octaves, semitones, and Hertz, while the Stretch and Error knobs allow you to create the 'stretched octave' tunings of the acoustic piano and add an element of slightly random tuning to every note of your orchestral strings, for instance. For thicker sounds, you can switch on double or quadruple Unison modes at the expense of similarly increased CPU overhead, or to quickly convert a six-string guitar into a 12-string version. Associated Detune and Delay controls add 'jangle' and 'spread' respectively. Finally, you can switch from polyphonic to monophonic mode for sounds like solo guitar, and select from low-, high-, or last-note priority to suit your playing style. The separate Portamento module lets you add pitch slide between the notes in both monophonic and polyphonic modes, and includes a Legato mode so that it only triggers when one note is pressed before the previous one is released.

The optional Arpeggiator module may seem an odd inclusion for a stringed instrument, but apart from its synth runs, you can also press it into service for harp glissandos. It provides a Range in octaves, a selection of four note-order options, a direction with the Span options (upwards, downwards, or both), and a latch mode that keeps playing the current arpeggio continuously until you play some different notes. However, its real strength is the Pattern display, where you can individually activate or deactivate any combination of steps in a length of anywhere between one and 16 steps to produce rhythmic patterns. Your modified patterns are saved with the associated presets. The overall Rate is either set by a rotary knob, or can be locked to a variety of synchronised options tied to the master internal clock of the Clock module. This is a clever design in itself, where Tempo can be typed or tapped in, while an External option lets you lock String Studio to the tempo of your host application.

The Output Effects comprise chorus, delay, and reverb, each with a separate Bypass option. All three provide a good selection of alternative algorithms including mono and stereo chorus and flanging, digital, ping-pong, slapback, and tape delays, and drum room, club, and various room and hall reverbs. The order of the chorus and delay effects can be swapped, and their tempo set manually or locked to a wide variety of sync options. Overall, I found the effects very useful in adding the final touches to instrument sounds, from added richness to swirling stereo movement, and short slapback to moving ping-pong delays, and the reverb is versatile and has relatively smooth tails, although you might want to replace it if you have more advanced plug-in alternatives. The final section is the Recorder module, where you can save the audio output of String Studio as a WAV or AIFF file.

In Use

Playing this synth is a joy, and it's easy enough to start creating your own presets by modifying existing ones. However, be prepared for a little initial confusion as you explore the various parameters — this is, after all, a totally unique synth engine, so quite a few of the controls will be unfamiliar. Thankfully most of them make sense fairly quickly once you try them, such as the Stiffness and Protusion of the plectrum, the Force and Friction of the bow, and the Mass and Stiffness of the hammers.

I soon had some lovely acoustic and electric guitar sounds with lots of character and expression, plus a bowed string that resembled the sound of a string quartet, and various ethnic instruments reminiscent of the Japanese koto. However, further exploration proved that the engine could be pushed into unexpected directions — the Bow Excitator, in particular, is capable of creating some wonderful ethereal pads, even before you add EQ and effects, and once you add this final polish you can end up with sounds that I very much doubt you'd achieve elsewhere.

Since this synthesis engine calculates all the sounds in real time as its various modules interact, I found that each note could sound slightly different depending on my performance, just like a real instrument, even before I linked MIDI controllers into the picture to provide even more expression. However, physical modelling is always likely to be more computationally intensive than sample-based synths, so it's important to keep an eye on your maximum polyphony.

You can select the number of voices from a choice of two, four, eight, 12, 16, 20, 24, 28, or 32, although the number of simultaneous notes available is also affected by the Mono/Poly mode and whether Unison mode is active. It's a shame that there's no six-voice setting, since this would be the perfect option for acoustic and electric guitars to avoid wasting CPU power. However, like Lounge Lizard, String Studio has dynamic voice allocation, which means that your CPU need only run those notes that are actually playing. Typically, the overhead for my PC's Pentium 4 2.8GHz processor was 30 percent for four voices, and 50 percent for eight.

If you've not already guessed by this point, I loved String Studio, but although many of the sounds are great fun to play, there are a few parts of the user experience that could definitely be improved. Some of the controls are really tiny (particularly the LEDs next to many controls), making some mouse maneouvres a frustrating experience, and given the amount of virtual wood grain and brushed metalwork in the graphical user interface, perhaps all of the controls could be made larger in a future update. The preset browser also has a fixed width sufficient to view the folder names, but once you open a folder you need to indulge in a lot of sideways scrolling to see the contents. Finally, there's insufficient space to display the full preset and MIDI link names on the menu bar, making it difficult to remember which you've selected, and the MIDI activity indicator disappears completely if you hide the Browser window.

MIDI

The bundled library is nicely organised, while the various MIDI Link controls let you tap String Studio's expressive potential. All parameters in the VSTi and DXi versions of String Studio can be automated from their host application by directly moving the controls and recording their movements. However, keyboard players will appreciate the ability you have to change any parameter value in real time using your choice of MIDI controller — you just right-click on the control, select the 'Learn MIDI Link' function (shown), and then move the controller that you wish to use.The bundled library is nicely organised, while the various MIDI Link controls let you tap String Studio's expressive potential. All parameters in the VSTi and DXi versions of String Studio can be automated from their host application by directly moving the controls and recording their movements. However, keyboard players will appreciate the ability you have to change any parameter value in real time using your choice of MIDI controller — you just right-click on the control, select the 'Learn MIDI Link' function (shown), and then move the controller that you wish to use. All parameters in the VSTi and DXi versions of String Studio can be automated from their host application by directly moving the controls and recording their movements. However, keyboard players will appreciate the ability you have to change any parameter value in real time using your choice of MIDI controller — you just right-click on the control, select the 'Learn MIDI Link' function (shown above), and then move the controller that you wish to use.

Refinements include the ability to define the upper and lower parameter values linked to the controller's movements — and these can also be reversed, so that parameter values are reduced as the controller value increases. Since multiple parameters can be linked to a single controller, you can make several String Studio controls vary by differing amounts and in different directions simultaneously by (for instance) moving the mod wheel to achieve more complex interactions. Or you could set up multiple controllers, each controlling an individual parameter.MIDI links to use with different instruments can be saved, imported, and exported just like the presets, and you can define one to be the default. These really are the key to being more expressive with String Studio — you could, for example, change your virtual finger-picking position using the mod wheel linked to the Excitator position, switch from neck to bridge pickup sounds via the pickup position parameter, or articulate bowed swells using overall level.

Conclusions

In a perfect world, we'd use a talented guitarist or string player when we wanted these instruments in our songs, but few of us are lucky enough to have such performers on tap all the time. With practice, String Studio can provide some incredibly realistic virtual versions when we have to play in the parts via MIDI, but for me its most exciting aspect is the ability to create new monophonic and polyphonic stringed instruments that sound believable, react to your playing technique like acoustic equivalents, and can be pushed in directions that no other synth can emulate.

You could download the demo version, skim through its presets and not be particularly impressed, but once you start playing this instrument seriously and experience the realistic way it responds to your performance (and particularly once you involve MIDI controllers), you'll be hooked. This is a unique synth that sounds like nothing else on the market.

Published August 2005