Applied Acoustics Tassman 1.2 Review

TASSMAN 1.2 (WIN) Flexible physical modeling and more in a software synthesizer. Have you ever wondered what a bowed marimba sounds like? Or how about

TASSMAN 1.2 (WIN)Flexible physical modeling and more in a software synthesizer.Have you ever wondered what a bowed marimba sounds like? Or how about the sound of a cello changing size as you play it? These feats and many others are possible with Tassman 1.2, a new modular software synthesizer from Applied Acoustics Systems (AAS).

Tassman employs physical-modeling techniques to create unique sounds. It provides a toolkit full of sound generators, resonators, filters, and other processes with which you can build accurate acoustic simulations or outrageously gritty vintage synths. Furthermore, many aspects of these sonic building blocks can vary in real time with MIDI controllers.

Software synthesizers are booming, and Tassman distinguishes itself by combining state-of-the-art physical modeling with a retro aesthetic, featuring lots of knobs, LFOs, and step sequencers. What's more, you have a tremendous level of control over your synthesizers' internal patching.

SYNTH BUILDING 101If I taught a synthesis course, my syllabus would include Tassman. It's the next best thing to physically patching together oscillators, filters, and so forth on an old modular analog synthesizer. In addition to an interface that clearly shows the cause-and-effect relationships between modules, Tassman comes with an impressive collection of more than 100 instruments that you can use as study models. The synths are organized into three categories: Analog, Acoustic, and Miscellaneous. Within these groups, you'll find all manners of bowed beams, blown bells, and bubbling basses. Each instrument includes several presets, and you can download more instruments at the AAS Web site.

Tassman actually consists of two separate programs: Builder lets you assemble the synths (see Fig. 1); Player then lets you hear the results. Builder is a straightforward application that includes a Library window (on the screen's left), where you find a bin full of building blocks; and a large Construction window (on the right), where you assemble your synths. A Help window is located at the top of the screen.

To begin your design, select the module type you need in the Library window. (To see a complete modules list, check out the AAS Web site.) First click on a module icon, then click on the Construction window where you want the module to appear. If you prefer multiple copies of a module, shift-click on the Construction window as many times as needed. Once you place the modules in the Construction window, you connect them by pulling virtual patch cords from one to another. To discover what a module's inputs and outputs consist of, position the mouse on them to see an informative display.

When you select a module in either the Library window or the Construction window, the module's description appears in the Help window. The printed documentation offers more detailed module descriptions, but the Help Window provides a good deal of practical information.

As a general rule, a module's output can be patched to any number of other modules. This allows, for example, a keyboard module's Velocity output to control an oscillator's amplitude and a filter's cutoff frequency at the same time. Builder also lets you save and import subpatches, which are groups of modules or entire synths that you can encapsulate in a single module. Subpatches let you reuse your favorite inventions as parts of new designs and can simplify a complex synthesizer's layout. You can enter a subpatch's description before saving the subpatch, and this description appears in Builder's Help window, just like with Tassman's stock modules.

GOOD VIBRATIONSTassman's sound sources are called Generators and Resonators. For the most part, Generators are objects that induce vibration in Resonators, although this category also includes an LFO and a VCO. The acoustic Generators collection consists of two mallets for beating on items and a plectrum for plucking others. A variety of acoustic Resonators are provided, including a beam, a marimba, a membrane, a plate, and a string. Each of these is also available in a bowed variation. Rounding out the Resonators are a single tube, a complex arrangement of four tubes, a flute, and an organ.

Instead of being available as an independent Generator, a bow is integrated into the associated Resonators. According to AAS, this is done for the sake of efficient coding. Bowing an object creates physical feedback between the object and the bow, and separating the two would bog things down. A future release should include a separate bow module, along with additional Generators such as reed and brass modules.

The complexity of Tassman's objects is impressive. For example, the flute module is a model of a recorder. When a player blows into a recorder, the air stream is directed across a sharp edge (called the labium) at one end of the recorder's body. This sets the instrument's air column in motion, creating its characteristic sound. Tassman's flute module takes this into account, letting you set default values for the turbulence noise of the player's air stream, the air stream's behavior, the labium's position relative to the air stream, and even the sharpness of the labium's edge, which affects the instrument's timbre and response.

The ability to define an instrument's characteristics is cool enough, but you can then control these parameters during performance, either from the virtual onscreen knobs or by assigning MIDI controllers to them. This lets you modify the instrument's behavior in numerous ways as it plays.

THE ENVELOPE, PLEASEAAS included a healthy complement of filters and envelopes for shaping the sound of Tassman's synths. Lowpass and highpass filters are available in static and variable varieties, along with bandpass and comb filters. Flexibility is, again, the name of the game.

You can control a filter's cutoff frequency with an onscreen knob, assigned to a MIDI controller, or set to track an incoming signal, such as pitch or Velocity. Resonance can also be assigned to a MIDI controller for complete control of the filter's sound during performance.

One of the benefits of Tassman's modular construction is the ability to combine elements in ways that expand their basic usage. For example, you can combine multiple bandpass filters to create a "quasi" parametric equalizer. The top of Fig. 2 shows the partial design for a patch in which a bowed marimba's output is sent to three separate bandpass filters. The filters include frequency and resonance controls, which means you can also control bandwidth, as it is inversely proportional to resonance. An image of the synth produced by this design appears in the inset at the bottom of Fig. 2.

The Envelope bin contains ADSR (Attack, Decay, Sustain, Release) and VCA modules as well as modules for volume (manual control only, no modulation input), portamento, and Root Mean Square (RMS). RMS is an envelope follower that lets you, for example, track an audio input's volume and then use that information to control some parameter of another module. You could use the ADSR to control a VCA's gain or a filter's cutoff or center frequency. You can assign all four envelope parameters to MIDI controllers.

CAUSE AND EFFECTYou certainly won't want to throw away your multi-effects units, but Tassman does provide a number of useful effects to incorporate into your creations. These range from staples such as reverb and delay to more esoteric effects such as a sample-and-hold module and the Scratcher, which is a delay with modulated delay time.

The reverb simulates the effect of sound generated at the intersection of three tubes. You can define the length and radius of each tube. Two or more reverbs can combine for a stereo-reverb effect, and you can route the output of one or more reverbs through the tube or tube array from the Resonator bin.

A number of interesting sonic possibilities are available by applying delay, flange, or pan effects. The Splitter module doubles its input's pitch one, two, or three octaves down, and a variable pitch-shift module is also available. There's also a phase inverter and a pickup module, which models a magnetic-coil pickup's effects as used with guitars and electric pianos. The pickup's distance and lateral position relative to the source are variable, and you can control input and output gain. Three LEDs on the pickup module in Player display the amount of distortion produced by combining these parameters.

INS AND OUTSTassman has many input and output devices. Monophonic and polyphonic keyboards come with or without Velocity sensitivity. You can add Breath Controller, Modulation, and Pitch Wheel, or drive the whole shebang with a step-sequencer module.

Any Tassman synthesizer must include a digital-to-analog converter (DAC) for its sound to be heard, and this module comes in mono or stereo. A number of other I/O options are also included, most of which are used for submixing elements or configuring subpatches.

IN PERFORMANCEOnce you create a Tassman synthesizer in Builder, open it in Player to hear it (see Fig. 3). This two-program approach is a bit on the clunky side; to audition any updates you made in Builder, you must close Player and reopen it with the updated synth. AAS is working on streamlining the process so that Player can load Builder's updates or new synths without closing first.

With brushed-metal faceplates, round "analog" meters, and lots of knobs, Tassman has a decidedly retro look. Modules are arranged in rows, and you can customize the components' positions in Builder. Tassman runs in 800 5 600 resolution, but you should run it in at least 1,024 5 768 or you'll have some difficulty seeing all the modules in some synths. However, you can easily scroll the entire screen left or right as needed.

Once you load a synth into Player, you must turn on its DAC before it will make any sound. This is a minor annoyance, but considering the number of included synths that begin to play instantly because of their built-in sequencers, it's probably a reasonable precaution against a loud surprise.

Player exhibits a high degree of latency. This is due to a fixed buffer size of 1,024 samples and the overhead of writing to the operating system's audio device - which requires three buffers - resulting in a delay of at least 68 to 200 ms when responding to incoming MIDI data. AAS says it plans to make improvements available in a free update. By shrinking the buffer size, the company anticipates latencies as low as 10 ms on a Pentium III/500 MHz. (I installed Tassman on two machines: a Pentium II/266 MHz with 96 MB RAM and a Pentium III/450 MHz with 128 MB RAM. In both cases, the latency was very noticeable.)

Unlike analog synths of yore, you can save all settings in presets. For the ultimate in tweaker flexibility, even individual modules and subpatches support their presets. It would be great to have a drop-down list of available presets for a given synth or module; currently, you can access presets through an Explorer-style window that opens by clicking on the Load button at the bottom of the Player window.

Speaking of presets, Tassman ships with one or more for each of its approximately 100 synths. You could spend days just working your way through this massive collection, and you can modify any of the synths.

TWEAKER'S DELIGHTTassman is the sort of program that inveterate tweakers love. With so many variables and customization opportunities, Tassman is almost overwhelming. Fortunately, it's laid out quite logically, so even novices can make sense of everything. What's more, its knob-laden interface begs you to start twisting away until you find a sound that moves you.

As an example of how customizable Tassman is, take a look at the plectrum, one of its Generators (see Fig. 4). You can specify the plectrum's stiffness, as well as the strength of its impact on the sound source. When you add a plectrum to a program, you can also assign a MIDI controller to vary its parameters in real time.

Four modulation inputs let you customize the plectrum's response to incoming MIDI data. The first is the trigger, which tells the plectrum to pluck the string (or other Resonator), typically in response to a gate signal from a keyboard module. The second input varies the plectrum's stiffness in direct proportion to some parameter of the incoming signal, typically pitch; that causes the stiffness to increase with pitch. The third modulation input is similar to the second, except it varies the stiffness in inverse proportion to some parameter of the incoming signal, typically Velocity. The fourth input varies the plectrum's strength directly with the amplitude of the incoming signal; that is usually used to cause strength to track Velocity, which is the expected behavior of an acoustic instrument. Three knobs - labeled mod1, mod2, and mod3 - determine the degree to which modulation inputs 2 through 4 track incoming signals. These can also be assigned MIDI controllers for real-time tweaking.

With so many knob twirling opportunities, Tassman cries out for some kind of external control surface along the lines of Keyfax's PhatBoy. If you only have a mouse, though, AAS has made Player reasonably easy to control. Grabbing a knob and dragging vertically makes coarse adjustments, and the arrow keys make fine adjustments to the selected knob. Right-clicking anywhere on a knob snaps its value to that point. Knobs with green LEDs indicate that you can snap to a centered position by clicking on their LEDs.

THE BIG PICTURETassman has some real strengths and a lot of potential, but it also has some first-version quirks. Until AAS finishes integrating Player and Builder, you will find yourself opening and closing Player constantly to audition new sounds or changes you made in Builder. (Fortunately, there are shortcut keys for these functions.) This minor bother is compounded by the fact that Windows often lets go of Player slowly, or not at all. If you open it again too quickly, you'll run into MIDI conflicts.

It's great to have MIDI control over so many parameters, but establishing those assignments means digging three dialog boxes deep into Builder; it would be much better to right-click on a Player knob to create or change an assignment directly. That isn't possible because Builder is actually a compiler that creates and gathers source code according to your instructions. On the other hand, each synthesizer's source code is stored in a tiny text file with a .mom extension, making it easy and efficient to trade synthesizers with friends.

The user manual includes a fantastic tutorial on building a synth in Tassman, along with clear and detailed information about every module. Unfortunately, it neglects to tell you how to run Tassman with a sequencer and how to create multitimbral synths. (You can create such synths either by splitting a keyboard or by using multiple keyboards on different channels assigned to different instruments, all within a single synth program.)

For your sequencer to see Tassman, you must use a MIDI loopback program, such as the freeware Hubi's Loopback ( This is an extremely easy program to set up, and Loopback will become unnecessary when Tassman is revised to operate as a VST Instrument within Steinberg's Cubase and Emagic's Logic or as a DirectX instrument within Cakewalk Pro Audio. (Tutorials on these subjects should be available at the AAS Web site by the time you read this.)

The models of acoustic objects are impressive for their attention to detail, but they have one important shortcoming: they can't perform smooth pitch bends. Any attempt to bend the pitch is stepped in semitone increments, rendering the effect all but useless. That is another computational compromise that AAS engineers are working on. On the other hand, the various analog-synth building blocks suffer from no such limitations.

While some musicians I respect were enthralled with Tassman's sound from the first note, it took me a while to warm up to it. A good number of the included synths are of the step-sequenced variety, which is not my cup of tea. I found more to like about the acoustic and analog sounds, but it wasn't until I started assigning controllers and tweaking knobs that I became truly enthusiastic. That is where Tassman's real potential lies. When not only the amplitude but the physical size of a cello model can be modulated as a function of Velocity, you have something unique.

The beauty of software synthesis is that you can audition Tassman. The downloadable demo version includes Builder and Player, so you have an opportunity not just to play Tassman but to design your own synths, remap patches, and assign MIDI controllers. That's when you'll feel Tassman's power and potential. Download the demo from the AAS Web site and tweak away.