Moog Music: DFAM and Spectravox – Physical Modeling Goes Modular

Moog Music opens the session by framing physical modeling as a synthesis approach that mimics the behaviour of acoustic instruments, breaking it down into two core components: the exciter and the resonator. Unlike classic subtractive synthesis, which relies on sustained oscillators shaped by filters, physical modeling focuses on short, harmonically rich bursts that excite a resonant structure. This analogy is made concrete with a demonstration of various ways to strike a drum, illustrating how the method and point of contact affect the resulting sound.

The video sets the stage for a modular interpretation of this concept, using the DFAM to generate the excitation signal and the Spectravox as the resonator. By drawing parallels between acoustic and electronic signal paths, Moog positions these devices as tools for exploring not just synthetic timbres, but the nuanced dynamics of real-world instruments within a modular workflow.

The synthesis chain begins with the DFAM, whose oscillators and noise source are sculpted by three independent envelopes. This setup enables the creation of a short, broadband transient full of harmonics—precisely the kind of excitation signal required for physical modeling. The video highlights the flexibility of the DFAM’s envelope structure, allowing for intricate control over the evolution of the transient.

Once the excitation signal is crafted, it’s routed into the Spectravox’s carrier input. With Spectravox set to Filter Bank mode, the DFAM’s output excites all ten resonant filters simultaneously. Additional patching—such as sending DFAM’s trigger output to Spectravox’s trigger input—brings a fourth envelope into play, further refining the decay and overall shape of the resonated sound. This modular approach mirrors the complexity of acoustic interactions, but with the advantage of voltage control and patchable signal flow.

DFAM’s sequencer is put to work, with its two rows—pitch and velocity—providing nuanced control over the excitation signal. The velocity row determines the intensity of each virtual drum hit, simulating the dynamic range of a real percussionist. Meanwhile, the pitch row can be assigned to both VCOs, introducing variation in the harmonic content of each strike.

The video goes further by patching the pitch sequencer output to Spectravox’s shift input. This modulates the position of all ten filters in the bank, effectively altering the perceived geometry of the resonant body. The result is a sequence where not only the force of each hit changes, but also the tonal colour and pitch, closely echoing the behaviour of struck acoustic objects.

By combining DFAM and Spectravox, Moog showcases a modular approach to generating acoustically inspired sounds. The flexibility of analog patching allows for deep exploration of physical modeling principles, with every parameter tweak offering a new sonic possibility. The video underscores how these tools can move beyond traditional synthesis, venturing into territory usually reserved for digital modeling or sample-based systems.

Ultimately, this pairing opens up a vast world of electronically generated, acoustically nuanced timbres. For modular enthusiasts, it’s an invitation to experiment with the boundaries between the synthetic and the organic, using voltage, envelopes, and filter banks to craft sounds that feel alive and tactile—even when no real drum is in sight.