What Makes an Exciting Sound?

Essential principles behind creating exciting, compelling sounds.

Tips & Tutorials  |  December 23, 2014


What makes a sound exciting? Try to imagine a natural sound. It could be any natural sound, from the howl of a wolf to the rustling of leaves when wind blows through the trees.

No matter what the sound is, it evolves somehow. The pitch of the wolf’s howl ultimately slides downward and the intensity of the sound diminishes over time. As the force of wind ebbs and flows, the density of the rustling changes with it. Things in the natural world change, respond to stimuli, and evolve. This type of audible motion in sound plays an enormous role in drawing our attention.

Adding Motion to Sound

When trying to create exciting, engaging sounds, we need to include motion. In the world of sound design and audio production, we can achieve motion through modulation. Modulation enables us to help a single sound open up, strike, growl, crawl around… it gives a sound the ability to react, to breathe, and to live.

Iris 2 is a unique, sample-based synthesizer combining the power of a sampler, the control of spectral filtering, and the flexibility of a modular synth. In Iris 2, you can modulate anything from pitch to panning to filter cutoff frequency. In the Modulation window, you’ll notice that we have four different types of modulation available to use: LFO, Envelope, Controllers, and Macros.

Let’s dive deeper into the different types of modulation available to us, and how they can help us build a more exciting and evolving sound!



An LFO, or Low Frequency Oscillator, can be a source of continuous and cyclical modulation. Because of this, LFOs are great for adding gradual motion; rhythmic morphing; and timed, cyclical modulation. The Rate, or frequency, of the LFO dictates how long it takes for a cycle to complete. In Iris 2, the Rate of the LFO can range anywhere from .001 Hz, where a sound can evolve over 16 minutes, to 50 Hz, where a sound is moving at audio rate, or can by synced to the tempo of your song for effects with rhythm.

LFOs are commonly used to modulate Filter Cutoff, Panning, and Fine or Coarse pitch, which is how to achieve a vibrato-like sound.



Envelopes can be used for adding motion that will only happen when a note is triggered. These are commonly used for shaping the beginning and end of a sound. Like LFOs, an envelope allows you to change a parameter by a defined amount, over defined periods of time. The four different stages of the Envelopes in Iris 2 are Attack, Decay, Sustain, and Release (ADSR).

The variable parameter of Attack, Decay, and Release are periods of time (in milliseconds), while Sustain is an amount (as a percentage).  The Attack portion of an envelope defines how quickly a parameter reacts to a note trigger.  For example, in a soft, bowed string sound, you might use longer Attack times so the sound builds up slowly, while a snappy kick drum sound would require fast Attack times.  The Decay portion of an envelope defines how quickly a parameter moves to its Sustain value after the Attack.  This means that the Sustain value is the amount that a parameter will hold at while a note is held down.  The Release time determines how long a parameter will take to return to its minimum value after a note has been release.

In Iris 2, you can also adjust the curve or slope of each time parameter to be linear, logarithmic, instantaneous or something in between. Envelopes are most commonly used to modulate Gain (often referred to as the Amplitude Envelope), and filter Cutoff Frequency.



Controller-based modulation in Iris 2 allows you to create motion through MIDI expression controllers like Key Tracking, Velocity, Afterouch, and Mod Wheel, making them a great modulation source for live performance. They are commonly used to modulate filter Cutoff, filter Resonance, and Effect amounts.

Iris 2 also allows you to attach knobs, sliders and buttons on your MIDI Controller to nearly any parameter using the MIDI Assign function. This allows you to create motion in real-time, reacting to the music and the audience be it at a live show or in the studio.



Macros enable you to easily modulate multiple parameters with a single MIDI controller knob or fader. Because of this, Macros make it easy to add large, sweeping changes to your sound, and perform these changes live either in a performance or in the studio. All presets in Iris 2 have a pre-built Macro bank for quick, easy modulation and customization.

Iris 2 makes it easy to add excitement and motion to your sounds with flexible modulation sources, hundreds of destinations, and infinite possibilities. For a simple, step-by-step video guide to learning Iris 2, check out our 20-Minute Manual series of tutorials.  For a more in-depth look at modulation and synthesis, check out this series of articles in Sound-on-Sound Magazine.

Try Iris 2 for yourself—download the free, 10-day trial today.

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