Max Easy Pieces – Episode #2: Boiler

Here is the second episode of the “Easy Pieces for Max” series.

The characteristics of these pieces are explained in the first post of the series.

This time I have prepared a procedural sound design example, i.e. a simulation of a real-world sound created with synthesis techniques (and not by merely sampling it). Btw there is a great book on procedural sound design, written for Pure Data: Designing Sound by Andy Farnell (MIT Press), highly recommended.

Since it has to be realized with a minimal set of objects (it’s an “easy piece” after all) it isn’t certainly a spectacular algorithm of procedural sound design, but it is nevertheless an interesting example of what you can do with a bunch of max objects.

It is a “boiler simulator” that tries to recreate the sound of a boiling liquid.

First of all let’s take a look at the video of the patch coding:

Here is how it works: a white noise is sent to a state-variable filter [svf~] object that has a cutoff frequency of 25 Hz. The [svf~] object has an interesting feature: it is actually four filters in one. Each outlet has a different filtering effect: the first (leftmost) output is a low-pass filter, the second one is a high-pass, the third a band-pass and the last is a notch filter.

The white noise is low-pass filtered and becomes a random waveform with maximum spectral energy around 25 Hz and low amplitude (about 0.1). The signal is then multiplied by 10000 so that it oscillates between 1000 and -1000, and it is used to modulate the frequency of an oscillator: this modulation produces the “bubble” sound.

Furthermore the band-pass outlet of [svf~] is slightly smoothed with the first order low-pass filter [onepole~] and used to modulate the [cycle~] phase to add a noisy component (let’s say it’s the noise produced by the flame and the water steam).

To make a stereo sound and give it more depth, I duplicated the [cycle~] object and added a [delay~] to the modulating signal of the left one. Note also that the delay time is modified by the modulating signal itself: the relationship between the two oscillators is therefore continually varied.

I polished the patch a bit and added a few presets; here is the video of the presets:

You can recreate the patch yourself following the videos, or you can download it by subscribing to the Virtual Sound Newsletter (see below) to have access to the special Bonus Page reserved for subscribers only.

If you seriously want to learn Max you can check out our book series Electronic Music and Sound Design, you will learn a lot of synthesis and audio processing techniques and have fun with Max!

And don’t forget to subscribe to the Virtual Sound Newsletter.

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