What is a sonar

Sound Design - How to Make a Cinematic Sonar Sound

by Klaus Baetz,

When you remember movie scenes in which submarines appear, you often associate two sounds with them: a mixture of deep engine hum and the gurgling of water as well as the typical cinematic sonar ping sound. And even if the sound probably has little to do with the real noises that the various sonar devices generate, you know how a sonar should sound like a laser cannon. In this episode of the sound design series, we want to build this classic effect ourselves.

The classic sonar ping sound is actually a curiosity. You don't see him often because submarines are rarely featured in movies or video games. Nevertheless, the effect is inextricably linked with these watercraft, so that many could probably assign the sound blindly. The feeling that the effect triggers is also a mixture of relaxation and tension and therefore very interesting in terms of sound design. It conveys the size and breadth as well as the peace of the ocean. At the same time, he also keeps reminding you that someone or something could be lurking out there. One of my favorite "ping scenes" is, as you might already know from the headline, the Morse code from "Hunt for Red October", in which Sean Connery only ever pings the Morse code from the US submarine with a penetrating ping answers.

The synth ping

Although the ping sound is theoretically just a short impulse with a long reverb tail, it can have a number of different facets and can thus easily be adapted to the prevailing mood. So that we have the greatest possible flexibility here, we assemble our ping from two different components, which I have called “clean ping” and “dirty ping”. For both parts, we need a standard synthesizer of your choice, which actually doesn't have to be able to do much more than generate a sine tone and shape it over the course using an amp envelope. In my case I use Steinberg's Retrologue for this.

In terms of the basic structure, our two synth pings are initially the same. We need a single oscillator that we switch to sine wave and also tune up an octave. Then we turn to the amp envelope, which we set to the following values ​​for the clean ping: Attack 9 ms, Decay 210 ms, Sustain 0% and Release 30 ms. With dirty ping, attack and decay times are shorter, namely 0 ms and 60 ms. Thus our clean ping sounds a little longer and softer, while the dirty attack has the crisper attack.

We then route both synth signals to a common group and initially mute the dirty ping. We also generate a one-bar MIDI event per synthesizer and play the note B3.

The ocean group

We first insert a reverb into our newly created group, this will simulate our ocean. To put it simply: we need a “damn big” room. Typical cathedral presets serve as a good orientation. A soft and diffuse sound is important for the ocean; we want to hear as little individual reflections as possible. A value of 50% is recommended as a mix or dry / wet starting point.

Our next effect in the ocean group is an EQ, which we mainly use for technical EQing. First of all, we use it to clear the deep bass range of any rubbish. Then we activate a high shelf band with which we can later lower the highs according to taste. A good starting frequency is 4-5 kHz.

The last step for the ocean group is the grinding in of a compressor. This should help us to make the transition from ping to reverb tail even smoother and rounder. For this we choose a low ratio of 2: 1, an attack time of 9 ms, we set the release to approx. 110 ms, and we adjust the threshold so that we get approx. 6 dB gain reduction. These are good starting values ​​to adapt the whole thing to your personal taste. The choice of the attack time now largely determines how strongly the actual ping is emphasized.

Dirty ping

Let's now turn to the second main component of our sound. The dirty ping should be that part of the signal that can add tension and angularity to the overall picture. To do this, we first give the simple sine sound a metallic or hard-sounding, highly reflective space, as if the sound stimulates the entire submarine to vibrate. The reverberation time should not be chosen too long, because the actual reverberation flag is taken over by our ocean group. The mix or dry / wet portion is also set to 100% wet, so we only receive the reverberated ping as another useful signal.

Then we feed the signal into a multiband distortion, of which we only need one frequency band. We limit this frequency band to the range from approx. 300 Hz to approx. 1.5 kHz and - should we have the opportunity and be able to decide between different types of distortion - choose a rather aggressive variant. In my case I took the Steinberg Quadra-Fuzz 2 again, selected the distortion algorithm simply called “Dist” and turned the drive potentiometer to half past one.

If you want to add additional details to the signal, the following tips are recommended. In addition to the oscillator, simply activate the synthesizer's noise generator and add a little white or pink noise. This creates a slightly metallic component and can also underline the “submarine feeling”.

In order to give the sonar a little more body or pressure, a second oscillator can also be activated during dirty ping. This is also set to a sine wave, but the pitch is adjusted so that the additional oscillator plays three octaves lower than the actual ping. This signal component can hardly be identified as an audible tone, but more as a kind of impact.

Fine tuning

In principle, our sound is done with that, and the actual fine-tuning now only consists of the interaction of the individual components or their mixing ratio. The room and compressor can then be adjusted again, and we shouldn't forget the high shelf band of our EQ to round off the highs of the signal and not make it sound too harsh. Our sonar ping is done. Have fun experimenting!



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