Circle Tutorial 8 - How To Create An Evolving Ambient Pad Sound

What is Covered?
An intermediate to advanced level tutorial on creating an evolving ambient pad sound
Introduces the design of sounds for ambience, that evolved and change over time.


All the patches we have created so far have explored the majority of basic functions within Circle. We have also started to explore more complex features of the synth such as multiple modulations, modulated effects processing and the use of the built in sequencer.

The rest of the sounds in this tutorial series will concentrate on using all the techniques demonstrated so far to create more complex sounds. These new patches should satisfy the more advanced user but even the less experienced synthesist can join in thanks to Circle's clear, intuitive interface.

Step 1 - Choosing the oscillators

This patch uses all of Circle's six available oscillator slots. Of course not every sound calls for this many sound sources to be activated at once but in this case I wanted to create a harmonically rich sound and using multiple oscillators really helped me achieve this.

The majority of this patch is made up of Circle's excellent wavetable oscillators. Each wavetable sound source is capable of containing two wavetable selections. You can then fade between these two oscillators in real time or even automate this movement with up to 3 modulation sources.

This unique set up means that Circle is capable of producing 6 wavetable oscillators at once. This is pretty impressive stuff and can result in some very interesting and original patches. In this case you can see I have used a varied selection of wavetables. There are a lot to choose from, so trial and error really is the best approach here.

The multiple oscillators

The method I used for picking the appropriate sound sources here was to simply keep mixing different oscillators until the sound started to take shape. I continually moved between the oscillator section and the mixer section to strike the correct balance.

Once my relative levels were correct I concentrated on the tunings, slightly de-tuning some of the oscillators and transposing the final wavetable up by 24 semi-tones.

The mixer section

The last two oscillators are really present to add effects to the sound and a further harmonic richness. Both the noise and feedback oscillators are mixed pretty low in comparison the main wavetables and these will also be heavily later in the patch creation process.

The wavetable, noise and feedback oscillators.

Step 2 - The amp envelope.

The next thing to set up is the main amplitude envelope and as this is a pad sound we are looking for something with a soft dynamic signature. This means we need to use both slow attack and release times. Even this simple adjustment makes a huge difference to the sound and moves it ever closer to becoming an authentic pad.

The main amp envelope.

This envelope is also used to effect the actual level of the noise oscillator in the mixer section. This gives this sound source and extra boost as the sound fades in.

The noise oscillator modulated by the amp envelope.

The patch with amp envelope modulation.

Step 3 - Setting up the filter and secondary envelope.

The next step is to get some filtering in place. As in the previous tutorials I have just gone with a straight forward low pass model. Examples of Circle's other filter models and their uses will come in later tutorials. The low pass filter has had a fair amount of resonance added to introduce some extra harmonics.

The resonant low pass filter.

A filter envelope with a pretty similar signature to the amp envelope is then set up and applied to the cut off frequency of our filter. One difference here is that the decay drops slowly after the initial attack of the sound, causing the cut off frequency to fade off as the sound progresses.

The filter envelope.

Another multiple modulation has been used at this point, the pitch of one of the wavetable oscillators has been slightly modulated with the filter envelope. This create a subtle, ghostly bend in the sound, which is ideal for this type of patch.

Modulating pitch with an envelope.

Modulated filter

Step 4 - Setting up the LFOs and sequencer.

The real key to making this pad sound 'evolve' is the use of two LFOs and a step sequencer. These modulation sources are all used in combination with each other and modulate several sources to introduce a dynamic and organic feel to our sound.

The first LFO is a pretty standard sine wave oscillator moving at an average rate, with no fades or delay. The speed of this LFO is then modulated over time by patching it to the initial 'amp' envelope.

The second LFO is a little more complex and mixes a sine wave and a step curve to create a custom waveform. The whole LFO is delayed and also has a pretty long fade programmed, so it will only take effect as the sound opens up. The speed is also modulated by our first LFO.

The last modulator is a step sequencer and this is purely used to introduce some random elements into our sound. The random button has been used to create a non uniform effect and the smoothing feature has been used to ensure clear 'steps' between the values are minimised. This is then patched to the resonance and the level of LFO 2.

LFO's and sequencer set up

Step 5 - Setting up modulations

Now our modulators are in place we can route them to various destinations. LFO 1 is patched to the mix of one of our wavetable oscillators. This creates wave morphing and creates yet more movement, all these small changes make up a sound that changes over time.

LFO creating a wave morphing effect.

The second LFO is then patched to the cut off frequency of the low pass filter. As this LFO is also being modulated by other sources the effect is has on the filter is not only delayed but ever changing and much more interesting to listen to than a standard LFO setting.

Filter modulated by LFO 2 and the sequencer..

This patch demonstrates how using modulators to modify more unusual parameters and using the different LFo waveforms can bring about very interesting results. Next we'll look at some slightly more complex instrument and fx patches.

Modulated filter

Step 6 - Effects and settings

For a finishing touch I have added some pretty heavy effects to the patch. A large reverb and intense delay add a huge amount of space, giving us the ambient feel we are after and these effects really compliment the sound.

Reverb and delay effects

It's worth mentioning that I also increased the overall polyphony for this patch. With a sound that has a large amount of release it is worth doing this so that no notes are stolen or remain un played. I raised it to the maximum value of 32 notes which should be enough for a pret ty demanding pad pattern.

Voice mode changed.

Final patch overview

Final patch with effects

Download Tutorial 8 Files

Tutorial 8:How To Create An Evolving Ambient Pad Sound
Download the tutorial in plain text format, the associated audio files and the completed Circle sound/patch.