Circle Tutorial 1 - Creating a Classic Brass Sound

What is Covered?
A starter level tutorial, introducing how to create a the classic brass sound.
Connecting modulation, subtract synthesis techniques and basic operation of Circle are covered.


Getting into creating your own patches can be pretty daunting if your new to the world of synthesis. Luckily Circle makes the process of learning to build your own sounds as painless as possible. If circles interface is quite new to you and you are building your confidence, it's a good idea to start with some basic sounds. A classic patch thats a good one to try is a basic synthesizer brass sound. This doesn't attempt to recreate an authentic brass section but is more an emulation of early analogue brass patches. This tutorial will lead you through the creation of the patch step by step and should help familiarize you with many of Cirlce's main components.

Step 1 - Initialising Circle

A good starting point is essential when building any patch. Creating a blank patch in Circle is extremely simple, hitting the 'new' button at the top of the instruments interface will immediatley bring up the initialised sound.

Creating a new patch in Circle

The new sound will not be completley empty, some basic settings are in place. A single saw wave oscillator and some simple envelope settings enable a sound to be played back. This is strictly a test patch, so there is no danger of you being distracted by complex modulations and effects.

Your new initialised patch

Initial patch

Step 2 - Choosing your oscillators

With your patch zeroed and ready to go we can start creating the basic building blocks for our patch. When using Circle pretty much any sound is generated by the oscillators. This is the case with most subtractive synthesisers and choosing your oscillators is usually the first step in building your patch.

Circle's oscillator section

Circle has four main oscillator slots and additional noise and feedback oscillators, that we'll look at in later tutorials. For now we are going to activate two square wave oscillators as these are traditionally used in synth brass patches. The reason for using two oscillators will become apparent in the next step.

Two square wave oscillators acivated

At this point be sure to check all the oscillators are mixed using the individual level controls in the mixer section, this way you will be able to hear both the square waves playing together.

Circles mixer section

Two square waves

Step 3 - De-tuning the oscillators

De-tuning oscillators is generally a good way to add width to a sound. Here I have de-tuned each square wave n the oscillator section a small amount. You can immediately hear a chorus effect adding width to our basic patch, this will be useful for creating the brass effect.

I have also changed the width setting of each oscillator a small amount to further enhance the difference beween each wave.

The de-tuned oscillators

De-tuned square waves

Step 4 - Setting the filter

We are now ready to start shaping the sound using Circle's different components. The first area we'll look at is the filter. We need to roll off some top end here so we will use a low pass filter with a touch of resonance. This will later be automated using an envelope but for now this is the perfect setting.

Initial filter setting

Basic filtering

Step 5 - Using the envelopes.

Circle has two independent envelopes, neither of which are 'hard wired' to any particular destination. This is often not the case in other synths and you are limited to pre determined destinations.

In this patch envelope one is controlling the amplitude / volume (the default setting) and we will use the second to modulate the filter cut off. The first filter is set with just a small amount of attack and release to soften the dynamics a little.

Circles envelopes

To route the second envelope to the filter simply drag the small orange 'circle' from the left of the second envelope area and place it on an empty modulation slot in the filter section. The amount that the envelope effects the filter cut off can then be set by clicking on the orange circle. A pop up fader will appear and negative or positive values can easily be dialled in.

Filter modulation

The filter envelope is fading the cut off in slightly as the sound is played. The effect of both the filters is a very loose approximation of a real brass instrument being played. You can hear that the patch is now starting to take shape and is resembling a synth brass sound.

Filter modulation

Step 6 - LFO pitch modulation

To add some extra interest lets introduce a little vibrato into the sound. We want the vibrato to come in later in the sound after it has played for a short time. To do this we will need to use one of the LFOs (low frequency oscillators) to modulate the pitch of the two square waves.

Creating the pitch modulation is very straight forward and is done in the same way as the filter modulation. Simply drag the small red circle from the first LFO and drop it onto an empty mod slot below the tuning area of each oscillator. If you find that this is a little extreme you can modulate the fine tune control instead.

Routing the LFO to oscillators 1 and 2.

The LFO is then set to a pretty high speed and some fade and delay are added, this will create a smooth fade in of the LFOs vibrato effect. Overall this adds a subtle wobble and makes the sound a little more 'human'.

Circles LFO

Some vibrato is added

Step 6 - Adding some effects

As a final touch I added some subtle reverb to the patch. Circle has a great multi fx processor with a total of three slots. These slots can be programmed to supply any effect you like. I have used the last slot for a room sized reverb patch and have sent a moderate amount of signal to it.

Reverb is applied

The patch is now complete and sounds pretty good. You can see from this short tutorial that basic patches are easily created from scratch in Circle and it is not to difficult to get into creating your own sounds. In future tutorials I will tackle more complex sounds and cover the advanced features of Circle.

The final patch is complete

Some reverb is added

The final patch

Download Tutorial 1 Files

Tutorial 1: Creating a Classic Brass Sound
Download the tutorial in plain text format, the associated audio files and the completed Circle sound/patch.