Sound Modifier

Before using this modifier for the first time please read the section 'Using the Sound Modifier' below.

Note: this modifier doesn't actually play the sound file! This is due to the way Cinema 4D implements sound playback. To play the sound you must add a sound track to the timeline window; full details are contained in the C4D reference documentation.

Interface

This modifier has the following tabs and sections:

Object tab
General quicktab
Control quicktab
Map Sound tab

For the 'Groups Affected' and 'Falloff' tabs, and for the buttons at the bottom of the interface, please see the 'Common interface elements' page.

Important: for particle groups, please see the note 'Limitation with particle groups' at the end of this page.

Parameters

Object tab

General quicktab

Enabled

Uncheck this switch to disable the modifier.

Mode

Independent [default setting]

In this mode, the modifier will work in the same way as a standard Cinema 4D particle modifier: particles will be affected if they come into the field of effect of the modifier. X-Particle Actions have no effect on the modifier in this mode.

Action-Controlled

In this mode, the modifier will only act on a particle when told to do so by an Action. Until that point, the particle will not be affected, but once activated for a particular particle, the modifier will continue to influence it as long as it is in the field of effect of the modifier. The modifier's effect on a particle can be halted by means of another Action, if desired.

Important: this modifier can affect particle emission and also change particles during the animation. Activating this modifier to work on a specific particle will only have an effect if 'Birth Only' in the mapping tab is unchecked.

Sound

The sound file to use. Click the button with three dots to load a sound file, which must be in .wav format.

Timing section

This section controls the mapping of the sound file time onto the particles.

Note: the controls in this section do NOT affect the actual audio playing of the sound file. Remember that this modifier does not generate an audible sound, Cinema controls this separately. If you want the sound to loop in the same way as the modifier, you will have to set this up manually.

Auto

If this switch is checked, the modifier uses the sound in time with the scene timeline. 'Auto' must be unchecked for the following settings to become available.

Start, End

These are time values which control when on the scene timeline the audio is mapped to the particles. For example, if 'Start' is zero and 'End' is three seconds, the audio file will play for three seconds and then stop. (This is influenced by the 'Retiming' value, see below.)

Retiming

This enables the audio's timing to be changed. For example, suppose 'Start' is zero and 'End' is three seconds. With 'Retiming' at the default value of 1, the audio file will play for three seconds and then stop. You can see that the cyan bar in the graph stops at a specific point. if 'Retiming' is increased to 2, the audio file will still only play for three seconds, but it will play twice as fast, as you can see from the position of the cyan bar.

Repeat

Checking this switch will loop the sound file. So if you have set the 'Start' to zero and the 'End' to three seconds, the sound file will run for three seconds then loop back to the beginning.

Color

Graph

The graph is a representation of the complete sound file. It is a graph of frequency intensity (on the vertical or Y axis) over time (on the horizontal or X axis). The frequency ranges from the minimum frequency at the bottom (i.e. bass frequencies) to the maximum frequency at the top. This range (minimum to maximum) can be changed by adjusting the 'Freq Min' and 'Freq Max' settings (see below).

The cyan vertical line on the graph is the current time in the sound file.

Color

This is the color gradient used for the graph. It is only used for the graph colour, so you can change it to anything you like without affecting the output. The colour used depends on the intensity (amplitude) of each frequency, low amplitudes using the colour on the left of the gradient and high amplitudes the colours to the right.

Frequency section

This section controls how the frequencies in the sound are analysed. It uses a process called Fast Fourier Transform (FFT) to do this; this is a complex subject but you don't need to know how it works to use this modifier! If you are interested much more detail can be found on the net, for example see https://en.wikipedia.org/wiki/Fast_Fourier_transform

FFT Resolution

This controls how many discrete chunks (FFT bins) the frequency range is split into. Lower values give a coarser result. For example, the above screenshot shows the graph with an FFT resolution of 8. If that is reduced to 3, this is the result:

You can see that the lower resolution has resulted in a much smaller number of FFT bins. This will affect the degree of control the modifier can exert over the particles.

Be careful when increasing this value. If you increase it too much the time taken for the calculation will increase greatly and it may even appear that Cinema has frozen. If that happens, wait until the calculation finishes and reduce this value.

However, if you have a very narrow frequency range (as determined by the 'Freq Min' and 'Freq Max' settings) you will need to increase the FFT resolution otherwise it will not have sufficient frequency resolution. However, increasing the frequency resolution reduces the time resolution so you end up with a slower calculation (needs a bigger chunk of the sound) and changes in the audio over time become smeared together.

dB Range

The audio intensity is converted into decibels (dB). Reducing this value will start to remove low-amplitude sound and you will see the colours in the graph move towards the left hand side of the gradient. Lower it too much and the frequency graph may become almost black (with the default colours) and the modifier will have little or no effect. If you increase this value, more low amplitude sound is used and the effect is greater.

Freq Min, Freq Max

These values control the frequency range used. Increasing 'Freq Min' will cut out lower frequencies, increasing 'Freq Max' will bring in higher ones. Whether you need to change these values will depend on the nature of the sound file. However, note that these values are used after the FFT has been applied, so if the range is narrow you may need to increase the FFT resolution, as explained above.

Control quicktab

Amplitude

This spline control enables you to map the amplitude values returned from the FFT. You can think of it as acting like an audio filter. For example, this spline would ignore the effect of any low volume sound:

EQ

This is the same as the 'Amplitude' spline but for frequencies rather than amplitude. This spline would boost the effect of bass frequencies and ignore any higher ones:

Map Sound tab

This tab is initially empty, but you can map various particle data items to the sound parameters. Click the 'Add' button to add a map. This interface is then shown:

This is the default map, but most others use a spline to control the mapping rather than a gradient, such as the Speed map:

Add

Click this button to add a map.