Waves Audio C4 Multiband Compressor User Guide

Table of Contents

Chapter 1 ........................................... Introduction .... 2

Chapter 2 .............................................. Quick Start .... 4

Chapter 3 ............................ Controls and Interface .... 6

Chapter 4 ................ Range and Threshold Concept .. 17

Chapter 5 ....................................... Examples of use .. 22

Chapter 6 ................................. Preset Descriptions . . 27

Chapter 7 ............. Essential Concepts (and history) .. 34

C4 Plug-In Manual

Chapter 1 — Introduction

Thank you for buying Waves C4! When used in TDM, the C4 is a 48bit double-precision processor, dithered to 24bits before handoff to the TDM bus. It requires a full Mix chip; we used every bit of power we could to create the finest multiband for the available power. Native uses are single-precision, to help conserve your CPU power.

You may think of the C4 as a multiband compressor with parametric adjustments, or as a 4-band dynamic equalizer. Both concepts are true, but the interface looks more like an equalizer with a moving line!

Waves’ unique DynamicLine™ display shows the actual gain change as an EQ display. We have taken the gain reduction metering function and merged it with the crossover display for a very intuitive interface.

When used judiciously, a multiband processor can do much more than merely make a mix “louder”. You can think of the C4 as a dynamic equalizer capable of gentle compression, expansion, limiting, and EQ, independantly and simultaneously. For instance, with care, you can de-ess, EQ, and expand in separate bands simultaneously. This is much easier than trying to adjust several split-band compressors (such as the somewhat common usage of de-essers in “non-ess” frequency ranges).

Waves wisely waited until sufficient processing power was available before releasing the C4. To properly create a multiband compressor, a phase-compensated crossover is essential. In addition, the crossover must have a flat frequency response when set to nominal values. The C4 has exactly such a crossover. However, many multiband devices may not have this type of crossover, and the resulting colorations have unfortunately been accepted as part of the multiband “sound”, which is completely unnecessary and generally undesirable.

Why is such a crossover so important? To avoid any undesirable coloration to the sound and to eliminate artifacts and pitch-shifting effects between bands as their gains move independantly. Any change to a signal can be considered a distortion (some much more pleasant than others), so it is a

desirable type of change we want, not uncontrollable,

“part-of-the-design” ones.

C4 Plug-In Manual

Waves C4 Multiband Parametric Processor is designed for ease of adjustment and a clear, uncolored sound, while still allowing extreme ranges of control when required. To that point, this “multiband dynamic equalizer” has parametric controls, in that you can change the crossover points (bandwidth), gain (both fixed-output and dynamic), and frequency range of each band, as well as the dynamic range and response controls.

The user interface and compressors in the C4 are designed to help you enhance a good mix. Poor mixes are better to be re-done, although the reality of daily production often makes a remix impossible, so the C4 can be used to “fix” these less-than-desirable mixes, to an extent. In the compressors you can actually limit the amount of gain reduction or expansion in each band. And the innovative graphic user interface gives you a precise feedback of what is going on.

C4 Plug-In Manual

Chapter 2 — Quickstart

The basic overview

Individual band controls

RANGE

Sets the maximum gain change for a band. If set to a negative value (–10), the band is a compressor; positive values

ANGE

(6) make the band into an upward or downward expander. If R dynamic action (therefore, can be used as an EQ). Range sets both the ratio and the maximum gain change. You

ANGE

may have noticed there is no Ratio control! Instead, the R

control serves as both a type of ratio control and a way to also control the maximum gain reduction in each band. To achieve higher ratios, simply increase the R value, and possibly lower the T

HRESHOLD

, if required. Increasing the K

the knee.

is set to zero, then the band will have no

NEE

to higher values also increases the ratio at

ANGE

Gain

This is the output level for a band (also called “makeup gain”); you can also think of this as an “EQ” gain control. If there is no dynamic change in the band, then this control simply boosts or cuts the band; if dynamic processing does occur, this is the “fixed level” that the band’s gain will return to when that band is not compressing or expanding.

Attack and Release

These work just as in any other compressor, controlling how quickly the dynamic process reacts to a signal (how fast

ELEASE

it acts at the start, and how quickly it “lets go”). The R

time utilizes Waves ARC auto-release technology first

developed for the Renaissance Compressor.

Threshold

This is also the same as in classic compressors, and controls the point at which a band is responding to signal level. In the C4, the Threshold will be the center of the R

value, that is, if R

ANGE

is –8dB, then the Threshold marks the

ANGE

–4dB gain reduction point (you’ll have 4dB of Gain Reduction if the signal is equal to the Threshold). This results in the standard behavior for a soft-knee compressor: you will observe compression or expansion below the threshold value.

C4 Plug-In Manual

Global controls

Just to the right of the 4 bands are 7 Master controls; for example, the master Threshold will adjust all 4 Thresholds simultaneously. The Behavior control affects the release behavior (Electro or Opto). The other Master controls work in a similar way. All have extensive descriptions in Chapter 3 — Examples of Use, and Chapter 4 — Controls and Interface, with examples and suggestions for optimum sound.

Basic multiband operation

• Load the “Basic multi” preset from the Waves Load menu (right corner).

• Play some audio. If the yellow line is not moving, drag the Master Threshold down until it is responding and you can hear the processing.

• Adjust each Threshold so that each band is responding reasonably, not too much or too little (just listen!).

• Adjust the M

ASTER GAIN

until the average position of the yellow line is around the center horizontal line. Set the compressor so that when you toggle the main Bypass button at the top edge of the window, the level is about he same in and out of bypass. Ignore any tonal imbalance, just aim for average level to be the same as in

AIN

Bypass.Finally, adjust each band’s G

so that the overall tonal balance is to taste. Since high frequencies will

compress and release faster, often the result is that as more multiband compression is applied, (say, by adjusting

ASTER THRESHOLD

) the signal becomes progressively brighter on average. You can simply lower the Gain for

the high band(s) to compensate for this.

ANGE

• For more compression, set the R

• For “tighter” sound, adjust the Q to a higher setting, or, the A

NEE

to higher values.

value lower.

TTACK

and R

ELEASE

controls to faster values, or the

• Read the rest of this manual; there are many tips that can help you optimize your sound.

C4 Plug-In Manual

Chapter 3 — Controls and Interface

Main display area

DynamicLine™ Graph Instead of individual gain reduction meters, which provide a limited amount of information, we felt that showing the basic function of a multiband processor must include the gain change in each band plus the “resultant EQ” by the settings of the crossover. Therefore we combined them into a new interface display.

If you have a crossover and set the output gains differently in each band, you have a 4-band EQ, in a manner of thinking. Putting compressors into each band makes it a dynamic EQ. Therefore, the graph shows a large amount of information:

• 3 crossover points (draggable)

• crossover slope (global)

• DynamicLine™ animated EQ curve (yellow line)

• maximum change in dynamic Range (the purple area)

• fixed gain (the brighter edge of the purple range)

• frequency center points (draggable)

• effective gain change (by comparing moving line to scaling on left edge)

This is a lot of information in a single display, but you’ll find it very intuitive after just a short time of using it.

Due to the complex nature of the possibilities of this processor, it’s best to give a complete example so that the list above is clearly understood.

C4 Plug-In Manual

Display example

Let’s suppose that you only want to do compression, just as shown in the screenshot below, so we’ll refer to the settings shown there (what is shown is the “Low-level Enhancer” preset with audio passing through the C4).

• The crossover points are shown by dotted straight lines and markers on the lower edge; the slopes can be seen as shown by the dotted gray curves.

• The yellow line is both the “resultant EQ” and the gain metering at the same time.

ANGE

• The R have an expander).

• Fixed range.

• Band center points are shown by 4 markers.

• Gain metering is shown by the moving line, and by observing the scale on the display’s left edge, a general idea of how much gain reduction (or increase) is achieved in each band.

controls the maximum gain change (if Range is negative, you have a compressor, if positive, you

GAIN

is the “output gain” of each compressor band is shown by the lighter purple edge of the purple

In this example about the display:

ANGE

is set to negative values, which means that the dynamic gain change for each band ranges downward (a reduction) from the fixed gain edge. Dynamic gain reduction is compression (!), no question about that. The purple area represents the R

within which the processor can change gain dynamically. If the R

ANGE

was set to

ANGE

a positive value, that band would be an upward expander, and then the purple range will extend above the fixed gain line. The Expander function can be used for distinctive and innovative low-level processing, which is covered in more detail in Chapter 4 - Range and Threshold Concept and Chapter 5 - Examples of Use. Multiband low-level expanders are quite amazing and good tools to have.

C4 Plug-In Manual

As you can see, G purple shading is the G

AIN

is set to different positive values for each band. In the previous graphic, the colored edge of the

AIN

line. If you are familiar with the Waves C1 compressor, just think of the C4 as a group of C1 compressors all in split mode. You compress the bass or some other band, then set the “makeup gain” for the level you want the compressed band to have.

ANGE

The purple area shows the R

AIN

to the band’s fixed G

, and is relative to it. The G

of possible dynamic gain changes in each band. This dynamic gain is in addition

AIN

value is always shown as the lighter-colored edge of the purple

range.

Simply put, G principle you should keep in mind is that R

ANGE

the wanted gain change below and above the

In this example, the T

AIN

is always the highlighted edge of the purple band, and R

AIN

always takes place when the signal is well below the T

offsets it when the signal is well above the T

HRESHOLD

and other controls are set for the desired sound and do not affect the display or

HRESHOLD

ANGE

offsets it to the other edge. Another

HRESHOLD

, and

. Keeping this in mind will help you to setup the C4 for

graph in any way (except for the speed of the graph which is affected by attack and release times).

Crossover points

Along the lower edge of the graphic display are 3 crossover point markers. These can be dragged to adjust the crossovers, or a numerical value can be typed into the control just below each marker.

C4 Plug-In Manual

Just to the right of the numerical crossover controls is the Q control, which adjusts the slope of the crossover filters. All 4 bands are affected at the same time. The slopes are visible as dotted curves in the main window.

Q ranges from 0.10 to 0.75. Higher values mean steeper slopes, which give sharper divisions between the bands. This doesn’t mean steeper slopes are better, otherwise there would be no reason to allow control at all. To achieve more intense processing (greater compression, smaller peak-to-RMS ratios, etc.), steeper slopes can offer significant benefit. To achieve more gentle processing and more inter-connected processing, lighter slopes will be more appropriate.

• Q = 0.1 => -6dB per octave slope, gentle separation

• Q = 0.6 => -12dB per octave slope (default, and recommended)

• Q = 0.7 => -18dB per octave slope

• Q = 0.75 => -24dB per octave slope

Band center markers

Above the yellow line are 4 colored markers representing each band, which are quite powerful. Dragging any marker can change 3 values simultaneously. Dragging horizontally will change the frequency center of a band (by changing the crossover point related to that band). Note that changing the center of a band will also change the adjacent band.

AIN

If you drag the marker vertically, will change the G

ANGE

key changes the R

. You can lock into one direction by pressing and holding the Command key (Mac only)

for that band. Vertical dragging while holding the Option/Alt

during any dragging operation, which will help you avoid changing the other direction’s values, i.e., Commanddragging horizontally will not change the Gain value. (See other power-user tips in the WaveSystem manual; there are many).

Summary of Band marker controls:

• Horizontal drag = Frequency center

• Vertical drag = Gain

• Option/Alt-vertical drag = Range

• Command-drag = lock into first direction moved (Mac only)

C4 Plug-In Manual

Band controls

Each band has 7 controls.

Solo

At the top left corner of each band is the S

OLO

button, which allows you to listen to just that band, with processing (post-compressor). The display also shows what you are actually hearing, so if you solo 2 bands, the display will show 2 bands with the dynamic yellow line and purple ranges, as seen below.

Bypass

Just to the right of the Solo button is the Bypass control, which returns the entire band to a unity gain status with no dynamic processing at all. The Gain control value is ignored. Therefore, if you want to simply have no dynamic processing at all id‚œ band, but still wish to have control of the Gain, don’t use the Bypass control. Instead, set the Range to zero and then use the Gain control as a fixed makeup gain control (which you can think of as a 1-band EQ).

C4 Plug-In Manual

1010

Threshold

This determines the point around which the dynamic gain changes will take place; in other words the center point of the R

ANGE

control. This control can be changed by vertically dragging the triangle beside the orange energy meter. Each meter shows the actual level in that band (so if the band is very low, high, or narrow, the level in that band will be low, most likely). It makes it very easy to set a Threshold; merely drag the triangle down until it is within the range of motion of the orange meter. The value of the Threshold is displayed at the top of the meter. You can also type a value into this display, or drag directly on it, as described in the WaveSystem manual. Note that only the first band is labeled with “Thrsh”. No reason to clutter such a nice user interface, eh?

Gain

You can think of this control as the makeup gain for each band (or as an offset gain). In the Waves C1 compressor, it is simply called Makeup. On many compressors, like the C4, it is called Gain, and is the output control of that band, whether it is set to be a compressor or an expander. Just set the dynamic behavior (say, light compression) for a band, then set the Gain control to the desired level.

It helps to remember that Gain takes place when the signal level is well below the Threshold — that is what we term low-level Gain.

C4 Plug-In Manual

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