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Electronic Help File

Contents

Welcome to the Renaissance Equalizer electronic help file.

REQ is a 6-band audiophile quality equalizer for professional audio production. It offers the choice of 6, 4, or 2-band operation for optimum use of processing-power. Stereo, dual-mono, and mono modes are part of the EQ, although not necessarily available on all platforms.

The following electronic help file explains how to use the Renaissance Equalizer.

Renaissance Equalizer Graphic Interface


Contents

What is a software plug-in?

Waves preset system - Load, Save, Delete

Waves Interface Controls

Quick Start

Filters

Controls

Factory Presets

FAQs


What is a software plug-in

A Plug-In is a software add-on that gives enhanced capabilities to the host software with which it is being used. Think of it as a software accessory. Plug-Ins do not function as stand-alone applications, they must always be accessed from within the host software. Once the Plug-In has been installed, it may be called up directly via the appropriate menu in the host application.


Waves Presets System - Load/Save/Delete

Factory Presets- These are permanent presets in the Load popup menu, created by Waves. They can not be changed or deleted.

User Presets- You can make the current settings of the plug-in become a preset in your Load menu. Users presets can be changed and deleted.

Setup Files- Setup files may hold more than one setup. When you open a Setup file, all setups inside it become part of your Load popup menu for fast access.

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Preset Load/Save

Use the Load/Save system to control the presets.

To use the Load or Save button, click and hold to see a popup menu for each.

Three options may be available; if a choice is not appropriate or available, it will be gray.

The first option is the "Load from file...". Select it to open your own Setup file.

The second option includes the Factory Presets.

The third option includes current open User Setup(s)

Example

Select the 'Load From File...' option, then navigate into one of your own Setup Library; Click once on the Setup Library .pst file to see all contained presets in "Preset Name" window Double click the setup file to open it, or highlight it and click the Open button. The first setup will be loaded. The first setup in any file you open will be loaded automatically (whether the file has one or many setups). This makes the files backward-compatible with previous versions of Waves plug-ins. Click the Load button again. In the right side of the menu you will see all the setups that are contained in the selected setup Library.

Saving Setups

Click and hold on the Save button. Three options may be available; if a choice is not appropriate or available, it will be gray.

The first menu item will lets you start a new Setup file. There are two prompts, first for the Setup filename, then for the setup name. This is the one major change to the saving of a new setup file, requiring two prompts for a name. If you are going to save only one setup in each Setup file, you don't have to name the setup; click OK to complete the save.

The second menu item will save the current settings into the loaded setup. This item has the name of the Setup file, followed by the name of the setup itself, all on one line.

Third on the menu will save the current settings as a new setup into the Setup file that is open. (If one is not open, the option is gray.) You will be prompted to give this setup a name.

Example:

We will assume you have "bob's song setups file" open. Select the "More bass" Please note that you can not save changes to the files of the Setup Library (they are read-only). Make some changes to the settings, if you wish, then click on the Save button. The second menu item can be selected to make the current settings become a User Preset. You can select this if you wish. The third menu item is available if you want to start a new Setup file of your own with the changes you made.

Deleting Setups

You can delete a User Preset, or a setup that is in a Setup file. Factory Presets and Setup Library files can not be deleted or written to.

Click on the Load button and select "Load from File" Navigate to the setup library which contains the preset to delete Highlight the preset to delete in the "Preset Name" window Click on the Delete button.


Waves Interface Controls

All the Waves Plug-Ins share the same interface philosophy, and most of the controls operations will be familiar to those with Windows experience. For example, selecting multiple objects (where relevant) may be achieved by clicking on multiple items while holding down the Shift key, or by dragging a rectangle with the mouse.

Plug-ins Dialog box

Activating a Waves' plug-in will pop-up a dialog box. This dialog box is divided in two parts :

a "shell" part that is common to all plug-ins, and a process box.

The shell part

The shell part allows you to:

- Undo the last action,

- switch between 2 memorized setups ("SetupA" and "SetupB")

- copy setups from "SetupA" to "SetupB" or vice versa,

- load a setup from within the factory list,

- reset the plug-in,

- access the Help file,

- show the About Box.

The control part

The Waves plug-in controls can be in one of three states:

1 -	Not Selected: no changes can be made to a control unless it is selected

2 -	Selected: the control responds to mouse control only and not keyboard entry. (If the control is a button, it will be depressed, and a marker or a slider will be highlighted).

3 -	Selected and Active: the control response to both mouse and keyboard entry and an outline frame is visible around the :"Selected" control.Normally, a control is either "Not Selected" or "Selected and Active". To make a control Selected and Active, simply click it with the mouse, or navigate to it using TAB; any previously active control will be deactivated.When multiple controls are selected, only one of them will also be Active, generally the first one selected. Within a group of selected controls, you can Activate a specific control by clicking on it. If a "Toggle" control, such as an on/off button, is the Active control, pressing Enter or Return will cause it to toggle in the same way as would clicking it with the mouse.

Numeric entry

Keyboard or keypad numeric entry applies only to Active controls. Some controls cannot be Active, since they are not valid for keyboard entry.To change a numeric entry, type in a new value;  - sign is accepted where appropriate. Once you have initiated a keyboard entry, it must be completed before any other action can take place. There are three ways to complete a Numeric entry:

1 -	Enter confirms the entry, and returns to normal operation. Clicking anywhere else in the Plug-In window will do the same

2 -	TAB (with or without Option/Shift keys) to accept the entry. The Active status will move to the next valid control (according to the TAB navigation rules - see below).

3 -	Escape key (or Command-period) cancels the entry.

Tab functions

TAB will move the "Selected" status to the next control or Value Window,

Shift-TAB moves through the Value Windows in reverse order.

Return activates toggle functions.

Escape key

Escape key allows you to cancel any move while moving the mouse on some controls.


Quick Start

All buttons, controls, meters, and faders function according to a common set of functions called the WavesSystem.

We highly recommend you read the WavesSystem manual. It is very worthwhile, as Waves offers controls unavailable on other products, such as simultaneous multi-parameter control (use the selection rectangle or shift-click to select a group of controls, then drag on any one of the selected controls to change then all together).

You can drag directly on any button to change its value, click on it and type in a value, or click on it and tweak the value with the arrow keys. You may also drag any marker in the graph directly to change parameters.

The following Quick Start guide begins with the default REQ-settings you see upon opening the 6-band REQ.

1.	Activate the 6-band REQ component. Unlike Q10 Paragraphic Equalizer, REQ activates frequency bands 2 through 6. In 6-band equalizer-mode, the 1st band begins 'off' because it is a low-cut (or high-pass) filter and should only be activated when needed. Activating the 2 and 4-band REQ components activates bands 1 and 6 and 1, 2, 5 and 6 respectively.

2.	Preview the source track (or play audio, depending on your platform). The default settings are designed to be immediately useful for a wide range of applications (see the Factory Setup Notes for explanations of "Gerzon shelves", "Baxandall" etc.). To alter the parameters (frequency, gain and 'Q') of each EQ-band, you can click and drag the band-markers or use the buttons to type-in settings for pinpoint accuracy.

3.	Click and drag any dot (band-marker) in the graph from side to side (i.e. horizontal plane) to change the frequency of that band. Each band has a range from 16 to 21,357 Hz.

4.	'Q' is also adjusted by horizontal movement of the band-marker. Press Alt and drag the appropriate band-marker. 'Q' is the relationship between filter frequency-width and the center-frequency of the filter band. You can read more about 'Q' the 'Controls' chapter.

5.	Click and drag any dot up and down (i.e. vertical plane) to adjust gain (range -18.0 to +18.0dB).

6.	If you want to activate a band-marker, either double-click or drag the mouse on it. Double-click on any band-marker to turn it off.

The Band In/Out and Filter-type buttons can be used to select between filter-curves (e.g. high-pass, low-pass, bell, high-shelf, low-shelf). Click on the Filter-Type button to toggle through the selection, it will change the filter-type corresponding to that button's frequency band. You can also change the filter-type using Alt/double-click on any band-marker. It will toggle through the available filter-types for that band. You can find out which bands have which filter-options on in the next chapter.


Filters

6-bands of EQ and their filters

Each REQ-band is different (unlike the Q10). This optimizes processing-requirements for as many professional users as possible, and for the platforms they use.

Bands 1 and 6 support three filter-types:

1.	cut-filters

2.	resonant shelves

3.	bell-filters

Band 1 supports low cut and shelf filters. Band 6 supports high cut and shelf filters.

Bands 2, 3, 4 and 5 each support two filter-types:

1.	resonant shelves

2.	bell-filters

Bands 2 and 3 support low-shelf filters. Bands 4 and 5 support high-shelf filters.

Bands 1 and 6 are common to all REQ components. If you select the 2-band REQ from your plug-in menu, then both bands adopt the same filter-options as bands 1 and 6 from the 6-band version. The 4-band version adds bands 2 and 5, and finally the 6-band version adds bands 3 and 4.

Default values

Each REQ-component (2, 4, or 6-band) has a different default setup to provide the most useful general setting.

When you plug REQ into your editor, by default you'll see all bands already switched "On", and their corresponding control/filter-type buttons "In", except for the 6-band EQ. The 6-band REQ sets band 1 intentionally "Out" because it is a low cut filter. Since the low cut is the most commonly used cut filter, it was included in the default, but we haven't presumed that you would use it by default!

For complete details of the default setup and the factory presets, see the Factory Presets.

Filters

You may be wondering what "resonant shelves" are. Or maybe you've already been using REQ and are just now interested in finding out just what a Gerzon Shelf or a Baxandall filter really is.

Resonant Shelf Filters

The late Mr. Michael Gerzon proposed the idea of a resonant shelf in a confidential paper to Waves in 1994. Analog filters achieved this type of EQ using multiple filters in a single "band" (and still do), to provide a type of overshoot/dip appearance. Mr. Gerzon defined a way to make this acoustically-desirable behavior into a single filter-type. The presets using these shelves are named in Mr. Gerzon's honor.

The two main differences between these shelves and traditional shelves, such as those in the Q10, are the visibly obvious curves of the shelf (shown below), and the possibility to change the Q of the shelf, which shifts the gradient of the slope. In a way, you can think of these as "parametric shelves".

Curve when Q = 1.41, frequency = 4kHz, high shelf filter-type

With the highest available Q of 1.41, the slope is steepest and the "resonant" parts of the curve are at their extreme. The lowest Q is 0.71, which is very similar to the gentleness of the slopes in the Q10 shelves.  Michael Gerzon suggested that values of Q just less than 1.00 would be pleasing for most applications. The classic Gerzon Shelf Q-setting is 0.99, with low and high shelving at 250Hz and 4kHz respectively. Variations of this shelf are in the factory presets of each REQ component (2, 4, & 6-band).

For more suggested uses of resonant shelves, please explore the setup library and read the Factory Presets chapter at the end of this manual.

Cut filters

These are sometimes called "pass" filters in the USA, in synthesizers, and by design engineers. High-pass filters are the same as low-cut filters, low-pass filters are the same as high-cut filters.

Again, a variable Q value makes these cut filters distinctively different from typical cut filters. Q changes the gradient of the line for values greater than 1.0 and includes a bump in the frequency response allowing the filter to be more musical and pleasing. It does this while still performing the basic operation of a cut filter, i.e. to "clean up" unwanted frequencies outside of a given range.

Initially, it might seem that using a sharp filter would be the best thing to really remove unwanted frequencies. However, if a very sharp brick-wall filter is employed to cut off these frequencies, there is a psychoacoustic effect of making the sound very dull (when using a high-cut filter). By allowing a few of these frequencies to remain, the removal of frequencies is performed and the resulting sound is sweeter and less dull. Please note this situation is not applicable to multimedia or other band-limited requirements such as various digital conversions that require very sharp brick-wall filtering. REQ filters are designed for the most musical and magical results in pro audio.

Bands 1 and 6 are third-order filters (equal to 18dB/octave). When Q = 1.0, then they are indeed 18dB/octave, without the bump, as seen below.

3rd Order Filter Curves, Q = 1.0

In order to show the bump of a higher Q value, which is below the edge of the REQ-graph, here is a screenshot of the Waves PAZ real-time analyzer. It was created by a sine-wave frequency sweep of a high cut filter at 2kHz, with a Q=1.41:

Curve of a High-cut Filter, Q = 1.41

When the value of Q is greater than 1.0, the notch and bump actually make the slope steeper. It is actually steeper than 18dB/octave before the notch and becomes 12dB/octave after the notch. The slope is higher than a 3rd order filter, but still allows some of the higher harmonics to pass through, although greatly reduced.

When Q = 0.81 this implies 12dB/octave

When Q is at its smallest (0.71), the slope is slightly less than a 2nd-order filter, about 10dB/octave, as shown below:

Q = 0.71, A Slope of About 10dB/octave

Bell filters (parametric)

George Massenberg invented the parametric equalizer most people are accustomed to using. They usually have symmetrical response characteristics. However, when we consider vintage or classic equalizers, the principle of asymmetrical response, a rather key point, is missing. Most of these asymmetrical equalizers were not fully parametric. Waves have combined both features in REQ to provide a fully parametric asymmetrical bell filter.

What does symmetrical mean? It means that most equalizers have exactly the same response in the boost or gain of a bell filter, as seen below:

Symmetrical bell filter, engineering Q = 1.0, using Q10

An asymmetrical response is, in a way, the most "natural" thing for an equalizer to do in analog. To put it in other words, for a constant value of Q, a boost and a cut at the same frequency of a bell filter will not have the same shape. Pultec equalizers exhibit this very characteristic, and the bell filters of REQ are modeled using the same algorithm as such classic-filter algorithms. Here is the same setting (engineering Q=1.0) but using REQ:

Asymmetrical bell filter, Q = 1.0 using Renaissance Equalizer


Controls

Band-markers

Simply click and drag any marker in the graph for easy control of frequency and gain. On the left edge of the screen you'll see little arrows near the labels indicating which way to move the mouse. You can have flexible control of each EQ band, or all EQ-bands together with a very small number of clicks and key-presses using the mouse and control keys.

Direction Labels

•	To control Q press the Option key (PC: Alt key) while dragging in the left or right directions.

•	To change the filter type of the band, press the Option key (PC: Alt key) and double-click on the band. Each double-click will toggle to the next filter-type.

•	To turn a band off double-click on the band-marker.

•	To turn a band on, simply drag it, or double-click it.

•	To constrain the band marker to moving in just the X or Y direction, start dragging the mouse in the desired direction and press the Control key (PC: Alt key). If you want to change to the other direction, on the Mac: simply release the key, then press it again, then move the mouse in the preferred direction, on the PC: release the Alt key and mouse, and start again.

Keyboard control

You can control REQ using extensive keyboard-functions. All parameters may be selected, and their values entered directly from the keyboard. TAB-based control is used to navigate through all parameters and Value Windows, and to move from one parameter to another when multiple items are selected.

Multiple Selection

Whether working with the graph or keyboard, one of the most powerful functions is the ability to select and drag multiple controls or band-markers at the same time. If you have created a complex EQ curve, for example, using a high shelf and a small presence boost, you can simply select both band markers and drag on either to change them both together.

Alternatively, you could drag a selection-rectangle around both bands' frequency value windows (or shift-click on bands not beside each other), then simply click and drag on any one of the selected value windows to change all of them together.

Using the Control, Option, and Command keys as described in the previous section, also applies to multiple bands selected in the graph.

The faders, meters, peak numeric meters, and method of changing values are part of the WavesSystem manual. Please refer to that document for such information that is common to all Waves products and only needs to be learned once.

Individual Band Controls

The small controls beneath the frequency curve display are the Value Windows for Gain, Frequency, and Q for each band. At the bottom of each column is the control to switch each band In or Out, and to choose the filter type for that band.

Individual Band Controls

Gain

Gain may be adjusted in the range +18.0 to -18.0dB, in increments of 0.1dB via the Gain Value Windows or by 'dragging' the EQ curve. The frequency response graph shows a range of +/- 18.0dB.

Freq

The Frequency control displays the center frequency for each band when a bell filter is selected. When in cut or shelf modes, the Freq parameter controls the corner frequency of the filter.

The Frequency control values are adjustable in one-sixteenth-tone steps (96 steps per octave), rounded to the closest integer. The left/right arrow keys may be used to step the selected Freq value in one-sixteenth-tone increments.

Q

The Q control displays the Q value, which functions differently for each filter-type.

•	Bell - Q corresponds to the width of the frequency range for that band.

•	Shelf - Q controls the slope of the "side" of the shelf and the resonant dips and peaks.

•	Cut - (bands 1 or 6 only), Q controls the slope of the cut filter (from about 10dB/oct to 18dB/oct), plus controls the "bump" in the slope, as explained in the previous chapter.

In all cases, when Q is a higher value (bigger number) the slopes of all filters are generally steeper; bells are narrower, and cut and shelf filters have steeper slopes.

More about Q

Q is a way of expressing the frequency width of a filter in relation to the center frequency of the filter band. This may be represented by the mathematical relationship: Fc/Fw (center frequency divided by frequency width at the traditional '-3dB point', both in Hertz). For example, a Q of 2.0 at 1,000Hz gives a bandwidth of 500Hz (1000Hz divided by 2).

REQ's Q-value is the traditional "engineering Q" for the bell filters. When used as a negative gain, the filter's asymmetrical property, described in the previous chapter, is actually narrower than an equalizer with symmetrical behavior. Therefore, an REQ bell filter with negative gain sounds sharper. It would be equivalent to a higher Q on a symmetrical bell equalizer, roughly double its initial value.

In-out/Filter-Type

At the bottom of the controls is a row of dual-toggle buttons. Each has two toggles: one to switch each band In or Out, and one to control the Filter-Type. Please recall that not all bands have the same filter types!

Bands 1 and 6 have cuts, bells, and shelves. Bands 2 and 3 have bells and low shelves. Bands 4 and 5 have bells and high shelves.

Click the Filter-Type button to toggle through the available selections for that band. On some platforms, you can option-click the Filter-Type buttons to display a pop-up for direct selection. Not all programs support pop-ups in plug-ins, so the toggle mode is the default method of selecting the filter.

Each filter curve is represented by an icon, shown here from left to right.

In/Out Button and Select Filter-Type Controls (6-band REQ component)

To switch the band In or Out, click the left edge of the control. When the band is In, the control will illuminate with the corresponding color of the band marker.

Here are the In-Out/Type buttons shown here in correlation with each band markers, to show the correlation (electronic documentation is in color):

In/Out and Filter-Type Buttons Corresponding to Band-markers

Trim

One special feature of 48-bit processing is the ability to use some headroom to completely avoid internal clipping. REQ automatically eliminates internal clipping in each band.

This makes input gain controls unnecessary. Only an output gain control is needed, as it is certainly possible to clip the output by boosting the EQ of an already-hot signal. Fortunately, the same headroom allows REQ to calculate exactly how far "over" a signal goes beyond 0dBFS (full-scale digital).

In the center area just above the meters is the Trim button, calibrated in dB. Just below it is the clip light, shown illuminated below; the Trim button indicates a signal 6.2dB above full-scale. The negative value indicates that to avoid clipping, the Output Faders located below the Trim button must be dragged downwards.

Trim Button

The red clip-light indicates clipping. The Trim indicates the output gain should be reduced by 6.2dB to just avoid the clip. Clicking the trim button automatically does this for you.

Should there be headroom, such as in the example below, the value is positive (and the clip light is not illuminated), which shows the faders can be moved upward 6.2dB without any clipping. This is sometimes called "margin" on some processors and recorders and simply shows how close the signal came has come to 0.0dBFS (full-scale digital). Again, clicking the trim button automatically does this for you.

Faders can be moved upward 6.2dB without clipping.

•	To Trim the faders simply click the Trim button once to automatically move the faders by the value shown in the button. As soon as you do this, the Trim readjusts to the new signal levels being played in the track, either showing a negative value for clipping or a positive value for more headroom.

•	To reset the Trim (and the meters) without changing the value of the faders, click anywhere in the meters or between them. If you accidentally click the Trim, click on the Undo button at the top of the plug-in window. Most Macintosh platforms support pressing the z-key (no modifier keys) to Undo the last action.

Link

Using REQ as linked stereo or dual-mono equalizers is easily chosen using the Link button, located below the meters.

Link Button

•	When the Link button is on (showing half yellow and half red), then changes to the equalizer affect both channels simultaneously, in all controls of the EQ (gain, freq, Q, filter-type, band in/out) and in the output gain faders.

•	For individual-channel EQ (or dual-mono) click the Link button to turn it off, then select either the Left or Right button to adjust the corresponding channel.

In the example shown below, Link is off, and the left channel is selected for adjustment. On REQ, the right channel is graphed in red, and the left in yellow.

Link Button 'Off'

Separate (Un-linked) Equalization of L and R (or dual-mono)

Using Linked offsets

It is possible to unlink the channels, set them to different gains (even with different filter-types and Q values), and then to finally re-link them. When you move one, the other channel will track the changes in values, even if you toggle to different filter-types. NOTE: If you type in a new gain value, then the typed gain value will be set on both channels, eliminating any gain offset. If you drag the band-marker or gain value, then the gain offset between the bands will be maintained.

Linking with automation

When using automation in your editing program, the linking button is not automated, nor is its status saved as part of a setup. This allows you to load a setup into only one or the other channel for dual-mono use. There is a downside to this functionality - true dual-mono automation is not currently possible within an unlinked stereo REQ. The automation systems of most editors only control one channel, so any settings you try to save or automate on the other channel will not be written into the automation.

If you have complex EQ that requires fully total-reset automation on each channel (whether dual-mono or L/R mastering), you should use two completely separate mono REQ processors and automate them independently.

Flat

Clicking on the Flat button will switch all bands Out and set the gain values of all bands to 0.0dB. The bands are switched Out in order to ensure a flat response, as cut filters are not affected by the gain value. Output-fader values are not changed by the Flat button, neither are any freq, Q, or filter-type values.


Factory Presets

REQ has three component versions available for selection from the plug-in or processor menu in your application: 2, 4 and 6-band. Since each of these are for slightly different uses and have different functions, the setups are slightly different in each.

Each has a default setup particularly suited to the number of available bands. In addition, there are two alternate setups that you may prefer to start with. They are: classic Baxandall (by the late Peter Baxandall), and Gerzon Shelves (by the late Michael Gerzon).

General notes

Since REQ is more suited to professional applications, including tracking, mixing, mastering, and fine adjustments, the default Q values are wider than some people would expect. In addition, the frequencies are chosen based on real situations, for immediate and practical application.

When you open REQ, all bands are already switched 'In' (except the cut-filter in the default 6-band REQ component) so you can just push the gain up for quick adjustment using just a few clicks.

6-band setups

Default 6-band reset (loaded each time when plug-in is inserted)

Filters:

50Hz cut (variable to 18dB/oct)

92, 351, 2890, 7885Hz bell, Q=0.80

10992Hz High shelf

The cut is neither In nor reset when loaded. Note that the slope of the cut filters can be adjusted from approximately 10dB to 18dB/octave by changing the Q value.

Bell (or parametric) filters are set for reasonable bass, warmth, presence, and high settings. With Q's of 0.8, you could dial the Q's down to 0.3 for very broad tonal adjustments, or to 1.3 for more 'Focusrite' or 'Pultec'-type sound.

Baxandall, lo-mid, warm, presence, hi

Filters:

Baxandall lo and hi (60Hz/0.29Q, ~12kHz/0.34Q)

200, 351, 3292, 7885Hz bell, Q's vary

An alternative mix/master setup with Baxandall filters and a mixed group of bell filters.

In the late 1940's, British audio engineer Peter Baxandall defined the classic "bass and treble" control with the values used in bands 1 and 6. Since the Q's are even wider than other values, the bells have more personality in this setup than bands 1 and 6 in the Default setting for 6-band.

200Hz is quite good for bringing out the "note" of the bass (being around the 2nd harmonic or so). For a gentle warming effect, the 351Hz has a relatively wide Q of 0.60.  The sharper Q for the presence boost at 3292Hz is not too sharp to be nasal. At 7885Hz, the classic brightness around 8kHz, is still sharp enough to be very different from the high-treble Baxandall, which is centered at 12kHz.

Gerzon shelves, 4 medium bells

This is more of a classic set of frequencies for those people who just can't stand to see frequencies that they didn't see on consoles! In a way, they have ingrained themselves into our ears.

Filters:

80Hz Low shelf

12kHz High shelf

125, 500, 2.5kHz, 7.5kHz (approximate) parametrics

This setup has sharper (higher value) Q settings, which in general are too sharp for mastering and mixing, but are so typically used in boards and "mid-line" gear that they sound more familiar to some people.

First described by Michael Gerzon, the very usable "resonant" shelving filters have a higher Q (1.25) which have a greater dip/overshoot in the shelf than in other setups, and sound more aggressive at lower gains. At high gains, these dips and overshoots may color the tonality too much, so just back the Q value down a bit. Classic bass and treble sound.

Four parametric filters all have Q settings of 1.3 for a sharper, more focused edge. These can be quite nice for small gains, but at higher gains, the tonality can be a bit too edgy, depending on what you want to do. The 125 is a high-bass, 500 is a little on the high-side for warm (it is truly a mid), 2500 is a little low for presence (usually 2900 to 3300). The 7551 is the only one near a classic "sweet" spot (7.5 to 8.5kHz).

Baxandall, 4 bells "mix" setup

Filters:

Baxandall (60Hz and 11986Hz)

200, 452, 1756, 5496 Hz bells (parametrics)

The Baxandalls are previously described, so refer to paragraphs above for details.

The four parametric filters are designed for tracking and mixing, with frequencies at common boost/cut points, with moderate Q values (1.0). For example, a kick drum might have a boost at the 60Hz Baxandall, and a cut at 200, plus a boost at 5496, to give the currently-classic "click", with a nice fist-in-the-chest low-end.  For guitars, a boost of 200 and/or 452 give a nice warming to sometimes too-bright amp stacks in the studio. And, a boost of 1756 and 5496 for vocals can lift the presence and increased intelligibility a bit without increasing the esses too much. And so forth!

4-band setups

Default 4-band reset (loaded each time when plug-in is inserted)

Filters:

3 bell (parametric)

1 High shelf

This is a subset of the 6-band default, without the 50Hz cut filter and the 7885Hz bright bell.

Baxandall, lo-mid, presence

Filters:

Baxandall bell filters (60 and 11986Hz)

200Hz low-mid bell

3292 presence bell

A subset of the 6-band setup "Baxandall, lo-mid, warm, presence, hi" but without the 351Hz and 7885Hz bell filters. This is an alternative mix/master setup. Bands 1 and 4 are classic bass and treble, with warm and presence bands in between.

For convenience, these notes are repeated from above:

200Hz is quite good for bringing out the "note" of the bass (being around the 2nd harmonic or so). The sharper Q for the presence boost at 3292 is not too sharp to be nasal.

Gerzon shelf, 3 bells "mix" setup

Filters

110Hz Low shelf

351, 2890, and 8476 bell (parametric)

Ideal for mix channels (track inserts), these filters are just good starting points for many applications. The low shelf is high enough to be general-purpose; the bells are set for low-mid warmth, presence, and brightness.  To get an "air" band, try setting band 4 to a high shelf, Q=0.9, Freq=13500 or higher.

Gerzon shelf, lo-mid, presence

Filters:

Gerzon shelves at 250Hz and 4kHz

351Hz and 2890Hz bell (parametric)

Michael Gerzon described these shelving filters in 1994 as being "even better than Baxandall" for general-purpose bass and treble controls. Keep in mind that Mr. Gerzon was a peer of Mr. B, so he meant no disrespect! They are clean and very usable for mixing or mastering, with a stronger distinction than Baxandall bell filters.

Bands 2 and 3 are the warm 351Hz and presence 2890Hz settings described in other setups.

2-band setups

Default 2-band reset (loaded each time when plug-in is inserted)

Filters:

92Hz and 8476Hz bell (parametrics)

Simple bass and brightness controls with broad Q for gentle tonal shaping.

Gerzon shelves

Filters:

250Hz and 4000Hz shelves

As described previously, it is the Q being very near 1.00 that gives these shelves their distinctive qualities.

Baxandall

Filters:

60Hz and ~12kHz bell (parametric)


FAQ's

Q: 	Why does REQ sound different from other equalizers, such as the Waves Q10?

A:	You may as well ask: "why do any equalizers sound different from each other?". All equalizers are based on a formula (a mathematical function or algorithm). In hardware, this formula is implemented by components such as tubes, transistors, integrated circuits, resistors, capacitors, and so forth. In digital equalizers, the algorithm works as a mathematical directly on the audio data. Every equalizer has a different sound, with different ranges of controls and behavior (the response of the equalizer). Additionally, REQ is a 48-bit processor, which increases the resolution of the equalizer and definitely affects the sound.

Q:	How can an analog equalizer be emulated in digital processing?

A:	Since each equalizer, whether analog or digital, can be essentially described as a mathematical function (and indeed, the values of analog components are directly derived from such math), then it is certainly possible to simply do the same math in a digital processor. More an issue are the curious effects of analog gear, such as extended frequency response - with some analog equalizers going all the way to 300kHz, inductor saturation, transformer characteristics, and so on.

Q:	Why are the bell filters of REQ wide when gain is positive, and narrower when gain is negative?

A:	In a way, this is the most 'natural' behavior of analog filters. Classic Pultec equalizers have shapes very similar to these. By design, REQ bell filters sound and behave closely resembling analog Pultec equalizers. For a constant value of "Q" (width), a boost or cut will look and sound different. These types of filters are non-symmetrical, unlike the symmetrical filters in the Q10.

Q:	Why do the shelving filters of REQ have a different shape?

A:	Primarily because they have adjustable slope. Simply change the Q to adjust the angle of the slope going to the shelf. Part of this type of filter, called a resonant shelf, is the characteristic "bump" in the graph. The overshoot/undershoot on the angle of the slope is quite important to the sound of these shelves, first described by Michael Gerzon in a 1994 paper.

Q:	What does 48-bit processing really mean?

A:	All calculations are carried out to a 48-bit value inside REQ. This preserves greater resolution of fine details, and definitely affects the sound of the equalizer. By working at this level of precision, the most exacting details are maintained throughout the processor. Only at the output does this 48-bit data path become reduced (to 32-bit for native use, 24-bit for DSP use). This reduction is performed by dithering the 48-bit internal data to the desired output.