Lexicon 224 Digital Reverb Manual

Updated September 12, 2023 22:24

An Era-Defining Digital Reverb

From the moment it was unleashed in 1978, the Lexicon 224 Digital Reverb — with its tactile, slider-based controller and famously lush reverb tail — single-handedly defined the sound of an entire era. From Talking Heads' Remain In Light and Grandmaster Flash & The Furious Five's The Message, to Vangelis' incredible Blade Runner soundtrack and U2's The Unforgettable Fire, the Lexicon 224 remains one of the most popular digital reverb units of all time. Now you can track and mix with this singular piece of audio history with the Lexicon 224 Reverb UADx plug-in.

Track and mix with the legendary Lexicon 224 Digital Reverb, using the same algorithms as the original hardware
Employ eight classic reverb programs and one chorus program on drums, vocals, guitars, and more
Use the Plate and Concert programs for vintage ‘80s sounds
Mix with presets from famous Lexicon 224 users Chuck Zwicky (Prince), Kevin Killen (Peter Gabriel), and others

A Breakthrough in Emulation

Using the exact algorithms and control processor code from the original hardware, the Lexicon 224 plug-in precisely captures all eight legendary reverb programs and the chorus program — based on the Lexicon 224's final and hard-to-find firmware version 4.4. The Lexicon 224 plug-in also incorporates the original hardware's input transformers and early AD/DA 12-bit gain stepping converters.

Easy Navigation

Every parameter from the original hardware is present in the Lexicon 224 plug-in, and exposed as dedicated sliders and buttons. Lexicon's distinctive Bass/Mid "split decay" adjustments and Crossover control set the highly tunable reverb image, while the Treble Decay rolls off high frequencies. Use the Depth control to adjust the distance between source and reverb, while Predelay produces a short delay between the sound source and the onset of reverberation. Diffusion affects how quickly the echo density in the reverb builds up over time.

Modeled to the Last Detail

For total authenticity, the UAD-only System Noise control enables or disables the inherent dynamic system noise of the original Lexicon 224 hardware — removing the modeled gain stepping, parameter zippering, and quiescent noise.

Clicking the OPEN text to the right of the display panel exposes several hidden controls, including Input/Output gain and Pitch Shift, and even a selectable "Bug Fix" mode which enables/disables historical bugs fixes from the Hall B and Chorus programs.

Taken together, the Lexicon 224 plug-in for UADx is the world's most authentic model of a true studio classic.

Lexicon 224 interface

Operational Overview

Graphical User Interface

The original Lexicon 224 consists of two hardware elements. The "mainframe" rack-mountable 4U chassis contains the power supply, circuitry, and audio input/output connectors. The remote control unit has a display, buttons, and sliders which control the 224 parameters and functionality. Some of these buttons and sliders have dual and even triple functionality, which makes using certain "buried" functions a tricky procedure.

The Lexicon 224 interface resembles the appearance and functionality of the original hardware remote control. Operation has been simplified however by reassigning the buried "shift" functions to the buttons that are no longer necessary in a plug-in (such as managing saved programs). Additional parameters are exposed by opening a panel cover.

Lexicon 224 Programs

The original Lexicon 224 hardware has programs that are defined by the firmware ROM (Read-Only Memory chip) installed in the unit. A Lexicon 224 program consists of a unique DSP algorithm and an initial set of factory parameter values voiced by Lexicon. In modern terminology, these initial values would be called a preset.

In Lexicon 224 hardware-speak, a program is called (loaded) which selects the DSP algorithm and sets the default "recommended" factory parameter values. These settings can then be modified with the various controls and saved in a user register for later recall. The plug-in behaves the same way, except user registers are not implemented. Instead, settings are stored within the session file or they can be saved as a preset for later recall (as with all other UADx plug-ins).

Lexicon 224 version 4.4 firmware contains nine programs (the maximum available for the unit), consisting of eight reverb programs and one chorus program. Descriptions of the various programs can be found in the Program Descriptions.

Lexicon 224 Algorithms

The active algorithm determines the inherent sonic character of the current program. Algorithms are changed by selecting a different program; the algorithm cannot be changed within the same program.

Lexicon 224 v4.4 contains seven unique algorithms. All seven algorithms and the nine factory programs have been authentically modeled in the Lexicon 224 plug-in. There are more programs than algorithms because some programs use the same algorithm. See Program Descriptions for details.

Lexicon 224 Buttons

Like the original hardware, Lexicon 224 buttons are momentary-style and don't latch in a down position. When a function is unavailable within a particular program, the button's LED will not illuminate when clicked (the LEDs also don't illuminate for the increment/decrement buttons).

The first click of an increment/decrement button displays the current value of the parameter; the value is actually changed only with subsequent clicks. This feature enables viewing the current setting without changing it.

Tip: For the inc/dec buttons (e.g., Reverb Diffusion), the value can be continuously changed by holding the button down.

Lexicon 224 Sliders

The six sliders control the main reverb parameters within a program. These are the most obvious controls to reach for when fine-tuning a reverb program to best suit the material at hand.

In P9 Chorus A, the first four sliders don't control the labeled parameters. See P9 Chorus A for descriptions of the sliders in this program.

Tip: Clicking a slider "cap" will show its value in the Numerical Display. Clicking the text label of any slider will return that slider to the default value for the
active program.

Inputs & Outputs

The Lexicon 224 hardware has two inputs (see Mono/Stereo below), and four discrete outputs, labeled as A, B, C, and D. Outputs A and C were designed to be used as the main stereo left/right outputs. The other two outputs, B and D, are implemented in some programs for use as quadraphonic reverb.

The UAD Lexicon 224 fully models the individual sonics of all four outputs when available in the program algorithm. The alternate B and D outputs are available via the Rear Outs control.

Note: The dry signal at the Lexicon 224 output is completely unprocessed.

Mono/Stereo Operation

The Lexicon 224 hardware has dual channel inputs (left and right) and is a true stereo processor. Like the hardware, when the Lexicon 224 plug-in is used in a stereo-in/stereo out configuration, the left and right channel signals are both processed.

When used in a mono-in/stereo out configuration, the mono input is sent to both channels of the stereo processor.

When configured as mono-in/mono-out (MIMO), output A is used exclusively except in programs 2, 4, and 9, where outputs A and C are summed into one monophonic signal. This implementation is recommended in the original hardware manual. If Rear Outs is enabled in MIMO mode, outputs B and D are used instead of A and C. See MIMO Program Outputs for a list of outputs used with each program in this configuration.

Primary & Hidden Controls

The primary controls (those that are most typically used) are on the main "remote control" panel interface. Additional (less typically used) controls are available in a hidden control panel. The hidden control panel (see Hidden Controls) is accessed by clicking the OPEN text label to the right of the Display Panel.

Parameter Ranges & Default Values

The parameter value ranges, default values, and availability of particular parameters within a given program may vary depending on which program is active. Parameter ranges are listed in the individual control descriptions. Default parameter values for each program are listed in the Program Descriptions.

Note: Extreme parameter settings can cause Lexicon 224 to self-oscillate or cause other unexpected sounds. This behavior is identical to the original hardware.

Display Panel

The Lexicon 224 display panel (shown below) consists of four display elements: Numerical Value, LED Value, Stereo Level Meters, and Overflow indicator. Exactly what is displayed here is dependent on the parameter being edited (if any) and the state of the Display Hold switch.

Lexicon 224 Display Panel

Numerical Value

The three-character Numerical Value Display shows the value of parameters as they are being edited. The value of the edited parameter is displayed for 3.5 seconds unless the Display Hold switch is set to infinite, in which case the last edited parameter value continues to be displayed.

If Display Hold is set to 3.5 (the default value), after parameters are edited, the value displayed here reverts after 3.5 seconds to a reverb time which is related to the combined Bass and Mid slider values. This relationship is based on approximations designed by the original Lexicon engineers; the actual decay times may not match the displayed value.

Value LED

The Value LED shows the units of the numerical value being displayed for a particular control. For parameters in the time domain, the "sec" (seconds) or "ms" (milliseconds) LED is lit. For parameters in the frequency domain, the "Hz" (Hertz) or "kHz" (kilohertz) LED is lit. For parameters that have no units value (e.g., Dry/Wet Mix), the value LED does not illuminate.

LED Meters

The five-segment LED meters display the left and right signal input levels at the Lexicon 224 analog-to-digital converters, which are fully modeled. The Meter LEDs indicate levels at -24 dB, -18 dB, -12 dB, -6 dB, and 0 dB. When the 0 dB LED illuminates, input clipping has occurred.

Overflow LED

The Overflow LED illuminates when an arithmetic processor overflow has occurred. Overflows can happen when loud signals are present at the input, when reverb decay times are long, and/or when self-oscillation occurs. Unexpected sonic artifacts and/or ringing can occur when the processor overflows.

Overflow behavior in the hardware is fully modeled in the plug-in. If processor overflows are causing undesirable sounds, overflow can usually be eliminated by reducing the levels with the Input controls, or by reducing the value of the Bass, Mid, and/or Treble Decay controls.

Primary Controls

Program

The Program buttons are used to specify which of the nine default Lexicon programs, and its associated algorithm, is active. See Lexicon 224 Programs for an overview.

Eight reverb programs and one chorus program are available. Click a reverb program button 1 - 8 to select that program. To select the chorus program, shift+click any program button, or click the CLK=CHORUS text label. The program button LED indicates which program is active except in chorus mode, when all eight program button LEDs are illuminated.

Lexicon 224 Program Buttons

When a program is loaded, the original default Lexicon "recommended" factory settings for that algorithm are also loaded at the same time, overwriting previous settings (except when Immediate mode is active). Program settings can then be adjusted to taste using any available controls.

The Program Descriptions contains details about each program.

Important: If the program is changed when Immediate mode is disabled, settings from the previously selected program are lost. To retain custom program settings for future use, save the settings as a plug-in preset by using the UAD Toolbar or host application preset management techniques.

Reverb Time

Reverb Time is the duration of the decay of the reverberant sound (the "reverb tail"). The reverb tail time is separated into two frequency component bands, Bass and Mid. The separation frequency of the two bands is defined by the Crossover control.

Bass

The Bass slider defines the reverb decay time for the frequencies below the Crossover value. Higher Bass values result in longer bass frequency decay times (when Crossover is not set too low). The Bass reverb decay time value, in seconds, is shown in the Numerical Display. The available range is 0.6 seconds to 70 seconds.

This control works in conjunction with the Crossover parameter, which defines the range of the bass frequencies affected by the Bass control. Therefore adjusting Bass may have little audible effect if Crossover is set to a very low value.

Mid

The Mid slider defines the reverb decay time for the frequencies above the Crossover value. Higher Mid values result in longer high frequency decay times (when Crossover is not set too high). The Mid reverb decay value, in seconds, is shown in the Numerical Display. The available range is 0.6 seconds to 70 seconds.

Mid works in conjunction with the Crossover parameter, which defines the range of high frequencies affected by the Mid control. Therefore adjusting Mid may have little audible effect if Crossover is set to a very high value.

Mid is a slightly misleading label, because this control actually affects the reverb decay for all frequencies above the Crossover value (not just the midrange). However, because the "highs" in the reverb can be rolled off with the Treble Decay control (and usually are), the midrange frequencies are often more prominent than a full-range tail.

Crossover

This control defines the crossover frequency (the split point) between the bass and upper frequency bands in the reverb tail. Higher Crossover values make the Bass parameter control a wider range of frequencies. Conversely, lower values make the Mid parameter control a wider range of frequencies. The available range is 100 Hz to 10.9 kHz.

Crossover affects the reverb decay because it works in conjunction with the Bass and Mid reverb time parameters, which both define the length of the reverb tail (one control for each frequency band). If those parameters are set to very short times, the result of adjusting Crossover may be very subtle.

Note: Crossover will have no apparent effect if Bass and Mid are set to the
same value.

Treble Decay

Treble Decay sets a frequency above which decay is very rapid. Lower values will produce a "darker" reverb with less high frequency content. If Treble Decay is set very low, then adjusting Bass, Mid, and Crossover may have little to no audible effect. The available range is 100 Hz to 10.9 kHz.

Tip: Treble Decay adjusts the AMOUNT of reverb tail highs, while Mid adjusts the TIME.

Depth

Depth sets the apparent distance between a source and its reverb, much like the positioning of microphones in an echo chamber. As the value is increased, the apparent distance from the source increases. The available range is 0 - 71, with zero being "close" and 71 being "far" (the numbers are arbitrary). The default value is program dependent.

Note: Depth is not available in P9 Chorus A. In this program, the display is not updated when the Depth slider is moved.

Reverb Diffusion

In most programs, Diffusion affects how quickly the echo density in the reverb builds up over time. In the original hardware, this parameter was usually referred to as "Shift-Depth" (changing the diffusion value required holding down the shift button while adjusting the depth amount).

Click the left ("<") decrement button to decrease the Diffusion value; click the right (">") increment button to increase the value. The available range is 0 - 63 (the numbers are arbitrary). The default value is program dependent; the Program Descriptions lists the default values for each program.

Note: Diffusion is unavailable in P4 Acoustic Chamber.

Zero is the least dense setting. Density increases as the Diffusion value is increased, but setting Diffusion higher than 40 can actually sound less dense. The fastest density buildup is achieved with Diffusion values near the middle of the range (approximately 32-37).

Higher Diffusion values are frequently desirable when the material has a lot of percussion. Higher Diffusion can also contribute to a smoother-sounding reverb. With low Diffusion values the early reverb will be "grainy" and sparse, but will produce a clear, bright sound that is very useful with strings, horns, and vocals. Low Diffusion is also useful in classical music or in adding a sense of depth to an overall mix. Note that in Lexicon 224, lower frequencies are generally less diffuse.

Note: If Immediate mode is active, the Diffusion value is retained when changing programs.

Predelay

Predelay produces a short delay between the sound source and the onset of reverberation. Higher Predelay values increase the time before reverb onset. The range of this parameter varies depending on the active program; see the table below for the available values. The default value is program dependent.

Lexicon 224 Predelay Ranges

Program	Predelay Range	Program	Predelay Range
1. Small Concert Hall B	24 - 152	6. Small Concert Hall A	24 - 152
2. Vocal Plate	0 - 107	7. Room A	24 - 255
3. Large Concert Hall B	24 - 152	8. Constant Density Plate A	5 - 185
4. Acoustic Chamber	25 - 255	9. Chorus A	0 - 253
5. Percussion Plate A	0 - 107	Note: Predelay values are in miliseconds.

Immediate

When Immediate ("IMMED") is enabled, current parameter values are retained when a new program is selected. When Immediate is inactive and a program is selected, the Lexicon default factory preset parameter values for the program are loaded and the control sliders move to the preset values.

Enabling Immediate mode is convenient for quickly auditioning the various program
algorithms using the same "persistent" parameter values. Disabling Immediate mode
is convenient for quickly auditioning the various programs with the Lexicon factory default settings.

The default Immediate value is OFF. Immediate affects the following parameters: Bass, Mid, Crossover, Treble Decay, Depth, Predelay, Diffusion, Mode Enhancement, Pitch Shift, Decay Optimization, and Rear Outs.

Important: When Immediate is off and a program is changed, previously modified parameter values are lost, unless the settings were saved as a preset or if the session file was previously saved so it can be recalled.

System Noise

This UAD-only control ("SYS NOISE") enables or disables the modeled inherent dynamic system noise of the original Lexicon 224 hardware. Disabling System Noise enables a more modern-sounding (i.e., cleaner) 224. Click the button to toggle the state; System Noise is active when the button LED is lit. The default state is ON.

The elements of the modeled System Noise include quantization effects (at input A/D, output D/A, and within the algorithm), zipper/stepping noise when adjusting parameters, transformer distortion, and the quiescent noise floor.

Zipper/stepping noise when adjusting parameters can be defeated by disabling System Noise. However, zipper/stepping noise in delay modulation (i.e., Mode Enhancement) can only be reduced, but not completely defeated, by disabling System Noise.

Note: System Noise is a global (per instance) parameter; its state does not change when different programs are selected.

Rear Outs

The Rear Outs control is available to select the alternate pair when the algorithm has alternate sonics at outputs B and D. See Inputs & Outputs for an overview of the hardware implementation.

Rear Outs Notes

The left/right outputs of the plug-in always reflect hardware outputs A and C respectively when Rear Outs is inactive, and outputs B and D respectively when Rear Outs is active.
Outputs A and C are "recommended" for stereo use (the rear outs are generally not used in typical applications).
Outputs A and C are identical to D and B respectively in the following programs: P2 Vocal Plate A, P5 Percussion Plate A, P8 Constant Density Plate A, and P9 Chorus A. Consequently, the Rear Outs control effectively swaps the left/right outputs in these programs.

Mode Enhancement

Mode Enhancement makes the sound of the Lexicon 224 programs more natural by preventing room modes from ringing in the reverb tail. Mode Enhancement works by continuously modulating certain delay lines (taps) within the program algorithms, which increases the effective density without thickening the reverb itself.

Mode Enhancement is factory-optimized for each program and should not require adjustment in typical use. For this reason, it was deliberately made difficult to access in the original hardware. However, creative use of the parameter is encouraged by making it easier to access in the plug-in.

Mode Enhancement has three control elements: Enable, Amount, and Pitch Shift. As in the original hardware, lower values of Mode Enhance Amount and higher values of Pitch Shift increase "movement" and make the result more prominent.

Note: The Mode Enhance Amount and Pitch Shift controls have no effect unless the Mode Enhance Enable control is active.

Mode Enhance Enable

This button ("MODE ENH") enables or disables Mode Enhancement for the active program. Mode Enhancement is active when the button LED is lit. The default state is ON for all programs.

Tip: This control, just as with the original hardware, resets the algorithm. Therefore Mode Enhance Enable can be used to quickly "kill" the reverb tail while staying in the same program.

Mode Enhance Amount

These two adjacent buttons control the amount of Mode Enhancement, or technically speaking, the amount of time between delay line updates. Click the left ("<") button to decrement the value; click the right (">") button to increment the value. The available range is 1 through 16. Lower values increase the effect.

Mode Enhance Pitch Shift

Pitch Shift is a secondary parameter of Mode Enhancement that controls the size of the delay line update steps. Lower values produce smaller steps, while higher values produce larger steps. Click the left ("<") button to
decrement the value; click the right (">") button to increment the value. The available range is 1 through 16. Higher values increase the effect.

The Pitch Shift controls are accessed in the Hidden Controls panel.

Decay Optimization

Decay Optimization improves the Lexicon 224 reverb clarity and naturalness by dynamically reducing reverb diffusion and coloration in response to input signal levels. However, if set too high, it can make the decay less even. Decay Optimization has two control elements: Enable and Amount.

Decay Optimization is factory-optimized for each program and should not require adjustment in typical use. For this reason, it was deliberately made difficult to access in the original hardware. However, creative use of the parameter is encouraged by making it easier to access in the plug-in.

Decay Optimize Enable

This button ("DECAY OPT") enables Decay Optimization for the active program. Decay Optimization is active when the button LED is lit. The default state is ON.

Note: Decay Optimization is unavailable for P8 Constant Density Plate A and P9 Chorus A.

Decay Optimize Amount

These two adjacent buttons control the amount of Decay Optimization. Click the left ("<") button to decrement the value; click the right (">") button to increment the value. The available range is 1 through 16. As in the original hardware, lower values make the result more prominent.

Note: The Decay Optimization Amount controls have no effect unless the Decay Optimization Enable control is active.

Mix Controls

The Dry, Wet, and Solo parameters control the effect mix in the plug-in. These controls are not available in the original hardware.

Note: The Mix controls are global parameters; their state does not change when different programs are selected.

Solo

When Solo is activated, the Dry/Wet mix is set to 100% wet and the Dry/Wet controls are deactivated. Solo mode is optimal when using Lexicon 224 in the "classic" reverb configuration (placed on an effect group/bus that is configured for use with channel sends). When Lexicon 224 is used on a channel insert, Solo should be deactivated. The default state is ON.

Note: Solo is a global (per Lexicon 224 plug-in instance) control.

Dry/Wet

These two buttons control the balance between the reverb processor and the source signal when Solo mode is inactive. Click the DRY button to reduce the reverb amount; click the WET button to increase the reverb amount.

The Dry/Wet mix is indicated in the Numerical Display as a percentage. A value of 50 produces an equal blend of the wet and dry signals. Values greater than 50 emphasize the wet signal, and values less than 50 emphasize the dry signal.

Clicking the DRY button once will decrement the value by one percent; clicking WET once will increment the value by one percent. To increase the fine resolution when adjusting these controls, hold SHIFT (on the computer keyboard) when clicking the controls. Shift+click will decrement (DRY) and increment (WET) by a value of 0.1 percent instead of one percent.

The Dry/Wet controls are typically used when Lexicon 224 is inserted on individual channels. When Lexicon 224 is used on a group/bus in a typical reverb send/return configuration, set to 100% WET or activate SOLO mode.

Hidden Controls

Additional UAD controls are available in a hidden control panel. Refer to the image below in parameter descriptions.

The Lexicon 224 Hidden Controls

Access

The hidden controls are exposed by clicking the "OPEN" text to the right of the Display Panel. Conversely, the exposed panel is closed by clicking the "CLOSE" text while the panel is open.

Note: The last-used state of the Hidden Controls panel (open or closed) is retained when a new Lexicon 224 plug-in is instantiated.

Pitch Shift

Pitch Shift is a component of Mode Enhancement. See Mode Enhance Pitch Shift for parameter details.

Input Gain

The independent left ("L") and right ("R") Input Gain parameters control the signal levels at the input to the reverb processor. They do not affect the dry signal, so Input Gain can be used to adjust the wet/dry mix. The default value is 0 dB. The available range is ±12 dB. The right channel control is unavailable when Lexicon 224 is used in a mono-in/mono-out configuration.

As signal levels into the Lexicon 224 increase, the analog and digital response of the device becomes increasingly nonlinear. If signals are too high, the Lexicon 224 A/D inputs and/or processor can overload, lighting the Overflow LED and causing sonic artifacts. See Overflow LED for more information.

Tip: Click the text label ("I") to return the value of both channels to zero.

Output Level

The independent left ("L") and right ("R") Output Level parameters control the signal levels at the output of the plug-in. The default value is 0 dB. The available range is - ∞ (infinite) dB to +12 dB. The right channel control is unavailable when Lexicon 224 is used in a mono-in/mono-out configuration.

Tip: Click the text label ("Output Level") to return the value of both channels to zero.

Link

Link/unlink allows the left and right controls for Input Gain and Output Level to be unlinked (non-ganged) in order to apply a different value for each channel. Link is inactive when the LED is unlit. Click the Link LED to toggle the state. The default state is ON.

If the left and right controls have different values when link is inactive and Link is engaged, the left channel value is copied to the right channel (thereby overwriting the right channel value).

When Link is active, automation data is written and read for the left channel only. The automation for the left channel controls both channels in Link mode.

Note: When link is active, modifying the right channel parameters will have no effect when changed from a control surface or when in "controls only" (non-GUI) mode.

Bug Fixes

The original Lexicon 224 code contains programming errors in the Hall B and Chorus algorithms. These computer code bugs can cause incorrect Bass decay times (Hall B programs) and undesirable "pops" and/or "thumps" in the right channel (Chorus program) with certain source signals and parameter configurations.

The bugs have been corrected in the UAD implementation of the plug-in, but we have provided the option of using the original code for the sake of pure authenticity.

The UA logo is actually a switch. When the UA logo is illuminated, the source code bugs are fixed. The default state is ON. Click the UA logo to disable the UA bug fixes and revert to the original hardware behavior.

Display Hold

The Display Hold switch alters the behavior of the Numerical Display (See Numerical Value). In the original hardware, the values of parameters that are being modified are displayed for 3.5 seconds before reverting back to displaying the average decay time.

The Hold switch changes this behavior. When set to infinite ("∞"), the Numerical Display will continue to show the last modified parameter value. When set to infinite and a program is changed, the average decay time is displayed until a parameter is modified.

Note: The last-used state of the Display Hold parameter is retained when a new Lexicon 224 plug-in is instantiated.

Power

The Power switch is a bypass control. Click the switch to change the Power state. When bypassed, plug-in processing is disabled, and the Display Panel and all button LEDs are dimmed.

Program Descriptions

P1 Small Concert Hall B

This program emulates the sound of a small concert hall, with moderate initial density and moderately non-uniform decay. It is optimized for reverb times of 1.5 to 5 seconds (for longer decay times, P3 Large Concert Hall B is recommended instead). The most natural sound is obtained when Bass and Mid are relatively close to the same setting. This program uses the exact same algorithm as P3 Large Concert Hall B.

P2 Vocal Plate

This is a plate reverb emulation optimized for voice. It has low initial density and coloration, resulting in a clear, bright sound. This program uses the exact same algorithm as P5 Percussion Plate A, but with slightly different inherent diffusion.

P3 Large Concert Hall B

This program emulates the sound of a large concert hall, with low density and minimal coloration. It is optimized for long reverb times. With percussive sounds, increasing the diffusion value is recommended. This program uses the exact same algorithm as P1 Small Concert Hall B.

P4 Acoustic Chamber

This program sounds like a chamber, but with less initial density. It tends to sound best with shorter reverb times (2 to 5 seconds). The most chamber-like sound is obtained with Depth at a value of zero. Diffusion is preset in this program and cannot be modified. Unlike all other Lexicon 224 programs, this algorithm has monophonic input.

P5 Percussion Plate A

This is a plate reverb emulation optimized for percussive sounds. It has high initial density and coloration, and sounds best with shorter reverb times. This program uses the exact same algorithm as P2 Vocal Plate, but with slightly different inherent diffusion.

P6 Small Concert Hall A

This program is similar to P1 Small Concert Hall B, except it is brighter overall and the Treble Decay control is more gentle. The original hardware manual recommends equalizing this reverb return about +3 dB below 200 Hz to "add to the richness and naturalness of the reverb."

P7 Room A

Program 7 is a room simulator with moderate to high initial density and low to moderate coloration. It sounds great on speech and many types of music. This program presents an especially wide output when used with a stereo input source.

P8 Constant Density Plate A

In naturally occurring reverb, new reflections are continuously added to the decaying sound over time. This sonic build-up increases density and coloration in the reverb tail. P8 Constant Density Plate A has high initial density and coloration (giving a "plate" type of sound), however the density does not increase over time and remains inherently constant. This can result in less "swoosh" in the reverb tail and provides another creative option. Decay Optimization and true stereo input are unavailable in this program (inputs are always summed to mono, even in stereo-in/stereo-out configurations).

P9 Chorus A

The Chorus A program is an eight-voice chorus with four voices on each stereo channel. Each voice has a time delay which varies randomly and independently, resulting in a thick, rich sound. To select the chorus program, shift+click any program button, or click the CLK=CHORUS text label.

When Chorus is active, each of the first four sliders controls the gain level for a stereo pair of voices. The sliders are linear faders, not log faders, so the default positions of all four sliders (about 1/2 way up) correspond to gains 6 dB below maximum.

The first two voice pairs have overlapping delay ranges. Phasing/flanging effects can be achieved by setting their gains to similar levels. Phasing/flanging can also be achieved (with a mono or centered input) when the left and right channels are mixed together, such as when used in a mono-in/mono-out configuration.

The Reverb Diffusion control is active in this program. Diffusion acts upon the third and fourth pair of stereo voices, producing a cluster of tightly spaced echoes whose shape is governed by the Diffusion control. The Lexicon 224 is one of the few processors that has diffusion on chorus voices; this feature is a primary factor in its distinctive character.

Note: The Bass, Mid, Crossover, and Treble Decay behaviors are unavailable in P9 Chorus A. Instead, each of these sliders controls the level of a stereo voice pair.

MIMO Program Outputs

When Lexicon 224 is used in a mono-in/mono-out (MIMO) configuration, the hardware outputs that are used for the plug-in are listed in the table below. These software assignments are per the guidelines in the original hardware manual and cannot be modified.

Program	Output(s)	Program	Output(s)
1. Small Concert Hall B	A	6. Small Concert Hall A	A
2. Vocal Plate	A + C	7. Room A	A
3. Large Concert Hall B	A	8. Constant Density Plate A	A
4. Acoustic Chamber	A + C	9. Chorus A	A + C
Percussion Plate A	A + C

Lexicon 224 Outputs Used With Monophonic Output

The original Lexicon 224 Digital Reverberator hardware

All visual and aural references to Lexicon products and all use of Lexicon trademarks are being made with written permission from Harman International Industries, Inc.