Lexicon MPX 500 V2 - UPGRADE User manual

Installation Instructions & Release Notes
MPX 500 Version 2 Software Upgrade
MPX 500 V2 Upgrade Guide 3/15/01 3:05 PM Page i

© 2001 Lexicon, Inc. Bedford, MA USA All rights reserved
This document should not be construed as a commitment on the part of Lexicon, Inc.
The information it contains is subject to change without notice. Lexicon, Inc. assumes no
responsibility for errors that may appear within this publication.
2
A Harman International Company
Lexicon, Inc.
3 Oak Park
Bedford, MA 01730-1441
USA
Tel [phone]
Fax [phone]
www.lexicon.com
Customer Support
Tel [phone]
Fax [phone] (Sales)
Fax [phone] (Service)
03/01 | Lexicon Part No. 070-14696
MPX 500 V2 Upgrade Guide 3/15/01 3:05 PM Page ii

3
MPX 500 Version 2 Software Installation Intructions
THESE SERVICE INSTRUCTIONS ARE FOR USE BY QUALIFIED PERSONNEL ONLY.
DO NOT PERFORM ANY SERVICING OTHER THAN THAT CONTAINED IN THESE
INSTRUCTIONS UNLESS QUALIFIED TO DO SO. REFER TO SAFETY
SUMMARY PRIOR TO PERFORMING ANY SERVICE.
MPX 500 Version 2 Software Upgrade
Software Installation Instructions
Note:
Installation of the MPX 500 Version 2 Software Upgrade will reset the system configuration
to factory-default settings. To preserve System Parameter settings and User Bank programs,
perform the following steps:
1. Dump the System Parameters or User Bank into an external MIDI device before installing
the upgrade. (These are two separate dumps.)
2. Install the Version 2 software upgrade.
3. Send the previously saved System Parameter or User Bank dump back to the MPX 500.
WARNING
MPX 500 V2 Upgrade Guide 3/15/01 3:05 PM Page iii

WARNING
Dangerous voltages capable of causing death are
present in this instrument. Use extreme caution
when handling, testing, and adjusting.
MPX 500 Version 2 Software Installation Intructions Lexicon, Inc.
4
SAFETY SUMMARY
The following general safety precautions must be observed during all phases of operation, service, and
repair of this instrument. Failure to comply with these precautions or with specific warnings elsewhere in
these instructions violates safety standards of design manufacture and intended use of the instrument.
Lexicon, Inc. assumes no liability for failure to comply with these requirements.
GROUND THE INSTRUMENT
To minimize shock hazard, the instrument chassis and cabinet must be
connected to an electrical ground. The instrument is equipped with a
3-conductor AC power cable. The power cable must be either plugged
into an approved 3-contact electrical outlet or used with a 3-contact to
2-contact adapter with the grounding wire (green) firmly connected to an
electrical ground (safety ground) at the power outlet. The power jack and
mating plug of the power cable meet International Electrotechnical
Commission (IEC) safety standards.
DO NOT OPERATE IN AN EXPLOSIVE ATMOSPHERE
Do not operate the instrument in the presence of flammable gasses or
fumes. Operation of any electrical instrument in such an environment
constitutes a definite safety hazard.
KEEP AWAY FROM LIVE CIRCUITS
Operating personnel must not remove instrument covers. Component
replacement and internal adjustments must be made by qualified
maintenance personnel. Do not replace components with power cable
connected. Under certain conditions, dangerous voltages may exist even
with the power cable removed. To avoid injuries, always disconnect
power and discharge circuits before touching them.
DO NOT SERVICE OR ADJUST ALONE
Do not attempt internal service or adjustment unless another person
capable of rendering first aid and resuscitation is present.
DO NOT SUBSTITUTE PARTS OR MODIFY INSTRUMENT
Because of the danger of introducing additional hazards, do not install
substitute parts or perform any unauthorized modification to the
instrument.
DANGEROUS PROCEDURE WARNINGS
Warnings such as the example below precede potentially
dangerous procedures throughout this manual. Instructions contained in
the warnings must be followed.
MPX 500 V2 Upgrade Guide 3/15/01 3:05 PM Page iv

Denotes important information. It calls
attention to a procedure, practice,
condition, or the like which is essential to
highlight.
SAFETY SYMBOLS
Following are general definitions of safety symbols used
on equipment or in manuals:
Instruction manual symbol: the product
will be marked with this symbol when it is
necessary for the user to refer to the
instruction manual in order to protect
against damage to the instrument.
Indicates dangerous voltage. (Terminals
fed from the interior by voltage
exceeding 1000V must be so marked.)
Denotes a hazard. It calls attention to a
procedure, practice, condition, or the
like which, if not correctly performed or
adhered to, could result in injury or
death to personnel.
Denotes a hazard. It calls attention to an
operating procedure, practice,
condition, or the like which, if not
correctly performed or adhered to,
could result in damage to or destruction
of part or all of the product.
MPX 500 Version 2 Software Installation Intructions
5
WARNING
CAUTION
CAUTION
Note:
ELECTROSTATIC DISCHARGE (ESD) PRECAUTIONS
The following practices minimize possible damage to EPROMs resulting
from electrostatic discharge or improper insertion:
• Keep parts in original containers until ready for use.
• Avoid having plastic, vinyl, or styrofoam in the work area.
• Wear an anti-static wrist strap.
• Discharge personal static before handling devices.
• Remove and insert boards with care.
• When removing boards, handle only by non-conductive surfaces
and never touch open-edge connectors except at a static-free
workstation.*
• Minimize handling of EPROMs.
• Handle each EPROM by its body.
• Do not slide EPROMs or boards over any surface.
• Insert EPROMs with the proper orientation, and watch for bent pins on
EPROMs.
• Use anti-static containers for handling and transport.
* To make a plastic-laminated workbench anti-static, wash with a
solution of Lux liquid detergent, and allow to dry without rinsing.
MPX 500 V2 Upgrade Guide 3/15/01 3:05 PM Page v

Note:
Installation of the MPX 500 Version 2 Software
Upgrade will reset the system configuration to
factory-default settings.
To preserve System
Parameter settings and User Bank programs,
perform the following steps:
1. Dump the System Parameters or User Bank
into an external MIDI device before installing
the upgrade. (These are two separate
dumps.)
2. Install the Version 2 software upgrade.
3. Send the previously saved System Parameter
or User Bank dump back to the MPX 500.
Contents
This update kit includes:
• 1 MPX 500 EPROM
• 1 EPROM Extractor Tool
• Installation and Release Notes (this document)
• 1 Anti-static wrist strap
This kit does not include two Phillips head screwdrivers
(sizes 0 and 1) and a wrench or nut driver, which are also
needed.
Instructions
Performing this upgrade is an easy process. But to avoid
problems, please follow these instructions carefully. Pay
particular attention to the precautions listed in the safety
summary, and those that appear throughout these
instructions. Any damage caused during installation is not
covered under warranty.
STEP 1 - OPEN THE UNIT
1. Using a size 1 Phillips head screwdriver, remove
the screws (Lexicon Part No. 640-02812) on the
top and bottom of the unit (three on top, three on
bottom).
MPX 500 Version 2 Software Installation Intructions Lexicon, Inc.
6
WARNING
TURN OFF AND DISCONNECT ALL POWER TO THE UNIT
PRIOR TO INSTALLING THE SOFTWARE UPGRADE.
Top View of Unit
Front
Back
MPX 500 V2 Upgrade Guide 3/15/01 3:05 PM Page vi

2. Carefully remove the side panels by pulling them
out. Begin pulling at the end closest to the front
panel.
3. Remove the screw (Lexicon Part No. 640-02812)
and nut (Lexicon Part No. 643-01732) closest to
the AC receptacle. This is the only screw with a
nut attached.
4. Remove the nine larger screws (Lexicon Part No.
641-11466) on the back panel.
5. Using a size 0 Phillips head screwdriver, remove
the four smaller screws (Lexicon Part No. 641-
12759) near the MIDI IN & OUT/THRU ports.
MPX 500 Version 2 Software Installation Intructions
7
Screw & Nut
inside unit 9 Larger Screws
4 Smaller Screws
Bottom View of Unit
Front
Back
MPX 500 V2 Upgrade Guide 3/15/01 3:05 PM Page vii

MPX 500 Version 2 Software Installation Intructions Lexicon, Inc.
6. Using a wrench or nut driver, remove the five
plastic nuts (Lexicon Part No. 643-11682)
attached to the 1/4-in. connectors.
7. Remove the U-shaped chassis cover by gently
pulling it straight back, away from the front panel.
8. Put the anti-static wrist strap on before
proceeding to the next step.
STEP TWO - INSTALL THE EPROM
1. Refer to the illustration below to locate the
EPROM on the MPX 500 main board (location U9).
2. Check the EPROM provided with the upgrade kit.
Because the manufacturing process leaves the
pins angled out slightly from the body of the
EPROM, the pins must be straightened before
insertion. Use the following procedure to
straighten the pins:
A. Place the EPROM on its side on a static-free,
flat surface.
5 Plastic Nuts
8
Pin 1
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B. Hold the body of the EPROM and, exerting
gentle pressure downward, roll it slightly to
force the pins into a position parallel to the
work surface (see diagram below).
3. Using the EPROM extractor tool (see diagram
below) remove the EPROM at location U9 and
insert the new EPROM in its place. Be careful to
align the EPROM correctly to avoid bending any
pins. When the EPROM is inserted, carefully
inspect each pin to ensure that it has not been
bent.
Note:
To reassemble the unit, follow instructions 1-7
under the heading “Step 1 - Open the Unit”
(pages 6-8) in reverse order.
MPX 500 Version 2 Software Installation Intructions
9
CAUTION
EPROMs inserted backwards will
be destroyed. Incorrect insertion
of EPROMs is also likely to cause
damage to the board.
Notch
Pin 1
MPX 500 V2 Upgrade Guide 3/15/01 3:05 PM Page ix

Lexicon, Inc.
MPX 500 Version 2 Software Release Notes
10
Note:
Installation of the MPX 500 Version 2 Software
Upgrade will reset the system configuration to
factory-default settings.
To preserve System
Parameter settings and User Bank programs,
perform the following steps:
1. Dump the System Parameters or User Bank
into an external MIDI device before installing
the upgrade. (These are two separate
dumps.)
2. Install the Version 2 software upgrade.
3. Send the previously saved System Parameter
or User Bank dump back to the MPX 500.
Using the Documentation
This document contains information specific to the MPX
500 Version 2 Software Upgrade. It does not replace the
MPX 500 User Guide. Rather, these installation instructions
and release notes are designed for use with the guide.
About the Upgrade
This section describes the enhancements contained in the
MPX 500 Version 2 Software Upgrade.
THE COMPRESSOR
The new software contains a compressor that is available
with all presets. It sits in the Wet component of the signal
path in front of the effect(s) for the current preset. It is
controlled with four new parameters: Compression Ratio,
Threshold, Attack Time, and Release Time, which are
available on a new Edit page in each preset.
Available ratio values are: 1:1 (Off), 2:1, 3:1, 4:1, 5:1, and
10:1. Threshold values range from 0dB to -32dB and are
relative to 0dBFS (meaning digital saturation). The
compressor is disabled (turned off) if either the Ratio is set
to 1:1 or the Threshold is set high enough to prevent the
incoming signal from crossing the compression threshold.
Attack and Release Times are approximate indicators of
how quickly the compressor responds, within 3dB of the
final output level dictated by the incoming signal. For
most music material, Release should be about four times
longer than Attack. Both must be long enough to
accommodate the bass content of the music. If the
compressor is set to react faster than the waveform of the
music itself, the resulting changes in output level will
re-shape the waveform enough to generate undesirable
audio effects. For example, 80Hz has a period of 12ms. If
this is a dominant component in the music material, set
both Attack and Release to be at least 12ms, even longer
for better results.
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11
MPX 500 Version 2 Software Release Notes
The compressor is a stereo effect that acts on both L and
R channels simultaneously, using the sum of the two
channels as its trigger. Because the compressor is a
separate "device" that acts on the entire Wet signal path,
it is available with all of the MPX 500’s effect
combinations. Compression-only effects are obtained by
sending the compressor’s output into a Dly/Eko program
set with zero delay. (A Compressor Bank with a selection
of presets is described on page 12.) Since the
compressor acts with zero delay (in addition to the normal
< 2ms delay produced by the A/D and D/A converters), it
is suitable for use in a live performance. The MPX 500 can
be operated as a single-channel compressor with a
side-chain trigger by selecting a dual-mono effect
configuration, using only one side to carry the audio
signal and feeding the other channel a signal that is at
least 6dB higher than the audio program. The higher
signal will dominate the compressor’s behavior.
A System Parameter called Compressor Mode has been
added. Its values are Global and Program. Like Tempo
Mode and Mix Mode, it determines whether new
compressor settings should be loaded with each
program load or whether current Global values should be
maintained. (If the MPX 500 is powered up with
Compressor Mode set to Global, the compressor powers
up "off.") The factory-default for Compressor Mode is
Program.
As with other Edit parameters, the four Compressor
parameters can be controlled via MIDI commands. The
default MIDI patchings for these parameters are
Continuous Controllers 19, 20, 21, and 22.
THE LEVEL METERS
The input-level meters on the left side of the LCD display
now show calibrated values, with 0dB indicating digital
saturation. Markings on the open portion of each meter
show -6, -18, and -32dB. The meters also have single-pixel
precision in which each pixel represents 2dB. As the signal
level rises to cover these markings, the lower portion of
each meter shows marks at 6dB intervals.
Gain reduction from the compressor is indicated by a
descending bar situated between the two input-level
meters. Like the input-level meters, it is calibrated in 2dB
increments per pixel.
NEW BANKS AND PRESETS
The MPX 500 Version 2 has 15 new presets in 2 new banks:
Comprssr holds presets 240-249 and Live-FOH (Live Front
Of House) holds presets 250-255.
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12
Lexicon, Inc.
MPX 500 Version 2 Software Release Notes
THE COMPRSSR BANK
Presets 240, 241, 246, and 247 are compressor-only.
Presets 242, 243, 244, 245, 248, and 249 are combination
compressor and reverb with parallel (dual-stereo) routing.
240 2:1 a 2:1 compressor for subtle
dynamic range reduction
241 3:1 moderate dynamic range
reduction
242 3:1 | Small moderate compression and
small-hall reverb
243 5:1 | Medium aggressive compression
and medium-hall reverb
244 3:1 | Large moderate compression and
large-hall reverb
245 5:1 | Large aggressive compression
and large-hall reverb
246 GuitarComp compression suitable for
lead guitar
247 Limiter severe compression with
high threshold
248 Male Vocal reverb and compression
optimized for male voice
249 Female Vocal reverb and compression
optimized for female voice
In all of these presets, the Adjust knob (knob 1, Edit page
2) controls "gain make-up" within a range of 0dB (none) to
9.5dB. This can be used to match volumes between the
Dry bypassed level and the compressed output level
obtained with typical music material.
With these presets, Mix should normally be set fully Wet
(100%) so the compressed Dly signal is the only output
signal present. Of course, the user can experiment with
Mix settings less than 100%. For example, if Mix is set to
75%, about 1/4 of the signal power will bypass the
compressor. Thus as the signal crosses the threshold, only
part of it will be compressed, resulting in an effective
compression ratio somewhat less than the indicated ratio.
However, when the gain-reduction increases to about
6dB, the compressed Wet portion drops relative to the Dry
component and the compressor becomes less significant.
This creates a subtle expansion effect until the final output
returns to a normal 1:1 ratio.
The six Compressor/Reverb presets are constructed to
offer both a reverb component and a zero-delay Dry
component, with the compressor acting on both. Mix
should be kept fully Wet and effective mix should be
adjusted via the Efx/Bal control (knob 3, Edit page 2).
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13
MPX 500 Version 2 Software Release Notes
THE LIVE-FOH BANK
The Live-FOH Bank contains presets that are quicker and
more intuitive for live-sound engineers to operate. These
presets use dual-mono routings because many small-to-
mid-sized venues own mono PAs with limited channels
and only two mono aux sends available for effects.
250 Flange/Dly Flange and Delay/Echo
251 Chorus/Dly Chorus and Delay/Echo
252 Flange/Rvb Flange and Reverb
253 Chorus/Rvb Chorus and Reverb
254 Dly/Reverb Delay and Reverb
255 Dly/Reverb Delay and Reverb with
alternate Edit pages
These presets have the following features:
• The Edit knobs have been re-mapped so that Edit
page 1 always contains the four primary parameters
for one of the effects; Edit page 2 always contains the
four primary parameters for the other effect. Other
Edit pages hold Mix and the less frequently used
parameters from both effects.
• In the Delay programs, two delay level controls have
been combined into one Adjust knob labelled
Tap/Dly. These programs contain two delays: one
controlled by the Tempo (generally used to create
longer echoes/delays) and one that can be set
manually with a knob labelled Delay (generally
used to create a "slap" of perhaps 60-135ms). The
Tap/Dly knob provides an equal-power tradeoff of
the delay levels. The default incorporates equal
levels of each. Note that although the Tap delay is
ideally suited for longer rhythm-sensitive effects and
the manually-controlled delay is better for shorter
times, both delays are capable of delivering a full
range of delay times and can be cross fed into each
other for more extreme effects.
• Some of the non-essential parameters (i.e. Efx/Bal
and HF Rlloff) have been removed from the Edit
pages. Because most live engineers control these with
the return channels of the system mixer, their
presence on the MPX 500 Edit pages was considered
distracting.
• The most commonly used dual mono combination
is Delay and Reverb, so there is a preset (#255) with
an alternative knob mapping for this combination. Its
first two Edit pages are arranged with delay
parameters on the left (knobs 1 and 2) and reverb
parameters on the right (knobs 3 and 4). This
arrangement splits the effects’ controls left to right
rather than by page.
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14
Lexicon, Inc.
MPX 500 Version 2 Software Release Notes
THE USER BANK
The Version 2 Software expands the User Bank to hold 64
programs, instead of the original 30. Programs are stored
and recalled exactly the same way as in the Version 1
Software of the MPX 500. However, User Bank dumps to
MIDI (accomplished on the System page) are performed
differently. Dumps are now performed in groups of 16
programs rather than the entire User Bank at once. When
“Dump User Bank” on the System page is selected, the
display asks which group to dump, either 1-16, 17-32,
33-48, or 49-64. Use Knob 3 (the same knob used to
change other System Parameters) to change selections.
When one of these dumps is sent back to the MPX 500
from an external MIDI storage device, the MPX 500
recognizes which set it contains and automatically stores
it in the appropriate User Bank locations.
The MPX 500 Version 2 software will also recognize and
accept User Bank dumps made from Version 1, and will
automatically store these programs in User Bank locations
1-30. Since the new User Bank programs contain
Compressor settings, default values representing "off" will
be inserted into each program.
Installation of the MPX 500 Version 2 Software Upgrade
will reset the system configuration to factory-default
settings.
To preserve System Parameter settings and User
Bank programs, perform the following steps:
1. Dump the System Parameters or User Bank into an
external MIDI device before installing the upgrade.
(These are two separate dumps.)
2. Install the Version 2 software upgrade.
3. Send the previously saved System Parameter or User
Bank dump back to the MPX 500.
Note:
Some of the Plate, Chamber, and Room presets
have been changed slightly, and the Ambience
presets have been improved. The characters of
all the presets have been preserved in Version 2,
with minor exceptions. If the User Bank contains
programs that were based on these, they may
not sound exactly the same. This is especially true
if significant edits were made via the Adjust
parameter.
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15
MPX 500 Version 2 Software Release Notes
MISCELLANEOUS
• Version 2 is designed to recognize Version 1 System
Parameter and User Bank dumps. This feature allows
users to preserve System Parameter settings, User Bank
programs, and MIDI patches.
Note:
Do not attempt to send Current Program dumps
from Version 1 to Version 2.
• In Version 2, the factory-default for Mix Mode, Tempo
Mode, and Compressor Mode is Program - not Global.
This change is intended to make using the Compressor
presets easier since they generally require a Wet (i.e.
100%) Mix. (Other effects such as Tremolo and Rotary
also require a Wet Mix. But with these, if Mix is not set
correctly because the Global value is not Wet, the
problem will be evident immediately.)
• The Tap button responds to consecutive rather than
alternate presses.
• The program knob is less sensitive.
Errata Notes
• On page 19, the MPX 500 User Guide incorrectly states
that Memory Protect Mode prevents changes to the
User Bank or the System Parameters. When enabled,
Memory Protect Mode does prevent changes to the
User Bank. But it does not prevent changes to the
System Parameters, nor does it prevent restoration of
the MPX 500 factory-default settings. This means that
Factory Init will erase any stored programs in the User
Bank.
• Paragraph four of the original Release Notes for the
MPX 500 contained a list of presets from which the
Tempo patch was removed after the original User
Guide was prepared. That list had a few omissions.
Following is a correct version: 3, 5, 6, 7, 63, 64, 170, 171,
172, 173, 174, 175, 176, 177, 178, 179, 210, 215, 236, 237,
238.
• A Tempo patch was added to preset #12.
Parameter Descriptions
The tables on pages 16-22 provide a comprehensive list of
the MPX 500 parameters. Brief descriptions of each are
also included.
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Reverb Parameters
16
Lexicon, Inc.
MPX 500 Version 2 Software Release Notes
Adjust Function varies from preset to preset. Adjust usually controls several parameters but may also
provide a set of special values for a single control (for example "Fast" and "Slow" for a
parameter that can also be set to any value via another control). Adjust has a range of 0 to
127 to provide a convenient attachment point for a MIDI controller.
Decay, MidRT Controls reverb time for mid-frequency signals. In Ambience, Decay controls the length of
the ambience "tail."
HF Rlloff Sets the high-frequency roll off of a low-pass filter.
Mix Controls the ratio of direct (Dry) vs. effect (Wet) signal output. When the MPX 500 is patched
into a console, this control should almost always be set to Wet (i.e. 100%).
PreDelay Controls the time delay between the input signal and the onset reverberation.
BassMult
Controls the reverb time for low-frequency signals. It works as a multiplier of the Decay
(MidRT) parameter. For example, if BassMult is set to 2x, and Decay is set to 2s, the
low-frequency reverb time will be 4s. For a natural-sounding hall ambience, BassMult
should usually fall between 1x and 2x.
BassXvr
Sets the frequency below which BassMult applies.
Rt HC Sets the frequency above which high frequencies are rolled off in the reverberated signal.
This causes reverberated signals to grow progressively softer and results in a more natural
sound as it simulates the effect of air absorption in a real hall. Setting a low frequency for this
parameter can actually shorten the reverb time because it dampens the audio as it
re-circulates.
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17
MPX 500 Version 2 Software Release Notes
Diffusion Controls the degree to which initial echo density increases over time. High settings of Diffusion
result in high initial buildup of echo density. (Echo density is also affected by Size, with
smaller spaces sounding denser.)
Size Sets the rate of echo density buildup after the initial period (which is controlled by Diffusion).
It also acts as a master control for Decay. Size changes a reverb sound from very small to very
large. Generally, Size control should be set to approximately the size of the acoustic space
being created before other controls are adjusted. The size in meters is roughly equal to the
longest dimension of the space. (Adjusting Size causes the program to re-load.)
Attack Controls the sharpness of the initial response to an input signal. High settings cause an
explosive sound, while low settings cause the sound to increase more slowly with time. Attack
affects the level of sound only within the first 50ms or so.
Level Determines the amount of Wet signal present in output. It functions similar to the Mix control
except it affects only the Wet component. It is generally used to balance the
overall output of two or more programs when Mix is set to Wet.
EkoDly L, EkoDly R Control the timing of single reflections that occur early in the Decay in the reverb (Plate, Hall,
Chamber, etc.) programs. These reflections simulate the sound resonating off the back wall
of a stage or other reflective surface
EkoFbk L, EkoFbk R Control the amount of repeating echo that simulates a flutter echo between parallel walls in
the reverb programs. The range of these parameters is -100% to 100%, with negative values
producing a polarity reversal. High values can cause signal overload.
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Tremolo Parameters
Ambience Parameters
Inverse Parameters
18
Lexicon, Inc.
MPX 500 Version 2 Software Release Notes
Duration Determines the length of time in milliseconds that passes before output cutoff
occurs.
LowSlope, HighSlope Found only in the Inverse programs. LowSlope determines the shape of the reverb envelope
for low frequencies. When set to zero, the level of low reverb remains unchanged over its
Duration, then cuts off abruptly. Setting LowSlope above zero causes the level of low
frequency reverb to rise smoothly from soft to loud until the sound is cut off. The greater the
slope, the softer the initial reverberation and the more pronounced its rise. With negative
values, the low-frequency reverb drops from its initial level to a quieter one before cutoff.
HighSlope is similar to LowSlope, but applies to mid and high frequencies.
Shape Controls the buildup of those early reflections that most audibly create the sound of a real
room (similar to Attack in the reverbs).
Spread Controls the timing between the initial reflections that most audibly create the sound of a real
room (along with Size). Shape and Spread work together; if either is set to zero, the other has
no effect.
Rvb Lvl Controls the amount of "extra" longer-decay reverb added to the, short-decay early
reflections that create a real room sound in Ambience.
Phase Determines the relative timing between the L and R channels.
Rate Controls the speed of volume modulation.
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Rotary Parameters
Chorus Parameters
19
MPX 500 Version 2 Software Release Notes
Depth Controls volume modulation.
Waveform Determines how the volume is modulated with time. Values are Sine (smooth modulation
with polarity reversal), Rectified Sine (smooth modulation with no polarity reversal), Triangle
(linear ramp up and down), Sawtooth (linear ramp up with sudden reduction), and Square
(level modulations between maximum and minimum).
MstrRate A master rate control that affects both the Horn and Drum rates.
Width Determines the effective separation between L and R channels.
Balance Determines the volume balance between the Horn and Drum.
Drum Dep, Horn Dep Determine the amount of modulation produced by the Drum and Horn.
Drum Res, Horn Res Determine the amount of resonance, i.e. signal fed back into the effect.
Speed 1, Speed 2 Control the rates at which various voices sweep through frequency.
Sweep 1, Sweep 2 Control the amount of frequency variation for two different collections of voices. (The
Chorus effect simulates six voices with slightly varying pitch. The user has separate controls
over two sets of three voices each.)
Spread Controls the initial time differences between the six moving voices.
Res 1, Res 2 Control the amount of feedback signal.
Diffusion Creates a time-smoothing effect similar to diffusion in reverb.
MPX 500 V2 Upgrade Guide 3/15/01 3:05 PM Page xix

Pitch Parameters
Detune Parameters
Flange Parameters
20
Lexicon, Inc.
MPX 500 Version 2 Software Release Notes
continued on next page
Speed Controls how rapidly the two Flange voices move.
Depth Controls how much Flange effect is created by adjusting the level of the two Flange voices.
Sweep Determines the maximum amount of time-delay applied to each voice.
Phase Determines the relative timing between the speed modulation of the two voices.
Tune 1, Tune 2 Determines the amount of detuned signal mixed into output.
Pch, Intrvl Controls the amount of pitch shift applied. Interval values are in semitones, Pitch values are
in Cents (1/100th of a semitone). These values are additive.
PDly Used to control the amount of "look-ahead" required by the pitchshift algorithm. Good
performance requires some amount of predelay, so this control cannot actually set the
PreDelay to zero.
Pch Fbk Controls the level of feedback looping around the pitch algorithm, allowing for manipulation
of pitch shifts to create dynamic special effects.
-L-, -R/S- Designations on the Pitch parameters that mean "Left" or "Right/Stereo". Pitch shifting requires
some time shifting. A true stereo (not merely dual-mono) signal contains components that
are common to L and R. A proper stereo image is maintained only if the phase relationship
between these signals is maintained, which requires that the exact same computations be
applied to both channels.
MPX 500 V2 Upgrade Guide 3/15/01 3:05 PM Page xx