AMS RMX 16 User manual

RMX 16 : Digital Reverberation System
User Manual
Issue 2
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Table of Contents
Intro.................................................................................................................................................4
RMX 16 S reenshot...........................................................................................................................5
The Basi Prin iples of Reverberation...............................................................................................6
Understanding Reverberation ...........................................................................................................6
The Fundamentals of Reverberation...................................................................................................6
Stereo From a Mono Source..............................................................................................................7
Operating Instru tions.....................................................................................................................8
Operation.........................................................................................................................................9
Input Output Level And Level Monitoring Section...............................................................................9
The Pot Control Section....................................................................................................................9
Program Selection...........................................................................................................................9
Keypad Entry..............................................................................................................................9
Using The Nudge Keys.................................................................................................................9
Pre-Delay Entry...............................................................................................................................9
Keypad Entry............................................................................................................................10
Using The Nudge Keys...............................................................................................................10
Pot Control Entry.......................................................................................................................10
Decay Time Entry.......................................................................................................................... 10
Keypad Entry............................................................................................................................10
Using The Nudge Keys...............................................................................................................10
Pot Control Entry.......................................................................................................................10
Decay Filter Controls......................................................................................................................10
Dry Wet .....................................................................................................................................11
Keypad Entry............................................................................................................................11
Using The Nudge Keys...............................................................................................................11
Pot Control Entry.......................................................................................................................11
Using the RMX 16 .........................................................................................................................11
Pre-Delay................................................................................................................................. 12
Decay Time.............................................................................................................................. 12
Decay Filtering..............................................................................................................................12
Keyboard text Entry.......................................................................................................................12
Spe ifi ations.................................................................................................................................13
Electrical.................................................................................................................................. 13
Appendix B.....................................................................................................................................14
Program Index..............................................................................................................................14
Program 1 AMBIENCE................................................................................................................14
Program 2 ROOM A1..................................................................................................................15
Program 3 HALL C1...................................................................................................................15
Program 4 PLATE A1..................................................................................................................15
Program 5 HALL B3....................................................................................................................15
Program 6 CHORUS...................................................................................................................15
Program 7 ECHO.......................................................................................................................16
Program 8 NONLIN 2.................................................................................................................16
Program 9 REVERSE 1................................................................................................................16
Program 10 REVERSE 2..............................................................................................................17
Program 11 FREEZE...................................................................................................................17
Program 12 ROOM A0................................................................................................................17
Program 13 ROOM B1................................................................................................................18
Program 14 HALL A1..................................................................................................................18
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Program 15 PLATE B1................................................................................................................18
Program 16 DELAY....................................................................................................................18
Program 17 IMAGE P1................................................................................................................18
Program 18 NONLIN 1...............................................................................................................19
Appendix C.....................................................................................................................................19
High and Low Frequency Decay Characteristics..................................................................................19
Nominal High Frequency Decay Control Characteristics...................................................................19
Low Frequency Decay Control Characteristics................................................................................19
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Intro
The AMS RMX16 was the world’s first mi ropro essor ontrolled,
full bandwidth digital reverberator and hara terized an enormous
number of seminal re ordings from the 1980s onwards. Its
designer’s love for musi and experien e in the aerospa e industry
meant it was way ahead of its time on release.
It has remained an essential pie e of kit for any self-respe ting
world- lass studio ever sin e, and the units sell today for a
substantial proportion of their original ost due to their great
desirability.
Designed from the outset to be musi al rather than simply
implementing mathemati al algorithms, ea h program was tuned
and re-tuned to provide as wide a “sweet-spot” of settings as
possible by means of “ arpet graph” parameter tables,
intera tively linked ontrol by ontrol. It was designed by ear over
an extended period of time and from first prin iples and this is
what has made it a lassi . Despite its longevity, there is little
more any present-day design ould better and its sound is unique
and instantly re ognisable.
Now available in a plug-in, the sound on e available only to
premier studios is now on tap for a mu h wider user base.
In addition to the 9 programs that the AMS RMX16 has as standard
there are a rare series of aftermarket programs that were made
available to AMS RMX16 users if they ould get their hands on the
unique and now elusive RMX16 remote ontrol with bar ode
reader input. These 9 extra programs are in luded in the AMS
RMX-16 Digital Reverb Expanded Plugin.
Image of an original RMX16 remote ontrol Image of an original
with bar ode reader bar ode hart
Note: The following text is reprodu ed verbatim from the original
user manual.
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RMX 16 S reenshot
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The Basi Prin iples of Reverberation
Understanding Reverberation
The acoustic phenomenon known as reverberation accompanies nearly all of the
sounds we hear, in fact we are so conditioned to hearing the accompanying
reverberant field that on hearing sound totally lacking in reverberation (in anechoic
chambers, well damped studios, etc.) we are immediately struck by its unnatural
character.
Natural reverberation not only adds a certain amount of character, or coloration, to
the actual sound it is accompanying, but also 'tells' our ears from which direction
the sound is coming; approximately how far away the sound is; how loud the initial
sound was; what type of acoustic space we are in; how large the space is; what the
boundaries are like (hard walls, curtained walls, etc.) and so on.
'Dead Room' acoustics, approaching anechoic proportions, are found more and
more in modern studio designs and because of the resulting lack of natural
reverberation, a good reverberation system has been found to be mandatory in
modern recording studios. 'Good reverberation' is not enough however, since the
studio must be capable of reproducing all types of reverberant situations from
'sitting rooms' to 'great halls'. Only modern digital systems with carefully designed
programs and large memory capacity, such as the RMX 16, are capable of
producing such a wide variety.
The Fundamentals of Reverberation
Let us say you are in the centre of a small hall and someone, standing a few feet
away, claps their hands. Immediately the resulting sound wave will radiate in all
directions at an approximate rate of one foot every millisecond. The first sound you
will hear will be that which comes directly towards you from the clapped hands.
Thanks to our well developed binaural hearing this 'Direct Sound' will tell us where
the sound source is.
Next come the 'early reflections'; remember sound was radiated in all directions and
some of this radiated energy, on striking room boundaries (walls, floors, ceilings,
etc.), will again be directed towards your ears. These early reflections may be
slightly different in character from the original sound since not only is some of the
energy absorbed by the boundary upon which the wave strikes, but this absorption
also varies depending on the frequency.
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These early reflections can extend from 5ms in a small room to some 200ms in a
large hall. Even at 200ms, if the sound is not impulsive, we are unable to pick out
individual reflections during this period, but we are able to extract important
psycho-acoustic information about the type of hall and the type of boundaries
involved.
These reflections eventually build up into an extremely dense, omni-directional
reflection pattern called the 'reverberant period'. At this stage so many reflections
are arriving at once that a pleasing diffuse sound is heard which slowly dies away.
Stereo From a Mono Sour e
Another important aspect of sound in any acoustic space is its binaural nature.
Sound occurs in three dimensional space and even a single hand clap is heard in
stereo, even though emanating from a single source. The stereo image is created
by each ear receiving a slightly different pattern of reflections, coming from
different directions at different times. The 'stereo image' in artificial reverberation is
an extremely important concept and should not be ignored. We never hear truly
mono sounds in nature.
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Operating Instru tions
With digital reverberation one can simulate mathematically any real environment
and also any 'old fashioned' artificial reverberant character such as 'plates', or
'springs'. Digital reverberation techniques are the first to offer such sophistication.
The RMX 16 digital reverberation system employs sophisticated micro-programmed
parallel processing of 16 bit data offering an 18kHz bandwidth; 90dB dynamic
range and 0.03% distortion in delay mode; independent control of each program's
fundamental reverberant parameters; alphanumeric program descriptions for ease
of use and 'at a glance' understanding of how the RMX 16 is currently programmed
as all data, including the variables (pre-delay, decay time, high frequency decay
profile and low frequency decay profile), are continuously displayed on the reverb
front panel.
The RMX 16 is designed to be simple to operate with nine factory programs
simulating different reverberant environments with the ability to control all
parameters.
A calculator styled keypad is provided for entry of user definable variables. Note,
the 'C' and 'D' buttons on the keypad have no function.
Both input and output levels are adjustable to accommodate sources and
destinations sending or requiring non-standard signal levels. Overflow indication on
digital processing is provided as well as the standard 'traffic signal' LEDs enabling
fine adjustment of input level for optimum signal to noise performance.
When changing basic reverberation programs, the output is muted so that 'memory
flush-out' is not output to the audio chain. A useful feature incorporated into the
RMX 16 reverberation system is the use of 'Nudge Buttons'. These buttons
increment or decrement data for all selectable functions.
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Operation
This section is intended to familiarise the user with the front panel controls of the
RMX 16 reverberation system. Frequent reference to the front panel drawing at the
front of the manual is therefore recommended when following this section.
Input / Output Level And Level Monitoring Se tion
When the unit is switched on, the front panel LEDs will illuminate. Between the
Input level and Output level control knobs there are four LEDs (green, yellow, red
and red). The first three (i.e. green, yellow and red) are basic 'traffic signal' level
LEDs. The red LED is illuminated 6 dB, the yellow LED 12 dB and the green LED
18dB before clipping. In normal operation, with a signal present, the input level
should be adjusted so that the red LED is illuminated only when the highest
programme peaks occur. The remaining red LED indicates processing overflow.
Should this occur, due to exceptional program material, 'backing off' the input level
slightly will prevent internal clipping of the signal.
Once the input signal has been 'level matched' using the traffic signal LEDs, the
output (stereo) can be adjusted to give a good match on the output.
The output from the RMX 16 is true stereo and while these outputs may be used
singly, a more solid spatial sound will be obtained by using the stereo pair.
The Pot Control Se tion
Depressing the decay time, pre-delay or Dry Wet keys, hands control of that
parameter over to the rotary control knob above the actual pot key. This facility can
only be used once that parameter key function has been selected.
Program Sele tion
To select one of the reverberation programs first push the 'program' key, the LED
on this key will now illuminate. Actual program selection can be accomplished in
two distinct ways:
Keypad Entry
To select a reverberation program using the keypad, enter a single or two digit
number between 1 and 18 followed immediately by the 'enter' key (#); the
required program will then be loaded. Once a program number has been selected
the LED on the 'program' key will flash until the 'enter' key (#) is pressed. If the
program number selected is not available (e.g. greater than 18), then the error
message (E) will be displayed above the 'program' key. No change in program will
result and therefore the program LED will still flash. Re-pressing of the 'program'
key will clear the error condition from the display.
Using The Nudge Keys
The 'nudge' keys are very useful for jumping from one program to another. Once
'program' has been selected, a nudge up will increase the program number while a
nudge down will decrease the program number. It should be noted that when
changing between basic programs, the output is muted for a short period so that
'memory flush-out' is not output to the audio chain.
Note: Any ustom settings made to a program are lost when hanging
between programs.
Pre-Delay Entry
Pre-delay, delays the onset of reverberation giving the impression of distance from
the sound source. To introduce a pre-delay before reverberation occurs, first push
the 'pre-delay' Key.
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The LED on this key will now illuminate. Again, actual pre-delay setting can be
accomplished in three distinct ways:
Keypad Entry
Using the keypad, enter the amount of pre-delay required followed by the the enter
key (#). The amount (ms) of pre-delay will be displayed above the 'pre-delay' key
and as information is entered from the keypad the LED on the 'pre-delay' key will
flash. If the requested pre-delay time is within certain limits, the output will be
delayed with respect to the input by this amount and the LED will stop flashing. If
the requested pre-delay time is greater than that which is available using the
program selected, the error message (E) will be displayed above the 'pre-delay'
key. No change in the program will result so the 'pre-delay' LED will continue
flashing. To clear this error the 'pre-delay' key should be pressed again.
Using The Nudge Keys
If the Nudge Keys are used, the pre-delay amount will be increased or decreased;
the step size being program dependent. It is important to remember that the
maximum available pre-delay time depends on the basic reverberation program in
use. The maximum pre-delay time for each reverberation program is given in the
program notes at the back of this manual (see APPENDIX B).
Pot Control Entry
You can also vary the pre-delay using the pot control. Once the pre-delay function
has been selected, control of the pre-delay is immediately available to the rotary
pot directly above the pot key.
De ay Time Entry
To vary the decay time first push the 'decay time' key. The LED on that key will
now illuminate. There are three ways of adjusting decay time:
Keypad Entry
Decay time may be selected using the keypad. Both the minimum and the
maximum decay times are dependent upon the program selected. Fractions of a
second are entered by using the '*' key as a decimal point. Hence 2.8 Seconds
would be entered by first pressing the 'decay time' key followed by the '2' key, the
'*' key, the '8' key and finally the enter key (#).
Using The Nudge Keys
Once the 'decay time' key has been pressed, an increase or decrease in the decay
time can be accomplished by the use of the nudge keys. Depressing the nudge up
key will result in the illumination of the nudge up LED and an increase in the decay
time. Depressing the nudge down key will result in illumination of the nudge down
LED and a corresponding decrease in the decay time. The decay time will increase
or decrease in 0.1 second steps.
Pot Control Entry
You can also vary the decay time using the pot control. Once the decay time
function has been selected, control of the decay time is immediately available to
the rotary pot directly above the pot key.
De ay Filter Controls
The availability and use of these controls is dependent upon the basic reverberation
program in use (See Appendix B).
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