REBIS RA701 User manual

REBIS AUDIO RA701
MIDI GATE
OPERATORS MANUAL
CONTENTS Page
Installation 2
Audio Operation 3
MIDI Operation 6
MIDI Key Number 7
General Use 8
Drum Separation 8
LED Indicators 8
DC Triggers 9
MIDI Data 9
Specification 10
Controls 11
Rear Panel 12
MIDI Data Table 13

INSTALLATION
Important: Refer all installation and servicing to qualified personnel.
Note: The RA701 should not be installed in close proximity to such
equipment as power amplifiers or power supplies which may produce
excessive heat or magnetic interference.
Earthing
It is normal practice when installing rackmount equipment to discon-
nect the earth from the mains lead, and earth the unit mechanically via
the rack cabinet.
Whatever earthing system is used IT IS ESSENTIAL THAT THE
CHASSIS OF THE RA701 IS ULTIMATELY CONNECTED TO
MAINS EARTH.
Audio Connections
Audio connections to the RA701 are made via 0.25 inch 'A' type mono
jacks.
To avoid earth loops it is normal practice in professional studios to run a
single 0V connection to the patchbay, and make signal screens discon-
tinuous. Input screens should be connected at the RA701 and output
screens at the patchbay.
DC Connections
DC connections to the RA701 are made via 0.25 inch 'A' type stereo
jacks.
The DC trigger output appears on the tip, DC input on the ring, and 0V
on the sleeve.
MIDI Connections
The MIDI out can be connected to the MIDI in on any suitable equip-
ment, with a standard MIDI lead.
If more than one RA701 is being used and a common MIDI out is re-
quired, units can be cascaded by connecting the MIDI out on one unit to
the Merge in on the next. (Note: Merge connections must be made us-
ing a true five way DIN to DIN lead. Your standard MIDI leads may
only have three connections).

AUDIO OPERATION
The overall effect of the RA701 is controlled by the GATE section.
The IN/out switch is used to bypass the Gate or make A/B comparisons.
The maximum attenuation is determined by the RANGE control. Mate-
rial with a high ambient level often sounds better with a reduced Range
setting to make the gating action less abrupt.
The FILTER section can be used for programme equalisation or
frequency conscious gating.
For programme eq switch the filter to the GATE position, the input sig-
nal will then pass through the filter into the gate. Tailoring the band-
width to match the frequency content of the material can result in a
significant reduction in system noise, with no loss of fidelity.
For frequency conscious gating switch the filter to the TRIGger posi-
tion. The input signal (internal or external) will then be fed through the
filter to the trigger section. In this mode the filter can be used to adjust
the frequency sensitivity of the trigger without affecting the gated signal.
Use the HF and LF controls to roll off any frequencies which may
cause erratic gating. (e.g. snare drum channel - use HF to remove cym-
bals and LF to remove bass drum, leaving a 'window' for the snare).
Use the MONITOR button (trigger section) to listen to the trigger sig-
nal while adjusting the filter.

The TRIGGER section takes audio signal and turns it into control
information for the Envelope section.
The Trigger source, normally the input signal, can be changed to the
Ext/Key input with the EXTERNAL button. External triggering allows
one track to modify the dynamics of another track or tracks. (e.g. use
the bass drum to Key a gated bass
line).Using the MONITOR button to listen to the trigger source will
now allow you to hear the external input.
The THRESHOLD control determines the level at which the trigger
operates. It is usually best to set the Threshold as low as possible with-
out letting through unwanted background noises or cross mic pick-up.
The THD LED is illuminated while the trigger signal is above the set
threshold.
When MASK is switched in, the trigger section will not re-fire for a pe-
riod set by the MASK time control. The MSK LED shows when the
trigger mask is active. Trigger Mask can be used to remove offbeats or,
by reducing the attenuation range, creating accents.

The dynamic parameters of the RA701 are
controlled by the ENVELOPE section.
The DELAY control introduces a time lag between the trigger and the
Envelope Attack. It can produce flam effects on drums or repeat ef-
fects on keyboards. Envelope Delay also opens new possibilities in re-
verb processing (e.g. when gating snare reverb use Delay to produce a
burst of reverb say one beat after the snare).
The DEL LED gives a visual indication of the delay length.
The ATTACK control sets the time taken for the gate to open. Very fast
Attack times are usually needed for percussive sounds, whilst vocals or
low frequency sounds normally require a slower attack.
The ATK LED fades up as the gate attacks and remains on full while
the gate is open.
When the trigger source falls below threshold the gate will remain fully
open for a period set by the HOLD control and indicated by the HLD
LED. Use Hold when you want to preserve the natural decay of the sig-
nal.
After the Hold period the gate starts to close. The time taken to reach
full attenuation is set by the RELEASE control.
The DUCK switch inverts the envelope, so when the trigger source is
above threshold the gate attenuates. Most Ducking applications will use
an external trigger source, and require a reduced Range setting. (e.g.
Duck a music track a few dBs using a vocal or voice over channel as
trigger source.)
When the FIXED mode is selected the whole envelope is triggered
when the signal rises above threshold. i.e. Hold will follow Attack with-
out waiting for the signal to fall below threshold. This mode is useful
for processing tom-toms if they have a particularly loud ring, or reshap-
ing sampled sounds.
When operating the RA701 in STEREO the right channel Envelope and
Trigger controls are disabled and left channel acts as master controller.

MIDI OPERATION
The primary application of MIDI on the RA701 is to trigger drum ma-
chine voices with a live or recorded drum track.
There are two important things to remember when using the RA701
with MIDI.
1. Good drum separation is vital. Every care must be taken to ensure
that the gate can not be fired by the wrong drum. See DRUM
SEPERATION P8.
2. The Hold time must be short enough for the gate to re-fire on the fast-
est successive beats.
Note on data is sent immediately the gate starts to attack.
The ATK LED therefore also serves to indicate note on sent.
The velocity value sent is normally 64 (50%). Switching in MIDI
VELocity allows the value to be determined by the level of the trigger
signal at the moment the gate starts to attack.
Note on transmission can be delayed up to 2 seconds with the DELAY
control. If the signal is no longer at a suitable level at that point it may
be necessary to switch out the MIDI VELocity. If the signal is no long-
er present at all, use the FIXED envelope mode to ensure that MIDI is
still transmitted.
Note off data is sent when the gate starts to release, indicated by the
REL LED.
Most drum machines do not require note off, but if you are using the
RA701 to trigger a keyboard remember that the HOLD time will add to
the note length. (In the FIXED mode the note length will be the sum of
the ATTACK and HOLD times).

Trigger MASK can be used to great effect to send MIDI selectively, say
on the first beat every two bars, by setting the MASK time to the equiv-
alent of just less than two bars.
Use DUCK in conjunction with Mask to replace occasional beats with a
MIDI voice. (e.g. a snare occurring every two beats can be alternately
replaced by a MIDI handclap by selecting DUCK and setting the
MASK time to the equivalent of three beats).
Occasionally, when complex gating and MIDI triggering are being car-
ried out simultaneously, there may be a conflict between the control set-
tings for audio and MIDI. The STEREO mode can be used to cope
with this situation.
Whilst the STEREO mode locks the audio dynamics of the two chan-
nels and disables the right channel Trigger and Envelope controls, they
remain operative for MIDI control. Using the left channel for audio and
the right channel for MIDI allows full independent control of Mask, De-
lay, Duck etc.
MIDI KEY NUMBER
On most drum machines it is a simple operation to allocate a particular
voice to a given MIDI key number, but if necessary the key numbers
(along with the channel and velocity data) transmitted by the RA701
can be adjusted to suit the receiving MIDI equipment.
Refer to MIDI Data Switch Setting Table (back page) for rear panel
switch positions.

GENERAL USE
The RA701 MIDI Gate is normally used in the channel inserts of a mix-
ing desk. If pre and post inserts are available the post eq inserts should
be used, and if other signal processors are being used in series with the
gate then it should be the last element in the chain.
In the studio, wherever possible, the RA701 should be used at the mix-
down stage rather than on the initial recording. If noise gates are used to
achieve the sound for the initial recording it is good practice to switch
them out for the 'take' and back in for replay and mixdown. This is par-
ticularly important when you are using the RA701 to make modifica-
tions to the envelope of a sound. Remember a noise gate works by
'taking bits away' and once they've gone you won't be able to put them
back.
DRUM SEPARATION
When using the RA701 with MIDI, achieving good drum separation is
of great importance.
Careful use of the Filter to remove unwanted frequencies from the Trig-
ger signal is usually all that is required. Using a contact mic to key the
gate, however, will make false triggering virtually impossible. Mic the
drum in the normal way, fit a contact mic to the drum (preferably in-
side) and use it to drive the Ext Key input.
LED INDICATORS
You will notice that the Threshold and Envelope LEDs remain operative
when the Gate is switched out. This can be particularly useful in live
situations.

DC TRIGGERS
The RA701 is fitted with DC Trigger outputs and inputs for each chan-
nel.
The outputs can be used to trigger drum machines of the pre-MIDI gen-
eration, or CV/Gate type synthesisers and samplers.
The inputs can be used for remote triggering of the gate or trigger/MIDI
interface.
Switch the Trigger to External when using the DC Trigger input.
MIDI DATA
The RA701 leaves the factory adjusted to the following MIDI data set-
tings.
Velocity Range: -10dB to +10dB. An input of -10dB will produce a
velocity value of 1. Higher input levels will increase the velocity value
through to 127 at +10dB.
Channel Number: 1. Set receiving MIDI equipment to channel 1 or
OMNI mode.
Key Numbers: Left channel 36, right channel 38. Corresponding re-
spectively to C1 and D1 on a MIDI Keyboard and bass drum and snare
voices in most drum machines in default (initialized) mode.

SPECIFICATION
Model: RA701 MIDI Gate
Channels: 2
Inputs: Maxlevel+21dBm.Impedance 100 kilohms
Outputs: Max level +21dBm into 600 ohms.
Impedance less than 50 ohms
Balancing: Optional electronic
Distortion: Less than 0.05% 20Hz to 20kHz
Noise: -104dBm. 20Hz to 20kHz. Max attenuation
-95dBm. 20Hz to 20kHz. Zero attenuation
Frequency Response: +0.5dB. 20Hz to 20kHz
DC Trigger Inputs: +5 volts to open gate
DC Trigger Outputs: +5 volts when gate opens
MIDI Output: After Envelope Delay sends -
Channel number (adjustable 1 to 16)
Note on
Key number (adjustable 0 to 127)
Velocity (0 to 127/fixed 64)
After Hold period sends -
Matching channel number
Note off
Matching Key number
Power Requirement: 220-240V AC. 30 watts max
(110-120V by internal connections)
Fuse: 500mA
Dimensions: 19" rackmount x 1U(44mm) x 245mm
Weight: 3.6 kg nett

CONTROLS
Gate
Bypass: In/Out
Range: 0dB to 90dB attenuation
Filter
Bypass: In/Out
Position: Gate (thru signal, pre side chain
send)/Trigger (side chain)
LF: 25Hz to 5kHz. 12dB/octave
HF: 75Hz to 18kHz. 12dB/octave
Trigger
Mask: On/Off
Mask Time: 0 to 4 seconds
Monitor: Trigger (post filter)/Main output
Source: External (key input)/Main input
Threshold: +20dB to -40dB
Mask LED: Mask active (trigger disabled)
Threshold LED: Trigger source above threshold
Envelope
Delay LED: Delay period
Attack LED: Attack period (MIDI note on sent)
Hold LED: Hold period
Release LED: Release period (MIDI note off sent)
Delay: 0 to 2 seconds
Attack: 10uS to 250mS
Hold: 10mS to 3 seconds
Release: 5mS to 2 seconds
Duck: Inverts envelope
Fixed: Envelope length fixed/Programme related
Velocity: MIDI velocity fixed (value 64)/ Programme related (0 to 127)
Stereo Link: Dual mono/Stereo (master/slave)

REAR PANEL
Per Channel
Audio input
Audio output
Audio external trigger (Key input)
DC trigger input (ring)
DC trigger output (tip)
(Audio and DC connections on 1/4" 'A' type jacks)
MIDI key number selector (0 to 127)
MIDI velocity range switch (1 to 3)
Per Unit
MIDI channel number selector (1 to 16)
MIDI output
Merge input (Accepts an RA701 MIDI output for serial connection)
Fuse holder
IEC mains inlet

MIDI DATA SWITCH SETTING TABLE
Switch positions 'ON' for each range/number
Velocity Range Note/Key Number
-20dB to 0dB OFF 47 1234 6 87 123 5 7
-10dB to +10dB 1 3 48 56 88 45 7
0dB to +20dB 2 4 49 1 56 89 1 45 7
50 2 56 90 2 45 7
51 12 56 91 12 45 7
52 3 56 92 345 7
Channel Number 53 1 3 56 93 1 345 7
1OFF 98 54 23 56 94 2345 7
25 10 5 8 55 123 56 95 12345 7
36 11 6 8 56 456 96 67
456 12 56 8 57 1 456 97 1 67
57 13 78 58 2 456 98 2 67
65 7 14 5 78 59 12 456 99 12 67
767 15 678 60 3456 100 3 67
8567 16 5678 61 1 3456 101 1 3 67
62 23456 102 23 67
Note/Key Number 63 123456 103 123 67
11 24 45 64 7 104 4 67
22 25 1 45 65 1 7 105 1 4 67
312 26 2 45 66 2 7 106 2 4 67
43 27 12 45 67 12 7 107 12 4 67
51 3 28 345 68 3 7 108 34 67
623 29 1 345 69 1 3 7 109 1 34 67
7123 30 2345 70 23 7 110 234 67
84 31 12345 71 123 7 111 1234 67
91 4 32 6 72 4 7 112 567
10 2 4 33 1 6 73 1 4 7 113 1 567
11 12 4 34 2 6 74 2 4 7 114 2 567
12 34 35 12 6 75 12 4 7 115 12 567
13 1 34 36 3 6 76 34 7 116 3 567
14 234 37 1 3 6 77 1 34 7 117 1 3 567
15 1234 38 23 6 78 234 7 118 23 567
16 5 39 123 6 79 1234 7 119 123 567
17 1 5 40 4 6 80 5 7 120 4567
18 2 5 41 1 4 6 81 1 5 7 121 1 4567
19 12 5 42 2 4 6 82 2 5 7 122 2 4567
20 3 5 43 12 4 6 83 12 5 7 123 12 4567
21 1 3 5 44 34 6 84 3 5 7 124 34567
22 23 5 45 1 34 6 85 1 3 5 7 125 1 34567
23 123 5 46 234 6 86 23 5 7 126 234567