Rebis Audio RA702 User manual

REBIS AUDIO RA702
MULTI GATE
OPERATORS MANUAL
CONTENTS Page
Installation 2
Audio Operation 3
Sync 4
General Use 5
Drum Separation 5
LED Indicators 5
Specification 6
Controls 7

INSTALLATION
Important: Refer all installation and servicing to qualified personnel.
Note: The RA702 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 RA702 IS ULTIMATELY CONNECTED TO
MAINS EARTH.
Audio Connections
Audio connections to the RA702 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 RA702 and output
screens at the patchbay.

AUDIO OPERATION
The THRESHOLD control sets the level of signal needed to open the
gate. Turning the control clockwise increases the gates sensitivity, i.e.
lowers the Threshold. The ideal setting will be a little above the loudest
peaks of the unwanted cross mic pickup or background noise. The THD
LED is illuminated while signal is above the set threshold.
ATTACK, (the time taken for the gate to open) can be switched be-
tween two ranges. The Slow attack range is suitable for most signals,
particularly vocals and bass instruments whilst the Fast range should be
selected for percussive sounds. Fine tuning of the Attack is done auto-
matically by the RA702 to match the dynamic profile of the material.
This semi automatic approach ensures optimum attack with the mini-
mum of adjustment.
The functions of hold and decay are combined in a single RELEASE
control.
The hold and decay parameters are perfectly proportioned across the
range of Release times. This avoids 'hunting' on signals around thresh-
old, and eliminates distortion when applying fast release to low frequen-
cy signals.
The HF and LF filters can be used for frequency conscious gating by
adjusting the frequency sensitivity of the side chain without affecting
the gated signal.
Use the HF and LF filters to roll off any frequencies which may cause
erratic gating. (e.g. snare drum channel - use HF to remove cymbals and
LF to remove bass drum, leaving a 'window' for the snare).
Use the MONITOR button to listen to the side chain signal while ad-
justing the filters.
The side chain trigger source, normally the input signal, can be
changed to the Ext Key input with the EXT/KEY 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 side chain source will now
allow you to hear the external input.
MASTER BYPASS opens all the gates with a single switch to allow
simultaneous drop in or drop out.
In live sound it can be used as a 'panic button' to save precious moments
if problems arise. For example it could be used to open all the tom tom
mics if the snare mic failed, to compensate for the loss of sound during
replacement or adjustment.
SYNC
When multi part backing vocals or brass riffs are performed live the per-
formers often rely heavily on visual cues to achieve good synchronisa-
tion.
When a single performer is multitracking the parts, and these cues are
absent, it can be quite difficult to end the last note of each phrase togeth-
er. This leads to ragged 'tails' on otherwise perfect performances.
The Rebis MultiGate solves this problem with its unique Sync feature.
In Sync mode the RA702 automatically selects the track with the short-
est phrasing, and uses it as a key to close all the gates simultaneously.
The result is a clean, tight track with the minimum of rehearsal and re-
takes.

GENERAL USE
The RA702 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 RA702 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 RA702 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
Careful use of the Filters to remove unwanted frequencies from the side
chain 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
inside) and use it to drive the Ext Key input.
LED INDICATORS
You will notice that the Threshold and Release LEDs remain operative
when the Gates are switched out. This can be particularly useful in live
situations, allowing the gate to be adjusted off line.

SPECIFICATION
Model: RA702 MultiGate
Channels: 4
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. Gate closed
-95dBm. 20Hz to 20kHz. Gate open
Frequency Response: +0.5dB. 20Hz to 20kHz
Attenuation: 90dB (gate closed)
Audio Connections: 1/4" A type jacks
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
IN: Individual gate in/out
Threshold: +20dBm to -40dBm
Threshold LED: Signal above threshold
Attack: Programme related, semi-automatic
Fast range 50uSto 100uS
Slow range 500uS to 2mS
Release: 40mS to 2 Seconds
(combined holdand decay)
Release LED: Fades to indicate release time.
Ext/Key: Selects external side chain source.
LF side chain filter: 20Hz to 5kHz. 12dB/octave
HF side chain filter: 80Hz to 20kHz. 12dB/octave
Monitor: Routes side chain filter to output.
Master Bypass: Holds all gates open.
Master Sync: Synchronises closure of all gates to channel with short-
est envelope.