Amplifier Research 701R Manuel du propriétaire - Page 3

Parcourez en ligne ou téléchargez le pdf Manuel du propriétaire pour {nom_de_la_catégorie} Amplifier Research 701R. Amplifier Research 701R 8 pages.

INTRODUCTION
The system you have purchased is a very portable package
with the flexibility of mixers twice the size at twice the price.
The 701R™ features seven channels, excellent 4-band
equalization, rack-mount versatility, balanced inputs, and
balanced outputs.
Rack-mountable mixers have a special place in sound rein¬
forcement applications, and many times no other type pro¬
duct will suffice. The 701R requires a very low profile, vertical
mounting space, and is exceptionally thin, front to back. These
dimensions are critical, as rack space is usually a premium
consideration. The input circuitry has tremendous dynamic
range and will handle sound reinforcement applications with
ease. As you read the enclosed literature, please try to learn
as much as possible about the product so your job of sound
reproduction will be easier and the results will be an overall
improved performance. The person doing sound or installing
sound systems is actually an extension of the performance
and should master the sound equipment, just as a musician
masters his/her instrument.
INPUT GAIN CONTROL (1)
The Input Gain Control of the 701R Mixer utilizes a dual con¬
trol element configuration so that input attenuation and gain
adjustment occur simultaneously. This arrangement allows
the vital input circuitry to handle almost any input voltage from
low level mics to speaker levels. The function and operational
requirements of this input gain stage are conventional and
should present no operational difficulty.
MONITOR SEND CONTROL (2)
The monitor send control is the channel mixing element for
determining the all important monitor mix. Signals for the
monitor sends are obtained right after the input preamp and
before the channel EQ. These are referred to as pre monitor
sends, i.e. they are before the channel equalization and chan¬
nel level controls. This makes them independent of these con¬
trols and any changes made to the EQ or channel level will
not affect the monitor system. Having the monitor send with
pre-EQ capability is absolutely vital to avoid feedback of the
monitor system when EQ and normal incremental setting
variations are made in the channel fader during the course
of the performance.
HIGH FREQUENCY EQ (4)
This control determines the relative boost or cut of the highest
frequency adjustment on this console and features a 15 dB
boost or cut at 15 kHz. This control operates in a shelving
configuration which prevents any additional gain above the
usable audio spectrum from causing undesirable hiss and
instability. The zero setting indicates a flat frequency response
with no alteration of the extreme highs and clockwise indicates
a boost while counterclockwise indicates a cut or a dip in the
high frequencies. Usually feedback is not much of a problem
at very high frequencies, but the control is very important for
giving that sibilant sound on the extreme highs and on the
s's and t's of the vocals.
HIGH MID FREQUENCY EQ (5)
This control determines the relative boost or cut of the upper
mid or lower treble frequencies and is capable of 15 dB boost
or cut at 3 kHz. A balance of mid range frequencies should
begin with a flat setting of zero so that adjustments may be
made with a cut or a boost of this control. The action of the
control is peak/notch type which interfaces with the adjacent
equalizers in a smoother manner to yield optimum summing
capability of the channel equalization. Usually a minus set¬
ting of this control is desirable to eliminate harshness with
most systems and control feedback.
LOW MID FREQUENCY EQ (5)
This control is operational in the lower mid range or upper
bass region and is capable of 15 dB boost or cut at 400 Hz.
This EQ control exhibits a peak/notch characteristic which
operates smoothly with the adjacent equalizer controls and
allows proper balancing of the upper bass and lower mid
range frequencies. This control is very vital for controlling the
mid range frequencies of the human voice when vocals are
being amplified. (Most vocals require a slight minus setting
of this control.)
LOW FREQUENCY EQ (6)
This control is capable of 15 dB boost or cut at 60 Hz and
demonstrates a shelving characteristic so that excessive lows
are not boosted below the usable range of typical sound rein¬
forcement. The shelving action of this circuit has proven to
yield much more satisfying and effective equalization
characteristics than some of the wide open EQ circuits claim¬
ing 20 to 25 dB boost and cut. Care should be taken with the
low frequency control not to over-boost lows on any particular
instrument or vocal due to the fact that tremendous amounts
of headroom will be used up and a general muddiness will
be apparent in the sound system reproduction. Woofers may
also be blown much more easily with extreme low frequency
boost.
EFFECTS SEND CONTROL (7)
This effects control is post and is effected by the equaliza¬
tion of each channel and its level is also effected by the chan¬
nel level control. NOTE: This action is totally opposite from
the monitor send controls on each channel which are pre and
unaffected by other features on the channel. When the ef¬
fects send control is activated on any particular channel, a
signal is sent through the master effects level control and ap¬
pears at the effects output on the rear panel. This output may
be patched into many various effects devices. (See effects
patch diagrams.) NOTE: The internal reverb drive receives
its signal from the effects send control also and a signal is
then sent to the master reverb control in the master section
in order for the internal reverberation system to function. When
operating an outboard effects device and the internal reverb
system simultaneously, the channel send control on the ef¬
fects mix must be optimized for the amount of both effects
on a particular channel.
PAN CONTROL (8)
This control is most often used to assign certain channels to
one or both subs. The action is conventional and clockwise
rotation assigns to sub "B" while counterclockwise rotation
assigns to sub "A". A setting of 12:00 places the channel
equally in both subs. NOTE: When recording, this control may
be used for stereo imaging (left, right, or both).
CHANNEL LEVEL CONTROL (9)
The channel level is the output control that determines the
mix of the various channels into the master mix. This control
should be operated near the zero indication of unity gain
whenever possible and the input gain control should be ad¬
justed accordingly for each instrument or vocal, etc. NOTE:
Above the zero point on the channel level slider there is 14
dB of gain as you increase to the upper limit of the level con¬
trol. It is virtually impossible to have too much gain during
typical sound reinforcement situations and when a low gain
situation presents itself it is nice to be able to increase the
channel gain by 14 dB with the level control and possibly avoid
having to readjust input gain sensitivity. NOTE: Operation
above "0" increases system noise. Operation below "0"
decreases system noise but at the sacrifice of system
headroom.