47 Pearl Street :: Enfield, CT 06082 USA :: charteroakacoustics.com CharterOak
ACOUSTIC DEVICES 47 Pearl Street :: Enfield, CT 06082 USA :: charteroakacoustics.com CharterOak
ACOUSTIC DEVICES
GETTING STARTED
The SCL-1 will provide a constant output level regardless of input level or frequency. The release characteristic is a function
of the total dynamic range and the average program level. The device achieves this through waveform differentiation and
integration. The SCL-1 employs a rectifier circuit that has a parabolic average charge curve. The intent of the circuit is to
provide fast releases of rhythmic and staccato peaks, which release to a continually changing average level or sustained
music, which is determined by the parabolic charge curve of the storage capacitors. The SCL-1 has low inherent noise and
broad dynamic range. Its rich and balanced sound makes it an ideal choice for extremely high quality dynamics control in
the recording, mixing, and broadcast environments. The SCL-1 is exceptional when used as a stereo buss compressor.
When used as a stereo buss compressor, the CharterOak SCL-1 completely eliminates the need for high pass and low pass
filters, other equalizers used in side chains, and other convoluted signal paths. Most compressor limiters when used in the
mix buss, will react to transient peaks in such a way as to make it sound like there is a ducker on the vocal or the rest of the
mix. The circuit employed in the SCL-1 releases to a constantly changing average program level with a characteristic that is
extremely musical due to the parabolic charge curve of the storage capacitors.
The SCL-1 employs NO MAGIC BLACK BOXES or other wallet shrinking components. All of the components used in the SCL-
1 are readily available and are employed in a manner so as to provide high headroom for years of use, without the need
for shut-down or service.
The SCL-1 can be used a stereo signal processor or two independent signal processors.
For stereo operation, set the MODE switch to STEREO and the meter switch to Channel 1. When using the unit with the MODE
switch set to STEREO, the STATIC THRESHOLD, DYNAMIC THRESHOLD, ATTACK, RELEASE, and SLOPE controls on channel
1 control the unit. The INPUT and OUTPUT controls remain independent and constantly variable in both STEREO and DUAL
modes of operation.
Begin by calibrating the STATIC THRESHOLD control on channel one for 2.9 VDC or “0” VU. To start, apply program material
with peaks of at least “0” VU to the input jacks at the rear of the unit. The SCL-1 is intended for +4 balanced operation.
Set the INPUT control at “7”. Set the DYNAMIC THRESHOLD control at “7” or close to the lowest possible threshold. Set the
ATTACK control at “3”, or medium fast. Set the RELEASE control at “7” or medium fast. Set the SLOPE control at “5” or 10:1
compression. Gradually turn OUPUT control clockwise to achieve the desired output level. NOTE: These settings are intended
to be a suggested starting point and can vary according to the level and rhythmic characteristics of the program material.
If the compressor is inactive you need to take one or more of the following steps; increase INPUT level, lower DYNAMIC
THRESHOLD, use faster ATTACK time, increase SLOPE.
It is suggested that you do not adjust the STATIC THRESHOLD control again until you are satisfied with your results. After
you are satisfied with the dynamics and rhythm of your program material, you can use the STATIC THRESHOLD control as a
constantly variable knee control. By slightly raising the control voltage towards 5.0 VDC or counter clockwise you can create
less potential for swing in the control circuit, thus softening the knee. Alternatively, you can slightly lower the control voltage
towards 2.5 VDC or clockwise, creating the potential for more swing in the control circuit thus hardening the knee.
For dual mono operation, set the MODE switch to DUAL. The METER switch can now be used to monitor the activity on
channels 1 and 2. Start by putting the METER switch in the channel 1 position. Calibrate the STATIC THRESHOLD control
on channel 1 for 2.9 VDC or “0” VU. Put the METER switch in the channel 2 position and calibrate the STATIC THRESHOLD
control on channel 2 for 2.9 VDC or “0” VU. To start, apply signal with peaks of “0” VU to the input jacks at the rear of the
unit. Set the INPUT controls at “7”. Set the DYNAMIC THRESHOLD controls fully clockwise or lowest possible threshold. Set
the ATTACK controls at “3”, or medium fast. Set the RELEASE controls at “7” or medium fast. Set the SLOPE control at “5”
or 10:1 compression.
Exactly as when you are using the SCL-1 as a stereo compressor, it is suggested that you do not adjust the STATIC THRESHOLD
control again after calibration until you are satisfied with your results. After you are satisfied with the dynamics and rhythm of
your track, you can use the STATIC THRESHOLD control as a constantly variable knee control. By slightly raising the control
voltage towards 5.0 VDC or counter clockwise you can create less potential for swing in the control circuit, thus softening the
knee. Alternatively, you can slightly lower the control voltage towards 2.5 VDC or clockwise, creating the potential for more
swing in the control circuit thus hardening the knee.
Gradually turn the OUPUT control clockwise to achieve the desired output level. NOTE: These settings are intended to be a
suggested starting point and can vary according to the level and rhythmic characteristics of the program material.
The SCL-1 has extremely high headroom and allows for several decibels of make up gain if necessary.
Always make sure you put enough signal into the compressor. Never be afraid to drive the unit. It will never pump or gasp
or distort. In order to achieve the best results, all of the controls on the SCL-1 are constantly variable. The SCL-1 is capable
of extremely fast attack times. Setting the ATTACK CONTROL on “0” or 100us can be useful, but is not recommended. Be
careful to adjust the ATTACK and RELEASE controls in a manner so as to allow the peaks in the music to come through
clearly. This will ensure that all of the rhythmic content of the music is preserved and enhanced.
Additionally, when using the SCL-1 as a stereo buss compressor, try to make sure that the average gain reduction is no less
than -3 dB and no more than -20 dB. Average gain reduction on the order of -4dB to -8dB, will result in a +3dB slope shift,
providing a higher average modulation level.
