Joranalogue ENHANCE 2 User manual

ENHANCE 2
STEREOPHONIC
ENHANCER
1
INTRODUCTION
Moving from mono to stereo sound: a logical
progression for any synthesist looking to expand
their sonic palette. Making use of two audio
channels, rather than just one, quite literally adds
another dimension to the capabilities of a
synthesiser.
Unfortunately, controlling stereo signals can be a
challenge within a modular system. This
realisation led to the development of Enhance 2:
a convenient yet high-fidelity tool for stereo
enhancement. It can be used to adjust balance,
width and spectral content, while also opening
up a world of mid/side processing; all under
voltage control and in just 8 HP.
The primary stereo parameters are balance
(moving the sound left or right) and width
(making it narrower or wider). The balance circuit
uses a true constant-power gain law, while the
width stage allows for seamless transitions from
pure mono to extra-wide stereo.
In addition, tone control is provided by a pair of
unique, wide-ranging mid/side voltage
controlled tilt filters with selectable corner
frequency. These make ‘cleaning up’ a muddy-
sounding mix straightforward, but also provide
unique binaural effects when modulated.
Mid/side processing encodes the stereo signals
into one containing only the mono material
(mid), and another containing the differences
between both channels (side). Apart from the
internal tilt filters, mid/side outputs also enable
external signal processing such as compression
or reverberation. An integrated mid/side decoder
returns the results back to standard stereo. And
at all times, a LED bar phase meter ensures that
phase correlation can be easily maintained.
Stereo field modulation, mid/side equalisation
and beyond; Enhance 2 brings true analogue
stereo control to the Eurorack world.
CONTENTS
In the Enhance 2 box, you’ll find:
Product card, stating serial number and
production batch.
16-to-10-pin Eurorack power cable.
Mounting hardware: two black M3 x 6 mm
hex screws, two black nylon washers and a
hex key.
The Enhance 2 module itself, in a protective
cotton bag.
If any of these items are missing, please contact
your dealer or [e-mail].

ENHANCE 2
STEREOPHONIC
ENHANCER
2
CONTROLS & CONNECTIONS
1 PHASE CORRELATION METER
The phase correlation meter is used to gauge the
similarity of the left and right stereo output
channels. The correlation figure can range from
+1 (fully correlated, so no stereo content, only
mono), through 0 (no inter-channel correlation)
to −1 (the two channels are completely in anti-
phase).
A good stereo image is achieved with a
correlation factor between 0 and +1. Negative
correlation however, indicates a phase issue and
is to be avoided. In this case, sound would be lost
if the stereo channels were to be mixed into
mono (for example, loss of bass during playback
on a mono speaker or a subwoofer-equipped
sound system).
Note that at least 100 mVpp of signal is required
on both channels to ensure correct phase
readings.
2 BALANCE KNOB AND CV INPUT
Use the balance control to shift the stereo image
left or right.
The gains of both channels are controlled
according to a carefully tailored balance law. The
opposing channel will be attenuated when set to
either extreme position, while the selected
channel will be boosted by +3 dB to maintain
constant loudness. Set to the centre position,
both channels remain at unity gain.
This parameter can be voltage modulated using
the corresponding CV input. With the balance
knob centred, the stereo image will shift fully left
for a CV of −5 V, or fully right at +5 V.

ENHANCE 2
STEREOPHONIC
ENHANCER
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3 WIDTH KNOB AND CV INPUT
The width knob adjusts the overall ‘stereoness’,
from 0 % (mono mix), through 100 % when set
centrally (no change to the stereo image), and
beyond up to 200 %.
The width CV input is used to modulate this
parameter at 20 %/V. You can achieve extremely
wide stereo sound this way, but keep an eye on
the phase correlation!
4 MID/SIDE TILT KNOBS, SWITCHES AND CV
INPUTS
Enhance 2 uses mid/side processing, a powerful
technique for sculpting stereo material. Two new
channels are derived from the stereo pair: the
mid channel contains only the centred material
that is common to left and right, while the side
channel isolates the stereo content which differs
between both sides. This makes for very intuitive
processing.
The tone of each of these channels can be easily
adjusted using the tilt filters. They smoothly
morph from a +6 dB bass boost and full treble
cut when set fully counter-clockwise, to a full
bass cut and +6 dB treble boost when set fully
clockwise. The centre positions are flat (unity
gain).
The corner frequency for each filter can be
toggled between bass (250 Hz) and treble (1 kHz)
using the range switches.
Modulate the tilt filters using the CV inputs.
Moving from flat to either extreme tilt requires a
5 V of CV.
5 STEREO INPUTS
Connect your pair of stereo source signals here.
The entire signal path is DC-coupled.
Mono signals can be processed using just the left
input socket, as there is normalisation to the
right. Keep in mind that in this case, due to the
lack of stereo content, only the balance and mid
tilt features will be functional.
6 MID/SIDE OUTPUTS
These are the mid/side outputs of the stereo
processor. You can use these for further mid/side
processing using external modules.
Keep in mind that for most stereo signals, the
mid signal will be much stronger, as there is
typically more mono than pure stereo material;
or in other words, a high phase correlation.
Both outputs are inverted with respect to the
input signals.
7 MID/SIDE INPUTS AND STEREO OUTPUTS
This mid/side decoder allows you to convert a
mid/side pair back to stereo. It is fully
independent from the stereo processor, except
for the normalisation from the processor’s
outputs to the decoder inputs.
This means that if you do not wish to perform any
additional mid/side processing, you can simply
use the module’s stereo inputs and outputs
directly. Otherwise, you can plug your processed
mid/side pair into this decoder and get standard
stereo outputs. External processing of only the
mid or the side channel is possible as well.
Note that the phase correlation meter uses the
decoder’s stereo outputs as its source pair. This
means that the meter will also take in account
any external mid/side processing that may
influence the phase correlation.
Also be aware that while Enhance 2’s entire
signal path is DC coupled, the meter will only
respond to audio frequencies. To complement
the module’s inverting mid/side outputs, this
decoder is inverting as well, restoring the proper
phase relationship of your stereo signals.

ENHANCE 2
STEREOPHONIC
ENHANCER
4
PATCH IDEAS
STEREO MIX WIDENER
The most obvious application for Enhance 2 is
that of stereo mix widening. However, a full mix
cannot simply be made wider without risking
phase correlation issues. It is also important to
keep psychoacoustics in mind: higher audio
frequencies are perceived as being much more
directional than low ones, limiting the benefits of
widening bass frequency content.
The tilt filters allow you to adjust the spectral
stereo field accordingly. Plug your stereo pair into
the input sockets. Centre the balance and width
controls, and toggle both frequency switches to
the bass setting. Next, set the mid tilt knob to 9
o’clock, and the side one to 3 o’clock. This will
boost the mid channel bass frequencies and
simultaneously attenuate the treble.
Meanwhile, the side channel undergoes the
opposite operation, ensuring that nearly all bass
content in the final mix is mono. Now you can
widen the stereo field by adjusting the width
control beyond its centre position. Experiment
with different filter settings to achieve anything
from subtle, natural-sounding widening to
drastic stereo effects.
LINEAR VCA WITH TONE CONTROL
Enhance 2 can be used as a simple linear VCA in
patches where no stereo processing is required.
Centre all knobs and connect your input signal to
the right stereo input. The width knob and CV
input will then affect the output amplitude on
the right stereo output, with +5 V corresponding
to unity gain if the knob is set to its minimum
setting. Without any CV, unity gain is reached
when the knob is centred.
Additionally, the side filter can be used to add
spectral control to the VCA. The balance
parameter also allows for amplitude control.
However, the response will be non-linear, as a
result of the constant-power balance control law.
STEREO TILT FILTERS
While by default the tilt filters are configured in a
mid/side pair, stereo tilt filtering is possible as
well, adjusting the tone of the left and right
channels directly.
To achieve this, centre all knobs and patch your
stereo input signals into the module’s mid/side
input sockets. Next, connect the stereo outputs
to the stereo inputs. The mid/side outputs are
used as the true stereo output pair.
By exchanging the mid/side encoders and
decoders this way, the module’s signal path is
effectively ‘swapped around’. The mid tilt filter
now only affects the left channel, while its side
counterpart affects the right.
Note that the balance control will influence the
stereo width instead, while the width knob can
be used to attenuate or amplify the right channel
and thus change the balance. The correlation
meter essentially becomes meaningless.
PHASE METER
Apart from measuring the correlation between
the two channels of a stereo signal, Enhance 2’s
phase correlation meter can also be used to
measure the phase shift between two otherwise
identical signals.
Simply centre all knobs and plug both signals
into the left and right input sockets. 30° of phase
difference is represented between adjacent
LEDs. This means that if, for example, the two
signals are 90° out of phase, the ‘0’ LED will light
up. Both signals are passed through unaltered to
the stereo output sockets on the bottom right of
the module.

ENHANCE 2
STEREOPHONIC
ENHANCER
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SPECIFICATIONS
Module format
Doepfer A-100 ‘Eurorack’ compatible module
3 U, 8 HP, 30 mm deep (inc. power cable)
Milled 2 mm aluminium front panel with non-
erasable graphics
Maximum current draw
+12 V: 70 mA
−12 V: 70 mA
Power protection
Reverse polarity (MOSFET)
I/O impedance
All inputs: 100 kΩ
All outputs: 0 Ω (impedance compensated)
Outer dimensions (H x W x D)
128.5 x 40.3 x 43 mm
Mass
Module: 115 g
Including packaging and accessories: 200 g
SUPPORT
As all Joranalogue Audio Design products,
Enhance 2 is designed, manufactured and
tested with the highest standards, to provide the
performance and reliability music professionals
expect.
In case your module isn’t functioning as it should,
make sure to check your Eurorack power supply
and all connections first.
If the problem persists, contact your dealer or
send an email to [e-mail].
Please mention your serial number, which can be
found on the product card or on the module’s
rear side.

With compliments to the following fine people,
who helped to make Enhance 2 a reality!
Björn Jauss Boris Uytterhaegen
Daniel Miller Frits Jacobs
Gregory Delabelle Jan D’Hooghe
Janus Coorevits Jérémy Bocquet
Jeroen De Pessemier Lieven Stockx
Marcin Staniszewski Quincas ‘Synth DiY Guy’ Moreira
Rick Van Oss Sebastiaan Tulkens
Enhance 2 User Manual
version 2021-09-13
21st Century Analogue Synthesis—Made in Belgium
© 2021
[e-mail]
https://joranalogue.com/