Flame CURVES User manual

“CURVES”
ANALOG RESONANCE FILTERBANK
MANUAL
Version 2.00
FLAME

Manual FLAME Curves Version 2.00
Contents
1. Short description................................................................ 3
2. Hardware / connections...................................................... 4
2.1 Connection to the modular system (Doepfer bus) 4
2.2 Module overview 5
2.3 MIDI connections 6
2.4 AUDIO schemes 7
3. Filterbank ........................................................................... 8
3.1 Structure of the filter bank 8
3.2 Structure of the filter channel 9
3.3 Filter bank control 10
3.4 MODE Sequence 11
- Knob ENVELOPE 12
- Knob VARIATION 13
- Knob FILL 13
3.5 MODE Manually 14
- FILTERTYPE 14
- CUTOFF 15
- SMOOTH 15
4. MIDI functions ................................................................ 16
4.1 Overview 16
4.2 Sync per MIDI 16
4.3 Play filter channels with note commands 16
4.4 Program Change 16
4.5 Control Change (Parameter control) 17
5. Firmware update ................................................................ 18
6. Appendix and technical informations .............................. 19
6.1 Technical details
6.2 Warrenty
6.3 Terms of production
6.4 Disposal
6.5 Support
6.6 Acknowledgment
2

1. Short description
The "Curves" Euro Rack Module is an analogue 12-channel filter bank with 24dB filters and an
integrated modulation sequencer (external clock only) with a wide range of control options. The
controllers of the sequencer can be used to influence the pattern but also to control the filter
channels manually (or via CV).
The filter channels are each divided into two channels (odd/even) and can be operated sepa-
rately in stereo or together in mono. There are two inputs for odd(mono)/even, as well as two
individual outputs for odd/even and a mono sum channel including dry-wet mix control and
level control.
Each of the 12 filter channels also has a separate VCA input (0..+5v) and a separate individu-
al audio output. The filter channels can also be played separately with velocity using MIDI
notes.
The modulation sequencer offers a variety of options. It can be synchronized with an external
clock (16th note) either via MIDI clock or analog via trigger and reset inputs.
There are 99 memory locations available, into which a maximum of 99 four-bar patterns can
be loaded. The patterns are selected either directly by button, by MIDI program change or by
CV input “SEQUENCE”.
With the help of the Curves Editor (PC or MAC version) the patterns can be edited and loaded
into the module. The sequencer is a midi sequencer in tick resolution with settings for gate
time, velocity, track last step and shuffle.
All MIDI settings are made with the editor (e.g. receive MIDI channel and note numbers for the
filter channels).
On the module itself there are 3 controls for influencing the pattern:
- Envelope (different envelopes in trigger or gate mode)
- Variations (random values of velocity and envelope lengths)
- Fill (turn up all filter channels)
All three functions can also be controlled by an external CV via CV inputs.
In manual mode (Sequencer=OFF), these three controls can be used to control the filter chan-
nels directly (and also via CV):
- Envelope (selection of hard detented and soft cutoff movement)
- Variations (choice of filter type: Allpass, Lowpass, Bandpass 1-3, Highpass)
- Fill (cutoff = movement/passing through the bands)
Future firmware updates can simply be loaded using a sysex dump.
AMIDI adapter cable is included.
3

2. Hardware / connections
4
2.1 Connection to the euro rack modular system (Doepfer bus)
The module is delivered with a connected ribbon cable for the Doepfer bus. The red lead marks
-12 volt. Connecting the module please note the right polarity!
If the module is poled accidentally wrong safety diodes avoid the immediate destruction of the
module but further damages cannot be excepted.
So please pay attention: Check the connection various times before switching on!
The current consumption of the module is on average +250mA and -170mA.
CAUTION!
Do not accidentally connect the MIDI THRU output to high CV voltages! This can possibly dama-
ge the hardware!
-12V
Ground Ground Ground
+12V

5
2.2 Modul overview
Fill / Cutoff
Random / Filtertype
Envelope / Smooth
Filter channel LEDs
Sliders channel volume
Filter channel direct audio outputs
MIDI input
CV inputs
Reset input
16th clock input
Audio inputs: odd/mono, even
Audio outputs: odd, even, ALL (mono)
Filter channel single VCA inputs
Input gain
Sequence selector
keys + display
Mix Dry-Wet audio output ALL
Level audio output ALL

KEYBOARD/CONTROLLER
Examples of possible connections:
6
COMPUTER
2.3 MIDI connections
The module has a MIDI INPUT socket (3.5mm mini jack in TRS-B standard) for controlling parame-
ters, loading/editing of sequences or firmware updates via sysex. Connect the MIDI input to the MIDI
output of your keyboard/controller or computer. An appropriate commercially available adapter (MIDI-
DIN to Mini TRS-B) or a 3.5mm stereo jack cable is used for the MIDI connection. Acorresponding
adapter is included.
3,5mm (1/8 inch) mini jack
stereo cabel
Adaptor schemata
MIDI DIN jack to
3,5mm (1/8 inch) mini jack
MIDI TRS-B standard

2.4 AUDIO schemes
The module has two audio inputs, which are alternately routed to the filter channels. Input ODD is
routed to the odd-numbered channels and input EVEN to the even-numbered channels. If only one
cable is plugged into the ODD/ALL input socket, the input signal is routed to all filter channels
(ALL=mono input).
EFFECT MIX
Both inputs ODD+EVEN are routed together to the GAIN controller, which is then present as a mono
signal at the MIX controller (dry) (original signal). The MIX controller controls the mixing ratio between
this original signal and the effect signal (wet), which consists of the output sum of all filter channels
(Mono Signa =EVEN + ODD outputs). When the MIX control is in the middle position, the volumes
of the original and effect signals are approximately the same. The LEVEL control then determines the
level of the mix signal at the ALL output socket.
The maximum level of both filter channel groups is always present at the two outputs ODD and
EVEN. This can be viewed as the stereo output of the filter bank. The filter bank is therefore suitable
for stereo applications.
Each of the 12 filter channels has an additional audio output (modular level). The output level is inde-
pendent of the slider position so that the signal can be processed externally even though it has been
removed from the mix.
The sliders only serve as a manual attenuator for the corresponding channel. In order to hear a con-
trolled sequence, the slider must be turned up. The maximum output signal is therefore determined
by the position of the slider.
7

3.1 Structure of the filterbank
The module has an analog filter bank consisting of 12 filter bands. The first 11 filter bands are
24db bandpasses (resonance filters) with fixed frequencies and medium resonance, the excep-
tion being channel 12, a 24dB highpass filter that lets through all higher frequencies from around
5Khz.
The center frequencies of the channels are:
90Hz, 150Hz, 240Hz, 350Hz, 500Hz, 700Hz, 1KHz, 1.4KHz, 2KHz, 2.8KHz, 3.9KHz, >5.6KHz
Each filter band has an output volume slider. This allows you to lower these frequencies in the
overall sound or remove them entirely. Up to this point, the filter bank resembles a graphic equa-
lizer. But the filters in the CURVES have other properties that clearly distinguish them from an
equalizer. On the one hand, there are the resonant filters that particularly amplify the range
around the respective center frequencies. On the other hand, the individual frequency bands do
not overlap. Therefore, the timbre is noticeably affected because it adds resonances at key
points in the sound spectrum.
Each channel has a VCA for electronic volume control through the internal sequencer or sepa-
rately through the BAND CV input. With a CV voltage of 0 to +5v the channel can be regulated
separately. The BAND Leds signal the level of the VCA. Each channel has an additional output
for the audio signal, which can be tapped independently at the socket. The channel control has
no influence on the level (in order to be able to process the signal separately, even though it may
have been removed from the mix).
3. FILTERBANK
8
u
v
w
x
BAND LEDs LED display VCA level of the filter band
BAND SLIDERS Audio filter band attenuators
BAND AUDIO OUT Audio individual outputs of all filter bands
BAND CV IN CV inputs of the VCAs of the filter bands
u
v
w
x

9
3.2 Structure of the filter channel
The filter bank of the module has 12 filter bands.
Each of these filter bands basically consists of a fixed frequency filter (24dB bandpass or high-
pass), a VCA for volume control via CV, and a slider for manually attenuating the audio signal.
The VCAs can be controlled in different ways:
- directly via channel CV input
- Filter simulations by manual controls/CV
- internal modulation sequencer
See the following chapter: “Filter bank control”
FILTER
SEQUENCER
ENVELOPE
GENERATOR
MANUALLY
FILTER
SIMULATION
CV input
CV
Mode
Sequencer
Manually
Audio input
Audio out
Slider

10
u v w
3.3 Filter bank control
x
KNOB ENVELOPE Envelope or smoothing (passing through the filter bands)
KNOB VARIATION Variations (random) or Filtertype (of the filter simulation)
KNOB FILL Turn up the level of all filter bands or cutoff (of the filter simulation)
SELECT MODE/SEQUENCE Pattern or mode selection (oF=filter simulation)
u
v
w
x
The knobs have different functions in the two modes:
MODE SEQUENCE (Display 01..99)
KNOB ENVELOPE Envelopes of the sequence
KNOB VARIATION Random = Envelope/Volume Variations
KNOB FILL level of all filter bands (mix in)
MODE MANUALLY(Display “oF”)
KNOB ENVELOPE Smoothing of passing through the filter bands
KNOB VARIATION Selection of one of 6 filter types
KNOB FILL Adjust filter type cutoff
In CURVES there are two different ways (MODE) to modulate the filter bank:
1. Through an internal modulation sequencer (one track for each filter band) with knobs and CV
controls for envelope, variations (random) and fill mix (additive raising of all filter bands)
2. Manually with the help of a filter type simulation and with controls for cutoff, filter type and
smoothing of the filter bands.
MODE SELECTION
Use the “SEQUENCE” buttons to either select a pattern “01..99” or set the display to “oF” (press
the sequence button “<” until “oF” appears)
01..99 Mode SEQUENCE (Modulation sequencer)
oF Mode MANUALLY(Filter simulations)