Baumann BME-700
---------------
This unusual German synth had a build volume of about 500 units and only one
useful source of information could be found on it: a report on repair work for
one of the few existing examples at www.bluesynths.com. The BME systems were
hand built and judging by some reports on build quality may have been sold in
kit form. The unit was produced in the mid 1970's.
The synth has a very interesting design, somewhat reminiscent of the Moog Sonic
and Explorer synths. It has two modulating LFO with fairly high top frequency,
two filter and two envelopes. The envelopes are either AR or ASR but they can
be mixed together to generate amongst other features an ADSR, very innovative.
There is only one oscillator but the sound is fattened out by the use of two
parallel filters, one acting as a pure resonator and the other as a full VCF.
The synth has been left with a minimum of overhead. There are just 8 memory
locations on the front panel with Load, Save and Increment buttons and one
panel of options to adjust a few parameters on the oscillator and filters. It
is possible to get extra memories by loading banks with -load: if you request
starting in memory #21 the emulator will stuff 20 into the bank and 1 into the
memory location. There is no apparant midi channel selector, use -channel <n>
and then stay on it. This could have been put into the options panel however
having midi channel in a memory is generally a bad idea.
A. MOD
Two LFO:
frequency from 0.1 to 100 Hz
Triangle and Square wave outputs
Mix control
Mod-1/2 into the VCO FM
Env-1/Mod-2 into the VCO FM
B. Oscillator
Single VCO
Glide 0 to 10s, on/off.
PW Man: 5 to 50% duty cycle
Auto depth:
Envelope-1
Mod-1, Mod-1/2, Tri/Square
Vibrato depth
Tuning
8', 4', 16' transposition
Shape
continuous control from Square to Tri wave.
Mix of noise or VCO output
C. Res Filter
Sharp (24db/Oct), Flat (12dB/Oct)
5 frequency switches
D. Envelopes
Two envelopes
Rise time
Fall Time
AR/ASR selector
Two independent mixes of Env, for VCF and VCA.
E. Filter
Frequency
Resonance
Env/Mod selector
Modulation
KBD tracking
Mod-1 or Mod-2, Tri/Square
F. Amplifier
Mix resonator/filter.
Volume
Mod depth
Mod-1 or Mod-2, Tri/Square
The oscillator is implemented as a non-resampling signal generator, this means
it uses heuristics to estimate the wave at any given time. The harmonic content
is a little thin and although the generation method seems to be correct in how
it interprets signal ramps and drains from an analogue circuit this is one area
of improvement in the emulator. There are options to produce multiple waveforms
described below.
The resonant filter is implemented with a single Houvilainen and actually only
runs at 24dB/Oct. There are controls for remixing the different taps, a form
of feedforward and when in 'Flat' mod there is more remixing of the poles, this
does generate a slower roll off but gives the signal a bit more warmth than a
pure 12dB/Oct would.
There is a selector in the Memory section to access some options:
G. Options
LFO
Synchronise wave to key on events
Multi LFO (per voice).
Oscillator
Detune (temperature sensitivity)
Multi - remix 8' with 16' or 4'.
Noise
Multi Noise (per voice).
White/Pink
Pink Filter
ResFilter
Sharp Resonance/Remix
Flat Resonance/Remix
Envelope
Velocity Sensitive
Rezero for note on
Gain
Filter
Remix
KBD tracking depth
The emulator probably gives the best results with the following:
startBristol -bme700 -mono -hnp -retrig -channel 1
This gives a monophonic emulation with high note preference and multiple
triggers.
The options from section G are only loaded under two circumstances: at system
start from the first selected memory location and if the Load button is given
a DoubleClick. All other memory load functions will inherrit the settings that
are currently active.