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This very original synth had a fat sound for a single oscillator design thanks to having two modulating LFO and two filters, one with a fixed frequency and one controlled via mods. The envelopes are also unique, two AR/ASR envelopes that could be mixed together independently and hence also capable of providing an ADSR as well. The result was quite distinct and bristol only hopes to deliver an extraction of that sound. From all known sources there only seems to be one of these still in existance and so it is truly esoteric. Bristol would like to thank the team at Blue Synths for being the only evident source of information and for providing details of its operation (review available at www.bluesynths.com) .

    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
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.