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Dr Böhm Digital Drums

A new sampled drum machine, available as a kit or finished item.

The electronic musician of today, whether he knows it or not, is greatly indebted to the home organist, for it was he that popularised the drum machine in its infant days. Traditionally, the drum box was built into the organ and featured a fixed set of rhythms - bossa nova, tango etc. which bore little resemblance to their names, but did help the player keep strict time, musically speaking. It was only when Roland launched the 'Dr Rhythm' drum machine in 1979 that other musicians really began to take an interest, as this device was programmable and contained fairly realistic sounding drums.

Since then, the drum machine market has literally exploded with the introduction of more and more sophisticated devices containing 'sampled sounds' ie. real drums recorded and stored digitally in memory chips that can be triggered whenever a beat is required.

Ironically, the home organist-type of drum machine has decreased in popularity, in this country at least, but on the Continent they are still big business, and it is one such device that we are reviewing here. Before some readers skip to the next pages, let me just say that the Dr. Bohm Digital Drums are worthy of your attention, for they have many attributes not yet available on any other machine and come in both ready-built and kit form, making them a unique proposition to anyone unable to afford the higher price of a Linn Drum, for example.

The Dr. Bohm also comes in many configurations but a complete unit with factory-set rhythms and fully programmable section costs around £900 ready-built and only £650 or so in kit form - very attractive I'm sure you'll agree.

The Unit

The ready-built Digital Drums, in freestanding form, comes in a strong ABS-type plastic case about the size of an average briefcase (19"W x 14"D x 6"H) with a retractable handle for ease of portability. The internal chassis is metal and the whole lid hinges for easy access to the circuitry during construction if this is being attempted.

Apart from the large instrument voice buttons and three rotary knobs, all other functions are controlled by momentary pushbuttons with built-in LED, for instant status indication, located neatly in two rows on the front panel.

The top row select the preset rhythms of which there are 180, accessed by 18 rhythm buttons and a group of Variation buttons. These are all generally usable as they are and range from 'Pop', 'Disco' and 'Reggae' to 'Jive', 'Samba' and 'Beguine' (great for Julio Inglesias impersonations). The second row controls allow access to every parameter necessary for programming your own rhythms, as well as the selection of automatic insertions of fills, drum breaks and solos which alter, depending upon the preset rhythm chosen, so as not to interrupt the transition from one rhythm to another.


The basic Digital Drums unit hs 24 rhythm instruments stored digitally in only two chips with a total storage capacity of 256K of memory. Each instrument has its own selector button which is used to enter that instrument into a rhythm pattern. Several instruments such as the bass drum, toms and snare have two preset volume levels. These allow accented beats to be programmed by selecting the louder instrument for that rhythm, and are enabled by depressing one of two 'Shift' buttons, rather like changing from upper to lower case letters on a typewriter. In addition to this, all instrument volumes can be re-programmed in 9 volume stages and then stored. This is a good facility for introducing dynamics into your rhythms, and there is a master volume control for overall adjustment of the instruments once their levels have been individually set.

In total, there are 44 instruments available which is almost double the amount offered on any other digital drum machine. The standard of the sampled sounds is excellent; they are very authentic and have no abrupt cut-offs (which the MXR unit suffers from, for instance). My personal favourite is the snare drum roll which is unique; no other drum machine has this feature. The full complement of instruments is as follows:

2x Bassdrum
3x Snare
2x Rimshot
Snare Roll
3x Tom 1
3x Tom 2
3x Tom 3
3x Tom 4
2x Hi-Hat closed
2x Hi-Hat sticked closed
2x Hi-Hat open
2x Ride Cymbal
2x Crash Cymbal
2x Tambourine
2x Maracas
High Bongo
Low Bongo
Wood Block
Conga 1
Conga 2

Continuing with the features, each of the 180 preset rhythms has an associated fill-in, and drum break which can also be programmed as either rhythm 'introductions' or 'endings', rather like Roland's TR808. The fill-ins can be manually selected by pushbutton, or automatically at random or after every 4 or 8 bars. This gives a variety to the preset rhythms which are programmable over two bars with a total of 32 beats. Additional variations can be implemented using the two 'Solo' buttons, which select short drum patterns of two or four bar lengths. There are 36 solos available but some are only slight variations on the others. However, they do add another dimension to a continual rhythm and are worth using.

The tempo of the preset rhythms can be adjusted from its normal setting by +/-30 beats per minute. Alternatively, the tempo can be re-programmed anywhere from 35 to 280 bpm, using the digital readout and rotary knob, and your new tempo stored in memory.

Unlike other devices, the Dr. Bohm has a permanently operational randomising facility which gives an animated feel to a rhythm, imitating the instrument stroke-length variations that a human drummer inadvertently creates.

Using the presets a song or 'sequence' of up to 500 bars can be programmed including drum breaks, fill-ins, solos and tempo changes. These sequences can be run in continuous form or stepped, with a digital readout of the bar number being played to tell you just where you are.

Programmer and Instrument controls.


As well as preset rhythms, the Dr. Bohm offers 36 self-programmable rhythms each with its own fill-in, drum break and 2 or 4 bar solos, which can be stored under the names of the 18 preset rhythms. You select the programmed rhythm using the 'Free Pattern' pushbutton and the required rhythm momentary button. If 'Free Pattern' is not pressed you'll call up whatever preset is stored in that location, instead of the user-created rhythm.

Rhythms composed by the user can be up to 32 bars in length with a maximum of 64 beats per bar. A metronome (using the 'clave' sound) can be activated as an aid whilst programming. The required time signature of a rhythm is chosen, using the 'Time' pushbutton, from the available list: 2/4, 3/4, 4/4, 6/8, 12/8, 5/4 and 7/4. Then you simply 'play' the instruments in real-time and they are remembered.

The alternative to this is the 'static programming' method where the relative instrument is selected with the momentary pushbutton and memorised at the next beat by depression of the 'Step' button on the programmer section. Editing of any bar, rhythm or total sequence is possible by transferring the data into the Edit Buffer and modifying things beat by beat. It is a straightforward operation using the 'Insert' and 'Delete' buttons to add extra bars to your rhythms or extra rhythms to your sequences, whatever takes your fancy. Rhythms and bars can also be copied when creating a sequence, obviating the need to re-programme the same bar twice whilst also saving on memory capacity.

Sequences, once created, are stored in a similar manner to the preset and programmable rhythms ie. using the same rhythm pushbuttons. Thus a maximum of 36 sequences are possible, which will automatically loop unless a 'stop' has been requested. The 'stop' facilities are very good on the Dr. Bohm for you can use either the main Start/Stop button or the Auto Stop. The latter lets you stop your rhythms or sequences on the first beat of the next bar, to create a natural ending with a downbeat instead of an immediate halt.

Rear panel features.


With the Dr. Bohm, add-on kits are available to increase the connection facilities on the rear panel. The basic drum machine has a stereo output split Left and Right on jacks, but an 8 channel split output for individual instruments can be used as well, if the kit is bought or requested on your ready-built unit (price £9).

Space is available for the addition of 5 pin DIN sockets for a cassette interface and triggers, allowing sync-to-tape and tape dumping of the memory contents (price £51). Further add-ons allow headphone monitoring (£21) and an Automatic Accompaniment device for home organists.


The Dr. Bohm Digital Drums are impressive and yet bewildering (due to the number of pushbuttons with dual functions and the sheer amount of variations possible). The sounds themselves are as good as any around, and there should be enough memory capacity for most users. The heart of the unit is the digital display which minimises the chances of getting things wrong, as it continually emits information that helps you to learn your way around the machine whilst also teaching the rudiments of rhythm composition, in a way.

This unit should appeal to a wider audience than, say, an Oberheim DX or a Drumulator, as neither of these provide pre-programmed rhythms. For a lot of people this is a problem, as they find it hard to create rhythms from scratch. With the Dr. Bohm you can use the pre-set rhythms as a starting point and then modify them, as well as composing full rhythms of your own.

Not to put too fine a point on it, I think this machine is a real winner, it is comparable in price to the Drumulator and Oberheim but with a wider range of instruments. In kit form it represents very good value for money, and anybody competent at fine soldering would be capable of constructing one in under 24 hours.

A free-standing Digital Drums (including programming facilities) costs £963 inc. VAT and carriage (ready-built) or £669 (self-assembly kit). Further details (plus a demo single for £1.45) can be obtained from UK Agent: (Contact Details).

Also featuring gear in this article

D is for Drum
(ES May 84)

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Eko EM12 Keyboard

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Roland Drumatix Modifications

Electronics & Music Maker - Copyright: Music Maker Publications (UK), Future Publishing.


Electronics & Music Maker - Feb 1984

Gear in this article:

Drum Machine > Dr Böhm > Digital Drums

Gear Tags:

Digital Drums

Review by Ian Gilby

Previous article in this issue:

> Eko EM12 Keyboard

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