Integrating a drum machine into your MIDI system - step by step...

Before entering into the 'fun' of getting a drum machine and sequencer to play in time with each other, let's first take a look at how we incorporate a drum machine into a basic MIDI system.

Until recently, when dedicated modules started to appear on the scene, the usual way to get your percussion sounds was to buy a drum machine, ignore its internal programming system, and link it up to your sequencer. To this end, there are three ways of working:

1. Playing the drum sounds from the drum machine's own pads (where these exist) and recording the pad hits on the sequencer.

2. Inputting drum notes directly, in step-time, to hardware sequencer or to a drum grid editor on a computer sequencer.

3. Playing the drum sounds via an attached MIDI keyboard and recording the key presses on a sequencer.

Irrespective of how you choose to work, various settings have to be made to get the system up and running. Beginning with playback from the sequencer: you need to ensure that the MIDI receive channel of the drum machine is the same as the transmit channel of the track on the sequencer and that the drum machine is set to receive and recognise MIDI Notes. Each of the drum machine's sounds will be allocated to a particular MIDI Note number, a list of which should appear in the back of the drum machine manual.

To work via the drum machine's pads requires a two-way link to be established between the drum machine and sequencer. The MIDI Out from the drum machine connects to the MIDI In of the sequencer, which effectively means that the drum machine is acting as a MIDI Controller: hitting the pads sends MIDI Note messages to the sequencer.

To complete the link, the MIDI Out from the sequencer needs to be connected to the MIDI In of the drum machine so that the drum sounds can be heard when the sequencer plays back (Figure 1). However, it will also be necessary to turn off the sequencer's internal 'soft-Thru' MIDI function, otherwise you'll hear the drum sounds twice every time you hit a pad; firstly from the pad itself and secondly from the MIDI Note returning via the sequencer.

Using a drum grid editor on a sequencer to trigger the drum machine simply involves making sure that the MIDI Note for each instrument on screen matches up with the sounds in the drum machine. Connection-wise, only the MIDI Out from the sequencer has to be connected to the MIDI In of the drum machine, so that the latter can receive notes as they are played back from the sequencer. If the drum machine is lacking a MIDI Thru port, remember to place it at the end of a 'daisy chain' MIDI arrangement if that's how your system is configured (Figure 2).

Playing the drum sounds via a MIDI keyboard is often a good option, especially if the drum machine pads are on the small side. Connect the MIDI Out from the keyboard to the MIDI In of the sequencer and the MIDI Out from this to the MIDI In of the drum machine (Figure 3). Notes sent by the keyboard to the drum machine are received by the sequencer which, by use of its soft-Thru facility, are re-transmitted to the drum machine. Make sure that the soft-Thru function is turned on (otherwise received notes will not be sent from the MIDI Out of the sequencer) and that the MIDI channel of the current sequencer track matches the MIDI receive channel of the drum machine.

A couple more commonly used terms for your MIDI glossary...

Local Control

A synthesiser can be viewed as two distinct items. There's the keyboard which transmits MIDI information, generated by the playing of keys and/or the pressing of buttons. And there's the internal sound generator which creates the actual sounds that we hear.

Local Control Off effectively splits the keyboard from the sound module so that they can be treated as separate entities (see diagram). This is very useful when used with a sequencer and configures the system as it would be using a master keyboard and an expander.

If the synth is multitimbral, you can ignore the MIDI transmit channel of the keyboard and simply set the MIDI channel of the current sequencer track to that of the sound you want to hear. Turning Local Control off is usually possible from the front panel of the synth, although some require a special MIDI message to be sent to them from a sequencer.

Running Status

The first part of any MIDI message tells the receiving device what kind of message it is: Note On or Off, Program Change, Pitch Bend - and so on. If, for example, you have a whole host of MIDI Notes, all on the same MIDI channel, the first part of each of them will be the same. So why, after the first MIDI Note has been sent, bother transmitting it?

This is the reasoning behind Running Status. If the first part of a MIDI message is the same as the first part of a previous one, then it can be dispensed with; the receiving device will know what to expect. This reduces the amount of MIDI information being sent from one device to another - a kind of data reduction system, if you like. All MIDI devices have to be able to recognise Running Status when receiving MIDI information, but do not necessarily have to transmit it, although most will if they are outputting large amounts of data - particularly sequencers and MIDI mergers.