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Alesis D4 Drum Module

Drum Expander

Your drum machine used to dictate the sound of your music - but the variety of sounds in Alesis' drum expander gives you back your freedom. Tim Goodyer says everything starts with a D.

Certain recent additions to the drum machine market have been notable for the sheer numbers of sounds they contain - Alesis' D4 boasts over 500 and there's more...

The Alesis D4 is useless. Useless, that is, if you're a confirmed sticks-n-skins drummer. If, on the other hand, you're in the market for a large and diverse collection of sampled drum and percussion sounds, tidily packaged in a 1U-high rack unit and equipped with trigger-to-MIDI inputs, the D4 might - just might - turn out to be more useful than your pacemaker.

So here it is, check it out; 99 bass drums, 99 snares, 55 cymbals, 92 toms, 76 assorted percussion voices, 80 "effects" sampled in glorious stereo at 48kHz, packed into a single rack space complete with 12 trigger-to-MIDI inputs equally suited to use with drum pads, drum machines and signals on tape. Feel free to turn the page if you still think drums have the monopoly on rhythm or you really are prepared to miss out on one of the neatest beatboxes to appear in quite a while.

Actually, the term "beatbox" doesn't quite fit the D4, since one of the few things it's lacking is onboard sequencing. As such, it's not so much a drum machine as a dedicated percussion sample reader. Where the D4 scores over certain other drum expanders, however, is through its integral trigger interface. This makes the unit equally well-suited to use with an acoustic drum kit fitted with piezo mics and as a means of replacing poorly-recorded or damaged drums on a studio multitrack.


Taking a more thorough look over the D4's hardware, we find a 1U-high rackmount whose front panel (from left to right) boasts a headphone socket, volume control; 32-character, two-line, backlit LCD; alpha wheel-style Data knob; large Preview button; left and right cursor buttons; ten function buttons (with active LED bars) and a power button. On the rear panel there is a socket for the separate transformer (supplied) footswitch jack, MIDI In and Out/Thru sockets, 12 Trigger Input jacks, Main stereo audio output pair and Aux audio output pair (on quarter-inch jacks). And that's it.

Alesis have commendably kept the number of "second page" functions small, leaving you to navigate the operating system with the cursor keys instead. Where this doesn't offer much of an improvement in the use of most synth or sample expanders, the D4's operation is simple enough (for the most part) to be quite intuitive. For most aspects of operation, only details of the 25 trigger types and the Group setup button really require you to refer to the manual.


On power up, the D4 greets you by telling you what it is and who made it (in case you've lost the box). Then it picks up on the page you were last working on. In the case of a brand new D4, this is the first of the unit's 21 Drumsets - Drumset 00 "Standard Stuff". Each Drumset is an assignment of 60 of the D4's 501 samples to 60 consecutive MIDI Note Numbers. The unit comes set up with what Alesis have called the Drumset Root Note at #36, but this can be changed to anything between #000 and 76 - which would put the highest D4 sound at MIDI's upper limit, Note #127.

It hardly needs to be stated, but the D4 happily operates on any of MIDI's 16 channels or in Omni mode. Also to be found under the button marked MIDI is the soft Thru on/off setting, program change enable/disable, MIDI controller enable/disable, program change number mapping and SysEx dumping. The D4 accepts Controller #6 incoming over MIDI as an alternative to its own data wheel. It will also respond to Controller #7 (volume), data increment and decrement (these act upon the currently-selected parameter), Non-Registered Parameters 98 (MSB) and 99 (LSB) which select the parameter to be edited by Controller #6, Reset All Controllers and Pitch Bend messages. It's worth noting that pitchbend only affects sounds before they're triggered. The default setting of the program change mapping simply cycles through the D4's 21 Drumsets (programs 00-20) every 21 patch numbers - so patch 20 is Drumset 20, patch 21 is Drumset 00 and so on.

Saving data via MIDI covers saving of the D4's entire setup memory, as you'd expect, but also allows you to dump the edit buffer, trigger setup and program table as separate files.

"Where the D4 scores over certain other drum expanders, however, is through its integral trigger interface."


Assembling drumsets from the D4's 501-sound library couldn't really be much simpler. Hitting the button marked Drumset allows you to step through the Drumsets with the Data knob - which, incidentally, is "stepped" so that incrementing or decrementing an entry is a comfortable, precise affair. The Set in the display is active and the one you go on to edit if you press the Voice button.

Pressing Voice causes the display to show the currently-selected Note Number and its pitch on the top line, while the sound category (Kik, Snr, Cym, Tom, Prc or Efx), number and name occupy the bottom line. The Data knob scrolls through the active range of MIDI Note Numbers, the sound category or sound number, dependent upon where you set the cursor. Alternatively, pressing the Note Chase button enables you to select the MIDI Note Number via MIDI - from a MIDI keyboard, for example.

Once a sound has been selected, it can be tuned over a range of +3/-4 semitones by pressing the Tune button and using the Data knob. It's worth mentioning that this edit is not retained with a sound, but applies to the MIDI Note Number - so if you select 'Dry Punch' for your snare sound, drop it by a semitone and then substitute 'Amb Punch', the new snare will play back a semitone low. To make auditioning sounds easier, Alesis have provided the D4 with a Preview button. This allows you to hear the currently-selected sound whenever you poke the button. Not only that, but the button is velocity sensitive, so you can get some idea of how it's going to respond to your programming. It's an extremely useful feature - not dissimilar to the Playback button found on Akai samplers - but I was left with the distinct impression that the review model had been set up with drummers in mind, since I was in danger of overturning my rack before I got much of a response from it. I did discover, however, that if you hold the Preview button in after hitting it, rotating the Data knob through any of its functions caused the sound to both change and be retriggered at the same time. In this way it's possible to hear a snare drum firing and changing in pitch just by turning this knob. I'm sure this isn't a feature Alesis intended the D4 to have, and I didn't actually find it at all useful but having discovered it, I'm determined to share it with someone...

Apart from the Ext Trigger button, there's only one other button on the D4 to deal with: the one marked Group. Here you have the option of assigning a sound to Multi, Single, Group 1 or Group 2. Multi determines that a sound should continue to play through to the end of the sample even if another MIDI Note On arrives before it's finished. This "unconditional release", as it was known in analogue days, prevents one of the early problems that plagued digital drum machines from afflicting the D4. With Multi selected, repeated cymbal strikes, say, don't cut each other off. But while this is an important aspect of the behaviour of a real cymbal, it's quite inappropriate to the sound of a vibraslap, for example. And, strangely enough, this is where the Single setting comes into its own. The remaining Group 1 and Group 2 settings are a duplication of the same facility - that of making several sounds mutually exclusive. By assigning open, foot-closed and struck closed hi-hats to one of these Groups, each sound can be made to cut off any other, more closely approximating to the performance of the "real thing".

One of the D4's hidden features is its parameter copy function. All settings for the Voice, Tune, Mix, Output and Group can be copied to another MIDI Note Number by pressing Store while holding Note Chase. The LCD now asks for the copy destination, which is entered using the Data Knob. It's easy and it's useful, but it's certainly not intuitive.

Having made a selection of sounds for your Drumset, you can set volume levels with respect to the other sounds in the Set by pressing Mix and setting a level somewhere in the 00 to 99 range. Also under this button you'll find the pan setting - nothing complicated, just a seven-position pan between the left and right audio outs of either the Main or Aux stereo pairs.

And on the subject of audio outs, pressing the Output button puts you in control of the sound's route to the outside world. Nothing too complicated here, either - on the top line of the LCD you select a MIDI Note Number - and hence one of the sounds in the Drumset - while on the bottom line, you're presented with a choice between the Main and Aux outs.

"Saving data via MIDI also allows you to dump the edit buffer, trigger setup and program table as separate files."

Once you're satisfied with your assignments you can save them by hitting the Store button. The display offers you the chance to abort the operation or, assuming you wish to continue, to name the Drumset with a 14-character name (characters are selected with the Data knob). A second prod of the Store button completes the procedure.

One last - and quite commendable - inclusion in the sound management facilities of the D4 is its ability to recall factory presets from ROM. Best of all, you don't have to recall all 21 Drumsets if you don't want to; instead you can select any Drumset to be written into any of the 21 Drumset locations. Again, this is a hidden function (press Store while holding Drumset) but as it's not something you're likely to do very often, who's moaning? Not me.


In some cases the performance of the D4's triggering facilities is going to be decisive in determining whether or not Alesis' latest drum box gets the gig. It's as well then, that there are no less than 25 different trigger types (selected via the Ext Trig button) making use of different combinations and settings of three separate trigger parameters. The manual breaks these 25 trigger types into three sections - for use with bona fide triggers from drum pads or drum machines, with signals from piezo transducers attached to acoustic drums, and with drum sounds recorded onto multitrack tape. The first group is subdivided into three further groups. All of this is to help you home in on the most suitable trigger option with the least fuss.

The parameters contributing to the performance of the trigger options are Recovery time (the period after a trigger signal during which subsequent triggers are ignored), Noise Floor (the threshold below which signals are not accepted as legitimate triggers) and Suppression (a trigger's ability to check the other trigger inputs for higher-level signals in case its own signal is a consequence of another channel being triggered). None of these parameters is directly accessible to the user, but the availability and variety of trigger types - in conjunction with a user-determined Trigger Gain - is a practical compromise between flexibility and ease of operation.

One further Trigger Type is available - Unassigned. This gives you the facility to use one of the trigger inputs not as a trigger itself, but as an input to the Suppression circuit. The idea is that if you know some particular signal source is going to be causing false triggering, you can optimise the suppression parameter to discriminate against it. It's likely to find more use on stage with a drummer than in a MIDI recording suite, but it's an indication of the diligence of the D4's designers.

I was able to test all the triggering options with the exception of piezo pickups, and had no trouble in getting the D4 to perform happily with a minimum of fuss. It was one of the aspects of the unit I was anticipating being the most difficult to review, but I was wrong.

"The trigger section was one of the aspects of the D4 I was anticipating being the most difficult to review, but I was wrong."

Stepping through the settings in the Ext Trig section, the last option you're presented with is called Footswitch Mode. This refers to the Footswitch jack on the D4's rear panel and allows you to configure the module to read it either as a foot control for the sound assigned to MIDI Note Number 44 (which is a hi-hat in all the factory presets, but doesn't have to be) or as a Drumset Advance, which steps through the Drumsets (upwards only) and wraps around from Set 20 to 00 - which the Data knob doesn't. One neat feature of the Footswitch circuitry is its ability to detect what type of footswitch you're using (contacts normally made or broken) and adapt itself accordingly. That's pre-empted one batch of problems.


With 501 sounds to consider, it's impractical to give a representative account of the sonic scope of the D4 in a review. The first remark to make, then, must be that although there are large selections of sounds, the sounds themselves are well programmed and well chosen. Essentially they all appear to be useful sounds. Factory Drumset 02, Classic Hex, makes extensive, but not exclusive, use of Simmons-style electronic kick, snare and tom sounds. Similarly, Drumset 19, Tribal Stuff, lines up talking drums, timbales, shakers, triangles and so on. Other Drumsets come under such titles as Jazz/Fusion, Ambient Rock, Industrial and Hard & Rockin'.

If the D4 can be said to have one, its emphasis must be on "realism". And given that one of the D4's predecessors, the HR16, is one of the most "natural sounding" machines to have hit the beatbox market in years, it's not really all that surprising. (In case you were wondering, the answer is yes - the D4 does draw on previous Alesis machines for some of its sounds but there's plenty "of fresh stuff here too.) None of this is to say that fans of more artificial percussion sounds have been left out in the cold, however - as well as the electronic kit sounds mentioned above, there are TR808-style kicks in 'Rap' and 'Rumble' (Kik 80 and 81) and 808-style snares in 'Rap' (Snr 33), 'Low Rap' (Snr 34) and 'Dance!' (Snr 65). To my ear, the 808-style kicks had a little too much attack and I preferred the sound filed under Efx 76, 'Analogue', as an alternative to the real thing.

Don't be misled by the shortage of drum categories either; Snr, for example, also carries sticks and brushes as well as flanged and phased snares, while Prc and Efx cover a multitude of percussive sins. There are too many attractive sounds to start listing them, but I did find some of the snares excellent and the talking drum was a particularly welcome discovery.


It's hard not to come down heavily in favour of the D4. Its sounds are powerful and varied, it's a breeze to operate and it shouldn't break the bank. You could happily make it your main drum machine - using the outputs to give you up to four concurrent, isolated outputs or by isolating, say, the kick and snare and using a stereo mix of the rest - or use it in addition to another machine.

In terms of sounds, the D4 is to the beatbox world what the Oberheim Matrix 1000 is to that of synths. You're severely restricted on programming, but there are so many sounds that you should always be able to find something to fit the bill. Perhaps the only area that's been neglected here is that of reverse sounds - the D4 ain't got any and short of sampling from it and reversing the sample, you ain't gonna get any out of it. It would also be fair to say that many of the sounds are simply edits of other sounds (not that Alesis are alone in building up beatbox libraries in this way), but the edits largely stand up in their own right and this doesn't compromise their usefulness.

Even the manual is friendly and informative, and comes with a useful sound chart (listing all 501 of the buggers complete with a table telling you whether they're sampled dry, with reverb or in stereo with reverb) and a reference chart of the factory preset Drumsets. There's also a separate sheet to help you set up the D4 triggers quickly and efficiently. The only real criticism I can come up with is that damned Preview button - not only is it horribly squidgy and unresponsive, but it actually made my fingers sore to use it. Perhaps it's just Alesis' way of reminding you about the origins of the sounds you're using...

Price £399 Including VAT.

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


Music Technology - Feb 1992

Gear in this article:

Drum Module > Alesis > D4

Gear Tags:

Digital Drums

Review by Tim Goodyer

Previous article in this issue:

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