You have noticed by now that there are quite a few different electronic drum sets that are designed around a whole batch of “brains”, as drum sound modules are often called. Among the major manufacturers of drum sound modules (let’s call them “modules” for now) the current generation of Roland electronic drum sets is based on five different modules, Alesis uses four modules and Yamaha uses five.

Almost all of these modules have more than one drum set built around them (such as Roland TD-4K2S, TD-4KXS and so on). This allows the designers to use each module for different levels of pads and other features. The less expensive set will use mostly rubber drum pads, the “step up” set will instead use realistic feel drum pads, real hi-hat action pads and so on.

So what are the differences between the modules themselves? Within each brand, the most obvious differences between different modules will be:

SOUNDS: The number of drum sounds the module comes loaded with.
(Please note: the most advanced modules include along with the total number of sounds, a selection of melodic sounds, including pitched percussion like bells, vibes, tympani and even keyboard sounds.)

How many groups of drum sounds, or kits are derived from the on-board sounds and designed into the module. These preset kits will arrange sounds around the drum and cymbal pads and each kit will bring up a new arrangement of drum, cymbal and percussion sounds.

Most modules will allow you to record and store your own selection of kits, building your own customized user drum sets by picking your choice of snare drum, toms, kick, cymbals and anything else, arranging or assigning the sounds to the pads and storing that user kit for future use. The user kit function has been a tremendous creative advance in the design of drum sound modules.

PRESET PATTERNS: All modules will contain a collection of preset patterns, which are short, usually two-bar drum parts or beats based on each kit and will represent many different musical styles, the selection of drums, cymbal and percussion sounds that are most often used for each style and a common arrangement for each style. The variety of patterns will be an excellent aid to working out on the beats you prefer by playing along with them and will also be a great aid to learning the less familiar musical styles. Remember that professional drummers, no matter what kind of music they are known for, can play anything.

USER PATTERNS and SONGS: As with preset and user kits, many modules allow you to create your own user patterns, where you create your own beats and drum parts using both the preset and user kits and then store the new part you’ve created. Did you make up a beat that you don’t want to forget and want to come back to? Just use the user pattern function to record it and save it!

Some modules have a Song function that allows you to string both preset and user patterns together into a song-length arrangement. This is very useful for creating long practice arrangements and is widely used for creating a complete arrangement of the drum parts for songs that can be sent directly to a sound system for live performance or to any recording set-up.

HOW MANY DRUMS AND HOW MANY CYMBALS?: Most of the electronic drum sets are like acoustic drum sets, a standard number and arrangement of drum pads and cymbal pads. This provides you with five drum pads (snare, kick, two toms in front of you and a tom to the side in floor tom position) and three cymbals (a hi-hat, a ride cymbal and a crash cymbal). There are some exceptions as we climb up each range of modules that we’ll list below.

ADDITIONAL PADS?: Many people ask if they will be able to add additional pads to their electronic drum set in the future. In the least expensive sets, this capability is limited and only the high-end sets can take a bunch more pads but this is certainly a possible option worth considering. Any pad being added will also require the appropriate hardware for mounting the additional pad to the drum rack or a separate mounting arrangement.

A little trick to adding additional pads beyond the total number of pads and additional inputs is to add single-zone pads and y-adaptor cables, thus splitting the output of a dual-zone pad and turning that pad into a single-zone pad as well. The dual zone input is then re-assigned within the module to the two different sounds that you will want playing from two pads. You can create quite a monster electronic drum set this way!

So, let’s look at the choices, brand by brand and brain by brain!
Guide to Roland Drum Set Sound Modules
Guide to Alesis Drum Set Sound Modules
Guide to Yamaha Drum Set Sound Modules