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Kat trapKAT

MIDI Percussion Controller By Paul White
Published July 1995

Following their flagship drumKAT MIDI percussion controller, KAT Inc have released the new trapKAT, designed with 'real' drummers in mind as well as rhythmically‑minded MIDI musicians. Paul White gets that groovy feline...

Drum trigger pads are nothing new — they were first forced into the mainstream of musical consciousness by UK designer Dave Simmons — but when it comes to programming percussion parts into a sequencer, you'd probably rather use something more compact than a full‑size drum kit laden with triggers. Of course, compact percussion controllers are hardly undiscovered territory either — the aforementioned Simmons developed his own portable kit, Roland built the Octapad series of instruments and controllers, and ddrum refined the individual pad approach. Relatively recently, KAT Inc joined the list of MIDI percussion controller manufacturers by bringing out their drumKAT, which is now available featuring version 3.5 operating software. Visit any music trade show and you're sure to see rows of drummers, clamped into their headphones and clattering away at drumKATs like demented knitting machines.

The drumKAT 3.5 is still KAT's flagship product as far as programmability goes (see the brief 'Further Hitting' box on the drumKAT for a little more about this), but if you're more interested in a natural playing surface, lots of pads and a simple operating system, then the new trapKAT (under review here) should certainly appeal to you.

trapKAT Pedigree

The trapKAT provides a much larger playing area than most all‑in‑one pad systems, and its 'tailplane' shape measures over 42 inches across and 19 inches from front to back; but it is just 2.5 inches thick. This larger size came about as a response to those drummers who felt cramped by compact pad systems, but even so, the trapKAT is a lot easier to transport and set up than a conventional drum kit. Drummers also traditionally complain about the feel of drum pads, so the guys at KAT (many of whom are drummers themselves) paid a lot of attention to getting the feel of the pads right. The trapKAT employs the same gum rubber playing surface as used on the drumKAT, which gives a realistic amount of stick bounce and seems very durable. In addition, the trapKAT's 24 pads are about twice the thickness of those on the drumKAT, and this improves the playing feel still further. The pads also come in a marbled finish, rather than the plain grey used on the drumKAT. If 24 pads seems a lot to cram onto an area no larger than two or three conventional toms, the secret is that 14 of the pads are configured as raised rim‑type sensors around the edge of the main playing area (not unlike the sensors on KAT's existing poleKAT MIDI trigger stick). These rim sensors are useful for triggering cymbal and general percussion sounds, though you can assign any MIDI note to any pad. In fact, you can store 24 complete kit assignments, and a further 24 preset GM kits are provided, so that anyone with a suitable GM module can hit the ground running. A small, two‑line, 16‑character LCD window at the top centre of the panel provides kit information, as well as more detailed information while editing. The editing functions are currently fairly basic, although there's promise of a future upgrade to add more sophisticated functions, possibly later this year. If KAT have done one thing with their products, they've avoided the 'buy it today, scrap it tomorrow' mentality — everything they've built has been upgradeable, and even early drumKATs can be brought up to the latest version 3.5 spec.

Power from the unit comes from a very small mains adaptor, which plugs in at the rear of the case. The socket is threaded so that the connector can be locked, but on the review model, the power supply provided didn't have a locking plug, and was actually quite a loose fit. Hopefully, this will be rectified, as it could cause problems in a live situation.

Kat Chat

As with the other KAT drum pad products, the trapKAT converts your playing to MIDI information, which must be fed to an external sound module. There are no internal sounds, though there are on‑board grooves, which can be played through any General MIDI module, over a range of tempos, to give you something to practise against — rather like the auto‑accompaniment found on home keyboards. A new tempo can be set simply by tapping in a new tempo on one of the rim pads. Though these grooves are unlikely to inspire you to write a hit album, they are very welcome when there's nobody else around to rehearse with.

Unless you are happy to play your bass drum parts with a stick, you'll also need a bass pedal of some kind, and though KAT do build their own superbly‑engineered beaterless pedals (as well as pads for use with your own kick drum pedals), they're quite expensive. In a forthcoming SOS, I'll be showing you how to construct a DIY bass drum pad that works with a conventional bass drum pedal, and which anyone can build in an evening for under a fiver. This DIY setup works fine with my drumKAT, and has a more natural feel than a beaterless pedal — so stay tuned!

The hi‑hats can be played from any of the pads, but you still need a pedal to open and close your virtual hi‑hat. Again, KAT build their own very sophisticated hatKAT pedal, but you can get by with a simple non‑latching footswitch or a passive volume pedal.

Your Kat And MIDI

Unlike the drumKAT, the trapKAT can only handle one MIDI note per pad, so if you want to do any fancy velocity cross‑switching or crossfading, you have to take care of it in your sound module or sampler. However, the pads are all fully velocity‑sensitive, and can be individually 'trained' to match your playing style. You also get a breath controller, and although this might seem odd for a drum kit, it does allow you to apply MIDI controller information without using up any valuable hands or feet, and may also be used to apply effects like pitch bend to those drum machines or modules that respond to it.

A footswitch is supplied with the trapKAT, and this is used to get you into kit select mode; it's also used in three different sockets (or you could buy more footswitches) when editing Note, Kit/Pad or Global parameters. As you may have noticed, the trapKAT has absolutely no buttons or knobs — the pads themselves are used as programming buttons, and in kit select mode, you just hit any one of the 24 pads to select one of 24 programmed drum kit assignments, though you do have to go into Global edit mode (see below) to switch between factory and user kits. By plugging the footswitch into the Note Edit input, you can step through the available sounds on each pad by just hitting it until you arrive at the one you want.


The first layer of editing is the Global edit mode, which uses each pad to step through or switch the available functions on and off. Kit/Pad edit also uses the pads to input data, though this time six of the pads are unused (see the separate box for a list of the Global and Kit/Pad edit features). The primary pad edit function names and pad numbers are embossed on the rubber pads, but in reality, these are almost impossible to read, even in good lighting, which means you have to rely on the paper map supplied with the kit. I have the same problem with my own drumKAT, but with the trapKAT, the fact that there are over twice as many pads means there are more to remember. If you're always using the kit, everything quickly becomes second nature, but as I found out with my drumKAT, if you don't edit it for six months, you almost have to start learning again from scratch the next time you want to work on it.

I did have a moment of panic, because the first review unit to be delivered just couldn't be made to work. I tried a second unit with exactly the same result, and knew that there was no MIDI output, because my trusty Studiomaster MIDI analyser showed that precisely zilch was happening. I use this analyser for every MIDI product review, because it helps me confirm what's going on, but after swapping MIDI leads and all the usual stuff, I eventually tried removing the MIDI analyser — and the trapKAT started working perfectly. The analyser has worked with every other piece of MIDI gear it's ever been plugged into, and I double‑checked that it was still working by plugging it into other parts of my system with no problem. I've reported this problem back to the UK distributor of KAT, but as yet, both they and I remain without a clue as to why this happens.

In Use

One great thing about the trapKAT is that it's a big, solid beast — it certainly isn't going to wobble when you hit it. On the other hand, you do have to budget for a substantial stand. The new, thicker pads feel even better than those on the drumKAT, and the degree of dynamic response, while still not equalling that of a real drum, is a great improvement over most of the electronic alternatives. I also like the large pads — you don't need to be such a good shot! Like the drumKAT, the playing area is covered by a single rubber playing surface with narrow moulded grooves separating the sections, which means the sections are easy to identify, and there's no paint to wear off.

Having raised rim‑type triggers around the edge of the kit really helps increase the effective size of the playing surface without making anything feel cramped, but I think most players will configure their hi‑hat pads so that they don't have to play cross‑handed. My preference when using my drumKAT is to use a poleKAT external trigger mounted on a stand as a hi‑hat trigger, but sadly, one of the the trapKAT's economies is that there are no external trigger inputs other than for the bass drum pedal.

Obviously, I can't tell you what the trapKAT sounds like, because it doesn't produce any sound of its own, but connected to an Alesis D4 drum module, the fact that you're playing the sounds rather than programming them really seems to make them come alive. It's also nice being able to select a 'chick' sound for the hi‑hat closing effect, which is then triggered whenever you press the hi‑hat footswitch. If you have a HatKAT pedal and a drum machine that responds to continuous controller information, it's possible to make your hi‑hat sounds change in decay time as you close the pedal, which adds a further degree of realism. Drum machines that can take advantage of this feature include the Roland TD7 and TD5, as well as Emu's Procussion.


For the gigging drummer or for use in studios where the extra size of the trapKAT is not a problem, I think KAT have found the ideal compromise between the drum‑like layout of discrete pads, and the far greater convenience of an all‑in‑one surface connected to the outside world via a single MIDI lead. Even the fussiest drummer should be impressed by the feel of the pads, and the fact that you have 24 of the things should satisfy even those double bass drum users who like to surround themselves with gongs and percussion.

My criticisms are few, but even so, I have to say that I still don't feel entirely comfortable programming by hitting pads rather than pressing buttons. Having said that, I've seen real drummers programme the original drumKATs nearly as fast as they can play rolls, so it's really all a matter of familiarity. I'm also a little worried by the non‑locking PSU connector on the review model, and I'd have been much happier if the unit had been directly mains‑powered. The final whinge is that a poleKAT input or two would have been nice, purely from an ergonomic point of view, but then that might be one of the future upgrades.

All in all, this product is a real winner. If you don't need the very advanced features of the drumKAT, but you still need an all‑in‑one drummer‑to‑MIDI interface, then the trapKAT is the obvious choice. Play a break, get a KAT kit!

Further Hitting: The drumKAT

If you're a percussionist who's prepared to experiment, the original drumKAT could still be of interest to you, as it offers greater programmability than the trapKAT. On the drumKAT, you can have up to eight notes triggered from one pad, either as velocity splits, random sequences or programmed sequences. There are special hi‑hat modes to simulate the expression of a real hi‑hat, and nine external trigger inputs, which allow you to add just about any type of drum pad to the the drumKAT's own 10 playing surfaces. You can use breath control, and the pressure‑sensitive pads may even be used to generate MIDI control information, such as pitch bend.

Paws For Thought: Kat Pad Technology

To survive in any market, you either have to undercut everyone else's prices or offer something your competitors don't. KAT fall into the latter category, though their products aren't unduly expensive once you discover what's on offer. KAT's first contribution to the drum pad market was to employ Force‑Sensing Resistors (or FSRs) instead of piezo‑electric pickups. Systems based on piezo pickups are cheap and easy to make, but because they work almost like contact microphones, vibration from one drum pad can cause triggering in an adjacent pad, and all kinds of convoluted crosstalk compensation circuitry is used to try to cure the problem. FSRs, on the other hand, respond only to physical pressure, so if you're not actually hitting a pad, it won't trigger. Another major benefit of FSR technology is that the pickup sensor is in the form of a film which can be made as wide as the drum pad, so you don't get any dead patches or lack of sensitivity around the edges.

Editing Features


  • Reinitialise.
  • GM MIDI note names On/Off.
  • Train hi‑hat pedal.
  • Bass trigger gain.
  • Beeper On/Off.
  • Display viewing angle.
  • Select breath function.
  • Train breath control.
  • Global data dump.
  • One kit data dump.
  • Foot control assign.
  • Splash adjust.
  • Record program change channel.
  • Cymbal choke enable.
  • Groove volume.
  • All memory data dump.
  • User/Factory kits.
  • User kits groove enable.
  • Memory protect.
  • Merge On/Off.
  • Pad train.
  • Pad threshold.
  • Pad low dynamic.
  • Pad high dynamic.


  • Kit copy 'to' kit.
  • Perform kit copy.
  • All notes off.
  • Pad gate time.
  • Kit hi‑hat select.
  • Kit splash note.
  • Kit program channel.
  • Kit program change value.
  • Kit volume.
  • Kit gate time.
  • Kit channel.
  • Kit minimum velocity.
  • Kit maximum velocity.
  • Kit velocity curve.
  • Pad channel.
  • Pad minimum velocity.
  • Pad maximum velocity.
  • Pad velocity curve.


  • Great playing feel.
  • Easy to use.
  • Absolutely no crosstalk between pads.


  • Not enough external trigger inputs.
  • KAT's own pedals are expensive.


An excellent MIDI pad system for both live and studio applications, which will be especially appreciated by those who want a realistic feel and response.