Hardware Overview: BopPad from Keith McMillen Instruments

Early this year I was working with David Stout on a NoiseFold performance centered around triggering particle systems to make real-time animations. While neither of us are really drummers, the piece was very percussive in nature and we started looking for a light weight pad controller that was affordable and portable, but also flexible and expressive. After looking at a lot of different options that were either too limited, bulky or expensive, we found the Kickstarter page for one of the latest devices from Keith McMillen Instruments, the BopPad Smart Fabric Drum Pad. Though it was not set to be released for nearly a year, I put it on my wishlist and have been waiting eagerly for it to go into production. Thanks to the folks at KMI, I finally got my hands on one a couple of weeks ago and have been digging into it.
Overview
The Hardware
The BopPad is an incredibly feature rich MIDI drum pad controller.
While it is markedly devoid of any buttons, knobs or displays and features only one micro USB port, the BopPad is not lacking for complexity. Made using KMI’s smart fabric sensor technology, the 10” pad provides highly accurate data on hit location, strike velocity, and pressure. It features four quadrants, each of which can be programmed to send up to 6 MIDI note values and up to 5 streams of CC data with a latency of only 3ms. Designed to accommodate everything from bare hands to sticks and mallets and can be tuned to work with a wide range of dynamics and playing styles. Weighing in at just about 20 ounces and less than ½” thick, the BopPad packs a lot of power into a tiny package.
You can also get the BopPad Mount, which allows for easy attachment to any 8mm threaded stand, and KMI’s MIDI Expander, which enables interfacing directly to any MIDI compliant hardware.
The Software
KMI provides an editor for both Mac and Windows as well as a web based editor that will work with any web MIDI compatible browser. The editor allows you to change everything from the note values and controller streams on each quadrant to the overall sensitivity and strike density of the drumpad as a whole.
Each of the data streams can be scaled, offset and and even run through algorithmic, exponential, or even user defined tables to get different curves.

One limitation is that the device can only hold up to 4 distinct presets at any time, switchable using MIDI Program Change messages. However, you can quickly upload new presets from the editor at any time.
In addition to the editors, KMI has made several templates for plug and play testing with Bitwig, Logic, Garage Band and Ableton Live. These utilize the factory presets and do a good job of helping new users make some noise and use the data right out of the box.
BopPad for Max’ers
The BopPad uses standard MIDI data for all of its controls, making connecting to Max simple. Whether you are designing your own drum machines or synths, or just looking for an expressive and streamlined controller to integrate with existing ones, this thing has a lot to offer. The four quadrants of the BopPad each give you up to 6 notes and 5 streams of low-latency velocity, pressure, radius (both on hit and deviation after the hit), and polyphonic aftertouch, so there’s no shortage of control data to use in your patches.
The editor provides a lot of flexibility, but when you dump that data into Max you can take it anywhere you want. The limitation of 4 banks of preset data feels much less restrictive once you can start manipulating the data outside of the device.
My Impressions
The BopPad
Right from the unboxing, I was impressed by the BopPad. It is solid, but not heavy, feeling well made and robust. I am confident that I won’t break it if I get too excited while playing or while transporting it (according to their Facebook page, they even ran one over with a car in the stress tests). The inclusion of the cable guard is also an important detail. Without one, it wouldn’t be long before I accidentally whacked my micro USB and damaged the port. The pad dumps out more data than I have yet figured out what do with, which is always exciting. I love being able to grow into a device and have it challenge me to pull more out of it. Maybe most important is that the sensitivity is tunable enough that I can make it behave in a way that fits any play style instead of feeling like I have to adapt to it.
The BopPad mount is, for me, a must-have. It only adds another five ounces and provides a lot of flexibility in physical setup. Having said that, I did find that just putting the pad on a flat surface works great.
I haven’t tested out the MIDI expander yet, but I think that the small form factor is worth the tradeoff of having built in MIDI ports. I am also primarily using it through Max, so I can always send MIDI out to hardware from the computer as needed.
In the end, I don’t find that I have much to criticize about the hardware, but there a couple of small things. The biggest complaint is probably the lack of any kind of control of or feedback about presets on the device itself. I appreciate the streamlined look and especially the lack of breakable parts, but would like the ability to change a preset without having to send a program change message. The second is that I would like to have more fine-tuned access to location data then the radius from the center. Though I admit that I do not know how easy it would be to expose the angle data, this feels like an artificial limitation.
The Editor
I found the editor interface to be well laid out, simple to use and understand, and similar enough in each implementation (Mac, Win, web) to make modifying it easy on any platform. A feature that I particularly like is the ability to query the pad to find out what is currently loaded on each preset bank. This is something I know will come in handy if I want to make changes while away from my main computer.
One area where I feel like there is room for improvement is not so much in the editor itself, but in the ability to control the device externally. Especially on Windows, where only one program can access the device at a time, it would be much more convenient to control the device with an embedded editor. The ability to change presets and manipulate the device settings programmatically would make this already powerful device feel even much more flexible. There is a developer tools section to the editor that exposes the html, so this definitely seems possible, but a developer spec would go a long way to making it accessible.
Final Thoughts
Overall, I am quite impressed by the BopPad and know that I will be using it in many projects for a long time to come. The device provides a dynamic percussion surface and a huge amount of data in a compact and easily portable package. It seems like it’s made to last and and comes at an impressively approachable price tag of only $199. They are slated for imminent public release and are currently available for pre-order from keithmcmillen.com and a variety of resellers.