Build an E-Cajon

The cajon is ready!

Building an e-Cajon (and do something useful with your life)

Some cajon background

When African Slaves were brought to South-America, they were not allowed to play drums. They started to use simple wooden boxes and shipping crates as substitutes. The Cajon was born. The English translation of the spanish word “Caja” is “box”. With time, the Cajon was developed as an instrument, and nowadays many different variations exist.

Cajons today is extremely popular to use and easy to bring with you when doing acoustic live gigs with friends etc. The variations of different kind of Cajons are big and there are a couple of DIY construction kits of Cajons available on the market from a couple of different vendors…to low prices. Building these kits is not rocket science either but the hard part is to make them to look nice…painting and finishing etc.

Check the whole article in the magazine digitalDrummer at http://www.emag.digitaldrummermag.com/index.aspx?issue=issue18&page=45

An e-cajon construction kit from Meinl Percussion

I bought a construction kit from DLX Music in Stockholm manufactured by Meinl Percussion (actually a Roland owned company) and spent some hours building it. No big problem to build and the ASSEMBLY INSTRUCTIONS was real good. Some shaping and sanding was needed to make the Cajon’s surface perfect for adding oil, lacquer, wax, or paint it with an entirely unique design. I did paint my cajon in white color and added a couple layers of lacquer as protection.

Playing on the cajon “as is” is actually real fun! My band Powerhell is currently rehearsing for a acoustic live performance…and my new cajon did fit perfect into that setup!

However…I am an e-drummer and wanted to add the e-dimension to my new cajon – and do it without destroying the opportunity to use it as an acoustic cajon.. So I did add a couple of piezo sensors mounted in the cajon.

Before moving into this project I used internet to see if anybody had been doing such a solution before. I could actually find a couple other solutions where people have been installing microphones in their cajon etc. (There are a couple of cajons sold with a mic built in) During my study I also decided that I was going to install a microphone in my cajon for live purposes and I installed a Shure SM-58 on a special mounted holder.

But I did also find an old post from 2006 about using piezo sensors in the cajon at the VDRUMS.COM. The writer of the post is very enthusiastic in the end…but not real proofs if it was working ok or not…! A big challenge using several sensors is crosstalk, especially when they are mounted on the same surface. (We are talking about some real crosstalk hell)

I decided to have 4 sensors in my solution. 2 of the these sensors was bought from 682drums.com but I am guessing any piezo sensors would work if using it in the 3000-5000 Hz range. The ones I bought has a diameter on 27 mm and operates at 4400 Hz. I bought them from Conrad.SE

4 sensors mounted – one sensor mounted on the side.

Ok – How and where should the piezo be mounted inside the cajon? From the old post the writer set them in the upper each corner for the snare sound (and hi-hat) and in the middle for the kick. I think I have been extremely lucky to have been finding the sweet trigger spots. In the old post on VDRUMS.COM from 2006 the top sensors are mounted very near each other. I figured out that looking on how others was playing the Cajon, that I was using the top edges instead and the sensors would of course reflect this. But the sensors need to be mounted on the top of the surface…about 4 cm from the edge.

I was pretty convinced that this project would end up in crosstalk hell …but I did not, In fact, if I do hit between the hi-hat and the snare sensor(at the top)…the kick drum actually fires. So the 3-4 mm cajon surface of wood seems to have other characteristics than a normal mesh head. 🙂 I had plans to milling down the sensors…1-2 mm in the wood…if the triggering would have been bad from a crosstalk and sensivity standpoint…but it all worked like charm directly.

The last added sensor for the cymbal came up when looking on a real professional playing the cajon – where the musician occasionally actually hit on the side of the cajon. I was really convinced that the thick cajon wood on the side (about one centimeter) would cause problems for this sensor. But not even that became a problem, the sensor is very sensitive…and don’t crosstalk. Lucky again…

Some soldering of the cables with hot shrinks, some double glue tape from www.stokvistapes.com and their model Superpads (30x30x1 mm), some hot melting glue to fix the cables,  some drilling for the connectors etc…Ready!

To handle the crosstalk hell between the sensors even more, one common way to do it is connect the sensors the Roland way. The way to do it is like most Roland snare drums are connected is that the head/rim sensors are connected reversed compared to each other. (Doing this will minimize the crosstalk even more). A post about how to do this can be found at the Quartz Percussion site http://www.quartzpercussions.com/#!philosophy/cfvg. Quartz is selling some very nice trigger systems called Quartz on Harness for A to E conversations.

When everything was mounted – the midi trigger hart, MegaDRUM was connected. To handle the crosstalk all sensors was placed in the same crosstalk group and the crosstalk suppression functions value was set to 7. Some tweaking of the high/low levels of the sensors was necessary but otherwise – more or less the default values was used. The configuration have now been posted in the  MegaDRUM library for the Kick, Snare and the hi hat/crash.

As the sound system, I am using both a Windows 8.1 based Microsoft Surface Pro as computer and a Macbook Pro with Addictive DRUMs + ADPaks for creating drum sounds and a M-Audio/Avid Fast Track Ultra 8R as sound card.

The final step (2014/12/16)

The MegaDRUM module installed in the e-cajon

One of my project goals was to build in a MegaDRUM trigger device module inside the e-cajon. I had an old MegaDRUM ATMega 1280 board laying so I updated it with the last firmware and my e-cajon settings from my previous tests with my external MegaDRUM device. It is a problem to update the firmware without any display or buttons…so I had to installed it in my external device where I have all these kind of features. (An Arm-based MD device is better to use as black box solution / no buttons or display needed) After the firmware was updated – there is no problem to handle the settings/tweaks of the MegaDRUM module over USB through MegaDRUM Manager from a PC or a MAC. The ATMega board differs compared to a Arm-based device on the high/low piezo settings so some adjustments is needed to make it perfect. So now it is only to connect the e-cajon through the USB port on the rear to a PC or a tablet with for an example Addictive Drums 2…and play! Very neat! I have also installed a couple of trigger inputs on the rear for a kick pedal and a hi/hat pedal…and which is also working great!

I have replaced the ATMega board in my e-cajon to a ARM-based version of the MD. Reasons for this is that the MD can totally controlled from MegaDRUM manager. (So no buttons or display needs to be used) Even functions like auto high level in MD can now be controlled from MDM by setting the high level to 64 and check mark the auto high level checkbox. You will now see how MD starts to measure the high level when hitting the actual sensor in MDM. A perfect black box. Dmitri at MegaDrum just released a lite version of the MD To a Right price….just perfect for an e-cajon!

2015-01-11
Regarding the trigger feeling in my e-cajon I was not 100% satisfied so far. When measuring the high level value in the MegaDrum, I’ve got values above 950 which was indicating that my 27 mm piezo sensors was too hot. I have finally made something about this and installed resistors on all piezo inputs. A 30K ohm resistor in serial with the Piezo seems to make magic to the high level, which now got down to about 500. From a playing standpoint the cross talk went down and the feeling up! 🙂

Then there was a lot of tweaking of the MD parameters to get it perfect. I will post these findings soon and a movie how it is working together whit a complete new post when using an iPad as the brain for drum module! Please visit my second post about the e-cajon where I have installed a MegaDRUM module inside and attach it to an iPad.

Everything installed!

A special request from digitalDrummer.

On request I have also made some e-cajon tests using my old Roland TD-6V module and have been investigating if the same trigger results could work just as well with this device also. Using four separate & different inputs on the TD-6V works very well. (It is not possible to really use the second rim input on the selected channel to combine two e-cajon triggers into one stereo input – MD offers some advantages here…) I have used in the TD-6V basic trigger menu settings, a RT-3T (A single piezo external trigger – the model prior to the RT-10T) and then set the sensitivity quite high (e.g =9-11) and the threshold between 3-5 and crosstalk cancel to 80. I did not change anything in the advanced trigger menu settings. Result – a just perfect e-cajon! Very sensible …you can play it with your fingers…nice wide dynamics and very hard to fire off crosstalk hits.

Check the whole article in digitalDrummer at http://www.emag.digitaldrummermag.com/index.aspx?issue=issue18&page=45

2015-01-26. Just for fun, I have made a small video when playing on my e-cajon using Addictive Drums 2 and their Cajon Kit Piece Pack. Playing with a e-cajon using e-sounds of a cajon…I think I have closed the loop or….:-)

 

 

2016-01-20 – Roland Corp just launched an E-Cajon – called EC-10 EL Cajon…which just proves that a e-cajon is a great idea and invention! Fantastic fun!

2016-12-20 – a week ago my band Powerhell went out and performed an acoustic gig. I was using my e-cajon, this time slightly upgraded with 5 piezo sensors(hmm the EL-cajon has 2) + hihat pedal and a Roland KT-10 kick pedal. Inside the e-cajon I used a internal MegaDRUM module which feeded a MacBook with Addictive Drums over USB.

The setup work very well during the performance.

 

2017-07-24 Bills of MTRL for building an e-cajon

Bill of MTRL, Price, Link, Product
Meinl Cajon, 40 €, https://www.thomann.de/se/meinl_cajon_construction_kit.htm, Meinl MYO-CAJ Cajon Construction Kit
Megadrum Lite board, 85£, https://www.megadrum.info/forums/viewtopic.php?f=3&t=2667, Megadrum Lite standard
Sensors, 5 EUR, https://www.conrad.se/Piezokeramiskt-objekt-EPZ-serien-2900-%b1-500-Hz-Inneh%e5ll:-1-st.htm?websale8=conrad-swe&pi=712943&ci=SHOP_AREA_17390_0235311, Piezo Sensors – 28 mm
Connectors, 10 EUR, USB, external sensor inputs 6.35mm teleplug

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