Building a Live Keyboard / Guitar Rig with Mac Mini

After four months and many different iterations of this project, I am finally ready to share with interested parties what I’ve been working on and testing this past spring. I think I’ve finally settled on a setup that works well. While I’ve been documenting parts of this project on OSXAudio.com, this article is the official source of information and will flesh out some additional details since the last posting. Please feel free to post comments and questions here as I’ve been so close to this project that I probably didn’t answer everything that people will want to know about this.

THE BACKGROUND: I’ve been playing in a rock band for the past 7 years. The latest band I’ve been in has a synth element that I’m required to fill for live performances - this duty in addition to playing guitar. Additionally, there was a period of time where this same band also did cover shows, which required many different keyboard sounds, many different guitar sounds, even from song to song. I’m a perfectionist I guess and I try to get the sound of the artist as close to the recording when it comes to covers. Anyway, I digress…

THE GOAL: Create a turn-key type guitar and keyboard instrument system that supports needs for a rock band in 4 standard 19″ rack spaces or less. It must fit in the trunk of a VW Jetta and be flexible enough to cover the needs of both an original band and a cover band. It must travel well and be easy enough to carry or wheel by one person.

THE TOOLS: Multiple LCD displays, Multiple power adapters, a Mac Mini 1.2Ghz, various audio interfaces, a rack, lots of zip ties, velcro, a Calzone Case, some rack shelves, a Dremel tool, guitar, keyboard, footswitch, and more. Ok ready to go? Let’s continue.

The Concept

The concept was simple. Create an easy to transport rig with an small LCD display. The LCD display would be used for visual feedback only and not as a primary means of interface.

The goal here, again, was to create a system that did not require much interaction once it was booted. It was important for me not to have to manually change patches or banks for sounds during a show. A 7″ LCD I thought would be the perfect match for this task - a minimal of launching programs and ensuring programs were loaded appropriately.

Interfaces

I would be using an existing Lexicon MPX R1 as a foot controller for guitar sounds and a M-Audio Radium 66 as a keyboard controller. I had the Lexicon MPX R1 sitting around from an existing Lexi MPX G2 processor purchase. The nice thing about this controller is that it supports the 9-pin cable connection that will also carry power. Unfortunately, in this configuration, I was unable to take advantage of that.

I preferred the M-Audio Radium 66 since its lightweight, is very reliable, and is so cheap it can take a beating or break and the cost to replace it is not too high. I’ve had this particular model for over 2 years of shows. Also, being powered by USB makes for less wires and connections. Really, this system will work with any USB powered keyboard interface.

For UI type input I would use a touchscreen, an Apple Bluetooth Mouse, and an Apple Bluetooth Keyboard.

Core System

Processor: The system itself is based around a Mac Mini 1.2Ghz machine with 1GB of RAM. Its a shame that only 1GB of RAM can fit into this machine as I think they only provide one slot. However, my prior setup was based around a 12″ powerbook which did reasonably well with this task. I opted for the 40GB hard drive instead of the 80GB and also configured it with Bluetooth and 802.11g for ease of configuration and flexibility.

Display: I found a Brand-X 7″ TFT LCD display that came with touch-screen capability via USB, probably made in China which I later confirmed based on its reliability. This system came with a standard VGA type video and audio adapter interface, making it easy to configure the Mac Mini to recognize it. The big issue here however was power. It required 12V at 800mA requiring a quick trip to radio shack and some quick soldering to connect up the leads.

Mounting: These two components were then mounted to a standard 19″ shelf rack and secured using a combination of zip ties, velcro, and bolts. I also included a front-ward facing Belkin USB extender to provide access to USB slots for both the keyboard interface and any other USB devices from the front face. Also, the Mini is mounted front facing for access to the CD drive and unused ports on the back of the machine were taped up.

Audio Interface: Lastly, for the audio interface I settled on the Motu 828 MkII. I had been looking at this unit for quite a while and having already owned a Motu 898 interface, I was familiar with what to expect. I chose this one for multiple reasons.

• 19″ 1U Form Factor
• Hi-Z input
• 1 Port Midi I/O
• Headphone Jack on front face
• 8 balanced 1/4″ outs

The 828 MkII is really a good fit. Depending on the venue or the situation, I may play into FoH (Front of House) for both keyboard and guitar, I may play just keyboards and send guitar to a stage amp, or I may play both through the same or even different stage amps. This interface truly gives me flexibility. Keyboards are routed through one stereo pair output while guitars are routed through another stereo pair output. This can be extended to multiple stereo pairs if needed but for the time being I’m only using 2 (4 channels total).

Installation

I had originally intended to put this beast into a rolling rack case for convenience. After some further thought, I had decided against it. First, a 4U rack shock-mount rack case with wheels would add unnecessary weight and height to the unit. Secondly, the thought of the impact of vibrations from dragging it through downtown Manhattan also made me reconsider.

I decided on a Calzone 4 space-shock mount. Now that its said and done and I may have considered a case with less depth but it all works the same. The shock-mount cases they design add a little more depth once the front and back covers are on. This is great however for storing the keyboard and mouse in using some velcro straps. Also, this setup gives me the flexibility of also installing components into the rear face of the unit, which is presently where the power is.

The Software

There are two main components to this setup’s software. The first is Apple’s Logic 7.0 pro. The second is Native Instruments Guitar Rig.

Guitar Rig is by far the best software guitar processor I have encountered. I have used Apple’s Guitar Amp, Amplitube, Amp Farm, and others. Guitar Rig, hands down, wins this contest for me. The ability to also easily map Midi controllers to such things as pedals and switches is flawless. Also, its bank/patch programming is very easy to use and very easy to keep things organized. In Guitar Rig, I have a bank for original shows and a bank for cover shows. This allows for super easy organization of patches.

Logic Pro 7 is amazing. There has been nothing I haven’t been able to do with this program given some time to do some digging and advanced environment manipulation. For this live setup, I have created a custom Logic environment that allows me to send PC change messages from the keyboard and in real-time reroute Midi performance data to different virtual instruments and samplers. In the screenshot you can also see a drop down box that allows for easy selection of patches when needed. Though, I found myself rarely using this and instead relying on the keyboard for PC message changes. Like Guitar Rig I have two logic setups, one for covers, and one for originals.

Finished Product

What you do not see in this picture is the Lexicon MPX R1 and the Radium 66. The Radium 66 is connected via USB and the MPX R1 is connected via Midi from the Motu 828 MkII. In the rear you can see the power supply and the feeds for the 1/4″ balanced snake that either goes to FoH or an amplifier.

Overall, the finished product worked well. However, there were some drawbacks that were identified and later remedied:

• The LCD covered part of the interface. This was a result of how it was mounted. Though there were probably other mounting options, this became the least of my worries.
• The touch screen drivers needed to be recalibrated after every start-up. They would not hold their settings and upon reboot would appear inverted. Touching the bottom of the screen resulted in a mouse click at the top of the screen. Very confusing and the last thing I wanted to be doing while setting up before sound check.
• The LCD display that was chosen would periodically shut off and have difficulty turning back on. I originally had attributed this to not enough power. After realizing that this was unacceptable, I tried to take matters into my own hands in a last ditch effort. Attempting to solve the solution with a larger more powerful power supply quickly fried the unit to a nice crisp. I was let-down that I did not see sparks or a flame though.
• Tuning the guitar was done through the guitar rig interface. If I was far away, it was difficult to see.

Second Version

After the LCD broke, I needed an alternative. The cheapest one I could think of was to by a tiny Lilliput 2″ LCD off of eBay. It cost me about $5 to buy and $25 to ship. $30 not bad. Though originally meant to be only a temporary solution, I was surprised with is how durable and clear this LCD is.

In this photo you can see the current setup. The larger LCD is gone and replaced with a 2″ LCD. This thing is TINY! However, with icons on the desktop set to a size of 128×128, its very sufficient for launching programs and checking the status of the system to make sure it has booted properly. Also, since the larger LCD was now gone, I was able to cut the size of the shelf mounting from 3U to 2U. This allowed me to put in a 1U tuner. Now I can actually see from across the stage whether or not I’m really in tune or if my drinks are just kicking in.

Lessons Learned

Most LCDs are cheap, especially touch-screen ones. Buyer beware.

Logic is extremely powerful. A customized Logic environment can do pretty much anything.

Creating a blank patch in Guitar Rig can free up the system utilization to about 3-4%. This is ideal for those keyboard only songs where I’d prefer to have three arms and the system tax for soft synth usage is high.

Keyboards through guitar amps sound interesting.

If you have a wireless mouse and/or keyboard … always bring extra batteries.

A full featured guitar/keyboard rig CAN fit into the trunk of a Jetta. ^_^