A basic keyboard rig consists of a keyboard and associated pedals, a computer, and an audio interface. In this chapter, you’ll find out exactly what to look for when shopping for gear. At the end of the chapter, we’ll take a brief look at how keyboard rigs are set up on Broadway shows.


If you’re reading this book right now, chances are you already own a keyboard. In fact, you might already know how to use your keyboard with MainStage. If that’s the case, feel free to skip this section.

Click here for our keyboard recommendations.


The computer is perhaps the most important part of a keyboard rig because you can’t use MainStage without it. There are a few things to consider when configuring a computer for use with MainStage. Before we talk about discuss the computer in detail, let’s go over some basic requirements needed to run MainStage 3.

  • 4 GB of RAM
  • Display with 1280 x 768 resolution or higher
  • OS X v10.8.4 or later
  • Minimum of 5 GB of disk space (35 GB for optional downloadable content)

Luckily, most of the Macs currently available from the Apple Store will exceed these requirements. Users with older Macs may not be able to install OS X 10.8, and therefore will not be able to use MainStage 3.


CPU (central processing unit) and RAM (random access memory) are the two most important components that affect MainStage’s performance.

The CPU is the brain of your computer. It is constantly performing billions of mathematical functions, and is in charge of internal data flow. You’ve probably seen marketing terms like “Core i7” or “Core2Duo,” These simply refer to the architecture of the CPU chip. Fortunately, you don’t need a degree in computer science to choose a suitable computer for running MainStage. Almost any current MacBook excluding the 11” MacBook Air is capable of running MainStage reliably.

When you hear the word “storage,” what immediately comes to mind? You’re probably thinking of your hard drive or perhaps the USB flash drive attached to your computer. RAM is also a type of storage. Hard drives and USB flash drives offer permanent storage. This means data won’t be deleted unless you decide to delete it. RAM, on the other hand, offers temporary storage at super fast speeds. It’s mainly used for temporary storage of data that needs to be recalled quickly.

A healthy amount of RAM is needed for MainStage to work at peak efficiency. When you load up an instrument in MainStage, the initial attack of the sound is loaded into RAM for instant recall. While the initial attack of the sound is streamed from RAM, the rest of it is being prepared to stream from the hard drive. The reasoning behind this method is that modern sound libraries are too large to be completely loaded into RAM.

So now you see why more RAM may lead to better performance in MainStage. Programming tons of sounds without the proper amount of RAM will lead to glitches. In most cases when sample attacks aren’t loaded into RAM, the computer can’t keep up with streaming directly from the hard drive, resulting in clicks and pops.

How much RAM is enough? While that largely depends on the types of sounds you plan on using, our minimum recommendation is 8 GB. Luckily, 8 GB is the standard on all the current MacBook Pros. Depending on the model of your MacBook, it may also be possible to upgrade the RAM. Unfortunately, the latest models do not allow for RAM upgrades, so it’s important to make a decision when purchasing.

Hard Drive

The hard drive is your internal permanent storage, and there are two major varieties. The traditional mechanical hard drive (HDD) is the more widespread option. In the past few years, solid state drives (SSD) have become more common in higher end computers. The two major differences between these two types of hard drives is speed and durability.

Mechanical hard drives stores data by magnetizing a thin disk of magnetic material. The disk is spun, and data is read by “read-and-write heads,” SSDs store data on flash memory, similar to USB flash drives. Since SSDs do not have moving parts, they are more durable and reliable than HDDs.

Consumer level HDDs come in two different speeds — 5400 RPM (revolutions per minute) and 7200 RPM. SSDs do not rotate, and therefore do not have a RPM rating. In the real world, solid state drives can perform anywhere from 2x to 5x as fast as their mechanical counterparts. If you’re on the market for a new hard drive, definitely go the SSD route because they’re pretty affordable nowadays. Click here to view our SSD recommendations.

In summary, if you’re looking to buy a new computer for MainStage work, get one with more than 8 GB of RAM and a SSD. If you’re looking to upgrade an older computer, start with the RAM before investing in a SSD. Visit our computer recommendations page for advice on the latest Macs.

Audio Interface

We briefly mentioned the audio interface earlier while discussing the differences between analog and digital audio. An audio interface is a device with an ADC and** DAC** chip among other things. It’s used to send audio from MainStage to your sound engineer. As a refresher, ADC stands for analog to digital converter, and DAC stands for digital to analog converter. It’s common for an audio interface to also contain microphone preamps and headphones amps, but we won’t concern ourselves with that.

In the grand scheme of things, the audio interface sits between the computer and the sound board. It’s job is to convert the digital data coming from the computer into analog voltage that can be amplified and eventually heard through speakers. Many audio interfaces also have MIDI input and output, which allows connectivity for your keyboard.

Choosing the right audio interface is very important when it comes MainStage performance. Most modern audio interfaces sound quite good, and it’s almost impossible to differentiate high end models unless you are monitoring through a great sound system. More often than not, the defining factor when choosing an audio interface driver performance.

A driver is a piece of software that enables communication between the computer and audio interface. The efficiency and stability of the driver has a huge impact on MainStage’s performance. Let’s step back to the concept of digital audio for a moment.

In a MainStage rig, the DAC chip inside the audio interface converts digital data into analog voltage. This conversion happens at an impressive rate, but it’s not completely constant. A certain amount of data needs to be converted before being sent to the audio interface’s output. This amount is measured in samples, and is called the** buffer size**. In the audio world, buffer size is typically measured in multiples of 16, and 32, 64, 128, 256, 512, and 1024 are common variations you’ll often see in audio software.

If a buffer size of 64 samples is selected, this just means 64 samples of audio will be collected in the buffer before being sent for to the DAC. Decreasing the buffer size puts additional strain on the CPU because more information needs to be processed more rapidly. A higher buffer size puts less strain on the CPU, but may result in noticeable latency between playing a note and hearing sound. It’s important to find a good balance between low buffer size and performance. Well written drivers are designed to minimize latency. Thus, a superior driver with a buffer size of 128 samples may end up performing better than a poorly written driver operating at 64 samples.

The Zoom UAC-2 is a great sounding and affordable audio interface.

Our top three audio interface brands from professional to consumer level are RME, Zoom, and Steinberg. These three companies manufacture great sounding and reliable audio interfaces, and are some of the most popular options for live performance. Visit our audio interface recommendations page for advice on the latest models.

Pedals & Accessories

A typical MainStage keyboard rig uses three pedals — sustain, volume, and patch advance. This section will also cover all the different cable and connector types you will likely encounter as a keyboard programmer.

Sustain Pedal

Chances are you probably already own a sustain pedal for your keyboard. However, as a keyboard programmer, it’s important to be aware of the different types of sustain pedals.

The most common sustain pedal you will encounter is the on/off type. These pedals can be designed to resemble an acoustic piano’s sustain pedal, but only offer on/off control. More expensive continuous sustain pedals feature** half-damper** support, which means values between on and off can be generated.

Remember how the MIDI specification has 128 possible values? When an on/off sustain pedal is used, any value from 0 – 63 sends an off message, while any value from 64 – 127 sends an on message. A continuous sustain pedal, on the other hand, supports varying degrees of on and off. This results in a more nuanced and realistic sound when a half-damper compatible keyboard and/or virtual instrument is used.

The Yamaha FC4A is a popular sustain pedal, and the Yamaha FC3A is a popular half-damper capable sustain pedal.

Expression Pedal

The expressional pedal is used to control parameters that aren’t exclusively on or off. Such parameters include volume, modulation, cutoff filter, etc. In a typical MainStage keyboard rig, the expression pedal is used to control volume. Expression pedals are continuous controllers and can transmit all values between 0 and 127. The Yamaha FC7 expression pedal is widely used in productions all around the world.

Footswitch Pedal

The footswitch pedal is often used to advance patches or trigger click tracks. The BOSS FS-5U is the industry-standard footswitch pedal.

Audio Cables

As a keyboard programmer, it’s important to know about the three major kinds of audio cables you’ll likely encounter — XLR, 1/4″ TRS, and 1/4″ TS. These three cable types have two main differences — connector shape and wiring. Check out the diagram below showing the visual differences.

“Balanced” and “unbalanced” refer to the way a cable is wired. XLR and 1/4″ TRS are balanced. This means the cable contains three distinct wires (positive, negative, and ground) for an electrical signal to travel through. The positive and negative legs carry the same signal with opposite polarity. If the cable is connected to a balanced connector at the end, one side will flip its polarity. Thus, any noise picked up along the way will phase cancel and disappear. Unbalanced cables do not have this third wire, and are more prone to noise and interference over long cable runs.

TRS stands for tip-ring-sleeve (positive, negative, ground) and TS stands for tip-sleeve (positive, ground). TRS cables are sometimes referred to as “patch cables,” and TS cables are often called “instrument cables,”

Digital I/O Cables

On the computer side of things, you’ll likely be using three different kinds of cables — MIDI, USB, and FireWire. A MIDI cable is used to connect a keyboard to a MIDI or audio interface. It can also be used to connect a keyboard to another keyboard or sound module. Some keyboards also offer USB or FireWire connectivity, which bypasses the need for a MIDI interface. Most modern keyboards feature USB, while higher end keyboard workstations like the Yamaha Motif XF8 have FireWire capabilities.

This post is part of the Apple MainStage Keyboard Programming series. The next post in this series is *Connecting Hardware with Software in Apple MainStage *.