If you’re a guitar player, understanding and utilizing MIDI messages can be highly beneficial when controlling your pedalboard or your complete rig. By learning how to use MIDI to control your guitar effects, amplifiers, switchers, loopers, and other devices, you can create a setup that works best for you.
MIDI is a straightforward and versatile one-way protocol that enables control between devices. To start using MIDI to control your equipment, it’s crucial to understand the basic principles of MIDI messages and how to use them. Keep in mind that each device may have its unique requirements, so it’s essential to read the manual for each piece of equipment.
Connecting MIDI devices:
MIDI devices commonly use the DIN5 connector as a standard. The devices feature female connectors, while the cables have male connectors. To connect your gear properly, link MIDI Out to MIDI In or MIDI Thru to MIDI In.
Some manufacturers use a 3.5mm stereo TRS jack instead of the DIN5 connector, especially for compact devices like guitar effects pedals. Although this TRS jack is an approved MIDI standard, always check the pinouts in your device manual to ensure proper wiring.
Input Devices:
These devices include MIDI footcontrollers, controllers, computers, synthesizers, and guitar processors. They feature buttons, sliders, faders, or footswitches that you can program to send out MIDI messages. The modern MIDI controllers offer advanced functionality and you can even program them using a computer or phone. For professional use, I recommend a MIDI controller with a display and the ability to send a sequence of MIDI messages, allowing you to control multiple devices simultaneously. However, if you’re on a tight budget, make sure to check the capabilities of any old-fashioned MIDI controllers before purchasing. Look for controllers with built-in expression pedals or a jack plug for an external expression pedal. While some guitar processors can act as MIDI controllers, they often have limited capabilities compared to dedicated MIDI controllers.
Receiving /slave/ devices:
Any devices that can receive and respond to MIDI messages, such as guitar effects, processors, amplifiers, switchers, and loopers, are known as receiving devices. Some devices, like guitar processors, can also function as MIDI controllers or receiving devices.
What is the difference between MIDI Out and MIDI Thru?
The key difference between MIDI Thru and MIDI Out lies in their function. MIDI Thru duplicates the messages received at MIDI In, while MIDI Out can send not only these messages but also additional ones generated by the device itself. For example, the MIDI Out of the 8X7 and 4X4 amp switchers retransmits all MIDI messages from the MIDI In, along with additional MIDI SysEx messages for direct control of the N-audio FX-Loop extensions.
Not all MIDI devices feature all three MIDI Out, MIDI In, and MIDI Thru connectors. Most include only MIDI Out and MIDI In. If a device lacks a MIDI Thru port, use the MIDI Out port to chain your devices.
Connecting your devices:
Musicians typically rely on a single controller to manage multiple devices connected in series via MIDI. Some of them include MIDI Out or MIDI Thru outputs for expanding MIDI control across additional effects. If you need more MIDI outputs, a MIDI splitter is the ideal solution. This device takes one MIDI input and splits it into multiple outputs, allowing you to control all MIDI devices in your rig.
MIDI channels:
MIDI communication uses 16 channels to transmit messages between the controller and the receiving device. When both devices are set to the same channel, the controller can control the device. If the channels are set differently, the controller won’t be able to do that.
To control multiple devices, assign them different MIDI channels. For instance, if you have two identical delay effects on your pedalboard, setting them to different MIDI channels will allow you to control them independently via your MIDI controller.
Some devices receive MIDI messages on all 16 channels through its OMNI functionality. It’s useful when you have a small setup or are testing your device, but it’s better to use independent MIDI channels for more complex setups.
Program Change (PC):
MIDI is a universal protocol with different types of MIDI messages used for specific purposes. One such type is Program Changes, which is commonly used to switch presets, modes, looper presets, amplifier channels, and more. There are 128 program changes available, numbered from 0 to 127. With 16 channels, you can access a total of 2048 MIDI program changes.
Control Change (CC):
Control Changes are MIDI messages used to actively control variable parameters like volume, pan, effects from expression pedals, volume pedals, encoders, sliders, and more. Each message is numbered 0 to 127, including an extra bit for a VALUE, which distinguishes Control Change (CC) from Program Change. This value allows you to actively control parameters, such as volume. For instance, volume control commonly uses CC#7, where a value of 0 represents mute, 127 represents maximum volume, and all values in between represent different volume levels.
Control Changes allow to represent pressing and releasing keys or tap tempo. When used for key presses or releases, some devices divide the value into two groups: 0 to 63 for key releases or disabling a specific function, and 64 to 128 for key presses or enabling it.
MIDI uses several commonly known control changes for various purposes. A table of these controls is available on the MIDI organization’s website.
Note On messages:
MIDI is not only used for guitar equipment but also for synthesizers with piano keys. Devices with piano keys actively utilize Note On messages. Similar to control changes, these messages consist of notes numbered 0 to 127, with values from 0 to 127 representing velocity. Velocity determines the intensity or force with which the note is played, with 127 being the loudest and 0 representing silence.
While guitarists typically do not use Note On messages, they hold significant importance for electric pianos and other keyboard-based instruments.
SysEx messages:
System Exclusive (SysEx) messages are a type of MIDI message designed for specific purposes, allowing for more advanced or custom control between devices beyond standard functions.
SysEx messages are typically longer than other MIDI messages. Manufacturers define their own formats and parameters for each device. These messages are used to store or recall patches, update firmware, and control device operations. Specialized software may be required to send or receive SysEx messages. The communication between the 8X7 and the 4X4 Switchers and their FX-Loop extensions rely on SysEx messages for example.
How to control your devices?
When it comes to controlling your MIDI devices, it’s important to read the MIDI implementation part of the manual first. There are two main ways to implement MIDI control: through a Learn function or through fixed MIDI messages.
The Learn function is commonly used by switchers, loopers, programmable selectors, and amplifier channel switchers to program their rig quickly and easily, especially for MIDI beginners. To use this feature, select a preset, press and hold the MIDI Learn button, and wait for an incoming MIDI message. These devices usually accept program change and control change messages. Note that in sequential MIDI messages, they only recognize the first message and save it to the preset you choose. To control multiple devices, reserve the first MIDI message for the device with the Learn function, then send MIDI messages for all other devices. Remember that different devices may use different MIDI channels.
The other method is fixed MIDI message control. Devices using this method usually have a section in their manuals with information on how to configure them via MIDI.
How to resolve MIDI issues?
When experiencing communication issues between two MIDI devices, the problem is likely due to either hardware or MIDI message issues. A defective cable may cause hardware issues. To test hardware communication between devices, check if your device has an LED that blinks when it receives MIDI messages. You can use this as a MIDI tester. All N-audio MIDI Amp Cabinet Switchers including 8X7 Switcher, 4X4 Switcher, and Two Amps To Cabinet have this capability.
Message issues are more common. To troubleshoot, start by checking the MIDI channel. Ensure both the controller and receiving device are set to the same channel. Then, verify that the correct MIDI messages are being sent.
Useful links:
- I have written a post on designing MIDI schematics on the N-audio Blog page.
- The website of the MIDI Association – the source where you can find everything about MIDI.
- Also, check this Sparkfun MIDI tutorial.
- The MIDI-OX for Windows is an excellent tool that turns your sound card into a versatile MIDI device.
Summary:
If you’re unsure about how to control your devices and you already have a controller, I highly recommend opening the user manuals for both devices. Start with something simple like switching presets, and then try improving your skills by adjusting some parameters. Once you’ve tested more commands provided by the manufacturer, controlling other devices will become much easier.
