MIDI for LANlubbers

The use of multiple computers has become common in studios today, because the power required for multiple tasks such as multitrack recording, signal processing,
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The use of multiple computers has become common in studios today, because the power required for multiple tasks such as multitrack recording, signal processing, and working with virtual instruments (VIs) can quickly exhaust the resources of a single computer. People also use multiple computers to run applications that have been written for a single platform. A typical system might consist of a Mac running an audio sequencer such as MOTU's Digital Performer (DP) and a PC dedicated to virtual-instrument applications such as Tascam's GigaStudio or Steinberg's V-Stack. The PCs in such setups function just like hardware sound modules, and so each computer usually requires a separate hardware MIDI interface and dedicated MIDI cables. You can avoid that duplication of accessories, however, by transmitting MIDI data over a Local Area Network, or LAN.

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FIG. 1: To transmit MIDI data over an -Ethernet -connection with MusicLab''s -MIDIoverLAN, enter your PC''s IP address in the MIDI Out section on your Mac, and your Mac''s IP address in the MIDI In -section on your PC.

Apple's OS X now includes a MIDI-to-Ethernet driver in Tiger (OS X 10.4 and higher) for connecting newer Macs. For cross-platform networks, however, you'll need a product such as MusicLab's MIDIoverLAN CP (available at www.musiclab.com).

Net Gains

Setting up MIDI communication over a network differs from traditional hardware MIDI setup, but many concepts will be familiar to anyone experienced with MIDI, and one needs to have only minimal network-setup skills. The following example shows how I configured my system for MIDI transmission over a network. These steps and principles should apply to other systems. My own network has the following system components:

  • A Mac G4 running OS X (10.3.9) and MOTU's Digital Performer 4.52 sequencing software.
  • A Pentium 4 PC running Windows XP with Service Pack 2 and V-Stack 1.2 to host various VSTi software instruments.
  • MIDIoverLAN CP Platinum Edition v. 2.2.1.
  • A broadband router (D-Link DI-604 4-Port 10/100) and Ethernet cables to connect the computers.

MIDIoverLAN CP requires a 500 MHz Pentium III PC with 128 MB of RAM running Windows 2000 with Service Pack 4 or Windows XP with Service Pack 1. Mac users will need a 400 MHz G4 with 128 MB of RAM running OS X 10.2.4.

Step 1: Install MIDIoverLAN on your Mac and your PC

Install and register your software. Installation requires manually dragging-and-dropping items on the Mac and launching an installer program on the PC. MIDIoverLAN CP includes drivers for both platforms.

Under Windows XP SP 2, you need to open an Exception in the Windows Firewall to allow MIDIoverLAN to pass through (that step is unnecessary under SP 1).

Go to the Start→Control Panel and double-click on the Windows Firewall icon. Select the Exceptions tab, and click on the Add Port button. Enter MIDIoverLAN in the Name field, and enter 11000 in the Port Number field. Click on the UDP radio button, and click on OK. The Windows Firewall Exceptions tab now displays your newly added MIDIoverLAN entry with a check mark next to it. Click on the OK button.

Step 2: Determine each computer's IP address

Under OS X, go to System Preferences→Network, and you will find your Mac's IP address listed next to “Built-In Ethernet.” To find your IP address under Windows XP, go to Start→Control Panel→Network Connections. Right-click on your network adapter's icon and choose Status; then select the Support tab. Write down each of your computers' IP addresses for use in the next step. For this example, we'll assume the addresses for the Mac and for the PC (your IP addresses may be different).

Step 3: Configure NetPorts

MIDIoverLAN uses NetPorts, which are software equivalents of the physical MIDI ports you would have on a hardware MIDI interface. You use them to route MIDI data between your computers. The MIDIoverLAN Standard Edition offers 16 In/Out NetPorts, while the Platinum Edition provides as many as 64 ports (in 8 groups of 8). Just as each device in a hardware MIDI setup requires its own port and MIDI I/O cables, each NetPort requires a unique IP address. Here is the setup for our example using a Mac running DP, and a virtual instrument host PC running V-Stack.

On the Mac, launch MIDIoverLAN and select the first port from the list displayed at left (Port 1 on MIDIoverLAN Standard Edition, Port 11 on the Platinum Edition). Check the MIDI Out box, and enter the IP address for your PC ( in this example) in the “Transmits to remote host address” field.

The procedure is the same on the PC, except you check the MIDI In box and enter your Mac's IP address ( in this example) in the “Recognizes from remote host address” field (see Fig. 1).

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FIG. 2: In OS X''s Audio MIDI Setup window, the MIDIoverLAN CP Driver appears along with any attached hardware MIDI interface. Click-and-drag to make the connection between the -MIDIoverLAN CP driver and your external PC.

Click on Apply, and close MIDIoverLAN on both computers.

Step 4: Make Connections in OS X

The final step is to make a MIDI connection between MIDIoverLAN and your external PC in OS X's Audio MIDI Setup. Launch Audio MIDI Setup. You will notice that the MIDIoverLAN CP Driver appears in the window next to any hardware MIDI interface you may have attached. If you haven't already, create a new MIDI device for your external PC by selecting MIDI Devices→Add New External Device. When the new device appears in the window, double-click on it to set its properties, give the device a name, and choose an icon. Click on and draw a line from the Out port on the MIDIoverLAN icon to the In port on your external PC icon to complete the connection (see Fig. 2). Congratulations, you are now ready to test your system.

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FIG. 3: When the connection is made -successfully, you can assign an external PC sound source to a track in DP.

Launch DP on the Mac and V-Stack on the PC. In DP, record-enable a track and assign V-Stack as its output device (see Fig. 3). In V-Stack on the PC, load a VST instrument, pull down the MIDI input pop-up window, and select NetPort 11 (see Fig. 4). The choice will be NetPort 1 if you're using MIDIoverLAN Standard Edition. The PC running V-Stack should now receive MIDI over the Ethernet connection from the Mac running DP. To add additional computers to your system, simply repeat those same steps, using another NetPort.

Future Net

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FIG. 4: To make V-Stack respond to incoming MIDI data on the external PC, select the NetPort as your MIDI input source.

MIDIoverLAN won't completely eliminate the need for MIDI hardware, because you'll need at least one MIDI interface to input MIDI information from your keyboard or other controller. But it can be a cost-effective solution if you are setting up a new system with multiple computers. Some users even claim they get better timing by using Ethernet for MIDI data. The network can also serve as a conduit for more than MIDI data alone. An emerging crop of applications such as Plasq Wormhole2 (http://plasq.com) and FX-Max FX Teleport (www.fx-max.com) are designed to transmit audio over a LAN. Who knows? With the ever-blurring distinction between instruments and computers, we may even see more Ethernet ports on tomorrow's keyboard workstations.

Babz is a composer/multi-instrumentalist and a freelance music-technology writerp based in New York City.