Wireless technology permeates our existence: wireless phones, computer networks, and audio-system controllers are everywhere. Wireless MIDI systems are
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Frequency Band 914.5 MHz Channels 1 Range (according to mfr.) 260 ft. Power transmitter: 9V battery;
receiver: AC adapter Dimensions transmitter: 2.76" (W) × 3.94" (H) 1.18" (D); receiver: 9.49" (W) × 1.26" (H) × 4.53" (D) Weight transmitter: 0.63 lb.; receiver: 1.87 lbs. Frequency Band 2.4 GHz Channels 31 Range (according to mfr.) 500 ft. Power (either unit) (2) AA batteries or AC adapter Dimensions (either unit) 4.4" (H) × 2.6" (W) × 1.1" (D) Weight (either unit) 0.38 lb.

Wireless technology permeates our existence: wireless phones, computer networks, and audio-system controllers are everywhere. Wireless MIDI systems are a boon for onstage performers who want to free themselves from as many encumbrances as possible. Wireless MIDI is useful in the personal studio, where recording near a workstation can be noisy and impractical.

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FIG. 1: The Kenton MidiStream wireless MIDI system sports a second antenna-and-receiver system. Should reception weaken over one antenna, the second can receive the signal.

Although well-implemented wireless MIDI control can simplify complicated MIDI cable runs, it doesn't eliminate them. MIDI output from your controller requires a cable to route data to a transmitter, which may be connected to an external power supply or powered by batteries. You will no longer be tethered to the receiving devices, which could be anything from a single synthesizer to a complex, computer-driven DAW. And therein lies the wireless system's appeal — performers are free to wander anywhere within the system's transmission range.

Celebrate Diversity

Two of MIDI's newest wireless systems are the MidiStream, from Kenton Electronics, a London-based firm, and MIDIjet Pro, from Classic MIDI Works (a division of Artisan Classic Organ), a Canadian manufacturer. Kenton's MidiStream receiver comprises two receiver and antenna systems in one housing, which is often referred to as a diversity system (see Fig. 1). The redundant antennas help to ensure that either one or the other will receive the signal under most circumstances. Antennas attach to the receiver's rear by way of BNC sockets.

The MidiStream operates on a single frequency of 914.5 MHz. Consequently, you can't use one system if it is too close to another. The manual doesn't specify what that exact range is, but you should probably avoid using more than one system on stage at the same time. Kenton plans to make additional frequencies available in the future.

A wall-wart AC adapter powers the MidiStream's receiver. Of the four LEDs on the front panel, one indicates when the power is on, another shows whether the MIDI signal is present, and the other two indicate reception on either of the antennas. The receiver has a single MIDI Out jack, and you connect your controller to the transmitter's MIDI In jack. Next to the transmitter's jack, an LED indicator flashes when the battery power is low. A thumbscrew at the transmitter's base opens the well that holds its included 9V battery.

According to Kenton, battery life is between four and five hours. Kenton provides a list of hexadecimal SysEx strings that you can send to the transmitter to conserve battery power by powering down when it stops transmitting. That allows you to customize the amount of time between MIDI messages before the unit switches to a low-power-drain mode. For the less hex-savvy among us, it would be more convenient to download a Standard MIDI File (SMF), which should be available on Kenton's Web site by the time you read this.

Binding Arbitration

Classic MIDI Works MIDIjet Pro's transmitter and receiver look identical except for their color; the transmitter is black and the receiver is white (see Fig. 2). Both are single-antenna, high-impact plastic units about the size of a cigarette pack. The system operates at a frequency of 2.4 GHz and has spread-spectrum transmission technology, which the manufacturer says is inherently resistant to interference. You can program the MIDIjet Pro to work over a range of 31 channels, which lets you use as many as 31 systems in a single locale.

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FIG. 2: The Classic MIDI Works MIDIjet Pro lets you set unique transmitter and receiver -channels for as many as 31 separate wireless MIDI systems working in close proximity.

At the MIDIjet factory, each transmitter and receiver system undergoes a process called binding, which ensures that a unit pair will communicate only with each other, even if other units are operating at the same frequency. If you do have multiple units, you can assign each pair a unique channel with a DIP-switch setting. The transmitter and receiver house the DIP switches behind their battery wells. Although the batteries don't impede access to the switches, you should perform any last-minute changes to the settings in a well-lit area; the tiny, recessed switches are difficult to access and set.

Classic MIDI Works claims a battery life of 30 hours. The MIDIjet Pro includes a pair of AA alkaline batteries for each unit and a wall-wart AC adapter you can use with either unit.

Long-Distance Runaround

MIDI is not as data-intensive as audio. Because of MIDI's serial nature and limited bandwidth, all MIDI systems are somewhat limited in the capacity of what they can deliver. Wireless systems do introduce small but ideally imperceptible amounts of latency. To test both systems, I played several software synths with my MIDI guitar controller transmitting Notes, Pitch Bend, and various MIDI CCs over six channels — a triple-whammy for accurate MIDI timing — and the arrangement was quite playable.

Large SysEx dumps will not work without software that can apportion the data into smaller chunks with more time between transmissions. That said, you can transmit the full range of MIDI messages through both systems. For example, I was able to use a knob on my Korg MicroKontrol to remotely regulate the tempo of a sequence playing back in Cakewalk Sonar.

The MidiStream claims a maximum range of at least 260 feet, whereas the MIDIjet boasts as much as a 500-foot range. Maximum indoor ranges are significantly shorter; Kenton claims an indoor range of about 100 feet. In practice, I did not have the real estate to put the extreme end of the unit's specs to the test; these claims posit an outdoor, line-of-sight signal path, and no sensible user should rely on the maximum range claims in a working environment.

Monitoring the effectiveness of the units with my guitar controller was restricted to shorter runs of a maximum 30 feet, in which I could realistically assess an instrument's response without acoustic latency symptoms. I also transmitted MIDI sequences of varying density to a Roland SC-55 Sound Canvas connected to the receiver and monitored the results through headphones connected to the synth. An extremely busy 13-channel sequence with multiple tracks of Pitch Bend, Modulation, and Program Change messages played my old Roland SC-55 Sound Canvas at a distance of roughly 50 feet without a hitch, even through obstructions such as walls and closed wooden doors.

Both units automatically send All Notes Off messages if the signal goes out of range or becomes obstructed. To test that, I shut off the transmitter while playing back a MIDI sequence. The MidiStream and the MIDIjet Pro responded quickly with no hanging notes, only to resume playback as soon as I switched the power back on. When I deliberately dislodged the MIDI cable from the transmitter (the most likely way to accidentally disrupt the MIDI data stream), notes in an ongoing sequence hung momentarily. If I reconnected the cable immediately, the stuck notes stopped and the music righted itself. Again, the MidiStream and MIDIjet responded identically. To determine whether MIDI density was the culprit, I played back a 3-channel MIDI sequence with no data other than Note messages and got the same results.

Down to the Wire

Both systems worked right out of the box and without any complicated setup procedures. Both give you basic documentation, but not much more information is necessary; wireless systems are essentially set-and-forget devices.

Although the MidiStream's redundant antennas might be helpful in situations in which unexpected signal interference occurs, the MidiStream costs quite a bit more the MIDIjet Pro. If you require more than one wireless system to work in close proximity with others, the MIDIjet Pro is currently the logical choice, especially considering their difference in price.

Both units deliver solid performance at a price far below the cost of earlier wireless setups. In Geary Yelton's review of the $2,995 Gambatte MIDIStar Pro wireless system (see “First Take: Capsule Comments,” in the June 1989 issue of EM), his article concludes with the wish that wireless systems were more affordable. I'm happy to report that simple, reliable, and affordable wireless MIDI systems are finally within reach.

Former EM assistant editor Marty Cutler's five-string banjo is completely wireless, except for the strings.




wireless MIDI system $649


PROS: Diversity system provides redundant receiver. Requires no setup.

CONS: Only one frequency available.


Kenton Electronics/Big City Music (distributor) or


MIDIjet Pro

wireless MIDI system $495 Canadian (about $395 U.S.)


PROS: Extremely compact. Supports as many as 31 discrete wireless channels in one local area.

CONS: Recessed DIP switches difficult to access.


Classic MIDI Works