Jam Bass e28 The guitarist seeking self-accompaniment on bass now has an alternative to the bass pedalboard. The Kellar Jam Bass e28 MIDI controller ($299)
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Jam Bass e28 The guitarist seeking self-accompaniment on bass now has an alternative to the bass pedalboard. The Kellar Jam Bass e28 MIDI controller ($299)

Jam Bass e28The guitarist seeking self-accompaniment on bass now has an alternative to the bass pedalboard. The Kellar Jam Bass e28 MIDI controller ($299) consists of a wafer-thin membrane switch panel that attaches to the back of a guitar neck and a small, black plastic Circuit Pack. The strip has two rows of 14 switches that duplicate the notes on the E and A strings of a bass guitar, allowing you to play bass parts with the thumb of your fretting hand. These switches should line up with the frets so you can play a chord's appropriate bass notes. The e28 model is designed for electric guitars, and the shorter a20 model ($299) is designed for acoustic guitars.

The strip is 1.5 inches wide and a bit more than 13.5 inches long. You can attach it to the guitar neck temporarily with masking tape, or permanently install it with the strip's adhesive backing. The strip is connected to the Circuit Pack by a 3-foot-long ribbon cable.

The optional SP1 sustain pedal ($39) is powered by a wall-wart adapter, or you can run the Jam Bass on a 9V battery in the Circuit Pack's battery compartment. The Circuit Pack has no power switch; you turn it on by plugging a guitar cord into the box. If you rely on battery power, bear in mind that you can drain the battery by leaving a guitar cord plugged in.

Bass-o-MaticSo why is the Jam Bass of interest to the electronic musician? The Jam Bass is actually a type of alternative MIDI controller with a built-in synthesizer. A MIDI Out port on the Circuit Pack lets you control any MIDI instrument and record anything you play into a MIDI sequencer. However, the Jam Bass has no MIDI In port, so a sequencer can't play its built-in sounds.

Though it's easy to play simple, sustained-note bass parts with your thumb, don't expect to play any bass solos on the Jam Bass. The switches serve other functions if you press them in a particular order. Instrument names, key functions, dynamic markings, and switch numbers are labeled on the switches in very small type. Pressing the Voice Select switch followed by any other note lets you choose from 18 preset sounds. Nine of these are bass sounds, and the rest are percussion and keyboard sounds.

You can also select any sound in the original General MIDI Instrument Map, but the procedure is a little complicated. First press the Shift switch, then MIDI Voice Group. Then select one of 16 voice groups from switches 1 through 16. To select any sound besides the first one in a voice group, hit Shift again, then MIDI Voice Number, then one of switches 1 through 8. When you turn the Jam Bass on, it defaults to the electric bass sound.

The quality of the sounds is marginal, at best. The default bass guitar sound is pretty versatile, but none of the other built-in sounds stand out as exceptional. Most of the General MIDI sounds are very disappointing.

All ThumbsYour best option is to use the Jam Bass with an external sound module rather than the onboard sounds. Simply connect it to a synthesizer's MIDI In port, and you're ready to rock. Though it's impractical to play more than single notes with your thumb while playing chords with your fingers, it works well with sweeps, washes, and other electronic textures. You can't play percussion parts at the same time as guitar, but you can set up a series of drum patterns, each one triggered by a different MIDI note from the Jam Bass. Other possibilities include changing sequences to accompany your playing and switching scenes on a MIDI-controlled light board.

Changing programs in external instruments works just like changing internal programs. The Jam Bass can play polyphonically, but when I played more than two notes at a time, I continually experienced stuck notes. Because it's impossible to play polyphonically with just your thumb, this shouldn't be a problem in normal use.

Because the control strip is nothing more than a membrane switch panel, it looks rather flimsy and fragile, but it's made of durable, aerospace-industry materials. The ribbon-cable connector appears especially prone to damage, but the manufacturer says they've never had breakage problems. The user manual issues a warning about the importance of handling the Jam Bass's components with care.

Location, LocationIn time, you may memorize the positions of all the function keys, but until then, be prepared to either play the default sound most of the time or stop playing long enough to flip your guitar over and squint at the tiny print. Once you've learned the buttons' locations, you need only associate their positions with the guitar frets. An instructional videotape is included to help you develop your playing technique.

The Jam Bass is more a unique toy than a serious musical instrument. It's unfortunate that Kellar Bass Systems can't manufacture it cheaply enough to sell it for $99.95. When I pay this much for a toy, I expect either more fun or more functionality than I found in the Jam Bass. If you're a guitarist who wants to provide your own bass accompaniment, however, you may want to give the Jam Bass a try. It might be useful - just don't take it too seriously.