ACOUSTIC GUITAR'S TENTH ANNIVERSARY SPECIAL

Acoustic Amplification Comes of Age

By Rick Turner

L.R.Baggs Dual Source System

The earliest attempts at amplifying guitars reportedly took place in the early 1920s with Lloyd Loar's experiments at Gibson. Gibson's management was so uninterested, however, that Loar left the company to pursue his inventions first at the Gulbransen piano company and finally with his own venture, Vivi-Tone. By the late 1930s, the pickup of choice for guitars was magnetic, and so it remained for nearly 30 years. Gibson re-entered the picture in 1960 with a bridge-piezo–equipped classical, the C-1E (often referred to as the Charlie Byrd model), which was the first modern amplified acoustic guitar. Baldwin followed shortly thereafter with a pickup best known as the one on Willie Nelson's battered Martin. The real leap forward came in May 1971 with the introduction of the Ovation acoustic-electric, which Glen Campbell played on his weekly TV show. The next two decades brought a virtual explosion of pickups designed to be installed in existing guitars from companies such as L.R. Baggs, Barcus-Berry, Fishman, Highlander, and EMG. This set the stage for the 1990s—the decade when unplugged came to really mean plugged, and a new generation of acoustic guitarists learned to play on electric instruments.

In the last decade, choices and options for amplifying acoustic guitars have expanded exponentially. The tools for the job now include under-saddle pickups that directly read string vibration, vibration sensors that respond to movements of the top, a new generation of magnetic pickups, and internally and externally mounted microphones.

Under-saddle piezo pickups are now the dominant technology, and the range of nuances is wider than ever. Most piezo-pickup designs started off using individual piezo ceramic elements under each string, but manufacturers such as Fishman, Baggs, and EMG have gone primarily to piezo-film pickups that sense along the full length of the saddle, and Highlander uses a piezo rubber cable originally developed for military applications. Now B-Band has come out with an under-saddle electret condenser pickup that uses a variation on mini-mic technology to sense what's happening in the bridge. RMC pickups are individual-string transducers that act both as audio pickups and discrete string pickups for MIDI interface.

Aside from improvements in the pickups' sensing elements, there have been great leaps in preamplifier design. Piezo materials, as used in under-saddle and vibration pickups, are high-impedance devices that require amplifier-input impedances much higher than those found on typical guitar amps, recording console inputs, or PA systems. The interface required is called a buffer preamp, and thanks to advances in transistor and integrated-circuit miniaturization, high-quality buffers are now small enough to be practically invisible. Highlander was the first company to make a buffer small enough to fit into an endpin jack, and similar packaging is now available from several other makers, including L.R. Baggs and Fishman. This means that installing electronics need not mean cutting big holes or mounting heavy boxes in your favorite guitar.

The FRAP vibration transducer system of the '70s has now been replaced by Trance Audio's high-end pickups, which are designed to be mounted to the bridge plate inside the guitar. I just installed Trance's stereo Amulet system in a guitar I recently finished for Henry Kaiser, and the results are amazing. While this pickup design will not give you as high an on-stage volume level as an under-saddle pickup, the sonic rewards are great. Magnetic pickups remain a viable option, as designers have developed pickups that have a wider frequency response than electric guitar pickups. The industry standard for frequency response has been the Sunrise, which is favored by players like David Lindley, Ry Cooder, and Jackson Browne. The Sunrise was the first "stacked humbucking pickup," and its low number of windings makes it more sensitive than most to the higher harmonics coming off an acoustic guitar string. But there are now several other wide-bandwidth options including the Rare Earth from Fishman and the ACS from EMG, which have built-in preamps to boost output. There are also a number of other magnetic pickups on the market whose main selling point is convenience—they can be quickly installed and removed from the guitar. One of the biggest changes in picking up guitar sound is the dual-source system, which combines various elements, usually a piezo under-saddle pickup and a mic, and blends the signals with either an on-board preamp or a stereo cable to an external preamp/mixer. Virtually all the big names in the pickup business, including Baggs, EMF, Fishman, and Highlander, offer such systems. The virtue of dual-source amplification is that you can get a more complex sound that includes more "air." The disadvantage is that these mics are very sensitive to feedback problems on stage.

Perhaps the truest sign of the changing times has been the emergence of that ultimate oxymoron: the acoustic amplifier. The real flood of amps designed for acoustic guitars started with the Trace Elliot acoustic amps, which were tiny in stature but big in sound. More and more companies jumped on the acoustic-amp bandwagon, designing products that have much wider frequency response than typical electric guitar amps and also have a range of features specific to the problems of acoustic guitar amplification. Most acoustic amps now feature two channels; one is usually designed with a high input impedance for a direct piezo input, while the other may be used for a microphone or magnetic pickup. The EQ stages are tailored for acoustic guitar tone, and many amps include a notch filter and phase switches to help reduce feedback. Nearly all have effects loops and built-in reverb or delay to fatten your sound. One of their most significant features is that these amps can also serve as mini PA systems, handling a vocal mic in addition to the guitar.

Where is this all going? The amps are getting better and better, and the real issue is whether the components and cabinets can keep getting smaller without making the amps sound like they're designed for ukuleles. Under-saddle technology is hard to beat as far as complete frequency response and immunity from feedback go. There is still that "wood and air" sound missing, but I expect digital signal-processing advances will solve that. I think that internal mics will be a thing of the past by 2010 and that both top-sensitive and magnetic pickups will be specialty items. Meanwhile, the issue of getting good acoustic sound on stage and in fairly loud band situations is virtually solved. Tone is the big issue. Looking into my crystal ball I can foresee a black box into which you might plug your Chet Atkins, Ovation, Yamaha, or Godin, from which you could dial up "1938 D-28," "1954 J-200," or "1956 Fléta." Does it sound like I'm hallucinating? Just wait until Acoustic Guitar's 20th anniversary.

Excerpted from Acoustic Guitar magazine's Tenth Anniversary issue, July 2000, No. 91. That issue features an extensive collection of stories, essays, and articles about the artists, trends, guitars, gear, and music that defined the 1990s.

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