Sign up for our mailing list to receive daily inventory updates and news from Gruhn Guitars


The World’s Premier Guitar Store

Newsletter #17, June 2004

(Please browse our newsletter archives)

Acoustic instrument amplification

I am frequently asked for advice on amplifying acoustic instruments. There are currently so many different systems available that it is impossible to cover all of them in the space of any newsletter, but I certainly have opinions on the subject and will share them.

For as long as musical instruments have been made, musicians have sought instruments with maximum volume, dynamic range and projection. While it is relatively simple to understand the concept of volume, which can be numerically quantified with a decibel meter, projection is more subtle. Some instruments sound loud to the player but simply do not project well across a distance or cut through the sound of other instruments in a band, whereas others which do not sound nearly as loud to the player can be heard very clearly across the room or through a band or orchestra. Violin makers have long been aware that it is possible to make an instrument appear louder to the player by thinning the top, but the result often compromises projection such that the instrument does not perform well in an orchestral setting. Similar results have been noted with guitars and mandolins.

The concept of dynamic range is also somewhat more subtle than simple volume alone. We all know that an acoustic instrument sounds louder if it is picked hard rather than softly. Some instruments respond extremely well to soft, medium and hard picking such that they can be played at a great variety of different volumes without distortion. These instruments also can vary significantly in tone depending on whether the strings are picked close to the bridge or in varying positions toward the fingerboard. Acoustic instruments with a great dynamic range of volume and "tonal color" are considered to be highly desirable. By contrast, some other instruments perform quite well at low or medium volume but distort if picked hard and are simply incapable of being played at great volume. Others may do relatively well picked hard in a band setting but sound harsh at low volume. While versatility is certainly desirable, it should be noted that no instrument will be equally good in all settings. The ideal instrument for playing rhythm in a band may not be the perfect one for lead solos. The guitar that seems to be ideally suited to acoustic jam sessions may sound quite different on stage through a microphone.

Studio musicians often find that they are less concerned with volume or dynamic range than with even balance and accurate intonation as well as physical comfort. Many Nashville session players use acoustic guitars that I find quite unappealing to my ear. When recorded close to a microphone guitars that I consider to be rich and mellow sounding frequently come out as "muddy" or having too much "boom." Many session players use guitars that I find thin and trebly, but that seem to suit recording engineers quite well. I have always found it frustrating to deal with musicians who come into the shop to try out instruments but say that ultimately they can't really trust their own ears to select a guitar but need to take it to the studio and listen to the playback on tape. Frustrating as it may be for me as a dealer, since these people are earning their living playing they have a perfectly valid point. The fact remains that it still runs counter to my sensibilities as a dealer and collector of high-grade vintage instruments to work with session players whose requirements frequently result in the selection of instruments which quite frankly sound bad to my ears. It often seems that the ideal acoustic instrument with great volume, dynamic range and projection is frequently the least-suited to being utilized in country and pop recording sessions in which a microphone is placed within inches of the instrument. Most classical musicians record in a very different type setting with the microphone placed at a significant distance away from the instrument such that the player can utilize the full acoustic range of volume, dynamic range and tone color of the instrument. While I would like to see more Nashville studios attempt to record in a manner closer to the classical approach, the reality of the situation is that musicians, especially studio players who are hired by a producer, must conform to the system. Until a player becomes a big enough star in his own right that he or she can dictate the terms to the label and the producers they must do as they are told. When a label "discovers" and promotes a new artist the label often dictates the choice of material, stage clothing, band member selection (often a different band in the studio than on the road) and virtually everything else in the artist's career.

While no single newsletter can cover the entire topic of sound reinforcement, amplification and recording techniques, I feel that it is helpful to take a brief historical view to better understand how we have come to the current situation. Prior to the advent of electronic amplification of radios and the introduction of talking movies in the late 1920s, musical instruments were played strictly acoustically. While recording was introduced prior to 1900 by Thomas Edison, before the late 1920s recordings were done acoustically. The musicians played into a megaphonic horn which vibrated a small diaphragm, which in turn vibrated a needle which made grooves onto a wax cylinder or disk. To play back the recording a casting was made of the wax. The playback utilized a unit quite similar to the recording device, in which the cylinder or disk was spun, which vibrated a needle which vibrated a diaphragm which was amplified by an acoustic megaphonic horn. Nothing in either the recording or playback involved electronics. The fidelity of the recordings as well as the length of a recording and volume at which it could be played were very limited. Very soon after the introduction of electronic amplification of radios (early radios were crystal sets with headphones and didn't plug into any power source) and the introduction of talking movies, these same technologies were introduced into music, stage performances and recordings. Electronic microphones, amplifiers and speakers were a huge advance over previous systems. By 1932 Rickenbacker had introduced its first electric lap steel with a magnetic pickup. Other companies followed in short order. It didn't take long to figure out that while a microphone could be used to amplify an acoustic instrument on stage, there were problems with feedback. It was exceedingly difficult to use a microphone to amplify an acoustic guitar to the same volume as an electric instrument with a magnetic pickup. This battle is still going on today.

Even into the early 1960s, most acoustic groups performing onstage used only one microphone. By the mid '60s, a typical five-piece bluegrass group used two microphones. One would be set up for the fiddler, and the other would be used by the rest of the band. Players would form a semi-circle around the mic and would adjust their balance by their physical position. Singers and players would step up to the microphone for their solos and back off to let others have their turn in what seemed much like a choreographed dance. Typically the microphone was placed such that the singer would have to stoop slightly to get in an ideal position. A guitar or mandolin player would have to hold the instrument upright with the headstock pointing toward the sky whereas a banjo or dobro player would do the reverse with the headstock pointing to the floor to bring the resonator closer to the mic. Sound systems were relatively primitive. The soundman had little to do other than set the volume high enough so that it squealed and then back off slightly from that point. After that it was up to the musicians to control their own sound. The result was visually interesting, and when the players were skilled it sounded remarkably fine. It was certainly possible to utilize a system of this sort in a 1,500-seat auditorium, but for large outdoor venues or huge stadiums seating multi-thousands of fans it was simply not possible to get the volume demanded.

Starting about 1970 mixing boards and stage monitors were introduced. Whereas by the late '60s the system had progressed to the point of three mics, with one set at a vocal height, one at an instrument height and one for the fiddler, by the early '70s almost overnight bands began using an instrumental and vocal mic for each musician and had stage monitors. Instead of the old system of forming a semi-circle around the microphone, the new system typically had the mics set up in a straight line across the front of the stage such that the musicians were facing the audience rather than being in eye contact with each other. They were very limited in their mobility. Rather than having an omni-directional microphone which would pick up sound at a distance, the new systems utilized microphones which necessitated close contact. The musicians might as well have had their shoes nailed to the floor. At the very least they had to stay on the X marked for their spot. It is my opinion that the old system with the "dance around the microphone" was not only visually more interesting, but also resulted in greater spontaneity. When musicians were in eye contact with each other, they could follow visual as well as auditory cues and could jam on stage.

It has long been my opinion that while mixing boards and stage monitors are a great technological advance, they can serve to stifle creativity on stage. Putting musicians in a straight line facing the audience rather than in eye contact with each other results in what I call the "sushi bar approach to musical conversation." If one goes to a sushi bar with one friend it is possible to sit and talk. If three people go, the one in the middle can talk to either of the others but the two on the end have difficulty communicating. If five or six people go it is virtually impossible to have a conversation with everyone arranged in a straight line. Conversation occurs best in a circle or semi-circle if there are multiple parties involved. Playing music is not unlike a verbal conversation in this regard. I have similar feelings regarding recording music in studio settings where each player is visually isolated or in which session musicians come in to lay down tracks without ever even meeting the other participants, but the studio setting is more forgiving than a live show in which miscues can't be redone. While it is obvious that some great albums have been made in this manner, they frequently lack the spontaneity of the old system in which players actually got together in one room and frequently were able to record an entire album in one day.

Bluegrass and old-timey acoustic musicians tend to be purists and have resisted the movement to place pickups or microphones in or on their instruments. Many of them, however, struggle to get good sound through PA systems. If they are lined up in the "sushi bar approach," not only are they out of eye contact with each other, but they must rely on a soundman to adjust their sound levels. All too often when a player takes a solo instrumental break, the soundman is out of sync and has the wrong mic turned up or has enough delay that a significant portion of the solo may be inaudible to the audience. In discussing this problem with my friend John Hartford over 20 years ago, we came to the conclusion that a good solution for him would be to carry one high-quality studio grade microphone with him and use it on all of his stage gigs rather than relying on a soundman or gear provided by the venues. John used one mic for himself and the entire band in an attempt to recapture the spontaneity and visual appeal of the old days. It worked beautifully. Today, many bluegrass bands have gone back to this system and find that it suits them far better than having 10 microphones for five players. Not only are the musicians able to be more spontaneous when they are in eye and ear contact with each other, but they are far more in control of their own sound. They control their balance within the group by their physical position with respect to the microphone, and they can be well assured that the soundman won't forget to turn on their mic when it comes time for their solo.

A recent development in many acoustic groups has been replacing stage monitors with small wireless headphones. Musicians using this set up tell me they can hear far better than with stage monitors. They have considerably less trouble with feedback, enabling them to play acoustically through a microphone without a pickup at much higher volumes that previously possible. This development, as well as the increasing use of the one-mic system, encourages me, since from my perspective as a collector and dealer of fine vintage instruments, I welcome developments which enable musicians to play onstage utilizing the full tone, volume, dynamic range and projection of great instruments rather than having to rely on close micing or use of pickups which greatly limit the musicians ability to utilize the full potential of a truly great acoustic guitar, banjo or mandolin. All too often in the past, playing technique has been modified and instruments have been selected to suit the sound system which, in my opinion, results in a greatly diminished musical experience.

A wide variety of pickup options have been available since the mid 1930s to amplify acoustic guitars. Magnetic pickups which fit inside the soundhole of a flat-top round-hole guitar or which mount under the strings of an archtop f-hole guitar usually produce a sound more akin to a standard electric guitar rather than an acoustic guitar heard through a microphone. However, some recently designed systems now offer a sound far closer to that of an acoustic guitar heard through a microphone. The fact remains, however, that even the best of these systems produce a sound that is dependent on the pickup and PA system rather than a true reproduction of the acoustic sound of the instrument on which they are mounted. In addition, all of these systems greatly limit the useful dynamic range of an acoustic instrument. Whereas a strictly acoustic guitar can be played over a great dynamic range varying from barely brushing the strings to punching out as much sound as the instrument and strings are physically capable of sustaining, pickup and amplification systems are easily overdriven such that volume is more frequently attained by turning a knob or stomping on a pedal rather than bearing down hard on the strings to drive the soundboard to its full potential.

Piezo pickups became very popular during the 1970s and now constitute a majority of the pickups utilized on acoustic guitars. Unfortunately most of these units produce a rather thin, trebly and somewhat artificial sound. Many manufacturers couple piezo pickups with preamps to model the sound as well as amplify the output, and they also utilize EQ systems to further modify tone and help reduce feedback. Additionally, many systems are now available combining a piezo system with an internal microphone to further approximate a genuine acoustic sound. It is my opinion that the best of these systems still greatly limit an acoustic player's ability to utilize the full dynamic range of an instrument and produce a sound which is far more dependent on the pickup and microphone system than the true acoustic quality of the instrument.

Most performers find that the ideal stage rig is not the perfect set up for use in the studio and furthermore that the guitars that they prefer to play in acoustic jam sessions or at home for their own personal pleasure may be different instruments from the ones they find most suited for the studio. While I understand these decisions, it is my opinion that technology when properly utilized need not be the enemy of creativity, nor should it prevent musicians from performing and recording with the instruments which sound best to my ears when heard strictly acoustically with no microphone, pickup or other electronics intervening. I am dismayed by the fact that the sound of a piezo pickup has become so ubiquitous onstage and in the studio that many people now think of this sound as being acoustic. I am strongly of the opinion that the classical music field would be a poorer place if musicians such as Jasha Heifitz, Yehudi Menuhin, Isaac Stern, Pinchas Zuckerman and Itzhak Pearlman recorded and performed on amplified violins rather than genuine Stradivarius and Guarnerius instruments.

Truly great acoustic instruments tend almost to fight amplification by use of an internal microphone or pickup. They will overdrive the system if played hard and typically do not work nearly as well as a heavier-built, acoustically dull instrument when set up with onboard electronics. In addition, it should be noted that in spite of claims to the contrary, any pickup placed under the saddle of an acoustic guitar reduces volume and tone significantly when the instrument is played strictly acoustically. I am firmly of the opinion that it is not a good idea to take a great sounding acoustic and set it up with an under-saddle pickup, thereby reducing its acoustic potential. Most modern acoustic guitars are made with a drop-in type saddle such that it is extremely easy to install or remove a piezo under-saddle pickup. However, many older guitars have glued-in saddles and bridge construction making pickup installation or removal far more difficult. I strongly urge players not to modify vintage instruments in any irreversible manner to install electronics. While I have nothing against new acoustic guitars with built in pickups and EQ systems installed with a large "window" in the side of the body, I would again strongly urge that such systems never be installed in vintage instruments. Furthermore, it should be noted that while electric guitar systems with magnetic pickups such as those utilized on the Fender Telecaster, Stratocaster Gibson Les Paul, and other such models have stood the test of time and have remained virtually unaltered since the 1950s, acoustic amplification systems have undergone tremendous change and are continuing to do so. It is difficult to get parts or service for many systems as little as 10 years old. A great acoustic or electric guitar made as much as 50 years ago can have virtually all the bells and whistles of a new one and in no way be considered obsolete, but many acoustic/electric instruments have systems that have the potential to be viewed as dinosaurs 10 years from now.

In spite of my many negative comments about the application of technology and its impact on music, I am firmly of the opinion that technology and creativity do not necessarily have to be at odds with each other. There are more great manufacturers and great players than ever before in the history of acoustic music. While I may not personally be a fan of each and every one of them, I see clear indications that there is indeed a critical mass of musicians, manufacturers, producers and engineers who are well aware of the critical interactions of technology, quality sound and creativity such that I am confident that good music is alive and well and will prosper in the future.

George Gruhn