JAY BERLINER, acoustic guitar player, recently recorded an advertising jingle for a fruit and fiber cereal. The sound of the guitar and a piano playing together in a studio ``were really beautiful,'' Mr. Berliner recalls. Unfortunately, the client liked the same music better when it was performed on a synthesizer - an electronic instrument. ``They thought it was more modern,'' Berliner says.
This shift to electronic music is not unique. Today, synthesizers are used to produce advertising jingles, sound tracks for movies, rock band backups, the music for Broadway shows and ballets. High schools, unable to find enough students to play in the orchestra for musicals, fill in with synthetic music. Students practice on synthesizers and music schools include courses on using computers to make and write music.
According to the American Music Conference, since 1973 manufacturers have shipped more than 2 million synthesizers worth $1.8 billion at the retail level.
Mirroring the rest of the economy, sales of electronic instruments are a little slower this year. However, Dominic Milano, editor of Keyboard, a Cupertino, Calif.-based magazine, says sales of computer software to produce music are on a high note.
The boom in synthetic music is the result of major technological advances. Since 1980, the companies had been using ``sampling'' technology, where sounds made from real instruments are digitally recorded. In 1982, a consortium of five companies developed the software communications language known as the musical instrument digital interface (MIDI).
This allows musicians to communicate with computers. ``Suddenly keyboard players could do the equivalent of word processing,'' explains Mr. Milano.
The latest generation of synthesizers is so advanced it even takes the breath away from professional musicians. After listening to an exhibition at the Yamaha R&D Showroom, David Titcomb, a professional trombone player, admits it is hard to tell the difference between man and machine. The main difference, he quips, ``is that the machine is not missing any notes.''
Every year 200,000 people walk through the Yamaha showroom, located near Carnegie Hall, to see how the state of the art has advanced. Yamaha's latest entry is SY77, introduced last November. ``I wanted to own it and lock myself in a room for a year to see what I could do,'' says Milano, who also believes the technology may be ahead of the users. Other major manufacturers are Korg, Kawai, Technics, Ensoniq, Roland, and Casio.
One of the SY77's appeals is that musicians can get greater modulation - that is, variations in the sound. The harder the keyboard is pushed, the richer the sound, explains Phil Clendeninn, a Yamaha product specialist.
For many professional musicians using traditional instruments, the rise of electronic music has muted the jingle of money in their pockets.
Take Mr. Berliner. As one of the nation's premier studio guitar players, he used to get 2,000 calls a year to play the guitar. Because of time constraints, he could play only 600 engagements. Today, he gets 200 calls and tries to play all of them.
The 30-second jingles used to be a major source of revenue for musicians who get paid $80 an hour, plus a ``residual check'' when the ad runs. ``Every month you could get a shoebox of $60 or $80 in residual checks,'' says Mr. Titcomb, the trombone player.
At first, film producers thought synthesizers would save them a lot of money recording scores. The movies ``Chariots of Fire,'' ``Blade Runner,'' and ``Witness'' used electronic music. Today, however, there is some tendency is to go back to large orchestras. ``The Hunt for Red October,'' for example, used a 100-piece orchestra - as well as a synthesizer.
``Sometimes it can be cheaper to use an orchestra,'' says Dennis Dreith, a film composer and president of the Recording Musicians Association. ``With an orchestra, everyone plays it once and it's done,'' he explains, while the programming time - the need to enter each instrument's instructions - for a synthesized score can be substantial.
And some composers insist on working with accoustic instruments. In a recent interview in Keyboard, Billy Joel says he likes working on the piano because ``I still enjoy the percussive timbre and resonance of the piano.''
The increasing use of synthesizers and other artificial means by musicians has raised some questions.
Recently, New York and New Jersey introduced ``truth in advertising'' legislation requiring performers to tell audiences in advance if the performers are not actually singing or playing.
Some musicians and their unions are worried that audiences will become so used to synthesizers that they won't be able to recognize virtuoso performances. John Glasel, the president of Local 802, complains, ``Our grandchildren will be poorer but no one will be able to show them they are.''
However, product specialist Clendeninn says this is an overreaction. The machines are here to stay, he says, and musicians just have to learn to use them to make better music. ``The scene is changing,'' he says.