PARIS — The human voice can purr enticingly or it can shriek like the twisting of a galvanized garbage can.

Writers exercise their skills to describe on paper how someone speaks. F. Scott Fitzgerald in “The Great Gatsby” wrote of a character, “The exhilarating ripple of her voice was a wild tonic in the rain.”

That voice you might want to listen to.

A voice can bellow. Think of the overamplified Frank Morgan in “The Wizard of Oz” disembodiedly booming from the Wizard’s throne room, “Come forward, Tin Man!”

No wonder he rattled.

But the human voice can attract attention enough to be commercially practical because it can inform or sell.

A media company that specializes in training aspiring voice actors for the broad landscape of spoken-word venues brought a one-night presentation to Oxford Hills Comprehensive High School on Wednesday night to provide a hint of that specialty.

“These days (voice acting) is about being relatable, being human, being conversational, being believable and credible,” said Tom Robinson, a voice actor who does training and production for Voice Coaches in Albany, N.Y.

Nine community members registered for the presentation and they were a chorus of different backgrounds, ages and genders. One woman was out of the house for the first time since her husband died two weeks ago. One is an online sportscaster. One is a pit boss at Oxford Casino. Three are Reiki practitioners. One is a writer. One works retail.

You learned these details because Robinson had class members introduce themselves at the start of the 150-minute presentation.

“Even 25 years ago, almost every single time you heard a voice doing narrative or commercial voice work (it might be) James Earl Jones,” Robinson said. “That is no longer the case.”

Robinson said he has been doing voice acting for 35 years and developed the interest while a preteen. In college he fell into his first commercial recording gig at a campus radio station when another announcer didn’t show up. He liked hearing himself on New York radio stations, and actively pursued the work. He now estimates his voice has been recorded over 3,000 times.

He began by going over terminology used in the business, such as defining what a voice-over is — it’s anytime you hear a voice without an accompanying face — and the difference between local, regional and national commercials.

He said his company works in the “B market,” in which the talent is not represented by a performer’s union or an agent, even though the clients can be national companies. Robinson said the parent company associated with Voice Coaches, White Lake Music and Post, does voice projects for the History Channel, Home and Garden Channel, Disney, Nintendo, Frito-Lay and others.

Robinson asked the class to guess what percentage of all voice work is recording commercials. It’s only 8 percent; the rest is narrative voice recording, he said.

He said part of the demise of commercial voicing work is due to consolidation purchasing of radio stations, in which a few announcers record spots for multiple stations owned by the same company.

Robinson provided descriptions of the kinds of narrative voice performing. These can include audiobooks, training videos, television reality shows, non-network documentaries, video games, animated cartoons, web developers, hand-held electronic devices, fixed installation such as airports and bus terminals, telephone “tree” recordings, museums and planetariums.

He said the market keeps expanding as new technologies are invented.

Robinson also suggested marketing strategies for the voice actor. He said most important is that every voice actor needs prerecorded and separate demonstrations of reading for the commercial and narrative markets. He said not to neglect sending a thank-you card to anyone who accepts your recorded voice demo, because it helps persuade them to actually listen to your submission.

Robinson recommended voice actors join local advertising clubs and chambers of commerce, and directly market their skills to local companies.

The fun part of the presentation was saved for the end, when Robinson invited each class member to record a paragraph from one of three written commercial samples he provided. He operated a notebook computer “on the fly” editing the various paragraphs together into single spots with appropriate music in the background, and even popping the end of one line into a reverberation effect. This process was a big hit with the attendees.

Robinson said other company employees could provide a two-minute evaluation of the reading via a telephone call the following morning, if desired.

He saved the actual sales pitch until the class had ended, and he was packing up his equipment. Voice Coaches charges several thousand dollars to each student for training, production of recorded voice demos and development of a promotional website for one year.

There’s no business like show business.