BUENA PARK, Calif. — When Denise Rosier sits down to write a new song for the organization Songs of Love, which provides recordings of custom-written songs to children with chronic or terminal illness, she has just about every instrument and style of music at her fingertips.

Songwriter, singer and instrumentalist Denise Rosier and her PSR-S900

Though her recordings sound lush and expressive, usually the only other instrumentalist on the tracks is her bass-playing husband, Keith. Every other instrument sound is created by the Yamaha PSR-S900 Arranger Workstation. Using the audio accompaniment feature, she lays down the basic tracks in her home studio, then overdubs individual instrument parts. She deftly uses the built-in harmonizer and taps the instrument's depth: one "song of love" features a jangling acoustic guitar, for instance. Another features a pumping dance beat and sound effects.

For some tracks, she also uses Cubase 4 music production software by Steinberg.

"People can't believe that these songs are created by a keyboard," said Rosier, who lives in Orange County, Calif. "It's an amazing instrument that lets me deliver great-sounding tracks to kids who really appreciate and need them."

In 2006, Rosier began writing one or two songs a week for the not-for-profit Songs of Love, based in New York City, after she saw an ad for children's songwriters. Since then, she has written dozens of original, one-of-a-kind songs personalized for each child. They generally appeal to the child's music taste and hobbies and also include names of friends and relatives.

"With the PSR-S900, I can write a soft jazz tune one day, an electronica dance number the next day and then a Disney-sounding song," she said. "For any project, I have exactly the right band."

In addition to her work for Songs of Love, which is done on a volunteer basis, Rosier also writes for other projects. She has released an independent pop CD "Only a Whisper Away" and is currently working on a new title featuring children's music.

She discovered the PSR-S900 while reading an article in Keyboard magazine detailing how Yamaha's Arranger Workstations can be effective and efficient aids to songwriters.

"I realized I had found the perfect tool for what I was doing," she said. "Not only do I use it for Songs of Love, but I also use it for making demos of my own songs. I can't imagine working without it now."

The PSR-S900 offers considerable bang for the buck and adapts several features previously found only on the Tyros2, Yamaha's flagship Arranger Workstation. In addition to modeled organ voices, a LAN Port and a USB for peripheral devices, the PSR-S900 includes Super Articulation for sonically realistic instrument sounds, which can include anything from a saxophone sound that includes the breaths taken by a human player, and a guitar part that can replicate the sound of fingers sliding across the strings.

It also includes USB audio recorder, video out, USB storage, 891 instrument Voices and a microphone input with automatic three-part vocal harmony. It also features 128 notes of polyphony, a color LCD screen and a broadband connection that lets users link the keyboards directly to the Internet, where they can download content.

"I knew that the range of professional features would make this a valuable instrument for a lot of performers and songwriters," said Mark Anderson, marketing manager, Portable Keyboards. "To be able to help people contribute something so positive, like what Denise is doing with Songs of Love, is wonderful."

For more information, write Yamaha Corporation of America, Pro Audio & Combo Division, Portable Keyboards, P.O. Box 6600, Buena Park, CA 90622; telephone (714) 522-9011; e-mail infostation@yamaha.com.