Ellen Bob has noticed a funny phenomenon lately: Customers at bob and bob will put down that kippah or mezuzah they are examining and ask, "Is that Rabbi Cartun singing?"

Indeed it is.

After leading High Holy Days services at Stanford University for so long, Ari Cartun's voice is recognizable to many of the shoppers in Bob's Palo Alto Judaica store.

His voice, along with those of some of his congregants, can be heard on the new CD "Sh'ma Kolenu: Hear Our Voice — The Spirit of Shabbat in Song."

Currently playing in the store's five-disc rotation, "It's our best-selling CD right now," Bob said.

About two years in the making, the 33-song CD was released recently, mostly for the congregants of Etz Chayim, the Palo Alto independent liberal congregation.

"We wanted to do something both educational as well as…to get people to sing better," said Cartun. "We also hoped people would play it for inspirational reasons, and it seems to be doing both."

The CD features not only songs sung on Shabbat, but the entire evening service — the Barchu through the Aleinu — ending with the Shabbat Kiddush. A "Lecha Dodi" medley offers five different versions.

In the accompanying booklet, Cartun explains that the CD can serve as a "service on a disc" which can be used to transport the Shabbat experience to wherever a Jew may be.

"Imagine a Shabbat evening as the sun is setting, around the rim of the Grand Canyon, with the sounds of Shabbat music accompanying you," he writes. "This CD can be your Shabbat companion for those evenings when you simply cannot make it to services."

The rabbi himself hasn't yet listened to the CD at the Grand Canyon, but "the next time I go, I'll take it with me."

Cartun's path to the rabbinate was propelled by his love for Jewish music. A youth group song leader, he began leading services.

And while he studied at the Reform movement's Hebrew Union College, he sang in the student choir. There he made an interesting discovery, that he didn't like choirs.

"It turns the service into a concert," he said. When it came Cartun's turn to lead services, he asked that the choir sit with everyone else.

"It meant that the congregation sounded so much better," he said. "They still sang their parts, but they did it from where they were sitting. Everyone was infusing the congregation. I'd rather infuse the congregation than sing at them."

When the project was first conceived, Cartun spoke to congregant Kathy Sherman, a classically trained musician who plays at least a half dozen instruments and in two bands. She agreed to sign on as the CD's producer.

At first, she and Cartun "spent many months trying to define what it was going to be, which was difficult because we had different visions," said Sherman.

Eventually, their visions came together — as did the CD, with the help of other talented musicians who were members of Etz Chayim.

"We have some incredibly gifted musicians who are trained beyond belief," said Sherman, "and then we have very talented people who don't read music and learn only by ear."

The singers met at a local Presbyterian church for several hours on Monday nights.

Cartun taught harmonies and counterpoint, the use of contrasting melodies and rhythms. The musicians did several takes of a song, some with duets or trios and others with larger groups. Additional instrumentals were added later.

"It was hard initially because we didn't know what to expect," said Sherman. "But people worked so hard and after a year and a half of doing this, the core chorus turned out so tight. People learned how to breathe and listen to each other and what harmonies work."

The results can now be heard, not only on the CD, but in the synagogue. "People harmonize and sing counterpoint even more so now that they have the CD to listen to," said Cartun.

Sherman, too, said the results were beyond what she expected.

"It definitely gets you into the spirit," she said.

When the CD was presented to the congregation at a Shabbat service, "people were singing their hearts out," said Sherman. "People could tell who had sung on it."

Sherman hopes that "Sh'ma Kolenu" is only the first CD that Etz Chayim will make; she is now thinking of another similar project, using b'nai mitzvah students.

Although the project required a huge amount of work, Sherman said, "I would do it again in an instant."