The sound of the ram’s horn trumpet — a shofar — is impossible to ignore.

It’s a non-musical tone that varies only by the strength of the air blown into it. The sound reverberates and can be felt as well as heard. For Jews, the sounding of the shofar is a yearly wake-up call; an alarm bell sounded that warns people to get their act together.

It’s the sound that begins the Jewish new year — Rosh Hashanah — that starts Monday evening. According to the Jewish calendar, this is the 5769th year since the creation of man.

Instead of a grand party, Jews mark the time quietly, thinking about where they’ve been and where they ought to be, Rabbi Daniel A. Roberts of Temple Beth Israel, Sharon, said.

“The concept of Rosh Hashanah is more than just a new year,” Rabbi Roberts said.

Instead of parties and revelry, Tuesday marks the first of the 10 “high holy days” of Judaism that’s supposed to be a period of reflection.

“What did I accomplish this year and where did I miss the mark?” Rabbi Roberts said Jews ask themselves then. “Where did I miss being holy?”

The concept of “missing the mark” is how Jews view sin. Sins are actions where one “missed leading a holy life.”

The blowing of the shofar that begins Rosh Hashanah is “like an alarm clock” that sounds each year, calling Jews to action.

“You say, ‘I’ve done things not consistent with God’s keeping,’ ” Rabbi Roberts said.

Jews are supposed to seek forgiveness from those they’ve wronged, then ask God for forgiveness of their shortcomings, he said.

This happens on Yom Kippur — the evening of Oct. 8, this year — the “Sabbath of Sabbaths” that is the Jewish day of atonement that marks “starting all over again,” according to Rabbi Roberts.

In 21st Century speak, “I start with a clean computer, everything is wiped off my hard drive,” Rabbi Roberts said.

The time between Rosh Hashanah and Yom Kippor is a period of reflection to “figure out where we have gone and (decide) where we want to go,” Rabbi Roberts said.

“Each of us has some purpose,” he said. “God is waiting for us to turn around and change and get back on the right path.”