By Wyre Davies, BBC News in Jerusalem
Lipa Schmeltzer looks and sounds every inch the popular ultra-orthodox Jewish singer that he is.
He sings in Yiddish. He dresses in the clothes of a Haredi Jew and all of his song lyrics come from the scriptures.
Yet some say Schmeltzer’s music, and that of others like him, is indecent and unfit for public consumption.
“They are leading the public astray and are causing a great negative influence on the young generation,” says Rabbi Efraim Luft, head of an ultra-orthodox organisation in Israel called the Committee for Jewish Music.
Supported by leading Haredi rabbis, Rabbi Luft has drawn up a black-list of musicians and bands – music that he says that is not kosher and cannot be played at ultra-orthodox weddings or public events because of its decadent nature.
What Rabbi Luft objects to so vehemently is not just contemporary, western music – rock, rap or pop – but the use of modern instruments and beats in the tunes of orthodox singers like Lipa Schmeltzer.
“The main part of the music should be the melody. Percussion should be secondary. They should not bend notes electronically and should not use instruments like electric guitars, bass guitars or saxophones in Jewish music,” he says.
Sitting in the dining room of his small flat in the orthodox town of Bnei Brak, close to Tel Aviv, Rabbi Luft explains his preference for traditional, even sombre, Jewish tunes like Kol Nidrei.
A serious, studious man the rabbi explains how he thinks modern music is disrespectful, leading young people astray and can lead to the collapse of education and the family system.
It is a broad charge, but the rabbi is convinced that in the last 25 years music has gradually eroded moral standing in society.
Saying that music is “powerful”, he says the “purpose of modern music – its influences – is to distract young people and change good characters into bad”.
The Rabbi says such music, even Jewish rock music, “where the dangerous beat plays more of a part than the melody, has no place in a society where people are trying to keep their moral standards high.
There are approximately 500,000 ultra-orthodox Haredi Jews in Israel. They tend to live in their own communities in, or near Israel’s major towns.
Their plain, modest clothing, rituals and centuries-old customs make the Haredis unmistakable and their lives revolve around their faith.
Because of the loyal relationship between orthodox Jews and their rabbis, the influence of bodies like the Committee for Jewish Music and the Guardians of Sanctity and Education is considerable.
They have already succeeded in banning virtually all public concerts by ultra-orthodox groups and singers in Israel.
Famous, successful singers like Avraham Fried – a devout, observant orthodox Jew – are not exempt.
Making up around 8% of the population of Israel, the Haredi community has real economic clout. Boycotts have been very effective.
Menahem Toker, an award-winning disc jockey, who was dismissed from a radio show under pressure from Haredi activists, warns the policy could backfire.
“In Jewish Orthodox culture there’s no cinema, no theatre, no television. The only thing we have is music”, says Mr Toker.
“We are the same, orthodox, people but if they don’t find an alternative they’ll lose the young people – they’ll go to non-kosher shows and they’ll have lost the next generation.”
It is a dire warning from a man who cares deeply about his religion and his music – but the hard-line rabbis are unapologetic.
In a world bursting with mobile phones, MP4 players and DVDs they say it is their moral duty to protect young people against the evils of the modern world.