The findings are based on a three-year study of music scholarship and teaching in 84 primary and 95 secondary schools around the country.
While the education watchdog rated music provision as "good or outstanding" in around half of the schools visited and noted that this had a positive impact on pupils' general wellbeing, it found that the other half– mainly secondary schools – offered an "inconsistent" quality and range of musical activities.
The study comes more than a year after the Government announced a £332 million investment in music education for children. Among the pledges made by Education Secretary Ed Balls were free music tuition for every primary school child for a year, more musical instruments for each school and £40m funding for a Sing Up initiative aimed at promoting singing in classrooms as well as at home and in the wider community.
Ofsted acknowledged the funding boost as welcome, but said it needed to be better targeted at the schools and pupils who needed it most, rather than providing for those with an established interest.
"Overall, there has been insufficient improvement over the last three years," it said.
In those schools where music was flourishing, it found that every pupil benefited, whether they were directly involved or not, from increased self-esteem and improved progress in all areas of school life.
Advancing musical technology pioneered by the music industry had boosted the number of boys taking music A Level but is "underused at present", it found.
Failing schools were those where music teachers were not properly supported and did not push their pupils to improve their skills enough with decent, regular assessments.
"Schools did little active selection of pupils who would benefit most, personally and musically. Simply offering opportunities to all did not necessarily ensure that provision included all pupils sufficiently," it added.
Among its key recommendations was that Department for Children, Schools and Families (DCSF) and the Department for Culture, Media and Sport (DCMS) direct its funding at choirs and orchestras that are making demonstrable progress with the children they involve, and ensure the Sing Up programme reaches the primary schools that need most help.
It also recommended that schools hold regular reviews of their music provision, considering how it could benefit the entire community rather than tick a box.
"Not enough emphasis is being given to longer-term impact; simply increasing the numbers involved in one-off events is a hollow achievement," it concluded. "Those involved in music education need to do more of less: to identify and agree on what is important and to work together systematically to make a difference."(By Aislinn Simpson Last Updated: 6:07PM GMT 03 Feb 2009)