Noise assessment:

Where any employee (or volunteer) is likely to be exposed to the lower action value or above, you should ensure that a noise assessment is produced by a competent person. The assessment should be adequate for the purposes of identifying which employees are exposed and providing such information as will facilitate compliance with the duties imposed under the Regulations i.e. the reduction of noise risks for these employees
The assessment should be subject to revision regularly and otherwise as appropriate e.g. in response to a change in working procedures or when there is reason to suppose that it is no longer valid. The assessment, including any revisions made, should be recorded and kept until such time as a new assessment is made.
If you are not sure how to complete a risk assessment you should look at the extensive guidance availabe from the HSE and on this site in free downloads

The risk assessment should include consideration of:

When considering strategies to reduce sound levels / exposure to sound levels you should consider:

When considering who is exposed to noise levels you should consider:

Protecting the audience:
There is no specific Legislation setting the limits for audience exposure to noise. The HSE recommends: