Gov. Code, § 25559

The board of supervisors may:

(a) Appropriate and expend money from the general or other appropriate fund of the county to furnish music and supply musical entertainment to the public, either by the employment of individual musicians or by entering into contracts, with or without bids, with orchestras, bands, symphony associations, or other organizations, whenever desirable in its judgment in the maintenance and operation of any stadium, exposition building, public pleasure ground, public park, botanical garden, recreation center, county fair, memorial hall or veterans’ meeting place, or memorial park, or other county buildings and places for public purposes. The board may furnish music in the same manner for any public meeting, gathering, parade, occasion, or patriotic memorial meeting or observance.

(b) Appropriate and expend money from the fund raised by special tax to exploit the resources of the county, and commonly known as the “Exploitation fund,” to furnish music, either inside or outside the boundaries of the county, by entering into contracts, with or without competitive bidding, with individual musicians, orchestra, symphony associations, bands, or any other organization or corporation maintaining a band, orchestra, or other musical group for the purpose of furnishing free concerts to the public.

The provisions of this section shall be applicable only to boards of supervisors of counties having a population of nine hundred thousand or over, as ascertained and determined by state law.