Graphic: How a festival stage works

BACKSTAGE AREA

The backstage area is organised according to different levels of access. At Glastonbury, Michael Eavis and Melvin Benn and safety personnel have access to all areas at all times.

The core stage crew have access to their area at all times; but musicians' access is limited to their individual stage times and not beyond. The secondary crew have access to dressing rooms, showers and toilets.

The Glastonbury Other Stage backstage area also features a 20ft steel store full of alcohol, delivered on a 17-tonne truck to supply all 35 bands.

BACKLINE TECHS

Backline techs - more commonly known as "roadies" - manage a band's equipment onstage during a show. Typically, each member of a major band has his own personal "tech" responsible for his instrument(s). Bands tend to usually bring their own staff.

Big festivals such as Glastonbury also employ a number of "local crew", who perform auxiliary tasks such as emptying lorries and stacking equipment.

DRUM RISER

An average festival stage may have to assemble, move and dissemble around a dozen drum kits per day.

All bands' equipment is mounted on moveable platforms known as risers, which each riser have an "umbilical" connecting it to electricity and audio control.

While one band is playing Glastonbury's Other Stage, the next act's instruments are assembled and prepared on their risers behind a drape. Once an act has finished playing, their risers can be rolled off and the next act's rolled on within around 10 minutes.

AMPLIFIERS

Almost all amplifiers used on a festival stage are a band's own. Glastonbury also employs a truckload of spare speaker equipment to rent to any acts who require it.

SPEAKERS

Glastonbury's Other Stage employs 11 racks of amplifiers driving a main system, each with 4 amps, generating a total 176 kilowatts output.

This output generates around 98-100 decibels measured at the mixing desk in the middle of the crowd.

The festival's licence stipulates that all sound must cease from the stage at 12.30 on Friday and Saturday, and at 12 midnight on Sunday.

CROWD ASSISTANCE AND SAFETY

More commonly known as security, their prime task is to prevent stage invasions but in recent years have become more responsible for general crowd safety and welfare.

The number of staff depends on the act performing. A band such as the Arctic Monkeys might have around 30 pit staff, while Bjork may take between six and eight.

LIGHTING AND EFFECTS

The Glastonbury Other Stage has a lighting rig with around 40 moving lights, 12 strobes, couple of spotlights. These are powered by two 400 amp 3-phase services.

Headline acts usually bring extra equipment and effects such as lasers, pyrotechnics and video screens.

MONITORS

Monitors are floor-based speakers which point at musicians enabling them to hear each other while performing. More high-profile bands usually bring their own monitor engineers, while in-ear monitors are gaining popularity. Normal monitors - sometimes called "wedges" - point 30-45 degrees upwards towards a musician's ear.

Typically, each band member has two wedges but some use more - for example Liam Gallagher uses four, and other artists use six.