A charitable trust set up to replace the city’s crumbling Ross Bandstand also wants to create a 200-capacity indoor venue which would overlook a new outdoor arena.
A two-storey undergound complex would host-year-round concerts, exhibitions, conferences and corporate hospitality functions, similar to those at Murrayfield.
The glass-fronted building would have a cafe-bar for around 50 diners, as well as an outdoor terrace allowing a further 80 to sit outside in summer.
And a viewing platform would be created on top of the new building, offering a “step-free gateway” into the gardens from Princes Street, as well as a space to watch outdoor concerts and photograph Edinburgh Castle.
The Ross Development Trust, which was set up by Apex Hotels founder Norman Springford to realise a long-held dream of a new bandstand, launched an international competition last month to produce a vision for a suitable replacement “pavilion”.
The historic arena, which dates back to 1877 and was last overhauled in 1935, was branded “no longer fit for purpose” last year by the city council, which agreed to join forces with Mr Springford.
The brief for architectural practices interested in the project also outlines the specifications for the indoor facility, which is aimed at hosting “small-scale daily events”.
It would replace a temporary cafe currently located next to the Ross Fountain, which would be restored and repaired under the £25 million vision for the gardens, due for completion by the end of 2019.
Project director David Ellis said: “Replacing the bandstand is very much our focus, but through early consultations and discussions we realised there is little point in spending money on a new one if neighbouring facilities aren’t up to scratch.
“There are a number of other elements in the gardens that need to be fixed and if we are creating a space that is ideally going to be used and enjoyed much more by the people of Edinburgh it is important that everyone can get into it.
“At the moment you literally have to use steep ramps or flights of steps.
“With the visitor centre we believe we can improve a number of the facilities in the garden, put everything in the one place and complement the new pavilion. The new facilities wouldn’t take up too much space in the gardens or detract from anyone’s experience.”
Richard Lewis, the city council’s culture leader, said: “While the redevelopment remains focused on the creation of a new Ross Bandstand and conservation of the Ross Fountain, the proposals for a brand new visitor centre could also be exciting.
“Depending on the design, such a centre could offer a multi-functional space to be used all year round, in all weathers and without impacting on the grass.
“We’re hoping for something which blends with the landscape and the surroundings yet has longevity. It should be accessible and encourage people to enjoy the gardens. It will certainly be interesting to see what the design teams come up with.”