St David's Hall

It was designed by the Seymour Harris Partnership as a polygonal room with terraced seating rising in blocks around the platform, and it is a listed building. Since 1986 it has been the home of the Welsh Proms every July.

The hall is not a converted theatre, not a civic assembly room and not a multi-purpose arena. It was built for one job, which is an orchestra of 80 to 100 players heard by 2,000 people at once, and almost every decision in the building follows from that.

The building, in figures

The building can be summarised in six figures and two names, and they are worth having straight before anything else, because most of what is said about the hall's sound is a consequence of them.

What terraced vineyard seating actually does to the sound

Terraced vineyard seating breaks the audience into separate raked blocks at different levels, arranged around and partly behind the platform rather than all facing it from one direction. Hans Scharoun invented the arrangement for the Berlin Philharmonie, which opened in 1963, and St David's Hall belongs to the small family of halls that took the idea up in the two decades afterwards.

The acoustic argument turns on early reflections. What the ear registers as being inside the sound, rather than listening to it from outside, is side-arriving sound that reaches the listener within roughly 80 thousandths of a second of the direct sound from the platform. In a long rectangular hall the side walls supply that for free, but the back rows end up a very long way from the orchestra. A vineyard plan solves the distance problem by wrapping the seats round the players, then has to manufacture the missing lateral reflections deliberately: every terrace has a solid balustrade wall, angled and surfaced so that it works as a local reflector for the block behind it.

Three consequences follow, and a listener can hear all three:

• Nobody sits very far away. A 2,000 seat vineyard hall keeps its furthest listener closer to the platform than a 2,000 seat shoebox does.
• The sound is detailed rather than blended. Inner woodwind lines and percussion attacks survive to the back in a way they often do not in a very reverberant rectangular room.
• Seats behind and beside the orchestra hear a genuinely different balance, with brass forward and strings recessed, which is a property of the plan and not a fault in the building.

Why a 1980s British concert hall being listed is notable

A 1980s British concert hall being listed is notable because buildings of that period are the least protected and the least liked in the country. Listing is normally reserved for architecture of demonstrable special interest, and the postwar and late twentieth century civic building stock has been demolished at a steady rate precisely because it fell out of fashion before it was old enough to be reassessed. Concert halls are more vulnerable still: they are expensive to run, single-purpose, and sit on valuable central land.

Listing St David's Hall recognises two things at once. The first is the interior, which is the actual work: a purpose-shaped acoustic room, not a facade. The second is the urban move, which was to put the national concert hall of Wales inside a city-centre shopping development rather than on a ceremonial site, so that the building is entered from an ordinary retail street. That was an unusual decision in 1982 and it is a large part of why the hall is used by people who would not visit a temple on a hill.

Closure, condition and what the listing means for the hall's future

Closure is the risk that hangs over every hall of this generation, and it is a question of maintenance economics rather than of design. A concert hall built in 1978 to 1982 reaches its forties with the entire mechanical and electrical fabric at end of life at once: the ventilation that keeps 2,000 people comfortable without audible noise, the stage lighting rig, the lifts, the roof. The capital sum needed arrives as a single bill, decades after the building was paid for, and the body that owns the hall is usually a local authority rather than a national one.

Listed status changes the arithmetic in one direction only. It does not produce money, and it does not oblige anybody to run a programme of concerts. What it does is remove demolition and gutting from the list of cheap options, which means that a hall in difficulty has to be argued about rather than quietly disposed of. For a room whose value is its interior volume, that protection is not a technicality.

What is played there, and why the programme looks as it does

The programme at a hall of this kind is set by the acoustic and by the organ, and the resulting mix is narrower than the word events suggests. A 2,000 seat room with a 2 second reverberation and a concert organ is ideal for symphony orchestras, for large choral works of the Verdi Requiem and Belshazzar's Feast kind, and for organ recitals. It is workable for solo recitals and for amplified popular music. It is poor for staged opera and for full-scale ballet, which need a fly tower and an orchestra pit, and which in south Wales go instead to the Donald Gordon Theatre at the Wales Millennium Centre in Cardiff Bay.

The Welsh Proms, founded in 1986 by the conductor Owain Arwel Hughes and held at the hall every July, is the season most closely identified with the building. It has no connection with the BBC Proms in London and never has had; the two share a word and nothing else. Over its history the Welsh Proms season widened from orchestral evenings alone to take in a Family Prom, a Tiddly Prom, an Organ Prom and a Jazz Prom, and the presence of that organ in the wall behind the platform is the reason one of those exists at all.

A hall is judged in the end by what it lets an orchestra do. St David's Hall was built to let 100 players sound like one instrument to 2,000 people, and the polygon, the terraces and the organ are all the same decision, taken once in the late 1970s and audible in every concert since.

Also in this programme

• Concert venues in Cardiff: the hallsThe concert halls of south Wales
• Wales Millennium CentreWhat is inside it, and who works there
• Going to a concertGoing to an orchestral concert for the first time
• Two ensembles, one founded and one inheritedCamerata Wales and the National Youth Orchestra of Wales