It was probably the biggest auction result on day when Sydney's overall clearance rate dropped to 84.4 per cent, from last week's record 89.2 per cent. The weekend before was also a record at 89.1 per cent.

Domain Group's senior economist Andrew Wilson said Saturday's result was surprising and one of the lowest clearance rates since March.

"What a difference a week makes. The Sydney housing market looked like pushing towards 90 per cent over the past few weeks," he said. "Is this the first sign of winter."

But there was no sign of winter in Woollahra, where arts philanthropist Peter Weiss, forked out $3.75 million for Sculthorpe's Holdsworth Street property.

The underbidder, showing a rare generosity in bidders' circles, said she was glad the house went to a supporter of the arts.

Mr Weiss and his wife Doris already own a home further along Holdsworth Street. Soon to turn 80, Mr Weiss has been avid supporter of the arts since the 1990s after making his name and fortune in fashion.

He told Fairfax Media earlier this year that his first passion was music. As soon as he had the time and money he returned to his love of music.

He has since supported the Sydney Symphony Orchestra, the Australian Chamber Orchestra and Australian World Orchestra.

The couple also own a weekender at Palm Beach and have their 580-hectare Wollumbi property on the market for about $15 million. It has an olive grove, award-winning Red Angus cattle stud and its vineyards produce the Wollumbi Estate Wines range.

Selling agent Pauline Goodyer, of Goodyer Real Estate, who had taken more than 200 groups through the cottage during the sales campaign, said she believed Mr Weiss bought the property to help secure Mr Sculthorpe's legacy.

A crowd of about 100 watched the auction from the front courtyard of the property which Mr Sculthorpe bought in 1976.

He died in August aged 85. Proceeds from the sale of the house will go to the University of Sydney which will recreate the composer's studio and establish a chair in Australian music.

The contents of the house will be offered at auction by Shapiro's auction house in coming months.

11 "The Masters" 102 Darley Street W Mona Vale, sold at auction on Saturday for $2,378,000.

In another big auction results on Saturday, a three-bedroom home in "The Masters" complex at Mona Vale, overlooking Bayview golf course, sold for $2,378,000 - $428,000 more than its reserve.

Agent Michael King, from Sydney's Sotherby's International Realty, said the result "went way beyond we'd imagined" and showed that "the northern beaches is really doing well at the moment".

In Waverley buyers were equally bullish, with a four-bedroom house in Campbell Street selling for $410,000 above its reserve, at $2.41 million.

While in Haberfield a house on almost 700 square metres in Kingston Street fetched $2.62 million - $320,000 more than its reserve.