Look like it's dull times ahead at the Fed. Monetary policy probably will be tighter and Paul A. Volcker, the new chairman who was sworn in yesterday, says he's really sort of ho-hum.

"I'm boring," he insisted at a White House reception. "It's the job of all central bankers to be as boring as possible."

And G. William Miller, the deadly-serious-looking former Fed. chairman who was sworn in as the new Treasury secretary yesterday, says he's almost just as bad.

"The Treasury will suddenly become sedate," he promised. "I've always been my quiet, reticent self."

There are those, of course, who would disagree. And a few did at a White House tea party that honored Miller, a man known for his outspokenness while he was Fed. chief, and Volcker, the former president of the New York Federal Reserve Bank who replaced him.Both men had been sworn into their new offices at yet another East Room ceremony to replace the Cabinet members Jimmy Carter has been firing lately.

Among those at the tea party who disagreed with Miller's self-assessment was Robert Grant, an old friend from Miller's days at Textron Co. "He's serious 90 percent of the time," confirmed Grant, "but he has fun 10 percent of the time." And how is that?

"He loves to sing," revealed Grant. "He has a good voice. He comes to our house for Christmas carols."

Most of the 300 people who attended the reception were either industrial moguls, Wall Street types, friends of the guests of honor, or a combination of the above. The Cabinet members who attended the standing-room-only swearing in ceremony skipped the reception and made for the doors - fast.

"They said the right things," said Defense Secretary Harold Brown as he ran for the exit. Was he encouraged by the remarks Miller and Volcker made at the ceremony? As far as one can be by words."

But Alfred Kahn, Carter's chief inflation fighter, stayed late and talked about movies with Nancy Teeters, a member of the Fed. Board of Governors.

"Have you seen "Get Out Your Handkerchiefs"?" Tetters asked Kahn, referring to the French film about a love affair between an older woman and a 13-year-old boy. "We took our 15-year-old son with us."

"Now he's got dreams of glory," said Teeters' husband Bob.

"I love movies," said Kahn.