Sirius XM Radio Inc added about 583,000 net subscribers in the second quarter, bringing its total base to 19.5 million as healthier car sales lifted demand for satellite radio.

The satellite radio company said on Wednesday it also improved the rate of subscriber turnover, known as churn, to 1.8 percent. That was down from 2 percent in the year-earlier period.

Gabelli & Co analyst Brett Harriss called the additions great, and said they beat his aggressive forecast.

The health of the company is great, and shows it was able to get the merger through and cut a big part of fixed costs, Harriss said, adding the improved subscription numbers point to an automotive recovery.

Sirius, which merged with rival satellite radio company XM, said the subscriber results were the strongest since the two companies joined in July 2008.

It said customers who added its service increased 46 percent, while those dropping subscriptions fell 8 percent in the second quarter.

Shares of Sirius, home to popular personalities such as Howard Stern and Oprah Winfrey, rose 5.8 percent to 99 cents in early trading.

(Reporting by Jennifer Saba, editing by Gerald E. McCormick and Maureen Bavdek)