Sirius Satellite Radio boasted more new signups during the first quarter of 2006 than its main competitor, but its net loss more than doubled.

New York-based Sirius brought in 761,187 new subscribers during the quarter ending March 31, bringing its total number of customers to just over 4 million. Despite the growth, Sirius still trails competitor XM Satellite Radio of Washington, which now has 6.5 million customers after signing up another 568,902 subscribers in the first quarter of 2006.

To gain its new subscribers, Sirius spent an average of $113 on what is known in the industry as subscriber acquisition costs. For Sirius, that represented a decrease from the first quarter of 2005 when it averaged $190 to acquire each new subscriber.

XM averaged $62 per subscriber in the first quarter.

The first quarter net loss for Sirius, however, more than doubled, growing from $193.6 million in first quarter of 2005 to $458.5 million in the first quarter of 2006.

That loss occurred despite a 193-percent increase in revenue , from $43.2 million in first-quarter 2005 to $126.7 million in first quarter 2006.

Sirius Chief Executive Officer Mel Karmazin said during a May 2 conference call with analysts that the company was on track to meet its goal of reaching positive cash flow by the close of the year, saying it could come as early as fourth quarter 2006.

“Sirius has a very strong balance sheet and a strong cash position,” Karmazin said during the call.

In a May 4 analysis, William Kidd of the firm Ladenberg Thalmann of New York said despite the fact that Sirius’ stock has not been soaring, its new products and expanding content should ease investor concerns.

“The management’s focus on cash flows seems to be one of the final pieces of the puzzle,” said Kidd in the analysis.

The influx of new subscribers related to the arrival of disc jockey Howard Stern in January should help boost numbers in the second quarter and throughout 2006, Kidd said in the analysis.

Karmazin would not comment on the possible timing of price increases for Sirius’ service, except to say that it would occur at some point. Sirius currently charges subscribers about $13 a month. “In the future, there will be price increases coming from Sirius,” Karmazin said during the call.