Together, Sirius and XM added nearly 1 million net subscribers during the second quarter this year, according to company releases, which brings their total subscriber-ship to 11.6 million individuals.

Together, Sirius and XM added nearly 1 million net subscribers during the second quarter this year, according to company releases, which brings their total subscriber-ship to 11.6 million individuals.

Sirius added 600,000 net subscribers during the April-to-June period and now says it has 4.68 million total subscribers.

XM added 398,000 net subscribers during the same period, to wind up the quarter with 6.89 million total subscribers.

Wall Street analysts this morning described the subscriber gains as either "in line" with their expectations, in the case of XM, or above expectations, in the case of Sirius.

Jason Helfstein of CIBC World Markets calls himself a long-term believer in satellite radio but adds that he expects XM's shares to remain volatile for a while, in part because the company did not update its projections on how many subscribers it expects to have by the end of 2006. The analyst expects XM to report 8.36 million and says XM has guided analysts with its own estimate of 8.5 million.

Bear Stearns analyst Bob Peck said Sirius' subscriber adds were "significantly higher than our 565k estimate." He also expects that Sirius will maintain its subscriber momentum into the summer -- driven, in part, by an expected push into offering a Wi-Fi enabled receiver.

In a note to investors this morning, Peck wrote: "The technological gap between the two has largely narrowed to an extent that the features available on one platform are virtually comparable to those on the other."

The next stage in this development, he says, will be Sirius's next-generation receiver: a "live wearable satellite radio-cum-MP3 player...that could feature WiFi access (as Sirius becomes agnostic to the method of distribution.)"

Peck says such a device could be released by the end of this summer.