Things never get dull for the country's lone satellite-radio provider. Shares of Sirius XM Radio (NASDAQ:SIRI) moved sharply higher on the week, climbing 10% to close at $3.72. The media darling's gain was well ahead of the general market.

There was more going on beyond the share-price gyrations, though. Sirius XM preannounced a healthy subscriber tally for the second quarter, sending the stock to a fresh five-year high. Pandora (NYSE:P) went the other way, warning of a large sequential decline in usage between tMay and June.

Let's take a closer look.

25 million reasons to remain bullish
Sirius XM has occasionally delivered strong subscriber numbers early, waiting a week or so after the end of a quarter to put out a press release bragging about its magnetism during the three prior months.

It happened this time. The satellite-radio star closed out the second quarter with 715,000 net new subscribers, crossing the mark of 25 million accounts along the way.

Tack on the first quarter's numbersm and Sirius XM already has 1.168 million net new subscribers through the first half of the year. Its earlier forecast for 1.4 million net additions for all of 2013 seems silly now, and Sirius XM is actually only raising that target to 1.5 million.

Don't worry. Sirius XM will probably gain more than 332,000 net new subs for the balance of this year. Mel Karmazin is gone, but Sirius XM is continuing his practice of offering conservative outlooks. Sirius XM bumped its subscriber guidance higher four times last year. There should be more of the same in three months.

Boxing Pandora
As good news at Sirius XM sent those shares to a fresh five-year high of $3.73 on Friday, Pandora went the other way after announcing problematic metrics for the month of June.

Pandora served up 1.25 billion hours of audio last month, less than the 1.35 billion it delivered in May. There are seasonal considerations here, but the sequential dip -- when it has happened -- has never been this bad.

Whether it's heavy users recoiling after February's move to cap mobile ad-supported usage or the growing realm of rival streaming applications, Pandora is going to have to prove that it can make more money serving up less content.

A Sirius future
It was an interesting week for Sirius XM. The new week isn't likely to be dull.

Longtime Fool contributor Rick Munarriz has no position in any stocks mentioned. The Motley Fool recommends Pandora Media. Try any of our Foolish newsletter services free for 30 days. We Fools don't all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.