A Headphone Maker, Beats by Dr. Dre, Said to Pursue Online Music Service Beats Electronics, the company that has transformed the high-end headphone market with its Beats by Dr. Dre line, is in the process of buying MOG, an online music service. The deal has not been completed, but negotiations are nearing a final stage, according to one person with direct knowledge of the talks who was not authorized to speak about it. The price was not known. Representatives for Beats and MOG declined to comment. The news of the sale was first reported on Monday by Business Insider. The deal would be as much a sign of the market power of Beats as of the growing competition in digital music. In less than four years, Beats, which was formed by the hip-hop star Dr. Dre and the record mogul Jimmy Iovine, has come to dominate field of headphones by making itself a mark of both high fidelity and high fashion. With their distinctive design, Beats headphones sell for up to $400 a pair, and as of late last year the company's annual sales approached $500 million. Last summer, the Taiwanese cellphone company HTC paid $300 million for a majority stake in Beats, and a deal with MOG could signal that HTC is preparing to tie a Beats-branded music service to cellphones, as Cricket Wireless has done with its Muve Music. MOG was founded in 2005 as a network of music blogs, and it still operates an advertising network for blogs. In 2009, it introduced a subscription streaming service, which, like Spotify and Rhapsody, lets users listen to a music library that includes millions of songs. The service costs $5 to $10 a month, but shortly before Facebook introduced closer integration with media services last September, MOG introduced a free level. The company has recently said that it has 500,000 users. It has not revealed how many of those are paying subscribers, but music executives estimate that it has fewer than 100,000. With Spotify's arrival in the United States last summer, and Facebook's changes - which have also benefited Spotify and other services - the competition for online music has become intense, and analysts have been saying for months that some consolidation in the market is inevitable. Last fall, Rhapsody bought Napster, another subscription service, from Best Buy. In January, Spotify announced that it had three million paying subscribers in the 13 countries in which it operates, and at the South by Southwest festival last week in Austin, Tex., Sean Parker, the investor who is on Spotify's board, predicted that it would "overtake" iTunes in less than two years.