Spotify made headlines late last month when news hit that the company filed with the U.S. Securities and Exchange Commission (SEC) to go public. The Form F-1 filing revealed a wealth of key metrics for the company, including its 71 million subscribers, well over the 38 million boasted by its nearest competitor, Apple (AAPL -0.35%).

Competition in the streaming music space is intensifying, according to The Infinite Dial, an annual survey of digital music by Edison Research and Triton Digital. The survey shows that while Spotify is gaining ground, competitors like Apple and Amazon.com (AMZN 3.43%) are growing at a much faster pace.

A desktop, notebook, and multiple smartphones displaying the Spotify app.

Watch out Spotify, the competition is coming. Image source: Spotify.

An Apple a day

Apple's music streaming service, which debuted in June 2015, is growing more quickly than Spotify according to the survey. 10% of respondents reported listening to Apple Music in the previous 30 days, up 25% over the prior period. 20% of those surveyed indicated that they had streamed Spotify in the prior month, up 11% from the prior survey.

Those findings mirror those reported elsewhere. Apple has been adding U.S. subscribers at a rate of 5% per month, compared to only 2% for Spotify, according to reports in The Wall Street Journal. At this rate, Apple will overtake its older rival in terms of domestic subscribers as early as this summer.

Apple recently released its HomePod smart speaker, which the company is specifically marketing to the Apple faithful and audiophiles. This may help increase the likelihood that Apple Music's growth spurt will continue.

A white Apple HomePod smart speaker on a shelf.

Will the Apple faithful flock to the HomePod? Image source: Apple.

The dark horse

Subscribers to Amazon's Music Unlimited service pay $9.99 per month -- similar to its competitors -- for access to the company's 40 million titles, as well as personalized stations and thousands of curated playlists. Members of Amazon Prime pay only $7.99 for the privilege. The advantages are even starker for owners of the Echo smart speaker, who pay only $3.99 per for month for the unlimited music streaming service. 

This strategy appears to be paying off. According to the survey, 9% of all respondents age 12 and older had listened to Amazon Music in the prior month, a 50% increase year over year. The study also revealed the number was even higher among smart speaker users, as Echo owners subscribe to its Amazon's music service at about twice the rate of overall respondents.

Amazon recently expanded its streaming music service to an additional 28 countries and is simultaneously introducing the Echo in those same locations. The higher frequency of music streaming among Echo owners has no doubt caught Amazon's attention, and the company is likely eager to leverage these users across its ecosystem.

A black Amazon Echo smart speaker on a bookshelf.

Amazon's Music Unlimited is popular among Echo users. Image source: Amazon.

The Trojan horse and the outlier

Google Play Music from Google parent Alphabet (GOOGL 10.22%) (GOOG 9.96%) appears far down the list when considering streaming music services, with 6% of those surveyed reported using it in the prior month. YouTube, however, deserves special mention. Respondents on the survey were asked if they had "used YouTube to watch music videos or listen to music in the last week?" A whopping 46% indicated that they had, more than all other on-demand streaming services combined. While this doesn't fit within the scope of subscription-based on-demand streaming music services, it bears noting nonetheless.

It's also worth mentioning that while Pandora (P) played prominently in the survey, the majority of its business is internet radio, and its on-demand streaming subscribers number of just 5.5 million is far below the levels of any of its on-demand-focused brethren. Additionally, the company recently reported 74.7 million active listeners, down 8% year over year, as the service continues to hemorrhage users. 

Early days

It is important to note that streaming music is still in its early days and many still question the long-term viability of the business model. Tech giants like Apple and Amazon can afford to use music as an incentive for those that choose its ecosystem. Spotify meanwhile has yet to produce a profit, underlining the difficulty in generating income in a business shackled with razor-thin margins.