Luke Pritchard and Jonny Laxton were 13 when they met at a boarding school in Crowthorne, England, in 2011. They bonded over a shared love of underground music and in 2014 started a YouTube channel, College Music, to promote the artists they liked.

At first, the channel grew slowly. Then, in the spring of 2016, Mr. Pritchard discovered 24/7 live-streaming, a feature that allows YouTube’s users to broadcast a single video continuously.

College Music had 794 subscribers in April 2015, a year before Mr. Pritchard and Mr. Laxton started streaming. A month after they began, they had more than 18,440. In April 2016, they had 98,110 subscribers and as of last month , with three active live streams, they have more than triple that amount, with 334,000. They make about $5,000 a month from the streams.