Ask HN: Generating relevant traffic for a landing page

I am new to the HN community.

I am entrepreneur developing a jamming platform to connect music players through jamming. As part of this process I have setup a landing page with an explainer video and a call to action to submit an email address to get notified when the app is ready.

I have started to collect signups but not as many as I hoped. I still think that the idea is valid and that the main issue is with a) tapping the right audience and b) run a marketing campaign to drive users to the page. Before I do these two things I will not be certain that the idea isnt validated yet.

My questions are: 1) Do most people run a PAID marketing campaign when trying to collect signups through a landing page?

2) what are good sources to publish the landing page other than the obvious FB groups and music forums? Any particular subreddits?

Thanks