There are a few things to know about playing music in your cafe, the more you research, the more you understand the impact.
You will need a licence - PRS/PPL https://pplprs.co.uk/ or https://www.prsformusic.com/
unless you use royalty-free music.
The licence is linked to how many seat you have - so be economical when applying and don't play in the back areas, keep a copy of what you tell them so you know what you have stated when you renew.
There is a load of streaming services that will provide royalty-free music now this is a good one - and works out cheaper than getting a licence https://licensing.jamendo.com/en/in-store/bars/coffee-shop
This might be the simplest and cheapest way if the music is acceptable to you. You won't get any really famous songs using this though!
If you want to play your own music choice, technically, it's against Spotify and Apple music terms and conditions - although Spotify work with https://www.soundtrackyourbrand.com/
We used our music collection loaded onto some old iPods we bought off eBay and played in a random loop in our places. TBF Spotify and apple music streaming did not exist when we started up, and we never bothered to update - in fact, we had lots of people ask for the playlist! There were about 15 hrs of music on our playlist so we didn't repeat the same song too much each day.
Your music is part of the DNA of your business and becomes part of the soul of your place; it has the power to make people happy, sad, speed up or slow down. It's a good way of defining your avatar by working out what music they listen to btw.
Good bars change the tempo, volume and style of music throughout the day. They have proven that increasing the beats per minute of the music increases the speed at which people drink! They often combine this with changing lighting levels and colour tone to transform daytime to nighttime.
With cafes, the music should be chosen carefully and not managed by the various teams on duty. Playing the radio is also a no-no as you get adverts, news, talk getting in the way of the mood.
The volume level is also important; it needs to be loud enough to hear and hum along to it if you are on your own, but not high enough to stop conversations or phone calls. A speaker for each area of the cafe will fix this as you won't need it to be loud in any one place to hear the music everywhere.
Watch out for the power ballad, where the song starts quietly and then becomes shouty after a few key changes.
Acoustic music seems to work well.
There is a difference between Muzak and Music to take into account.
In terms of speakers, then I would recommend the Sonos one. They need just a 13amp plug but not speaker cables. They work on the wifi and can be added to later and sound great.