Hi Swerd,
My budget is 1000$.
I want to stay with ceiling speakers.
What does the "pre out" mean ?
The speakers spc is 50W RMS, can I connect all 4 as front and use amp ?
I think the coffee shop comment might have been in reference to the ceiling speakers as they are not common for dedicated music systems. It sounds like this is more of an "area fill" ambient kind of system, rather than an all out music system?
Pre-out is exactly what Swerd said: preamplifier output, labeled as
pre out.
Speakers are 95% of the resulting sound quality, so speakers is where you would want to improve. Is it just not loud enough or the sound isn't the quality you are looking for? Celling speakers are a compromise and good ones tend to cost a bit more. $1k should still get you good ceiling speakers though.
Adding two pairs of speakers to a single output is likely to strain the receiver. Adding an amplifier with enough channels for the number of speakers you want via the mentioned pre out will work.