If that's the case, just get the NHT SuperZero on sale for $60 each (MSRP $120) and use as surround speakers.
SuperZero 2.0 | Bookshelf Speakers | Premium Audio Equipment
They are great speakers, even for front speakers.
Multiple subs is for smoothing the bass response in the room so that your listening positions have the best bass (punchy tight bass).
But, alas, if only ALLOWED one sub
, then get one Rythmik FV15HP.
Well, perhaps you could get all NHT speakers. They have a 30-day in-home trial. I think NHT makes great accurate speakers. For example, their $219 Absolute Zero (on sale @ AVHiFi for $175 each delivered, but no free trial
) had a superlative listening window (200 Hz - 10kHz) frequency response of +/- 0.9 dB, which is the best I've seen. Superb FR is not everything, of course, but it doesn't hurt.
$175 x 5 = $875; or ($175 x 3 Absolute Zero) + ($60 x 2 SuperZero) = $645. A lot of money saved.
The NHT subs are also very good, but will not perform as well as higher price Rythmik, HSU, SVS, PSA, etc. The NHT 30-day free trial is great.
My first audiophile system was the NHT SuperZero + NHT SW2P sub (one 10" sub). I think it outperformed about 90% of the tower systems I auditioned.
You don't really need to spend a lot for great sound quality. I just spend a lot because I'm imprudent and irrational.