Without rears it may not appear. Get rears if you can, even small ones.
The aspect ratio is a method of telling the 565 what shap your listening zone is.
i.e. 'narrow and deep' to 'wide and shallow'.

Good luck, Chris smile

No 18 in the Hall of fame smile I have simple tastes; I am content to settle for the best:
GIK monster bass panels, rear wall. QNAP TVS 471i3. Roon into DSP5200SE via 210/ 218 zone... Explorer 2. Bluesound Pulse 2, Mini & Flex. 596v1, 518, Foxsat HD, Sony BDP, Pioneer 5090, 2 Chromecast's for LRB videos. MS200 to F80 for a Roon zone