Hi

The Arc will still function. However, shortening the distance to the right wall will cause a difference in how the Arc measures an adjusts. TruePlay will definitely need to be employed to get the best acoustic performance from the Arc and other Sonos (i.e. sub and surrounds) you may have in your setup.

Cheers! 

Thanks, would it be the same as getting a flat TV unit minus the raised section on the right?

The speakers on the right i’m guessing fire straight and trying to figure out if TruePlay can tune so the sound stage is the same. Also, i only have the ARC.

PS : seating position on the couch would be exactly infront of the raised section on the right.

Trueplay is not measuring individual speakers one at a time as one might think. Trueplay is taking a measurement of the entire room as you walk around the room in a circular pattern encompassing the Arc and your listening position. After measurements are taken Trueplay will adjust the output of the Arc for each bank of speakers. Those being LF/C/RF, Upward Firing and Side Firing. In the end the Arc will deliver the best possible sound based upon its position, room size (H x W x D) and distance to  reflective/non-reflective surfaces. 
 

Note: Trueplay is only possible with an iOS device…not Android. A short video will play at the beginning of Trueplay to familiarize you on how to use it for the best possible results.