What is the minimum distant for Zu?

Morganc, All speakers need the same attention as your Zu speakers, but once you learn your room you will find other speakers will sound their best in the same place as the Zu.

My Def 4s are closer to the wall than were my Def 2s. Also, the Def 2s seemed more fussy with regards to placement. I suspect that the Def 3s are more similar to the Def 2s because of the rear firing bass array.

Rrog's idea makes sense if the speakers have similar frequency, power and radiation responses and the listening position is fixed.

You all have good points, but my prior speakers were the Zu Presence and they were rectangular so totally different shape than the Definition 3, I think they worked best close to the side wall like 14 in but the def3 doesnt like it so much

Zu has said in the past that Def models with rear-firing sub-bass arrays can be used as close as 2" from the wall behind them. And it's true. Is that ideal? Depends on your room and how much flexibility you have for placement.

What's more important with Definitions is making sure the distance between you, the listener, and the speakers is usable. Def 1.5 and Def2 did not soundstage nor tonally integrate well if the listener sat closer than 10' from the speakers. Sean Casey told me that Def3 and 4 are usable as close as 8' from the listener. While I suggest more, I have to say the deleterious effects of sitting too close to Def 4s are much less troublesome to illusion of fidelity than doing same with Def2 or earlier.

The rear-firing sub drivers are active below 40Hz unless you set the EQ to roll them I higher. Don't. Let your Def3s end up as close to the wall behind them as is necessary for you to achieve full tonal and spatial integration at an appropriate distance listening. Prioritizing distance to the wall over correct minimum listening distance will make deny you the speaker's full benefits. Work with your room.

Phil