It may sound good, but, you never know if it could sound better unless you experiment with placement. It would be incredible luck if you just happen to find the ideal spot without extensive trial and error. Even if you are not perfectly centered and equidistant to the speakers, you can compensate, if necessary, if you have a balance control.
I personally think balance control is necessary for any system, even when speaker placement can be optimized, I find that even a small adjustment makes a surprising difference. When I had my Mark Levinson No. 32 preamp in my system (permits very small incremental changes in volume and balance), I could hear a .2 db change in channel balance even though a whole db change in overall volume was not easily detectable when playing music (steady state test signals make changes easier to hear). I insisted on balance control (and remote volume control) on a custom built linestage built by a very old school builder who normally does not offer such features.
I personally think balance control is necessary for any system, even when speaker placement can be optimized, I find that even a small adjustment makes a surprising difference. When I had my Mark Levinson No. 32 preamp in my system (permits very small incremental changes in volume and balance), I could hear a .2 db change in channel balance even though a whole db change in overall volume was not easily detectable when playing music (steady state test signals make changes easier to hear). I insisted on balance control (and remote volume control) on a custom built linestage built by a very old school builder who normally does not offer such features.