Mass on Impact Zone

[Vincenti]

Many of the modern first class player's irons have mass direct on the back of impact area ("Muscle Back Cavity" e.g. Beres 901, Epon, Tourstage etc.), while some still put pure cavity and put the mass in the impact area welded to the sole (e.g. Beres 8xx, Slingshot).

From the physical nature, direct mass on the impact area means better impulse ( v * t) and automatically more energy will be transferred to the ball on the impact point. This can explain the soft feeling people always talk and this is definitely independent whether the club is forged or casted.

What I don't understand is if you keep a cavity back face and a mass in the impact area indirect embedded on the back of the face, this will not have the same feel and same energy amount transferred to the ball.

So the feel must be different and the distance must be different too. Q.E.D or am I wrong?

(The marketing s**t really confused us)