The proper distance from the front of the speaker cabinet to the wall behind the speaker is entirely dependent on the particular speaker and it's interaction to your particular room.
Unless your speakers are specifically designed to be placed right up against the wall (ex. Audio Note, Larsen, etc) you will need to use a little trial and error. I have not yet found a formula or modelling application that is 100% accurate.
Unless your speakers are specifically designed to be placed right up against the wall (ex. Audio Note, Larsen, etc) you will need to use a little trial and error. I have not yet found a formula or modelling application that is 100% accurate.