what do you mean?The golden rule in PASSIVE treatment is simple: BALANCING the relation between absorbing and reflecting and diffusive surface...We need the three in some ratio according to each room specificities...
I did it by listening experiments...
For the first reflection point all is relative to other factors in the room: geometry, topology, size, acoustic content of furniture, walls, ceilings floors etc.
Then NO RULE is valid for ALL room save a balance that must be created by the tuning experiments by our own ears...
For the reflections point coming from front and back meditate this short abstract of a scientific paper:
«A new physical measure for psychologicalevaluation of a soundfield: Front/back energy ratio as a measurefor
envelopment.M. Morimoto (Environmental Acoust.Lab.,Facultyof Eng.,KobeUniv., Rokko,Nada,Kobe,657Japan)and
K. Iida (Kobe Univ., Kobe,657 Japan andMatsushita Commun.IndustrialCo., Ltd., Japan)
Broadening is one of the important characteristics for the psychological evaluation of a soundfield.Several investigations
indicated that broadening was comprised of two elemental senses, i.e.,auditory source width(spaciousness) and envelopment [M.
Morimoto et al., Proc. 13th ICA, Belgrade2, 215-218 (1989); J. AcoustSoc.Jpn.46, 449-457 (1990); and Hidaka et al., J.
Acoust.Soc.Am. 92, 2469 (A) (1992)]. They inferred that the degree of interaural cross correlation of late reflections correlated
with envelopment. This paper,however, shows the results of psychological experiments that envelopment is affected by theenergy
ratio of reflections coming from the front of the listener to those coming from the back of the listener,even if the degree of
interaural cross correlation of the late reflections are equal.Namely,envelopment grows as the energy of the reflection coming
from the back of the listener increases. This result suggests the need to measure the ratio which has never been measured.»
This is only an example of one of the paper that inspire me...
The ACTIVE mechanical controls of the room has 2 aspects: control of "timing" of early and late reflections complementing the passive treatment but control of the relation between each speaker direct wave with the location of different resonators near the speakers and around the room, this use of each speaker will make easier for each ear the recreation of distance then of "imaging"....It is possible to modify the timbre perception and the listener envelopment at will...The goal is the more natural is the best....
I am not a scientist only someone who listen by experiments....But i discover my idea reading some papers in psychoacoustic research...