How To Place The Speakers For Better Sounds?
The question deserves a very long answer and all the designers who are wondering since the advent of stereophony and have no precise answer. The number of systems currently in existence proves that we have not found the panacea and that there will still be new systems.
The right and left speakers (main)
In stereo, depending on the speakers available, the spacing of the main can be done by successive tests without too close to the side walls (> 50 cm), usually oriented towards the listener, but sometimes it is worth it. exaggerate the rotation to allow several listeners side by side to have the same left and right volume.
The central speaker
With a central speaker, in a 2.1home theater system, we should not be afraid to move them further than stereo (which widens the side image) since we no longer fear the effect of central hole. The contribution of the central is particularly sensitive in music 2.1, where the effect of hole in the center disappears, even when one is relatively happy in stereo (good ghost image).
The backs / effects
It is necessary to begin the tests at 90 ° of the listener, then to move back until the moment when the lateral image becomes less precise and to advance to find it again. The point of retreating more than 90 ° is to give a rear image, the goal being to have the impression of a total wrap, to bathe in the sound. To foresee a difference of 15cm or more between the 2 backs compared to the listener causes an auditory difference to compensate in DPL for the mono effect of the back. If we have a mono effect of the back, we hear the rear sounds squarely in his head as if they came from a single rear source very close. The worst being to have the impression of having the rear speakers 15 cm from the head.
Sometimes, for the rear speakers, to achieve this effect, you have to direct the speakers to the wall or ceiling, and then you hear the reflections. Another solution, when you cannot put the surround height, and they are glued against the sofa, there is the solution to put them up, the speakers in the air, and also surprising that it may appear, this solution has already been successfully tested: The speakers seem to be in height, and more far than they really are.
Connecting the subwoofer
There are several solutions according to the cases of figures:
1) In general, the amp has a special output sub, cinch (RCA). For Dolby Pro-logic (and stereo or mono) signals, this is the sum of the right and left channels of the stereo (not the right and left prologic), and depending on the amps, this sum is filtered or not (usually no).
2) The second solution is to connect the amplified outputs of the amp (those intended for speakers) on the type of speaker inputs of the box. This type of cabling is less sensitive to disturbances over long distances. The impedance of this input is very large, and therefore will not disturb either the signal that goes to the speakers, or the amp.
In this case, be careful to declare the main speakers in “wide”, other speakers in small, and “no subwoofer” so that the frequencies for the box go to the main. They will then go to the box.
On the other hand, the high level outputs of the box are filtered “high pass” at 120Hz. The frequency adjustment knob does not vary this frequency. The speakers are always filtered at 120 Hz. So if you want to avoid this filtering, connect the speakers from the amp and not the sub. The potentiometer is only used to set the low pass filter that selects the frequencies sent to the sub.
In short, the simplest being still to cut the main above the upper limit of the box (e.g. box between 20 and 50Hz, and speakers from 70Hz). But this poses a big problem: the location of the box is very clear, and if it is not placed in front with the main, it quickly becomes unbearable.
Often, we do not have the financial means or the space enough to have speakers restoring the whole spectrum, we then reorient the lower part of these towards the subwoofer by setting the amplifier in “small”, “wide “following each speaker.
Attention, the adjustment of the phase is fragile: if you move a speaker or the sub of 10cm, remove a piece of furniture or add a green plant, this setting could be redone.