Set-Up Tips - ELAC SUB 2030 Bedienungsanleitung

Set-up tips

General advice
10 cm minimum free space between the subwoofer and the wall is required for proper cabling and cool-
ing.
Some ELAC subwoofers are down-firing or provide a bass diaphragm on the bottom. Therefore, they are
equipped with mounted bottom plates. The plates are realizing the proper distance. If you want to place
objects on the ELAC subwoofer, make sure that they do not slip and that they are protected from vibra-
tions. Shops for car accessories may sell specific mats that avoid slipping. Mats of rubber or felt should be
used where a loudspeaker is placed on an ELAC subwoofer (not generally recommended).
The influence of room acoustics
'Low frequencies need space' - this is an important yet ambiguous statement when applied to subwoofers.
For practical purposes the following facts may be more useful:
The low crossover frequency limit of the ELAC subwoofer at near-maximum levels is below 30Hz, de-
pending on the product. This corresponds to a sound wave with a length of approx. 10 meters. Neverthe-
less, low bass can also be heard in small rooms (extreme example: headphones). However, some peculi-
arities should be taken into account: In a closed, box-shaped room less than 7– 8 m in length, the centre
of the room should be avoided as a listening position if you want good bass. Like waves in a bathtub, the
energy "rolls" back and forth between both ends of the room and the alternating pressure build-up is fo-
cused at these ends until it overflows. The lowest pressure remains exactly in the middle which means no
low bass. The following table shows the frequency at which this effect is the strongest.
Distance between parallel walls
10 m
8 m
6 m
5 m
4 m
3 m
2.5 m (room height)
The effect appears exactly in the range where a Subwoofer should show its strength. It applies to all par-
allel boundary surfaces, even to the floor and ceiling, if these are solidly constructed. The solution is sim-
ple: move the listening position away from the centre of the room - even a move of only 50 cm is sufficient
to hear the low bass again. If the listener is sitting directly adjacent to a wall, bass reproduction is often
too strong. This can be balanced by reducing the levels at the subwoofer. However, for all higher frequen-
cies and a more natural spatial impression, it is better to move the listening position away from the walls.
According to the acoustic theory of low frequencies in small, closed rooms the location of the listener and
subwoofer can be exchanged without affecting the acoustic results. Thus the best position can be easily
found by mounting the subwoofer at the potential listening position, walking around in the room to locate
the place where the bass is reproduced most evenly, and then placing the subwoofer there.
Although the theory cannot be relied upon totally and low bass should not be judged alone (without the
main speakers), the recommendation to never place the subwoofer/ listener exactly in the middle of the
room or centrally in front of long walls, still holds true. Due to its flexibility, and frequency range, the ELAC
subwoofer can take full advantage of a location near a wall or in a corner. The minimum necessary free
rear space for cooling and cabling is 10 cm. A greater distance from the wall is recommended only if
changing the "PHASE" does not result in a better bass reproduction - Shifting the subwoofer by 0.5 - 2 m
(depending on the crossover frequency) may clarify the situation. Good bass can be obtained in open
rooms and with slightly asymmetric placements. Irregularities in the building, sometimes even just an
open door, may have a surprising and often positive effect.
Under practical conditions the position of the ELAC subwoofer cannot be located by ear and therefore
does not need to be placed exactly between the main speakers. A position on a side wall, even behind
the listener, is also possible, especially with a low crossover frequency. Once optimization is complete,
the subwoofer may even be placed out of sight.
Frequency of pressure minimum in the middle be-
tween the walls
17 Hz
21 Hz
29 Hz
34 Hz
43 Hz
57 Hz
68 Hz
17