ELAC SUB 2050 - Setup Tips

Setup Tips
General advice
A minimum free space of 10 cm between the subwoofer and the wall is required for proper cabling and cooling.
Some ELAC subwoofers are down-ring or provide a bass diaphragm on the bottom. Therefore, they are equipped with
mounted feet in order to maintain a minimum distance between the underside of the subwoofer and the oor. If you want to
place objects on the ELAC subwoofer, make sure that they do not slip and that they are protected from vibrations. Many shops
for car accessories sell special mats that prevent slipping. With a mat of rubber or felt, it is possible and may well make sense
to place a loudspeaker on an ELAC subwoofer.
The inuence 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 30Hz, depending on the product.
This corresponds to a sound wave with a length of approx. 10 meters. Nevertheless, low bass can also be heard in small rooms
(extreme example: headphones). However, some peculiarities should be taken into account. In a closed, box-shaped room less
than 7– 8m in length, the center 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 focused at
these ends until it overows. The lowest pressure remains exactly in the middle which means no low bass. The following table
shows the frequency at which this eect is the strongest.
Distance between parallel walls Frequency of pressure minimum in the middle be-tween the walls
10 m 17 Hz
8 m 21 Hz
6 m 29 Hz
5 m 34 Hz
4 m 43 Hz
3 m 57 Hz
2,5 m (room height) 68 Hz
The eect appears exactly in the range where a Subwoofer should show its strength. It applies to all parallel boundary surfaces,
even to the oor and ceiling, if these are solidly constructed. The solution is simple: move the listening position away from the
center of the room - even a dierence of just 50 cm is sucient to make low bass audible 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 frequencies 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 aecting 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 exibility, and frequency range, the ELAC subwoofer can take full advantage of a location near a
wall or in a corner. The minimum free rear space required 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 eect.
Under practical conditions, the position of the ELAC subwoofer cannot be located by ear and therefore it 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.
There is only one serious restriction which should be observed: a subwoofer should not be placed much closer to the listener
than the main speakers (max. 1 m). A larger distance is better (i.e. a position behind the main speakers up to approx. 1 m, or
from special subwoofer outputs and when reproducing surround video eects up to 3 m.)
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