Theoretical implementation of ELODIS-SUB-VB21(VB24):
As I was neither constrained to use certain components or materials, nor to meet any restrictions with regard to costs and time, I did not have to make compromises when developing this subwoofer.
With the help of efficient simulation and measuring software a big number of possible approaches was optimised until no further improvement was possible.All these results were carefully compared to each other. By carefully considering the respective advantages and disadvantages it was tried to find the solution which would yield the best and most balanced final result.
A big vented box (bass reflex) with a single, but enormously robust and powerful and above all acoustically outstanding 24-inch-driver (ELODIS-SUB-VB24) respectively a 21-inch-driver (ELODIS-SUB-VB21) eventually proved to be the best and most balanced solution.As a result the best ratio between enclosure size, achievable sound level and power demand could be achieved.
Practical implementation of ELODIS-Sub-VB21(24):
To implement an enclosure that does not have an impact on the sound quality it is necessary to use suitable materials and stabilisation measures.
Panzerholz® (Pressed wood) for the enclosure and aluminium for the bracing proved to be the ideal materials.
With a particularly stable aluminium frame (110 kg), which at the same time serves as bracing for the enclosure components, all parts of the enclosure as well as the aluminium frame itself are screwed together with M8 screws (about 700 screws and the same number of threaded Ensat bushings) and are carefully sealed.
As a result complete non-destructive disassembly of the subwoofers would be possible if required. This might offer very interesting possibilities in case of upgrades.
The result of this design is an incredibly stable construction which is poor in resonances, nearly totally sound-tight and remains permanently stable if implemented correctly.
All fasteners (screws, bushes etc.) are made of stainless high-grade steel.
The use of these materials allows a comparably efficient material use and the achieved acoustic advantages would hardly be achievable with conventional materials such as MDF or multiplex, not even when using considerably higher wall thicknesses.
Pressed wood in the used quality is about 20 times more expensive than MDF and nearly 10 times more expensive than multiplex boards of the same thickness.
Pressed wood is an extremely hard multi-laminated material in sheet form. It is manufactured from beech veneers and phenol resins under high pressure (approx 40N/mm2) and heat.
The used wall thicknesses of the pressed wood are as follows:
28 mm each for bottom and cover
The measured value for the enclosure losses QL (enclosure leakage losses) is at least 50 when using an undamped enclosure, which considering the big enclosure dimensions is an astonishingly high value and a clear metrological indication for an acoustically totally neutral enclosure.
The used pressed wood has substantially higher strength factors than the materials that are commonly used even for very expensive speakers, such as MDF, HDF or multiplex, while at the same time achieving excellent vibration absorption.
The practical implementation of this concept represents some particularly high requirements such as:
A very special and targeted damping inside of the enclosure eventually guarantees that the standing waves occurring in the interior of the rather big enclosure are suppressed effectively wherever necessary, without increasing the enclosure losses that are nearly undetectable and therefore acoustically hardly relevant anyway. Amongst others this can only be seen from the impedance peaks that are reduced by less than 5% and an impedance increase by 0.1 Ohm at tuning frequency compared to the undamped variety.
For the interior cabling high-quality big-section silver cables from Van-den-Hul are used. The connecting panel is equipped with M8 brass screws.
The first acoustic and metrological test runs justified in an impressive way the high material and manufacturing expenses.
The result is an absolutely realistic and natural reproduction of low frequencies, which are completely free from any kind of enclosure noise.
It particularly stands out that the high acoustic performance is always available to the same extent regardless of the selected volume.
This means pure listening pleasure, in which the technology involved, stays in the background.Practical experiences have repeatedly shown that such a realistic sound reproduction is not achievable with compact constructions. These have to compensate the inevitably missing degree of efficiency in the low-frequency range by means of particularly high diaphragm excursion and very high power demand, which leads to limited dynamics, higher distortion and a shorter lifetime of the drive unit.
Why have ELODIS-SUB subwoofers not include any amplifier or filter circuits
The subwoofers are particularly suitable for use in systems which include a central control unit that controls the entire system and adapts it to the room.
To be able to make full use of the efficiency of the subwoofers, powerful outputs with a high damping factor are highly recommendable.
For this purpose high-quality PA power amplifiers are recommended. These yield a very high sound quality and furthermore offer comprehensive safety switching and protective circuits. Especially circuits to limit the maximum output power or output voltage may prove as useful protective measures to protect the speaker from destruction.
Positioning of the subwoofer:
When choosing the place where the subwoofer is to be positioned, it is important to bear in mind that the site should meet all static requirements with regard to the high weight of the device, and in addition should be as little vibration-prone as possible.
Decoupling the subwoofer from its site by means of vibration absorbers or a vibration-prone site may cause imprecise bass reproduction.
The height-adjustable legs with which the subwoofer is equipped guarantee an accurate connection to a suitable site.
ELODIS-SUB-VB-24 is no longer manufactured as future availability of the used bass drive unit is not guaranteed any longer.
All ELODIS-SUB subwoofers excel through their extremely low distortion and minimum enclosure losses.
ELODIS-SUB-VB21 is available in 2 different tuning varieties:
ELODIS-SUB-VB21L with a very low tuning frequency (-3 dB at 19 Hz and very moderate prefiltering)
ELODIS-SUB-VB21H with a slightly higher tuning frequency (-3 dB at 23 Hz without prefiltering)
ELODIS-SUB-VB21H yields a maximum acoustic pressure that is 3 dB higher than that of ELODIS-SUB-VB21L as it renounces a very low cut-off frequency.
A feature that stands out in both varieties of the ELODIS-SUB-VB21 is the particularly low power requirements that are necessary for reaching the maximum acoustic pressure level (about 500 Watt at X-max). The result is a particularly low dynamic compression, while allowing at the same time to choose from a wide range of amplifiers.
With ELODIS-SUB-SB218 a compact alternative to the big bass reflex models will be available soon. ELODIS-SUB-SB218 is based on a closed enclosure which is equipped with 2 of the best 18-inch bass drive units that are currently available. These work in 2 separate chambers thus enabling stereo operation.
Recommended frequency range:
20 Hz – 120 Hz in home cinema systems (the LFE channel in DD 5.1 systems ranges up to 120 Hz)
ELODIS-SUB-VB-24: 19 Hz
Maximum acoustic pressure in the ideal operational range of the voice coil (< Xmax) in a Quarter-space environment (1 Pi, wall/floor junction placement) and at optimum prefiltering:
ELODIS-SUB-VB-24: ≥ 128 dB/1 m (131 dB/1 m X-damage)
ELODIS-SUB-VB-24: 6 Ohm
ELODIS-SUB-VB-24: AES Standard – 1000 W, Program power – 2000 W
ELODIS-SUB-VB-24: X-max = +/- 12 mm, X-damage = +/- 18 mm
Recommended protective measures for the speaker:
To protect the speakers from mechanical destruction a subsonic filter must be used. The ideal crossover point and filter order may vary individually according to the use and positioning of the subwoofer in the listening room and therefore can only be optimized after delivery and set-up of the subwoofer.
ELODIS-SUB-VB24 and ELODIS-SUB-VB21
Height: 960 mm (37,8 inches) with lowered legs, 990 mm (39 inches) with extended legs
Height: 619 mm (24,4 inches) with lowered legs, 649 mm (25,5 inches) with extended legs