Characteristics and sound properties

The NoBox BB unites a number of preferences in a single concept: it achieves the directness of a full-range loudspeaker, in particular in the voice range, and also manages to produce powerful, stable bass without having to fill the room with hardware.

The B 200 6 Ohm is used in the NoBox BB together with a 38 cm BGS 40 8 Ohm woofer in an open baffle as a dipole. The electric separation between the two drivers is low enough (250 Hz), which enables the full-range speaker to make full use of its capabilities and the BGS 40 8 Ohm is effectively the supporting woofer. The BGS 40 8 Ohm is a musician's driver with high sensitivity and can, as a result, easily be adapted to the B 200 6 Ohm without giving anything away in terms of mean sound pressure.

Despite the baffle being open, which theoretically causes an acoustic short circuit in the bass range, the system produces a dynamic low bass output down to 32 Hz (-10 dB). One reason for this is that the baffle is cut off from the floor and so no acoustic short circuit can take place in this direction. In addition, the side panels of the cabinet, which are mainly for stability, increase the acoustic distance travelled.

Characteristics and sound properties

When the QUADRO was developed, the primary objective was to produce a loudspeaker with a very high sensitivity rating because the trend in recent times has been a retrograde one towards high-end tube amplifiers. However, these are often restricted to very low outputs of only a few watts. There are plenty of loudspeaker constructions which promise extremely high volume levels with only one watt but, on closer examination, are seen to produce that level only at medium and high frequencies. Extending the high sensitivity level to include low frequencies is indeed a challenge. To achieve that aim, it is crucial to include a very large diaphragm area which, in turn, requires a large sized cabinet if one wants decent bass volumes.

The generously sized enclosed QUADRO cabinet provides sufficient space for four of the excellent B 200 6 OHM full-range loudspeakers to ensure that, even at the lower end of the bass frequency range, there is plenty of cone excursion. The drivers are closely bunched one above the other, which provides for an excellent radiation pattern: a broad angle in the horizontal plane and a relatively tightly bundled beam to top and bottom. To prevent the bundling effect becoming too strong in the vertical, all the drivers are powered in parallel in the bass frequencies and, as the frequency increases, the B 200 8 OHM 's are phased out one after another so that, at very high frequencies, only the second driver from the bottom is working. The slightly tilted front baffle means that this full-range loudspeaker is then aimed directly at ear height, assuming one is seated at least 3 metres from the speakers.

Anyone with experience of the sound properties produced by the SOLO or SOLITUDE speakers will have a fairly clear idea of the clarity of sound produced by the QUADRO. These qualities are, however, boosted by the fact that the air in the room is set in motion by a large diaphragm area but that force is hardly aimed at the floor or ceiling at all. A noticeable feature of the QUADRO are its clarity and analytical qualities, while, at the same time, not becoming obtrusive. The QUADRO may not be able to match the extremely deep bass output levels of the SOLITUDE, for example, but that is in fact a positive feature in rooms that are not so large because the reverberating room resonance frequencies are not stimulated at all. However, the physically tangible kick-bass effect, a feature expected from musicians' speakers, can indeed be produced if the amplifier is powerful enough. In addition, the QUADRO shows its strengths in the faithful reproduction of voices and recordings of large orchestras. It is fair to say, then that this is a good, all-round high-end loudspeaker.

Characteristics and sound properties

The SOLITUDE set-up combines the direct, highly precise sound reproduction of the B 200 6 Ohm wide-range speaker with the dynamic bass of two GF 200 2 x 4 Ohm. The B 200 6 Ohm is fitted in a completely enclosed, heavily damped compartment. The two GF 200 2 x 4 Ohm woofers are mounted in a voluminous cabinet with a generously dimensioned bass reflex tube. Owing to the very low-frequency separation, SOLITUDE is, in effect, a wide-range speaker with a subwoofer.

First impressions: fantastic sound! A synthesis of the precision localisation, clarity and analytical precision of the SOLO 100 or SOLO 50 (straight down the axis) and the level accuracy of the CONCORDE MK III. The bass is deep but not heavy, the medium range clearly evident, with no fuzzy fringes. We could not detect a break between the bass and the rest - the sound was more homogeneous and pure than we had ever heard from any other wide-range speakers.

The two sections have to be reverse connected. In so doing, it does not matter whether the bass is connected correctly or not as long as the SOLITUDE is playing on its own. In conjunction with other speakers (e.g. in a multichannel system) the bass must, of course be in sync.

Characteristics and sound properties

The B 200 6 Ohm was fitted in a narrow column speaker with a net volume of around 100 litres. Due to the high Q-factor, one would normally have a relatively strong increase in reverberation response at around 60 Hz in a normal enclosed chamber or bass reflex cabinet. To prevent this, and indeed to take full advantage of the bass reflex principle, we thought up this little arrangement which, to our knowledge, has not been done before.

The chamber is split into two equal parts by a separator. On the rear wall, we built a vertical tunnel as a Helmholtz resonator which was tuned exactly to the frequency of the increase. This tunnel was then loosely filled with a packing of wool. In its undamped state, this resonator absorbs just the amount of the increase and even causes a slight dip in this range. You can vary the amount of packing used to achieve the required frequency response. In this way, we managed to ensure that the bass reflex did not produce overpowering bass despite the bass reflex tuning.

In keeping with the frequency response so typical of wide-range speakers with increasing medium- and top-range frequencies, this speaker, too, has an unacceptably high-pitched sound. So we applied a passive correction circuit (five simple components) to smooth off the frequency response in a very simple but effective manner for a full-range loudspeaker. Depending on the acoustics in the room and personal preference, the 15 ohm series resistance can be changed. Reducing it to 10 ohms will result in an increase in the high-frequency range, while increasing it to 22 ohms will dampen the treble more effectively.

Characteristics and sound properties

The smallest member of the SOLO family with its high-end B 200 6 Ohm full-range loudspeaker has an inside capacity of only 20 l. The lower limiting frequency is at 52 Hz (-10 dB) and 65 Hz (-6 dB).

The correcting circuit for making producing a linear volume increase in the B 200 6 Ohm can be made even more simply in the SOLO 20. All we need is three components. There is also an linearisation of the impedance which means that the SOLO 20 can also be connected up without problems to amplifiers with a low attenuation factor.

The compact design enables these speakers to be placed unobtrusively on a sideboard or in a shelving unit or to be mounted on their own stands. If a powerful subwoofer for the low-range frequencies is integrated, the user has a system which provides enough flexibility to deal with even difficult acoustics in many rooms by careful positioning and adjustment of the output levels.

The SOLO 20 is also highly suited to home theatre applications. The speakers can be used for all the channels and should be supported at the lower end by a subwoofer.

In terms of its sound qualities, the SOLO 20 provides all the positive properties of its larger cousins, the SOLO 50 or SOLO 100, as regards sound source, transparency and analytical clarity. Add to this the increased, robust output stability due to the fact that the B 200 6 Ohm is relieved of the bass frequencies.

Characteristics and sound properties

The SOLO 50 applies the SOLO 100 concept to a more compact cabinet. This makes the units suitable for smaller rooms where the larger version would be too physically overpowering or the bass too powerful.

With a net volume of 50 litres, it is essential to have an internal resonance absorber as with the SOLO 100 owing to the Q-factor of the B 200 6 Ohm. This can also be used to fine-tune the bass reflex. The lower limiting frequency is not as low as with the SOLO 100 but is certainly sufficient for small to medium-sized rooms. The absorber must be carefully damped again.

The correcting circuitry is designed by analogy to the SOLO 100. If you replace the 15 ohm resistance with a 22 ohm, the increase in high-frequency frequency response will be eliminated and the result as measured in the measuring room was a well-balanced spectrum. Listening tests showed, however, that, as a result of the beaming effect of this wide-range speaker, a slight increase is beneficial in most listening environments.

Characteristics and sound properties

It is a physical characteristic of all wide-range high-sensitivity loudspeakers, and that includes the high-end B 200 6 OHM speaker, that they reproduce higher frequencies louder than the lower ones. To compensate for this, we have designed speaker cabinets for the corners of the room. Corners tend to boost the bass but not the higher frequencies. This allows us to use a very simple correcting circuit (consisting of a coil and a resistance) and we still get a very pleasing, natural overall sound.

With relatively little effort, it is possible to produce efficient, high-end speaker cabinets with excellent sound properties which also fit in optically. If you want to, you can even make them blend in completely or almost disappear by wallpapering them the same as the walls or painting them the same. The shape can even be adapted to take full advantage of the height of the room, for example. What matters is that the inside volume is kept the same.

A complete kit for this suggestion is available via www.vc-mailorderservice.de.

Characteristics and sound properties

To be clear from the start: these small sized Stella Light speakers pack a considerable punch. While the outer appearance of the speakers might be described as compact or even sweet, this definitely does not apply to the maximum sound pressure of which they are capable. The combination of universal full-range FRS 8 8 Ohm loudspeaker and W 170 S 8 Ohm woofer stands out because of its unbelievable level accuracy.

The fact that the separating frequency is at a very low 200 Hz benefits the Stella Light's positioning accuracy and generates an image of the stage that easily earns the "live" label. The FRS 8 8 Ohm full-range loudspeaker is remarkably detailed in its output: even the higher frequencies are reproduced accurately and with clear focus. Complemented by the W 170 S 8 Ohm woofer, this combination covers almost the full range of frequencies required.

Whether used as computer speakers to the left and right of the desk or as a stereo set for the sitting room or bedroom, thanks to the excellent value-for-money price, these speakers can be used universally in many different environments without making too large inroads into your wallet. The simple, effective and intriguingly designed series crossover rounds the system off to produce a low-priced, quality building kit.

After all the cables have been positioned in the cabinet, the cable opening in the divider will have to be sealed off with e.g. hot-melt glue.