MHT 12 - 8 Ohm

The ARIA 2 MHT CENTER is equipped with the popular combination of drivers consisting of the TI 100 - 8 Ohm and the MHT 12 - 8 Ohm. As a result of this choice of drivers and the linear frequency response, it is ideally suited as a complementary centre speaker in conjunction with the VOX 253 MTI or TOPAS, for example, to produce a high-end home theatre system. As already seen in the ARIA 2, the magnetostat is positioned in the middle of the slim-line baffle and is flanked by the two titanium mid-bass units.

In contrast to centre speakers featuring a genuine D'Appolito arrangement, the ARIA 2 MHT CENTER is well suited to horizontal positioning e.g. above or below the television set, because it does not have anything like the same beaming effect. The sophisticated 2.5-band crossover circuitry is responsible for this feature. The crossover separates one of the two mid-bass units at 1800 Hz while the second is not separated until 4500 Hz is reached, to leave the higher frequencies to the magnetostat.
This deliberate individual treatment of the two TI 100 - 8 Ohm prevents noticeable directivity which, in a vertically placed D'Appolito arrangement, would be intentional but in a horizontally placed centre speaker must be avoided at all costs to ensure that all the seating positions in the home theatre are treated to the same volume levels.

The ARIA MHT is a variant of the popular smaller ARIA shelf-top speaker. Instead of being fitted with a fabric dome driver, the ARIA MHT has the excellent MHT 12 - 8 Ohm magnetostat. As a result, the crossover had to be tuned exactly to match the two drivers. Since magnetostats should not be separated at too low a frequency, the transfer frequency was set at 5000 Hz. This results in extremely clear high-frequency output even at high volumes. Getting the crossover to the right level to allow the TI 100 - 8 Ohm to operate up to 5000 Hz took some effort. This high-end mid-bass unit can produce unusually long cone excursion due to its long voice coil, which means it can generate a bass output level that is surprising considering the compact size. Thanks to the extremely rigid titanium diaphragm, the TI 100 - 8 Ohm stands out in the mid-range due to excellent overall presence and vocal clarity. In conjunction with the silky smooth treble range for which magnetostats are famous, this combination is a clear contender for the premium high-end loudspeaker league. Although the ARIA MHT produces powerful bass when used as a shelf speaker, it makes sense to add an active subwoofer if you need to emphasise the lowest frequencies.

TI 100 - 8 Ohm and MHT 12 - 8 Ohm are clearly two of the best drivers VISATON has to offer. The Hobby HiFi editors developed the TOPASmodel on the basis of these drivers by combining them in a delicate-looking, unusual speaker cabinet and demonstrating that they do, indeed, harmonise together beautifully. Compared with the original Hobby HiFi proposal, we have now slightly modified the crossover in order to achieve a warmer-sounding effect which guarantees long-term, relaxed enjoyment. By modifying the inner damping, it has also been possible to simplify the housing and suppress resonance even more effectively.

It is not only the spatial effects and the accuracy of the separation that are impressive, the frequency response is also unusually broad. The upper limiting frequency is at 40 kHz which is well outside the audible range. The lower 35 Hz limit is remarkably low for a 10 cm woofer. This is achieved by fine-tuning the cabinet in the borderline area between vented bass and transmission line. Obviously, the small-diameter TI 100 - 8 Ohmcan only reproduce such deep bass at a limited volume level. The physical limits are dictated by the surface area of the diaphragm and the length of stroke. The TOPAS is, as a result, not intended for reproducing powerful rock music or action-packed movies. But it is surprising how often visitors say to us, after hearing a demonstration of really large, powerful speakers, "That's all very well. But at home I can hardly turn them up to that sort of volume anyway." The TOPAS has been specially designed for people like that. Small and homely but with bass quality that will have your visitors' eyes roaming the room looking for a hidden subwoofer.

The TOPAS will take loads of 40 / 60 watts measured using standard measuring techniques. This does not mean, however, that the amplifier can not have a higher output level than this. It is possible to use an amp with a far higher output than this provided you take it easy with the volume settings and do not turn up the volume to a level that causes distortion in the sound quality. TOPAS speakers should be kept out of the reach of small children and overtly merry partygoers.

Due to the deep starting frequency of the MHT 12 - 8 Ohm it is possible to make use of this magnetostat in the VOX 253. Of course, the crossoverhas to be changed from that used in the original version with its KE 25 SC - 8 Ohm. Fortunately, the AL 130 - 8 Ohm 's only have to be separated slightly higher which means we are still a long way from the baffleresonance levels. Here, too, the transfer frequency is 3000 Hz. As can be seen from the dotted frequency curves for the individual drivers, the AL 130 - 8 Ohm drop off at 2000 Hz and the MHT 12 - 8 Ohm at 4500 Hz and meet again at 3000 Hz and -6 dB. The magnetostat need not by any means produce its full output at 3000 Hz, as some people often believe. This would not make sense in terms of achieving the lowest possible distortion factor.

Since the front panel of the MHT 12 - 8 Ohm is slightly larger, the AL 130 - 8 Ohm 's have to be spaced a little further apart (10 mm).

As regards their sound quality, both versions (original VOX 253 with KE 25 SC - 8 Ohm and VOX 253 MHT) are at the same high level. The version preferred by each particular customer will depend on personal taste, the type of music you listen to and how you listen.

The VOX 253 MTI is the current highlight in the VOX series. The uncompromising approach, involving fitting the TI 100 - 8 Ohm as the low- to mid-range unit and the MHT 12 - 8 Ohm as the tweeter, worked highly successfully in the TOPAS. Following the basic design concept of the VOX series, this system is fitted with two TI 100 - 8 Ohm 's as low- to mid-range units and the TIW 250 XS - 8 Ohm as the woofer.

One particularly convenient innovation is used for the first time in the VOX 253 MTI: it is now possible to tune the bass output level on the crossoverunit. Depending on the acoustic properties of the room and personal preference, the bass output might be too strong, if the speakers are placed close to a wall, for example. The adjustment unit is mounted on the crossover unit directly parallel to the woofer and enables to listener to adjust the output level between 70 Hz and 150 Hz. The lower-frequency bass is not affected. Increasing the resistance affects the bass output: 10 ohms for a minimal reduction in bass and 3.3 ohms for maximum reduction. If the adjuster is left open (i.e. resistance is infinite), bass output reduction is deactivated.