Technology

You´ll find the most important technology information about the AURUM speakers. If your question isn´t answered here feel free to contact us.

The bandpass principle?
Are computers involved in designing AURUM speakers?
How does the casing influence tone?
How important is magnetic linearity to sound purity?
The AURUM RiCom tweeter
The ALTIMA® diaphragms
How does the pressure-chamber reflex principle work?
What do “soft clipping” and “peak limiter” mean?
What is runtime correction?
What is special about AURUM’s bipolar surround speakers?
The AURUM ribbon tweeter
Tweeters with a refined character: the MONTAN ribbon

The ALTIMA^® diaphragms

The loudspeakers in the AURUM range never fail to impress with their innovative power. ALTIMA® is a perfected composite of the three light metals aluminium, titanium and magnesium, specially developed to achieve optimal vibratory characteristics.

The main reason behind the differences in the way that diverse materials sound lies in the fact that vibrating diaphragms bend uncontrollably and do not then follow the parameters of the voice coil. The extent of these so-called “partial vibrations” largely determines the intrinsic sound produced by a diaphragm. Against this background the loudspeaker manufacturers endeavour to suppress material-induced resonances as effectively as possible, distributing them over various frequencies in order to conceal them to the greatest possible extent.

ALTIMA®, in contrast, opens up completely new possibilities: on the one hand, it enables the forcing out of material resonances from where they are taking place in the speaker and, on the other, it enables the resonances to be gathered and then eliminated via network. This sounds like a simple enough process but it is hardly possible with other materials, so the characteristics that set our cone diaphragms apart from the rest are speed, meticulous precision and the absence of undesired resonances.

The bandpass principle?

With the AURUM 970 and 770 models, we have done everything to ensure that you can enjoy the very best of response in the lower frequencies – though in this case by way of the band pass principle.

Here as well, the diaphragm’s front and rear faces operate in two separate chambers: one in an enclosed environment and the other in a bass-reflex environment. This means that the woofer remains hidden from view since it is located in the middle section of the cabinet. The advantage of this configuration lies in its effect which is similar to that of an integrated subwoofer, and the benefits of a two-way loudspeaker such as homogeneity and directional accuracy are retained in their entirety while the sonority and expressiveness in the low-frequency range correspond to the performance of a three-way system.

How does the pressure-chamber reflex principle work?

Are computers involved in designing AURUM speakers?

What do “soft clipping” and “peak limiter” mean?

To prevent overload or overdrive, limiters are normally used to regulate input. Ordinary limiters work like a stretchy rubber band that is connected to a ball and stops it from hitting a wall and causing impact or damage. However, that sort of rubber band affects all of the ball’s movements, not just the big ones. This type of limiter gives a subwoofer a washed-out or even distorted sound, even when it effectively curbs extreme input.

In direct comparison, this softening of bass tones is completely audible. For this reason, quadral has always opted for a soft clipping circuit, which behaves more like a wall that yields and softens the ball’s impact in order to prevent material damage.

To supplement this is our own proprietarily developed, costly peak limiter, which takes action when the electronics and bass chassis have truly reached their performance limits, but no sooner than customary. Accordingly, the bass tones from an AURUM subwoofer always remain crisp and clean, even though overdrive — accompanied by hard distortions — is perfectly prevented.

How does the casing influence tone?

What is runtime correction?

In almost all central speakers, there is a tweeter between two mid/bass drivers, and they reproduce music correctly only on a precise axis. Anyone sitting to one side of the tweeter axis has to be satisfied with considerable loss of acoustic pressure in the listening area (between 1 kHz and 4 kHz), which affects more than just voice reproduction.

Most manufacturers just shrug off these limitations, while a few retaliate with a fourth chassis, a mid-range tweeter positioned under the tweeter. This just shifts the problem from the horizontal to the vertical plane. It means that the central speaker can no longer be placed on or under the TV monitor, but must be set exactly at ear level, at an angle, in order to get the sound right. A dubious compromise.

The AURUM central speaker takes another route: Runtime or phase correction in the frequency separating filter makes sure that the unavoidable depression in the listening area is much less pronounced than it otherwise might be — and vertically it is barely perceptible at all. That’s why the AURUM central speaker does not need to be aimed toward listeners sitting to the side, nor at the listener’s ear level, in order to sound clear and accurate to everyone.

How important is magnetic linearity to sound purity?

What is special about AURUM’s bipolar surround speakers?

While practically all speakers distribute low tones all around, they tend to bundle the sound with increasing frequency. The relationship between the membrane diameter and the corresponding frequency plays a decisive role in this. But even small spherical membranes bundle higher-frequency sound the way a headlamp does with light. This effect is desirable, has weaker reflections in the listening room and therefore results in greater detail precision and resolution.

But what is a great advantage to the front speaker is not necessarily beneficial to the rear satellites. Above all, when you sit very close to the rear speakers, you perceive the signals of the rear channels as being directly in the speaker cabinets, rather than somewhere behind to the right or left, as it really should be.

That’s why we gave the AURUM 10 an additional tweeter on the rear wall of the casing. It ensures the desirable amount of indirect or diffused sound, even at high frequencies. The low/mid membranes, on the other hand, are small enough barely to bundle within their operating range, and instead also ensure satisfactory indirect sound.

Tweeters bundle sound at high frequencies, which makes for good detail precision. A second tweeter on the rear wall of the cabinet, on the other hand, ensures greater spaciousness and airier acoustic characteristics — a clear plus for surround reproduction.

The AURUM RiCom tweeter

Our RiCom tweeter has had much acclaim in a diversity of tests conducted by some of the most prestigious publications. It has an ultralight, flat, ring-shaped flexural-resonator diaphragm which, in contrast to reciprocating resonators (as, for example with conventional dome units), has to shift far less air mass in order to generate sound.

The impressive clarity and high degree of transparency are audible strengths of this concept, and the RiCom is very similar to the ribbon tweeter in this respect. However, the fact is that the RiCom also has advantages over the ribbon as well; for example in the upper mid range – where the ribbon has to give up – where the RiCom tweeter plays its trump cards.

This is made possible by a fastresponse diaphragm made from fine, supple silk fabric. Its design principle gives the RiCom an exceptionally fast speed of response that reinforces the impression of
musical lightness and effortlessness. A conventional diaphragm would be unable to provide a comparable degree of direct and spirited liveliness. In addition, the RiCom principle also creates a
larger area of dispersion, so its aural advantages can be experienced almost independently of
the listening position.

The AURUM ribbon tweeter

The ribbon tweeter newly developed by AURUM operates according to the magnetostatic principle. Its wafer-thin, ultra-light diaphragm works in close conjunction with four neodymium magnets, the magnetic strength of which is so great that you simply could not separate them with your bare hands if they were to come together.

This diaphragm’s surface area is almost four times larger than that of its tried-and-tested predecessor, with the result that the new AURUM ribbon tweeter can be used a whole octave lower (as from 2 kHz) and generate an extra 10 dB of pressure – thus enabling its use at double its predecessor’s volume.

Tweeters with a refined character: the MONTAN ribbon

Like the AURUM TITAN and VULKAN, the AURUM MONTAN VII has a newly developed, albeit smaller ribbon tweeter, whose nearly weightless film membrane swings between two super-strong bar magnets.

Thus the new MONTAN renders all high overtones with a joy for detail, a lively flourish and maximum accuracy. And a grid-like acoustic distributor in front of the membrane helps this tweeter achieve the unusually wide angle of dispersion familiar from spherical membranes, but not from ribbons. Advantage: The joy of finely chiselled overtones can be experienced even by listeners sitting away from the main axis.

Moreover, we have succeeded in configuring an unusually large usable operating range for the ribbons (3 kHz to 65 kHz), while maintaining unadulterated purity up to party volume.