User Manual

ManualsBrandsADAM Professional Audio ManualsMusical InstrumentsA5 Piano White Studio Monitors (pair) - STUDIO MONITOR

Amplifier Technology and Woofers

Fig. 10: HexaCone woofer

The HexaCone woofer

HexaCone woofers are an integral component in ADAM’s SX-Series

monitors. The core is a honeycomb Nomex structure that makes

them both extremely light and very stiff. The front and back of

the cone have been coated with Kevlar, one of the most advanced

synthetic materials available. Kevlar withstands elongation by a force

factor greater than 1000 times that of steel, enabling the cone to

resist deformation.

No break-up resonances

HexaCone woofers are far more rigid than paper, polypropylene or

aluminum devices of similar dimensions. Due to this rigidity, break

up resonances in the diaphragm cone are prevented. The effective

length and diameter of the voice coils in conjunction with the size

of the magnets and the available cabinet volume are all precisely

aligned for a musically optimal low frequency reproduction.

Authenticity instead of inadequate pressure levels

Another general problem observed frequently in many so-called

reference monitors is a disproportionate low frequency volume.

With massive woofers (and frequently inadequate acoustic pressure

levels!), the average listener is supposed to be impressed. However,

this approach results in an inaccurate representation of the overall

sound quality. ADAM woofers have been designed to reproduce

the given sound material with the highest possible authenticity,

guaranteeing ideal translation to the widest range of systems and

environments.

Switching amps, switching power supplies

In recent years, ampliﬁer technology has experienced its second big

change after transitioning from tubes to transistors some 40 years

ago. Semiconductors can still be found in this new generation of

ampliﬁers, but the signals to be ampliﬁed are treated in a completely

new and different way.

Pulse Width Modulation

PWM (Pulse Width Modulation) – sometimes referred to as Class D

ampliﬁcation in contrast to the normal A or A/B transistor ampliﬁers,

and sometimes called Switching Amp Technology – converts the

incoming signal to a series of rectangular waveforms of equal height.

The width of the rectangles varies in time and the relation of the width

of the rectangles represents the musical signal. This waveform can

be ampliﬁed much more simply, as the transistors are not modulated

anymore. Instead, they are used as switches that only turn the power

supply voltage on and off. In the case of a single sine wave this looks

as shown at the bottom of the page.

It is possible that a very fast mechanical switch could do the job, but

power transistors are a better choice for the task, so PWM ampliﬁers

still work pretty much like conventional Class A/B designs. It is

important to note there are no bits and bytes involved, so ”Digital

Ampliﬁer” is a misleading and inaccurate term.

Advantages

The main advantage of PWM ampliﬁers is their extremely high

efﬁciency (>90%). As a result, the heat to be dissipated is only one

ﬁfth of earlier designs, leading to much lower temperatures within

the amps and making the use of heat sinks obsolete.

This principle has been known for decades, but time was needed to

develop units that perform at the leading edge in sonic reproduction

quality and yet still maintain the high efﬁciency mentioned previously.

The ADAM units presented here use the new technology for both

the amp and the power supply section (i.e. no more transformers)

combined with state of the art input and ﬁlter sections to achieve the

best in multi-channel active studio monitoring.

Fig. 9: Sinus curve with PWM signal