AZ-Two Deluxe

The AZ-Two Deluxe is a floor standing, rear loaded, folded quasi parabolic horn design with a rear facing mouth, and uses two drive units per cabinet. It is very efficient and offers the amplifier an easy ‘load’, making it highly suitable for our range of superior quality, low powered valve amplifiers.

 

As a company, our main aim is to design and manufacture equipment that provides the maximum sonic performance for the price, and to achieve this we use many unconventional solutions. In our quest to deliver an affordable, compact, high sensitivity, wide frequency response loudspeaker to suit ‘real world’ rooms, we re-investigated and re-evaluated the main principles of rear loaded horn cabinet design. This research, coupled with our expertise in driver, cabinet and crossover development, has resulted in a loudspeaker that not only redefines the quality / price relationship, but more importantly offers an emotionally engaging performance that is quite in a class of its own.

 

If you examine the vast majority of conventional loudspeaker designs, you will discover that they have very poor acoustic impedance characteristics, resulting in low efficiency. In contrast, a correctly designed horn loaded system allows the acoustic impedance to be optimised for the driver across several octaves, resulting in higher efficiency and better dynamic power transfer from the amplifier.

 

However, horn designs are not without their challenges, and one of the greatest problems is physical size. For a simple horn the lower cut-off frequency is directly proportional to the effective diameter of the mouth; a cut-off frequency at - 3dB of 50Hz, would require a horn with a mouth area of 3.8 square meters.

 

Clearly unsuitable for most domestic purposes!

 

So, we had to find a method of reducing the size requirement whilst maintaining the low frequency response. By re-configuring the size and shape of the rear horn flare, the (increasingly capacitive) throat impedance is off-set to a point below the cut-off frequency. This, combined with positioning the loudspeaker in close proximity to a corner further reduces the radiation impedance, and effectively increases the bass horn moth area by a factor of around x16 (x8 when placed against a rear wall), which provides a substantial boost at low frequencies.

 

As with all Audio Note (UK) loudspeakers, no corners have been cut in terms of component and driver quality despite the modest price of the AZ-Two Deluxe. Both the bass driver and tweeter are high quality units (the bass unit being the same as that found in the more affordable AN-J and AN-E; the tweeter is the same as is used in our AN-K models), and are combined with a heavy-duty crossover featuring air core inductors, Audio Note (UK) silver plated speaker terminals and Audio Note (UK) AN-D internal wiring.

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Consistent performance is a major issue in loudspeaker design and unfortunately all drive units vary slight from each other, even if they look the same and have the same basic specification.

 

Many loudspeaker manufacturer’s will tell you that they provide “computer matched” crossovers, and whilst this may be true in one sense (each crossover may have been matched to have the exact same capacitance, inductance and resistance) this essentially “passive” method does not adequately take into consideration the mechanical and acoustic variance present in the drive units themselves, where minute differences in acoustic behaviour will result in quite substantial differences in performance and sound.

 

Therefore, to obtain the best possible combination of drivers and crossovers, we have developed a dynamic matching process. This ensures that each loudspeaker in a stereo pair matches a ‘master curve’, and also its partner.

 

Another much overlooked area of acoustics is the material choice for the drivers. It is vitally important that the sound and characteristics of an individual drive unit are complimentary to those of its chosen partner, so that when an instrument is reproduced by both drive units (which is almost always the case), the upper range does not sound detached from the lower range and visa versa. This is an aspect of performance that cannot be measured by even the most sophisticated test equipment; it can ONLY be judged by listening.

 

It has become very fashionable to use all manner of exotic materials (beryllium, diamond, carbon fibre, ceramics etc.) as cone materials in modern drivers, mainly because it gives the impression that the manufacturer in question is making great strides in their research into better sounding speakers.

 

The sad fact is none of these materials work as intended, as they all have their own distinct sonic signature. No instrument manufacturer in their right mind would dream of making a trumpet from carbon fibre or Beryllium for example, or a cello or violin from aluminium or plastic (not if they were serious anyway!), so no matter how the crossover is designed, this sonic signature will be present when the speaker reproduces music. It may be less obvious and audible with some types of music, but ultimately the chosen material will always imprint some of its own signature on whatever sound is reproduced.

 

We at Audio Note are keenly aware of this and have deliberately chosen drive units whose sonic signatures are as closely matched as possible. This has led us to favour good, old fashioned paper for the woofer cone and impregnated silk for the dome tweeter. These materials, when matched correctly, marry the low and high frequencies seamlessly, providing the best level of performance possible in the real world of acoustics.