There are often heady discussions revolving around the differences between stereo and surround mixing. Almost immediately conversations quickly gravitate to the use of the center channel or the need for subwoofers and use of the LFE channel. And how many of us have read where the perfect place for the surround speakers is? Very rarely, in contrast, does the discussion start with the basic observation of what the speaker(s) must deal with and what it is they do.
Lets start by looking at the numbers. Stereo is two speakers. Surround is five, maybe six, with the 6th attempting to reproduce the most difficult and strenuous portion of the audio bandwidth. But lets not get ahead of ourselves.
Speakers are pretty much nonlinear devices, although the goal is to faithfully reproduce in some linear way and with some semblance of accuracy, the electrical signal presented to it. It is a great challenge.
But to the extent a speaker cannot do what is asked of it, would it not seem difficult to more than double the number of speakers for multichannel and expect something better? Hardly.
This conundrum then extends to the fact that these newly located speakers often wind up in acoustically difficult placements.
At Genelec, our observations are that in the world of multichannel, the speaker itself must be improved in order to make the transition from stereo to multichannel as good as possible. Of course, this is not the only reason to want to build something better.
Since 1978 Genelec has been designing and manufacturing high-performance active monitors for use in broadcast, music, and postproduction environments. In that time period, more than 40 different models have been produced and released as professional products. In many ways Genelec is no stranger to research, development, and ongoing product improvements.
It is always a challenge to improve on good and established products, but we set about it by putting technical performance in all material aspects and excellent functionality and reliability at the top of the list. As Genelec has measured and studied the effects of the operating environments and room acoustics in hundreds of control rooms each year, every generation of monitor is designed to perform even better in typical spaces and to provide real solutions to audio professionals. The 8000 Series MDE two-way active systems represent a step forward where the goal is to faithfully represent the electronic audio signal as an acoustic event. Much of the engineering protocol for this project revolved around the phrase distortion reduction techniques, where the technology for improvements comes not from a single magic bullet, but rather the summation of several technological advancements.
First was the enclosure itself and its parts. In conventional speaker box designs, the front baffle typically has four well-defined edges. For a sound wave, they represent an acoustic discontinuity and form a secondary radiator. The driver itself emits an original sound, but the total radiation to the listener also includes the effects of the other four secondary sources. The strength of this diffraction effect depends on [the reproduced] frequency and directivity of the drivers. The summed frequency response usually has irregularities due to the summing of the acoustic components with different arrival times. When the listener moves off-axis, the summed response changes because the arrival times change.
In 1983, Genelec made its first Directivity Control Waveguide product (1022A) to overcome some of these inherent problems, especially as they relate to frequencies where the ear is most sensitive.
In the 8000 Series we extended our knowledge base of the DCW technology to include more of the cabinet design as a critical element in shaping the overall acoustic attributes.
The outer contour line design is based on mechanical and acoustical attributes. A curved structure is stiffer than a straight-sided one, but also directly addresses the diffraction issue by minimizing its effect due to its rounded edges.
Such a design could not be achieved using typical wood materials. To reduce the outer dimensions of the speaker cabinet and at the same time maximize internal volume for improved LF-efficiency [read Sound Innovations/Pro Sound News, February 2002], we decided on die-cast aluminum manufacturing technology. Aluminum is strong and lightweight and can be designed to yield a mechanically dead structure. Aluminum also serves as an excellent heat sink for the amplifiers, and provides good EMC shielding.
Superior port performance in the 8000 Series was an additional and essential attribute of the design process, as a part of the aim of these new products was to improve the articulation, extension, and SPL at low frequencies. Air speed in a port is directly related to its cross sectional area. Thus, if one wishes to minimize air flow speed, the port will have to be large and, for the same tuning frequency, it must become long. In order to keep the front baffle consistent and smooth, a decision was made to vent the port through the rear baffle. The shape and geometry of the molded tube has been carefully engineered to minimize audible noise, compression, and distortion.
Advances in driver designs and electronic topology also go hand-in-hand with the new appearance. All woofers have been re-designed to improve distortion performance in their entire operating frequency range, as well as improve their capacity at the lowest frequency range.
Since the overall product specifications were meant to improve distortions wherever possible, electronic design was also carefully considered. New electronic crossover filtering techniques are utilized that yield improved transient response and lower noise. In addition, new room response controls have been integrated to improve the speakers response in the listening environment. The 8040A and 8050A have a new desktop [console] mounted response switch that reduces the characteristic bump around 160 Hz when placed on a meter bridge or table surface.
Last, but very important, is the Iso-Pod. This isolation/positioner/decoupler is integrated as part of the product design. It has four shallow feet and is made of special rubber-like material that decouples it from the mounting surface. It is fitted to the enclosure and allows itself to be slid across the bottom of the enclosure, allowing proper aiming of the acoustic axis to the listener.
The new 8000 Series are truly unique products capable of faithful and consistent audio reproduction. All share the same design goals, manufacturing techniques, and low distortion performance criteria. They are all champions in the long established Genelec quest for product performance and improvement as well as overall long-term value.
William Eggleston is the Director of Marketing for the USA based Genelec Inc, and Christophe Anet serves as Customer Support Acoustics Engineer for Genelec Oy. For more information, visit
www.genelecusa.com.
