From DSR to DSP

 

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After the advent of the 7 Series speakers with DSR, ESB engineers began to think about the next challenge in sonic accuracy. We determined this step would be to overcome the last obstacles. First, we needed to create a larger soundstage over a wider listening area. Then we needed to get the correct pairing of each speaker to the particular environment it was placed in. Up until now, the problems were unsolved and the solutions were of trial and error by changing the position of the speakers and intervening with corrective, mostly very expensive, measures for the treatment of the environment... measures that often still end with an unsatisfactory result. Obviously, the questions are complex and the intervention must be made in two directions which are: 1) Adapting the speakers to the environment, and, as much as possible; 2) Adapting the environment to the particular characteristics of the speaker.
 
The speaker manufacturer can only act on the first point. So, ESB’s goal was to change the behavior of the speakers, correcting level, phase and delay, in an effort to offset environmental anomalies. The level is similar to what happens in modern headphones with noise cancellation (it produces a sound identical to the one to be deleted, but in opposite phase, with a result of zero noise). This is a phase’s correction of 180 degrees. In a loudspeaker, assigning the level of opposite sign to the excessive frequencies detected in the environment can lead to a linear response curve. Also, adjustments of levels and delays are just as effective at eliminating or correcting unwanted reflections and standing waves of certain frequencies. Yet as we have said, the situation is complex and never 100% solved. To do all that can be done to solve these problems is the responsibility of each speaker company. So, ESB set this as their ambitious goal. However, with all the necessary considerations on the matter, the project was abandoned, because the complexity of analysis and calculations to arrive at correct levels, phase and delay of the speakers, demanded technologies (signal processors) that were not available then except for expensive professional applications, not practical for the consumer market. 

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A few years later, in early 2000, the technology became available with ever more powerful processors that, thanks to equally advanced algorithms and software (and firmware), could solve many acoustic problems... first in professional solutions and eventually in the consumer market. This technology is applied more and more up to the present date (late 2015), and now seems to be the only way to install car speakers quickly with satisfactory results in cramped car cockpits. Satisfactory, but not extraordinary. Unlimited crossover choices (choice of frequency of each single loudspeaker), equalization of frequency response, signal delay and phase control, all combine to provide great sound at one location...but only at one location. There was always a single point of listening, a “sweet spot", in the home environment, at least before the arrival of the 7 Series with its DSR speaker array. In the car environment, with the correct digital processing, the listener had good sound at that single spot, with limited sound system adjustments and without any change to the environment. One could still argue that a sweet spot in the car is not enough, because there are at least four listening points to satisfy. Nevertheless, a good result was reached. So was born DSP (Digital Signal Processing).

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Today, ESB research resumes with the goal of combining DSP with a DSR speaker driver array to create an electro-acoustic system that will achieve concert sound in a vehicle at all four listening positions. Will it be possible? Well, we shall see... Obviously, whatever we succeed in achieving in the car environment will have value other listening environments as well, because we are only acting on the electronics and speakers, and not on the environment where the audio system is placed. We would add that to achieve this result will require electronic and acoustic engineers working together on this one project. As this has not happened often in the world of Hi-Fi, perhaps we could say it's time. We believe the proper marriage of high-end amplifiers, new digital processing technology, and high-end speakers can yield a truly exceptional audio experience.