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LISTENING POST

magine approving the specifications for a sound system, having it installed in your venue, and then pulling it out because it didn't meet your needs or expectations. 

Now imagine doing that ten or more times over the course of several years, installing systems from a number of vendors, each time finding that while the system looked good on paper, it didn't sound good in your facility. 

That really did happen in a very large religious facility. This costly and frustrating experience was caused not by incompetence or carelessness, but by the complex nature of sound and the limitations of the tools that had been previously available to us for understanding and controlling it. There is no reason for it to ever happen again. Every large venue owner and manager needs to know that a revolution has occurred in sound design over the past five years. There are tools available today that are infinitely more successful at predicting the interplay of room acoustics and loudspeakers. 

Today, Bose sound engineers can conduct feasibility studies, offer recommendations, and guarantee results with the same precision as their counterparts for HVAC, structural engineering, or elevators. Clients and architects can hear and judge for themselves whether the recommended solutions meet their objectives, not only prior to installation but step by step through the design process.

That Old Cliche 
For years, sound systems have been designed by manipulating and measuring a small set of what had been thought to be key parameters for sound quality (i.e. sound pressure level, frequency response and STI.) Clients were presented with charts and graphs of numbers showing how the proposed system would perform based on these parameters. 

Once the system was installed, auditory measurements were taken in the room to see how closely they matched the numbers. In theory, if they matched, the sound would be good. In practice, there were often unpleasant surprises. You may have heard the story of the German Bundestag, where careful acoustic planning resulted in such poor speech intelligibility that the brand new facility was unusable. 

Conventional design methods measure only a handful of acoustic factors - when there are probably hundreds that affect the sound we hear. Because of this discrepancy between what we can predict and what we hear, sound design has been the odd man out among the professional engineering services typically engaged for large venue construction projects. 

When you hire an engineering service to make sure your HVAC system will meet certain objectives, surprises aren't part of the bargain. Most reputable firms, moreover, guarantee their work. This level of assurance was not available in the past from sound consultants. Today, you can get guaranteed results, and you should insist on them. You should also insist on having the opportunity to listen to and judge the sound yourself before you approve the construction of the project. 

Take for example the facility that went through years of unsuccessful installations. It's a religious facility that holds more people than most arenas. Here, the challenge of providing high-quality sound is made more difficult by the need to respect the religious, cultural and historical importance of the building and, in particular, to minimise the impact of loudspeakers on the spectacularly beautiful interior architecture. 

In fact, a key reason for the series of failures was that the customer had been willing to entertain proposals only for very small, unobtrusive speakers. While the various small speaker designs were able to meet key specifications on paper, preliminary installation in a portion of the space quickly revealed that they couldn't provide the improvement in sound quality the customer was expecting. 

When Bose took on the project, the patented Modeler software was used to input data from blueprints of the facility and create a computer model of the space and its acoustic characteristics. Unlike the companies that had struggled with the problem before, Bose wasn't limited to working with a small set of known parameters and didn't have to judge results based on charts and graphs alone. By feeding Modeler software data into the Auditioner system, hundreds of factors were rapidly explored, and the results listened to at each stage. The client listened too. 

At critical points in the design process, the Auditioner technology was used to enable members of the religious facility's administration to hear and judge for themselves. In fact, the client was able to evaluate more than ten design alternatives (something that had previously taken years) in just a week. It is important to point out that after years of signing off on one set of specifications after another, only to be disappointed with the results, this time facility administrators will be signing off on the sound itself. 

When the client hears exactly what they want in the Auditioner demonstrator, Bose will guarantee it. This is not simply a guarantee of the sound solution components nor that they will meet certain specifications when installed. Bose guarantees that the sound quality in the facility will be as good or better than the Auditioner demonstrator or a full refund will be given. Bose has offered similar terms on more than 400 projects worldwide, and not a single client has asked for a refund. Bose engineers around the world are using Auditioner systems daily to design Bose sound solutions. 
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Well Informed  
Auditioner technology takes the risk out of selecting sound for your venue. For example, one of the most interesting things about the sound system Bose is designing for the facility mentioned is that the speakers recommended are about ten times larger than those the client would allow when the Auditioner process started. Given the opportunity to hear the impact larger speakers make on sound quality, the client gradually changed the specifications. By listening to the incremental differences between various designs, facility administrators were able to determine exactly how much compromise was necessary between the need to protect the visual impact of the space and the need to deliver sound worthy of it. All this was done conveniently via the computer and playback system. 

In other cases, the trade-off is between sound quality and cost. When Melbourne's Optus Oval was undergoing expansion, managers of the Carlton Football Club were able to hear not only how a proposed system would sound in the expanded stadium but also judge the impact of moving the Oval's scoreboard to a new position and of acoustically treating billboards at the back of the new stand. These Bose recommendations involved additional expense, which the club's management approved only after hearing the difference for themselves in Auditioner Demonstrator. 

 
Simply the Best  
All of the examples described involve an existing facility where the challenge was to improve sound. When Bose engineers are brought in early in the design phase of a new building, however, there are far more opportunities to create truly great sound and find the best possible balance between sound and other design objectives and constraints. 

Recently, Bose used one of their own construction projects, the new 350-seat auditorium at Bose headquarters, as a laboratory to explore just how good sound can get. A Bose Engineering Services team worked hand in hand with the architect and builder throughout design and construction, using Auditioner Demonstrator to listen to the results throughout the process. The goal was to design a facility in which the human voice would sound absolutely natural, without reinforcement, in every seat of the house. 

Bose also wanted to prove that in such a space, a well designed loudspeaker system would sound equally natural. This would not be easy because when a space is acoustically superb, any flaw in the speaker system stands out loud and clear. Bose started by visiting, recording, and benchmarking the best facilities of this type in the world. One of the discoveries was that even these outstanding facilities had a common flaw; there was an audible decline in sound quality as one moved away from the front of the room. Without reinforcement, the sounds from the stage weren't loud enough to compete against ambient noise. 

In all cases, while these auditoriums were designed so that sight lines were excellent even in the back of the house, one had the feeling towards the rear of being in the 'cheap seats' primarily because of having to strain just a bit to hear. Was this fall off in sound clarity and intelligibility inherent (thus impossible to eliminate) or, using Auditioner Demostrator to explore factors that had not been fully explored before, could something better be done? 

Let us first consider the results given by conventional audio design tools, which focus only on a few parameters. These are the factors that can be easily measured both in a model and in a room. On the other hand, there are numerous other factors that sound engineers thought might possibly act as levers for better sound, but how much of an influence and whether or not the result would be worth the effort had been impossible to ascertain. 

To perform a valid experiment, you'd need to find or build two facilities that were exactly alike in all respects, except the factor you were testing. And even if they were built right next door, so that you could perform a direct comparison, you wouldn't be able to hold the memory of the sound in your head long enough to run from one facility to the other. With Auditioner Demonstrator, however, it's not only possible to rapidly explore a virtually limitless number of these potential levers, but to perform direct comparisons by the touch of a button. 

You can hear whether something that should work in theory actually does work in practice and, if so, how much benefit it produces. You can discard those things that don't work and keep working with and optimising those that do. There were some interesting discoveries: 

For example, some materials that are very expensive because of their acoustical properties actually produce only a minor benefit. 

Also, a technique viewed as having unproven benefit by most sound consultants is in fact one of the biggest levers for sound quality. It is one of the simplest things you can do in a space and among the least disruptive to visual aesthetics and other design requirements - the engineering team was very excited about the discovery, but wanted the client and architect to judge for themselves. Dr. Amar Bose, Chairman and CEO of the company, and Tony Pisani of Pisani & Associates  were presented with an Auditioner demonstration. Tony had prepared foamcore models of the auditorium with and without our system recommendations, so they could look and listen at the same time. We started out by having them listen to the best-in-class facilities we had "from a seat" benchmarks in the back rows of each of those rooms. 

Then they listened to the sound from a seat in approximately the same location in the unbuilt Bose auditorium. Both agreed that the sound was significantly better than the benchmarks. Next, they listened to the auditorium with the suggested recommendations. The difference was astounding - a simple modification produced a huge improvement in sound, eliminating any audible fall off from the front of the auditorium to the back. 

 
How does that Chair Sound? 
Auditioner Demonstrator  was also used to make decisions on furnishings such as lighting and seating. The architect had specified a computer-controlled lighting system, but there was concern that the fan cooling the light elements might create too much noise. With Auditioner Demonstrator they could listen to the lighting system in various configurations "from various seats" in the house. This process enabled a decision on exactly how many lights could be used without introducing noise, leading to an optimal decision for both sight and sound in the auditorium. Like concert acousticians, Bose were seeking the 'Holy Grail' of chairs - ones that behave acoustically like people. As little variance as possible is required so that whether a hall is full or nearly empty the sound will be the same. There are chairs that measure the same as a person in terms of sound absorption. This, however, is another example of numbers being unreliable, since the ear will often still perceive a difference. 

Using Auditioner Demonstrator to listen to the impact produced by small changes in chair design, the variance was tightened up and Bose got closer to the ideal of an auditorium that sounds great no matter how many seats are occupied. 

The Toughest Client 
Did Bose meet its goals? Well, their client is certainly satisfied, and he is probably the toughest client a sound engineering team could possible have. Today, Dr. Bose routinely speaks in the auditorium, to up to 350 people, without loudspeaker reinforcement. And speakers who opt for reinforcement still sound natural to everyone in the house. 

But what does Bose Corporation's success in a relatively small auditorium in Framingham, MA mean to large venue owners and managers? It means that great sound in public spaces is far more predictable than almost anybody imagined or hoped. It means that the limitations in sound quality long been perceived as inherent to large venues are probably going to fall in the near future. 

While sound in arenas has improved dramatically over the past decade, tools such as Auditioner Audio Demonstrator, which make it possible to test a virtually unlimited range of theories and hunches, are now accelerating the pace of improvement. 

Bose are taking what was learned in the design of the Bose Auditorium, and what is being learned with Auditioner technology at hundreds of large venues all over the world, and bringing it back to the lab for incorporation into the Modeler software - the tool used to design all Bose sound solutions. 

In 35 locations around the world, Bose now offers a wide range of audio engineering services, from feasibility studies to complete room and sound system design. They can collaborate with your architects to test and recommend acoustical treatments, furnishings and fittings. And, like any other engineering service you engage, will provide you with the detailed information you need to make decisions on your project. For any recommendation, you can listen to the results yourself and judge whether the cost is worth the benefit. If you decide it is, the sound you heard is guaranteed to be the sound you'll get, no surprises, no excuses. The way Bose sees it, great sound is a contract deliverable. 
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