Research and Development

Acoustic Simulation Technology

In the world of acoustic design, it has become essential to use simulation techniques to predict results before committing to an actual build. In earlier days, designers simply accepted that they had to build something before they could hear how it sounded. Even then they brought considerable skill and experience to the task, pursuing a development cycle that involved the building of numerous prototypes, evaluating what worked and what didn't, and moving sometimes forward and sometimes backward until reaching success. But this approach had significant drawbacks: it was very time consuming, costs were high because many prototypes had to be built, and many of the designs were of no value and had to be discarded.

Acoustic simulation was developed as a way to resolve these difficulties. Simulation makes it possible to identify properties and conditions that will adversely affect acoustics while still working at the design stage, so that these can be eliminated before building a prototype. With the advent of simulation, design quality went up, and the time and costs of product development fell rapidly.

What Can Acoustic Simulation Accomplish?

Simulation technology uses computers to visually and objectively display and analyze the acoustic and other physical phenomena that will occur under given sets of conditions. In particular, the technology can:

•Assess the reality: Analyze what happens under these conditions.
•Analyze the causes: Analyze why these things are happening.
•Predict: Predict what is likely to occur.

It is an easy matter to conduct many simulations under different conditional settings—from ideal conditions to extreme—making it possible to quickly test a wide variety of conditions that could not be tested before. For example, it is now possible to analyze acoustics under conditions that would be difficult to physically measure, and to keep analytic results free of environmental interference. In particular, simulations are extremely effective when designing buildings and large products where specifications cannot easily be changed once construction is completed.

The video below shows how a two-dimensional acoustic waveform simulation was used to observe the acoustics for Yamaha Hall (in the Yamaha Ginza Building). These simulations allowed designers to assess the acoustic characteristics of the hall during the design stage, whereas prior to this technology the designers would have had to wait until the hall was built to understand these details.

Highly Skilled Work

While acoustic simulation makes use of computerized analysis, a high degree of craftsmanship is required to strike the delicate balance necessary to secure valid analytic results. The suitability of the analysis may depend on any single conditional setting, and researchers must employ considerable experience and expertise in identifying which conditions to include and which to avoid when setting up a simulation. At Yamaha, important simulations are carried out by professionals with over 30 years of simulation experience.

Case Examples

Sound from portable keyboard speakers

Portable keyboards represent a true challenge in mechanical design, as developers must work in a limited space and aim for light weight even as they strive to get a good sound. Acoustic simulation technology enabled our designers to identify factors that would interfere with good acoustics, allowing for faster optimization of design parameters and significantly reducing the number of prototypes needed before reaching the final product.

Sound from 3D acoustic speakers

Acoustic simulation is an effective means for predicting precise sound transfer functions that represent how sound emanating from different directions will be heard by the human ear. Such prediction is effective all the way up into the higher frequencies. This approach makes it possible to analyze the acoustic reflections and diffracions displacements of sounds in the vicinity of the head and ears, taking into account the detailed interference patterns that may result from these movements. Our simulations enabled us to develop a 3D audio system that gives the effect of sound moving from the left front toward the right rear.

Creating New Value

Acoustic simulation is effective in a variety of other areas as well, particularly where cost/performance assessments are required. When debating costs, it is all too easy to fall into the argument that “we can save X dollars by cutting out feature Y.” But simulations allow us to look more deeply, and may turn this argument on its head: “If we add feature A, our cost will go up by B but we will also creating extremely high added value.” Because simulation enables us to freely add, remove, and adjust the weightings of the limiting conditions, it allows for far more comprehensive development work.

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