Accelerating BAYZ Radial Speaker-BRS design using COMSOL Multiphysics

Designing a high-quality, customer-specific loudspeaker with optimal sound performance poses a complex challenge that entails trial-and-error prototyping, meeting specifications, and navigating various physical settings and material parameters.

However, this challenge has been addressed through the implementation of COMSOL Multiphysics, enabling the creation of a virtual prototype for the new 180° tweeter designed by BAYZ Audio.

The results have been remarkable, with a reduction in design process time, the development of a custom user interface, and the achievement of a loudspeaker with a flat frequency response up to 20 kHz, excellent polar response, consistent membrane performance, and unique spider-less construction.

Challenge

A tweeter is the smallest component within a set of speakers. It handles high frequencies and creates crisp sounds to enjoy during music playback. There are three main tweeter types on the market today:

1. Dome
2. Ribbon
3. Planar magnetic tweeter.

Challenges faced in the design process of Zoltan Bay’s 180° tweeter concept were the following:

Quality: Designing a high-quality, long-lasting loudspeaker that produces customer-specific sound performance, in an environment that may be harsh or noisy, is challenging. Engineering experience and extensive knowledge of the complicated physics of sound and acoustics are prerequisites to creating the perfect system for an application.

Testing: Traditional trial-and-error loudspeaker development requires producing many physical prototypes. Furthermore, meeting customer needs and specifications poses significant challenges in traditional development processes. The presence of countless physical settings and material parameters makes it even more difficult to pinpoint optimal development paths.

Modeling multiphysics: Designing a loudspeaker that incorporates shell elements, acoustics, magnetic phenomena, and their strongly coupled forms requires an advanced finite element program. The challenge was to model and simulate these complex physics phenomena accurately and ensure their proper integration within the loudspeaker design.

Development of a new and unique technology: The challenge was to develop a completely new and innovative technology for the 180° tweeter. This technology, different from traditional cone transducers or ribbons, posed challenges in terms of research, development, and understanding of the underlying principles.

Performance optimization: Achieving optimal loudspeaker performance, including frequency response, sensitivity, and power compression.

User interface development and application deployment: Creating a custom user interface and compiling the application for use with various platforms presented challenges. The development process involved designing an intuitive and user-friendly interface that provides easy access to the loudspeaker model and its parameters while ensuring compatibility and functionality across different devices and operating systems.

Solution

There are few better multiphysics phenomena than a loudspeaker. The modeling of all the relevant physical elements, such as shell elements, acoustics, magnetic phenomena, and their strongly coupled forms requires the use of a modern and, at the same time, easy-to-use finite element program.

COMSOL Multiphysics can model and create a virtual prototype of the new 180° tweeter designed by BAYZ Audio.

It is an electro-acoustic transducer unlike any other. It’s not the evolution of a cone transducer, but appears to be simple and similar to a ribbon despite being an entirely different technology. Sound pressure emanates from a black area that’s about 100 millimeters in height.

OEM suppliers have the choice of ribbons, electrostatics, horns, and thousands of domes. So, the question is, why use a BRS?

Three compelling reasons for choosing this cutting-edge technology:

• Performance
• Quality control
• Cost

This coil does not have a voice coil per se like a regular tweeter. Instead, it has a different type of  configuration, which lends itself well to cooling, thus there is no power compression.

Lastly, as far as performance goes, while this is a 100-millimeter BRS with a sensitivity of about 94 dB, you can scale this down to 50 millimeters with about 86 dB, or up geometrically to 115 dB sensitivity.

After having built the loudspeaker model, we can easily and efficiently create a unique custom user interface with the help of the application builder. After testing the application, it can be integrated into any platform.

Results

• Reduced time: The design process was reduced to months rather than years with the help of a simulation app.
• User interface: With the help of the Application Builder, a custom user interface was created and integrated into a standalone application. Additional modules can be easily combined within one COMSOL Multiphysics model, allowing for the extension of the model via optimization calculations.
• Frequency response: The model exhibits a reasonably flat frequency response, with a roll-off at about 4 kHz when simulated without the IEC baffle, exhibiting the same outstanding performance as a 360-degree omni.

  

  Fig 3. Frequency response plot: solid blue line is continuous PSD and green bars for 1/6 octave band

• Length and response: The unit is 100 millimeters long and has a response of about 94 dB, remaining flat out to 20 kHz.
• Polar response: The polar response from 1 kHz to 20 kHz, even at 20 kHz, is only down 5 dB at 75 degrees off-axis, surpassing other dome speakers. The loudspeaker has a very low impedance, and entails moderate magnitude, simplifying crossover design.
• Membrane performance: The loudspeaker contains oscillating membranes, maintaining consistent measurements regardless of the time of manufacture, and being largely impervious to humidity and temperature.
• Construction: The BRS has a unique construction that deviates from the standard design by not including a spider, which is typically present. In traditional loudspeakers, spiders generally have a tolerance range of plus or minus 15% in terms of spring rates. However, in the BRS, a super high-quality spider is used with a narrower tolerance range of plus or minus 10%. The loudspeaker entails gap-free construction, eliminating the need for shims and reducing component attrition concerns.

  

  Fig 4. Snapshot of the application

Summary

Challenge

Designing a high-quality, customer-specific loudspeaker with optimal sound performance is complex and involves trial-and-error prototyping, meeting specifications, and navigating various physical settings and material parameters.

Solution

The use of COMSOL Multiphysics to create a virtual prototype of the new 180° tweeter designed by BAYZ Audio.

Results

Reduction of the design process time, creation of a custom user interface, loudspeaker flat frequency response up to 20 kHz, excellent polar response, consistent membrane performance, and a unique, spider-less construction.

Products Used

• COMSOL Multiphysics

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