Technology & Engineering

Dynamic Balance® Design Technology

Our universal theory of high performance audio.

Stu says: building a high performance loudspeaker is a lot like juggling. It involves the balancing of multiple dynamic elements. The act of juggling these elements is, like juggling axes or knives, fraught with danger. One misstep, and the imbalance can result in poor performance, or worse. (Especially if there are knives or axes involved.) Thankfully, we're talking about loudspeakers here. The engineers at Polk decided a long time ago that they were going to dedicate themselves to intensive research in an effort to defeat some of the classic flaws of loudspeaker design.

Picture- laser lab at HopkinsLaser Interferometry Lab at the Johns Hopkins University

We developed a unique, all-inclusive design theory we called Dynamic Balance. Dynamic Balance uses advanced analysis of a design’s entire electroacoustic and mechanical system to help select better materials and more efficient geometry. With deep analysis, we can pinpoint and eradicate elements that reduce performance standards. In other words, we can build more realistic-sounding loudspeakers.

Our engineers began by examining the ubiquitous, performance-robbing resonances that develop on and within loudspeaker materials, such as the modal resonances of speaker cones. Modal resonances are distortions caused by vibrations on speaker cones. Modal resonances are a major cause of frequency response aberrations in loudspeakers. That is, bad sounds.

Saving the World from Bad Audio

The battle against bad sounds began in 1988, when Polk engineers joined engineers at Johns Hopkins University to develop a full field heterodyning laser interferometer system. Basically, a laser-equipped electron microscope, ok? The laser part was able to illuminate the microscoped part in previously impossible ways.

This super-advanced tool allowed Polk researchers, for the first time ever, to see the entire vibrating surface of a speaker cone's material on a molecular level. It revealed the real-time development of never before seen modal resonances on the cone material!

Lots of trial and error led Polk engineers to several materials that worked together to defeat this modal resonance. Combining unique materials in new ways, along with new geometry and state-of-the-art construction techniques, we were able to virtually tune out the destructive modal resonances on speaker cones. We could actually see our innovation work using the laser interferometer system. (You can, too, in our cool animations below!)

The good

You’re looking at a holographic photo of a Polk Dynamic Balance driver in motion. A perfect driver, such as one using our Dynamic Balance design, would look like a cake (flat on top)...like the photo you see above.

The bad

This is an example of what you DONT want. The laser interferometry photo shows this driver is experiencing radial breakup... which results in performance robbing resonance.

...And the ugly

Yes, we believe we're making our point here! This photo depicts concentric breakup, which translates to distorted sound.

Using this Dynamic Balance theory of design, our driver material is specially tuned to produce a flat, uncolored frequency response. Its true transparency reveals a wide dynamic range, with sharp details, and no hint of strain. Polk sound is always clean, clear and effortless. 

Let the Seamless Soundstage Envelop You

Another benefit of this process is that our drivers all have the same sonic signature, for seamless blending between speakers. As your image travels from speaker to speaker in a stereo or multi-channel mix, you will never be jolted by a false note or bad blend. With timbre-matched Dynamic Balance drivers, our sound systems create a more realistic sound stage that envelops you in the action!

The result of Dynamic Balance is a speaker system that is exceedingly smooth and free of resonant aberrations from top to bottom.

This article was last modified on Mar 26, 2013

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