Planar Headphones Sound Reality
History of creation
My journey with planar headphones began with the purchase of the TDS-5M way back in 1985. At that time, they were among the best-sounding headphones in the post-Soviet space, and their design was entirely copied from the Yamaha YH-1000. Back then, compared to everything else available, their sound was simply fantastic!
Many years have passed, and planar headphones continue to offer several advantages over dynamic ones. Despite significant advancements in both driver types (dynamic and planar), the audience of connoisseurs who value high resolution in planar headphone sound is constantly growing
Some time ago, driven by client requests, I returned to the topic of planar headphones and, generally, to listening to music through headphones. I had to thoroughly delve into studying the structural features of drivers, enclosure designs, and their compatibility to achieve the desired result. The result I aimed for was the highest possible sound resolution and the most comfortable fit on the head
I didn't need to "reinvent the wheel." It was enough to base my work on the key components that influence a driver's ability to reproduce the most realistic audio picture:
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Diaphragm weight: Previously, diaphragms were made of Kapton; now they are Mylar. Mylar is lighter, thinner, and more elastic, allowing for a greater amplitude of diaphragm displacement
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Diaphragm area: The larger, the better. A larger diaphragm area allows for higher driver sensitivity. Also, with a larger diaphragm area, the frequency range can be significantly expanded in the low-frequency region
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Interaction of magnetic fluxes from "permanent magnets" and the alternating electromagnetic field created by the inductance of traces on the diaphragm's surface. The better the interaction, the higher the driver's efficiency. This is determined solely by the power of the installed magnets and the density of the traces on the diaphragm's surface
The most specific aspect of planar driver production is the manufacturing of diaphragms with conductive traces applied to them. The most effective material for conductive traces is extremely thin aluminum foil. There are a few unique individuals here in Ukraine who have managed to produce quite decent diaphragms with applied traces, even in home settings
However, by studying the topic deeper, I managed to find a manufacturer with good industrial equipment who can produce much more technologically advanced diaphragms with conductors on the surface, according to provided technical specifications
This became the starting point for bringing some of my technical and creative ideas for building planar headphones of my own design to life
Approach to implementation
Drivers
In standard versions of planar-type drivers, engineers typically consider a so-called "pistonic" mode of operation, where the membrane moves simply like a piston, "up and down"
However, I also considered the creation of a sound wave across the entire surface of the membrane, where a wave-like "trembling" of the membrane occurs across its entire plane. This achieves better micro-dynamic processing of the audio signal. This is known as the "wave mode" of driver operation. As a result, the driver operates simultaneously in both modes – "wave" and "pistonic"
To achieve this, I implemented ideas for densely populating the entire surface area of the Mylar membrane with conductors of the smallest possible cross-section. This allows for significantly better processing of micro-dynamic shifts of the membrane in a single plane. And, as a result, we get higher resolution in the reproduced audio picture across the entire frequency range
This approach has fully justified itself – the advantage in resolution of this type of driver truly proved to be substantial
Earcup Acoustic Design
Planar-type drivers are most fully revealed in a so-called "open-back" acoustic design
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The driver enclosures are made from fiberglass laminate, as it offers arguably the best strength-to-weight ratio
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The headband arcs with height and axis adjustment mechanisms are the same type as those used in Denon D-9200 headphones. This headband design proved to be the most comfortable among the many we considered
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The earcups are made from very soft, fine-celled siliconized foam, covered with thin eco-leather. In the higher-end versions of the headphones, the earcups are covered with perforated eco-leather, allowing them to "breathe" better. Such earcups are more expensive to produce, which is why they are used only in the higher-end models
The range
From the very beginning, I planned to create a series of headphones similar in design and driver construction principles, with the lowest possible weight
Understanding that people's financial capabilities vary significantly, I've currently implemented ideas for three models that differ in price and, consequently, in sound
The designs of the headphone enclosures and headbands are absolutely identical. The models differ only at the level of the drivers themselves
Duet
By densely populating the diaphragm surface with conductive traces, this model achieves higher resolution compared to the well-known HiFiman Ananda headphones
Impedance: 100 Ohm
Diaphragm weight: 56 mg
Sensitivity: 100 dB
Weight: 319 g
Price: $420 (including cables for $50)
Trio
The membrane's surface is filled with an even denser array of traces. The cross-section of these traces decreases as their quantity increases. This design more effectively achieves the so-called wave mode operation of the membrane than in the "Duet" model
Impedance: 470 Ohm
Diaphragm weight: 56 mg
Sensitivity: 100 dB
Weight: 319 g
Price: $750 (including cables for $120)
Orchestra
The diaphragm's filled surface area is significantly larger while maintaining the same membrane weight as previous models. Although the trace length has almost doubled, their cross-section has been reduced. The magnetic system is of the maximum possible enhanced type
Impedance: 1000 Ohm
Diaphragm weight: 56 mg
Sensitivity: 103 dB
Weight: 319 g
Price: $1,120 (with cables worth $120)