oBravo was established in 2006 around the concept of “Listening to music is enjoying the journey, audio system is merely a tool.”
With patented driver design, oBravo is the only company on the market with Air Motion Transformer / Neodymium Dynamic Drivers hybrid and Planar Magnetic Drivers / Neodymium Dynamic Drivers hybrid IEMs. OBravo first introduced the world’s only PMD/DD hybrid IEM design, ERIB series, in 2015 and officially announced the EAMT series, the only AMT-DD hybrid IEMs in 2016.
This makes oBravo the only company in the world to offer a full line of AMT/DD and PMD/DD hybrid over-ear and in ear headphones.
What is Air Motion Transformer Technology?
Air Motion Transformer
The Air Motion Transformer speaker technology was first designed by German physicist, Dr. Oskar Heil. The design was similar the conventional 7” cone type midrange, however the difference is that the air motion design is an accordion-folded down to a compact 1.5” grouping for point source dispersion.
The low-mass diaphragm is suspended within a dipole magnetic field concentrating an intense field around the diaphragm. When signal current passes through the aluminum strips, the ensuing bellow-like motion of the folded pleats moves air five times faster than with a conventional cone driver to producing unsurpassed sound quality and response.
Why choose AMT and PMD drivers for hybrid designs?
oBravo breaks down current headphone driver technology to determine how to make an advanced headphone design.
Current main headphone drivers:
1. Dynamic Driver:
Good: Very good moving coil piston driver generates wonderful Middle to Low frequencies.
Bad: There is no single moving coil driver that can generate full-range frequencies due to material limitation. This is proven by the loudspeaker market where none of the high-end brands uses just a single driver.
2. Planar Magnetics Driver and the similar structure Electrostatic:
Good: Performs excellent Middle to High frequencies by using very thin and light voice film.
Bad: The structure is a very thin voice film fixed by a frame. Because it is fixed and not able to perform piston motion like the moving coil driver, the PMD always require a larger size to generate enough bass. This causes a negative factor of an increased mass load for high frequencies. That’s the reason why it requires a very expensive amplifier to drive the PMD for a certain frequency response performance. But even then, the PMD still can’t replay a good bass as compared to a Dynamic driver.
3. Balanced Armature Driver (BA Driver):
Good: Size is the only advantage because its original application is in the hearing aid device, which doesn’t require such high precision sound acoustics as hi-fi needs.
Bad: The problem of the BA driver is its voice film is designed to lie down on the metal box. The sound is output from a 90-degree port, which causes a very confusing phase problem that can’t be solved. Imagine if we go to Wilson Audio or MBL or any loudspeaker maker and ask them to design a loudspeaker with every driver in the box lying flat and then to use 90-degree pipes to output the sound out of the box.
4. BA/Dynamic driver hybrid:
Based on the above driver strength and weakness analysis, oBravo decided the AMT/DD and PMD/DD hybrids were the best ways to go for highest fidelity sound. This is precisely what oBravo works and aspires for.
At the same time oBravo found the coaxial structure design was one of the best ways to solve the phase issue of multi-driver products. This is the only structure oBravo uses for all of their headphone and earphone lines.