The MDR-W11 is a pair of vintage stereo headphones made by the Sony Corporation of Japan in the early 80s. The “Twin Turbo” provided a much deeper bass, and consequently the sound quality is still one of the best when compared to modern headphones.
The sound resolution is very clear even at a loud volume levels and the bass has a way of kicking in automatically. Sony must have utilised advanced acoustics techniques by shaping the internal plastic case to produce an accentuated dynamic sound.
The drive units are permanent magnet voice coil assembly made to a high specification. The coil impedance is 16 Ω.
The termination is a 3.5 mm stereo jack plug. These headphones sound brilliant when used with modern MP3 players and smart phones.
This is one of the best examples of Twin Turbo. If you are a research student, then this is the design you should focus on.
If anyone has any more information about these headphones, then feel free to drop me an email.