Some time ago I published a backgrounder on 3.5mm headset connectors. It detailed a bit of history of the 1/8″ (3.5mm) mini-plug, from the Sony Walkman of old to present day. That evolution could also be described as from “Tip-Ring-Sleeve” (TRS) to Tip-Ring-Ring-Sleeve” (TRRS.) That post has proven surprisingly popular.
It’s been said that the universe is continually expanding. That includes the universe of mini-plug variants. Today I got my first look at the next step in the evolution of the lowly mini-plug; TRRRS!
Yes, that’s five connections passed over a common 3.5mm connector. A thinking person would ask why this is necessary? It’s motivated by the tight integration of Sony’s mobile devices with their noise cancelling headsets.
It seems that Sony has implemented a noise cancelling scheme in their Xperia Z2 devices. This process actually runs on the handheld, but leverages an extra microphones located in the ear buds. The additional microphone signal must be passed to the phone, separate from the normal microphone and left/right audio signals.
This quite different from the earlier Sony MDR-NC series noise cancelling headphones. For example the original MDR-NC10s that I once used had a lump in the middle of the cord. This lump held the noise cancellation electronics and the AAA battery it required for power. While that allowed them to be used with any music player or smart phone, it also meant that they had their own battery to be replaced.
The MDR-NC31EM, initially released for use with the Experia Z2, have no such line lump, relying instead upon the internal noise cancelling function of the Z2. No line lump to alter the drape of the cord. No battery to be replaced.
Presumably this new configuration of connector doesn’t interfere with normal operation when a 4-pole TRRS headset is used.
Do we care about any of this? Not much. Googling for TRRRS connectors returns zero related results. So for now, this new style of 3.5mm connector is unique to Sony.
Update 10/9/2017: Sam Bordujenko of Polycom AUS/NZ pointed out an other article on this sort of thing, posted just a few days later in Pro Video Coalition.