Nexus 4 and Nexus 5 are arguably the most popular members of the whole Nexus lineup and while both of these handsets are able to handle every app and game that you can throw at them, some users are now reporting issues with the Nexus 4′s and Nexus 5′s headset mics.
Nexus 5/Nexus 4 Mic Voice Input Issues Explained
As it emerges, the microphones that allow callers to be heard are generating extremely low signals, making it difficult or impossible to have a conversation over the phone whilst using a wired headset. Reports say that Nexus 4 and Nexus 5 callers affected by the bug often sound like they’re on the other side of the room, or occasionally the speaker just can’t be made out.
Here are a few videos, which demonstrate the mic issues with the Nexus 5 (a distant background screech can be heard while watching the videos).
Precaution: Turn down the volume a bit, the sound is quite high in this video.
Nexus 5 and 4′s Automatic Gain Control at Fault?
The problem seems to have been narrowed down to the Automatic Gain Control, which is a piece of software which dynamically adjusts the input gain depending on what it thinks the quality of the signal is and the background noise that is present. This means that if a Nexus 4 or Nexus 5 user is speaking very quietly, it’s the AGC’s job to increase the input gain, and conversely to drop it if that user is shouting down the phone (that’d be people on public transport).
To compound the issue, there seem to be inconsistencies with the wiring of many headphone jacks, which can contribute to the problem. You’d think that something as simple as wiring a headphone jack would be standardised, but there’s currently two different ways of wiring the 3.5mm 4 pole plugs. The Open Mobile Terminal Platform standard was introduced years ago with the aim of unifying accessories across all devices and OEMs.
There’s a newer, pervasive wiring standard out there now as well, which is known as CTIA – made by our friends at Apple. As Apple is wont to do, they decided to ignore the OMTP standard and create their own by flipping two poles – the mic and the ground channel. Whilst in the early days many headset manufacturers created two different variants of headset to cover CTIA and OMTP phones, the story is slightly different now.
These days, companies that make headphones generally just use the CTIA standard instead in response to market demands, and so phones which still use OMTP (such as LG) have developed a way to detect what type of headset is being used and switch the pins when necessary.
It’s quite possible that the problems with the Nexus 4 and Nexus 5 stem from the software that governs this pin switch which is either buggy, or perhaps even non-existent. Right now we’re not sure, but it’s possible that this is a contributing factor.
Ways to Circumvent the Voice Input Issue
So what can you do if you’re affected? Firstly you can swap your headset for one that is reportedly working fine with the Nexus 4 and Nexus 5, or switch to a wireless Bluetooth headset instead. Obviously this is the most expensive option.
Some have had luck with OMTP to CTIA adaptors, although results are reportedly mixed. For some users it has completely solved the problem, whilst for others it has achieved nothing. These adaptors cost next to nothing, so it might be worth a shot.
There’s another workaround for those with a physical button on their headsets for ending calls, which is to hold down this button whilst plugging in the headphone jack. This seems to trick the Nexus 4/Nexus 5 into believing there’s no mic on the headset, causing the phone to revert to using its built-in mic instead. This won’t work for all of you, but it’s certainly worth a shot.
Google Responds to Nexus 5 Users; Nexus 4 Users Still Left Hanging
Yesterday, a Google employee took to the Google Product Forums to announce that a fix for the Nexus 5 is inbound with no specific timeframe, but did go on to say there’s no fix for the Nexus 4 at present. I’m sure it won’t be long until Google works out how to resolve the problem on the Nexus 4 as well, so hang in there if you’re experiencing problems.
If you’ve been affected or have found any more workarounds, feel free to chime in with your experiences in the comments below.