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2019/08/29

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External Microphones for Use with Android Devices

Mic-07 mounted on top of smart phone

Mic-07 mounted on top of smart phone

Postscript (April 2001): I have not seen many external USB microphones for Android devices, but I have just found Am7 from Zoom, which has a Type-C plug.

I want my smart phone to be able to shoot videos of what is going on far away. I don’t think there’s any thing I can do about the image quality, but perhaps there is as to the sound quality.

Cameras on smartphones have come a long way. However, even though the image quality has drastically improved, the sound quality may have lagged behind. Built-in microphones are just not usually designed for capturing sound far away.

Modern smartphones usually come with multiple microphones for such functionality as noise suppression. Some vendors enable sound recording in stereo on some of their models. I was not expecting much, but I was surprised to learn through my own experiments that my Oppo R17 Neo supports audio recording in stereo with its built-in microphones, although you will have to use third-party apps for that.

That’s like an unexpected perk, but I still doubt the microphones are good enough to capture sound from a long distance. So I need an external microphone — that’s a given. With the expected scenario in mind, probably it would be better if the mic was (uni)directional, as opposed to omnidirectional. This would mean I’d want a “shotgun,” not a “lav” ( from “lavaliere” ) (See “Microphones for nature recording I.: types and arrays – Wild Mountain Echoes” ).

“Audio Recording With a Smartphone – Wild Mountain Echoes” lists ways in which an external microphone can be connected to an Android smartphone, namely, through its 3.5mm audio port, its USB port, and via Bluetooth.

Right off the bat, I am excluding the Bluetooth route because I cannot find any Bluetooth stereo microphones. The article above lists two such products but they are ominidirectional, so they do not fit the bill.

Using the 3.5mm audio port is certainly an option, although recent smartphones are ditching those ports in favor of the “all-in-one” Type-C port. My current main handset Oppo R17 Neo still has a 3.5mm audio port and also a micro-USB port. There are multiple types to 3.5mm audio jacks, the most popular of which on smartphones is called TRRS.

By the very way it is designed, you cannot record audio in stereo through the TRRS audio port; such usage is just not factored in. Products recommended in the following lists all use the 3.5mm audio port, so all of them are unable to record sound in stereo. (To make matters more complicated, even though the jacks and the receptacles are exactly the same on the surface, there are incompatible standards for TRRS as to how the four contacts are used, i.e., CTIA and OMTP. See the “PDAs and mobile phones” section in “Phone connector (audio) – Wikipedia,” and “Understanding TRRS and Audio Jacks – Cable Chick Blog.” )

Some that are not specifically designed for use with smartphones, such as those stereo ones made for use with camcorders, require a TRS-to-TRRS adapter (see, for example, “【Open Camera】Androidの動画撮影で外部マイクを使う方法 – ガジェマガ“).

However, there is a type called TRRRS (note the extra “R”; it is not a typo). And some Sony Xperia models are said to have this type for their 3.5mm audio ports. For example, one commentator to that previous article states:

The Xperia Z3 has a (proprietary) 5 pin trrrs socket for headphones and microphones, enabling noise cancelling headphones and stereo mics. I have not found anything on the pinouts of this socket. The geometry is clearly visible here https://www.sonymobile.com/global-en/products/accessories/digital-noise-cancelling-headset-mdr-nc31em/
Without any more detailed specs of the pinout it may be difficult to make another stereo mic work on the Z3

I have a semi-broken Xperia Z3 of a friend that I have been meaning to fix some day, and I should have a stereo microphone somewhere, which I used to use in recording my voice lessons at college in the US. If I just manage to fix the Z3 and find that stereo microphone, then that combination might just do, although I do not know the pin placements are compatible. Z3, considered rather old now, still has a much better camera than my R17 Neo anyway.

Now the connect-via-OTG-USB option is a mixed batch. This is in stark contrast to the offerings for the iPhones with Lightning ports, which include small stereo mics that simply plug into the Lightning ports with no cables involved.

What has been hindering the adoption of external USB microphones with Android phones is that you cannot really rely on their USB Audio class support. You could say this is one big difference from Apple products. That is why such an app as USB Audio Recorder PRO exists, a paid app which comes with its own USB Audio driver. The rub is that its driver is for that app only, so you cannot use it from a video recording app.

How can I know if my device supports USB Audio fully? If you already have an external USB audio device, you could use USB Audio Tester. But if you do not, then you could use USB Audio Tester ROOT, which requires the root privileges. I guess I will have to root my phone so I can use this app.

In this category of products, the following caught my attention.

I referenced this article for the products in this category: “What are the best USB-C microphones for Smartphone filmmaking? – Smartphone Film Pro.”

In the end, I decided on the MIC-07 shotgun microphone.

On a related topic, I bought an omnidirectional condenser microphone, Boya BY-A100. Its direct-plug-in structure did not work with my smartphone in a thick cover.