Stereo Microphone inputs for iPhone, Android and other Smartphones

I'm assembling a camera rig for shooting video using the iPhone (or Android smartphone), and need dual channel (stereo) mic inputs. By default, the audio jack on these phones is 2 channel out, one channel in (TRRS type connector). So it's only possible to have mono input if using the headphone jack. Therefore, the only way to get stereo input is to use the digital input, Lightening or Micro USB connector, on the phones.

I've found several such devices that allow for mixing 2 or more inputs, and sending a stereo output to the smartphone.

Requirements:

• 2 mono inputs

• stereo digital out through Lightening and MicroUSB connector

• Device powered

• Pass through charging of smartphone

• Adjustable levels for each channel

• Ability to power microphones

• Must be small and light

• Must be able to use a right angle Lightening connector at the iPhone jack. This is being used on a DJI Osmo Mobile gimbal, and there's only enough space for a right angle connector.

Would be nice to have:

• XLR inputs

• mini plug inputs (This will keep the device more compact, since I won't need a mini plug to 1/4in adapter.)

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Available Options

Saramonic SmartRig+Di (with Lightning Connector for iOS) - 2-Ch XLR/3.5mm Microphone Audio Mixer (Phantom Power Preamp, Guitar Interface)

Price: $149

Includes:

• 2 mono inputs

• XLR Input

• 1/8 inch jacks

• 1/4 inch jacks (Through XLR plug)

• stereo digital out through Lightening connector

• Adjustable levels for each channel

• Ability to power microphones

Missing:

• Device powered

• Pass through charging of smartphone

Extras Needed to make it work:

• 90 degree lightning connector - The quality of these is questionable.

• Alquar Dual Lightning Splitter Adapter

• 2IN1 Lightning Splitter Adapter for iPhone

Saramonic TRS to Lightning, LC-C35 Locking 3.5mm Male Connector TRS to Apple Certified Lightning

This adapter doesn't do any audio mixing, but it is the digital interface between an analog mixer and the iPhone's lightning connector. With this adapter, you can use just about any analog mixer.

The problem that I still have with this is that I need to be able to use a right angle lightning connector at the phone.

One of the main problems with this is that it doesn't charge the phone. A lightning cable splitter is required, and introducing more 3rd party dongles is a recipe for stuff not working when you need it to.

Price: $59.95

Includes:

• Stereo input

• stereo digital out through Lightening

• Device powered

Missing:

• Pass through charging of smartphone

• XLR Input

• 1/8 inch jacks (Uses 1/4 inch jacks)

• Adjustable levels for each channel

• Ability to power microphones

• Looks very compact

Extras Needed to make it work:

• Audio Mixer

• 90 degree lightning connector - The quality of these is questionable, and not sure if they work for this application because they say no data transfer.

• Alquar Dual Lightning Splitter Adapter

• 2IN1 Lightning Splitter Adapter for iPhone

StudioJack Mini: Portable Multi-Channel Audio Interface for Desktop and Mobile

This seams sort of ideal, but is unfortunately oriented to connecting a guitar in rather than line level inputs. The line in is stereo, but I can't figure out if it splits that stereo if no guitar is connected. Also, it appears that the gain knobs only control the individual inputs. If you did connect 2 mics through the line in, only one gain knob would be used for both mics.

Price: $149

Includes:

• 2 mono inputs

• stereo digital out through Lightening and MicroUSB connector

• Device powered

• Pass through charging of smartphone

• Adjustable levels for each channel

• Looks very compact

Missing:

• Stereo Line in only has 1 gain control

• Guitar line in is not suitable for microphone inputs

• XLR Input

• 1/8 inch jacks (Uses 1/4 inch jacks)

Extras Needed to make it work:

• Micro USB to USB female adapter (This is required so that a right angle lightning connector can be used)

• Mini micro usb to usb female adapter

ROLAND - GO:MIXER Audio Mixer for Smartphones

Price: $99

Includes:

• 5 inputs

• stereo digital out through Lightening and MicroUSB connector

• Device powered

• Adjustable levels for 3 channel

Missing:

• Pass through charging of smartphone

• XLR Input

• 1/8 inch jacks (Uses 1/4 inch jacks)

ZOOM U-242in/4out, Handy Audio Interface

Includes:

• 2 inputs

• XLR inputs

• 1/4in inputs

• USB out

• Device powered (Maybe only through regular USB?)

• Pass through charging of smartphone

• Adjustable levels for each channel

• Ability to power microphones

Missing:

• 1/8 inch jacks (Uses 1/4 inch jacks)

• Large and clunky

Extras Needed to make it work:

• Apple Camera Connection Kit

iRig Pro Duo

Includes:

• 2 inputs

• XLR inputs

• 1/4in inputs

• USB out

• Adjustable levels for each channel

• Ability to power microphones

Missing:

• 1/8 inch jacks (Uses 1/4 inch jacks)

• Large and clunky

• Device powered

• Pass through charging of smartphone

Extras Needed to make it work:

• Have to use the iRig PowerBridge if you want to power the iPhone, but the Powerbridge doesn't provide power to the iRig Pro Duo

http://www.ikmultimedia.com/products/irigproduo/

Others that might work

By using the Apple Camera Connection Kit, there are many other USB devices that could work. Charging the iPhone will still be a problem while using the ACCK.

• ART USB Dual Pre - USB 1.1 Digital Audio Interface with Dual Microphone Preamps