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Fostex AR-4i Battery Powered Audio Interface for iPhone 4/4S/iPod Touch


Fostex AR-4i Battery Powered Audio Interface for iPhone 4/4S/iPod Touch



Connector:    3.5mm dia stereo mini
Input impedance:    more than 2k ohm
Gain:        -12 / -59.5dB (variable)
Plug-in power:    2.5V (continuous)
Level Meter LED:    4-dot (doubles as system status indicator)


Connector:    3.5mm dia stereo mini
Loaded impedance:    more than 16k ohm
Maximum output:    15mW (32 ohm loaded, THD less than 0.1%)


Frequency Response:    20Hz / 20kHz +-4dB (Mic-Phones / 15mW / 32ohm loaded)
Signal to Noise Ratio:    more than 73dB (Mic-Phones / Input gain maximum)


Physical dimensions:    735 (W) x 106(H) x 50(D)mm  incl. protrusion
            Hand Grip. 235mm dia x 101mm excl. screw
Weight (approx):     200g (main) / 102g (hand grip)
Power:        2 x AAA batteries (alkaline 3V / Nih 2.4V)
External Power:    USB mini B type (5V)
Power Consumption:    0.3W
Accessories:    2 x cardioid plug in mics, Hand grip,
Carrying bag, 2 x AAA batteries (manganese)

Note: AR-4i works with iOS 4.2 or higher

Manufacturer's Description

Fostex AR-4i Audio Microphone Interface for iPhone 4-4s, iPod Touch/ 4G & iPad

The iPhone 4 is fabulous and takes great HD quality video. However if there’s one area that lets it down, it’s the sound. The small internal microphone only records in mono with no control and as for the quality.... Well let’s just say it not exactly high-fidelity. Enter the new Fostex AR-4i. Offering excellent quality stereo audio recording, via Dock connector and in-built AD/DA converter, with LED input level metering, gain control and headphone monitoring, the AR-4i has been designed to  dramatically increase the quality of the sound of the videos you take with your iPhone 4.

Perfect for TV & Radio reporting, live video streaming to the web, video blogs / YouTube uploads plus ideal for family and domestic use.

New - Now Compatible with iPhone 4S

Fostex is pleased to announce that the AR-4i Audio Interface is now compatible with the Apple iPod Touch 4G in addition to the iPhone 4 by way of a dedicated adapter which now comes as standard with every new AR-4i. The adaptor, which is made of precision cut plastic with an elastic pad on the back is designed to securely hold the iPod Touch 4G in the AR-4i.

Designed to enhance the video you capture with your iPhone 4.

The audio quality and versatile operation of the AR-4i make it ideal for both professional applications and domestic / consumer use. For example, in ENG applications where budgets are tight, the AR-4i turns the iPhone 4 into a high quality, hard working audio / video capture device while everyone who shoots video will appreciate the improved sonic quality and audio control the AR-4i brings to the party.

Whether you’re a reporter, stream video to web services such as Twitter, U-Stream etc., use video upload sites such as YouTube and Vimeo, or simply want to dramatically improve the sound of your videos, the Fostex AR-4i is for you.

iPhone App

The dedicated, easy to use iPhone App (available at the App Store) allows for easy control of input level, microphone setting, Equalisation, Filters etc.

The app can be downloaded on the apple Store.

iPhone not included. 


  • Exceptional audio quality - record/playback via Dock connector with built-in AD/DA converter
  • Equipped with 3 x stereo inputs (Line/Mic) for using 2 of the 3 simultaneously for vertical or horizontal use
  • 2 x plug-in powered condenser cardioid type microphones with pop-shields supplied.  Third-party microphones can also be used.
  • 4-dot LED level meter for input monitoring
  • Thumb wheel input gain control
  • Setup App supplied free from App Store for setting Pan (L/C/R), Low Cut Filter, Limiter, etc.
  • Headphone output for recording & playback monitoring
  • Long operation time with 2 x AAA alkaline batteries for 8 to 10 hours
  • Supplied with a sturdy hand grip
  • 2 x threaded tripod mounts on the bottom and side for use with tripod, camera rigs, etc.
  • Cold shoe for use of third-party camera option

The AR-4i works with

  • iPhone 4S - 16GB 32GB 64GB
  • iPhone 4 - 16GB 32GB
  • iPod Touch 4th Generation* - 8GB 16GB 32GB 64GB (*with the supplied adapter)