Thursday, July 15, 2010

In-camera audio solutions for iPhone 4

So you want to make mobile movies or post interviews directly to Youtube?  Good audio is crucial.  Let's say George Lucas is standing next to you, and he's dying to be a part of your blog.  You don't have the time to whip out the Zoom H4N and field mixer, but you do have time for the following:

1) Low End:
• Radio Shack hands-free tie-clip Omni directional lav mic ($26.49)
• Radio Shack 20' monaural earphone extension cord ($7.17)

JB's review: I had to go to two different RS stores, but I made it happen.  The sound quality isn't great, but it's not bad when speaking directly into the mic.  Like DIRECTLY into the mic.  It's an affordable, and low maintenance solution to get better than phone mic audio.  You can carry it in your pocket.

2) Mid-range:
Rode Mic ($149)
• 3.5 mm mic input adapter from

JB's review: Since the mic is mounted on the camera, it only covers about 5 feet.   Getting better, but check out the next section.

3) High end:
• XLR mic like the Rode NTG2, or wireless lav system like Sennheiser EW G3.
• 3 - 15' XLR cable
XLR to 3.5mm mic input from
RD-VXLR 3.5mm mini-jack to 3-pin XLR converter (for wireless lav)
• For some XLR mics, you must add low to high impedance transformer (see update below).

JB's review: This was by far the best option.  You can boom with the XLR mic, or go wireless with the Sennheiser mics.  It's still not a great solution for professional audio, but it will definitely solve your mobile audio needs for interview-type work.  Note: I tested this system with the older Sennheiser G2 system.

UPDATE (8-6-10): I emailed KVConnection regarding XLR mic specs, and this was their response:  "The output impedance should be at least 800 ohms or more for the iPhone to recognize that an external mic is plugged in. The mic should be battery powered if it requires power. We have tested all kinds of XLR mics and all have worked so far including condenser mics with an external phantom power supply connected inline."

To solve this low impedance conflict on the NTG-2 Rode mic, I ordered the Pearstone LMT100 low to high impedance transformer, and connected it to the 3.5mm mic input adapter from  Worked really well.

Special thanks to George Jones for kicking me the ka-nowledge.  From George's awesome research, I'm testing other solutions right now (including the Micport pro and the Shure SM58 mic), and will update when finished.  Also, a big shoutout to Jeff Geerling for blogging excellent audio solutions for the iPhone 4.

Update (9-11-10)
Below is an excellent option given to me by George Jones, who created a custom cable from  Follow the link to get the 15' XLR cable with a headphone jack input for playback and right-angle 3.5mm input (iPhone 4).  With this setup, you DO NOT need the Pearstone LMT 100 transformer for a low ohm mic like the Rode NTG-2.  

I also tested this system with the SHURE SM58 mic, and found the results to be pretty lame compared to the NTG-2.  The NTG-2 mic is def the way to go.

Just remember you're recording MONO sound, and 1280 x 720 30fps video with the iPhone 4 (that's true 30fps, not the 29.97 kind).  The iPhone 4 has a fixed f/2.8 aperture and a relatively large 3.85mm lens.  It has an automatic, variable shutter speed between 1/15 and 1/10000, and an auto ISO of around 80-1000.  The bitrate is about 10 mbps, and the audio is a low mono 66 kbps @ 44.1 kHz.  I haven't had the time to run this through my field mixer or Beachtek DXA-SLR.  Will update this soon.  If you have any other solutions, please let me know.

The OWLE BUBO iPhone camera rig with sun hood (I adapted a 7" Ikan hood) mounted on Redrock Micro DSLR baseplate, with 501 HDV fluid head, carbon fiber rods, plate, and Manfrotto tripod.

The Rocketfish iPhone 4 case available at Best Buy.  This was the best way to mount my iPhone 4 into the Owle Bubo.
Update (8-21-10): They now make this version in black.

• Filmmaker Dan McComb uses his iPhone 4 with his Zoom H4N.  See the set up HERE.


  1. James, thanks for the info here.
    Am thinking of an iPhone 4, have read in various places that the new iPhone's mic-input doesn't play nice with external dynamic mics, is this your experience? Does the mic need to be powered? This wasn't the case for the 3GS I believe.

  2. James,

    The people at KV Connection say that a mic for the iPhone 4 and their KC 3.5mm adapter should have an impedance of >800 ohms. The Rode NTG2 does not meet this spec. It is: Output impedance 250Ω (phantom), 350Ω (battery) as seen at Have you actually tried this mic on the iPhone 4? Please also email me at


  3. How about stereo recording, with Rode NT5 dual mics for solo piano recording + iPhone 4, any ideas