Use an iPhone as your DSLR Microphone

If you’ve shot any video on a DSLR you already know it’s not ideal. The form factor of the camera isn’t made for video and the need to manually focus on a moving subject can be tricky. One of the weakest parts is the camera is its microphone.

A DSLR mic is only good enough to capture quick casual clips and thus not good enough for any serious video production. If you create videos with it, you’ll probably find yourself trashing the audio track in favor of some nice music. But what to do when the audio is as an important as the video (like an interview)? What can you do?

I think most people choose to get an external microphone like the popular Rode VideoMic ($150) which sits on top of your camera and connects directly to the camera’s microphone input. But what if you could just use your existing iPhone (or any other digital recorder)? In fact, you can.

The Dual System

Using a totally separate audio source for videos is actually quite popular. It’s called “dual-system sound”. It lets you concentrate on sound quality while also freeing up your camera. You can even use multiple cameras at the same time with a shared audio track.

The concern I have with a dual-system is that I figured it must require a lot of post processing. I can’t imagine trying to manage and sync dozens of disparate video and audio files. I definitely wouldn’t want to crack open Final Cut or Premiere just to sync sound on every clip I took.

Sure enough, there is a better way and it’s called “Dual Eyes”. It’s a simple pieces of software which has existed for a while but it only just came out for Mac this week (beta version). All this software does is sync separate audio and video files together and it couldn’t be simpler.

I know the iPhone is not ideal for audio quality but it’s a digital recorder I already own. I had to see if it would work.

Before and After Demo Video

My son Keane was enjoying his breakfast this morning when he decided he wanted to re-live halloween one last time before Christmas. He donned is monkey costume while eating cereal so I had to record this funny moment. I asked him to sing me a song for my audio test and he willingly gave me his rendition of Twinkle-Twinkle Little Star.

Before

Here’s the original video with the audio recorded directly from Canon 7D’s internal microphone. A few things to listen for:

• You can hear me focus the lens at the start
• I’m louder than my son given my proximity to the camera
• It’s overall more sensitive to ambient sounds in the room

After

While shooting the video above, I had placed my iPhone in front of him and was recording him. You can see he’s distracted by the phone. I then took that audio and merged it with the 7D video file and got pretty good results for very little effort.

A few things to listen for this time:

• No lens focusing sound
• Much more intimiate sound as my son’s is crisp and clear
• It’s less sensitive to ambient sounds

How I Did It

To pull off this stunt, you’re going to need…

• A digital voice recording device (iPhone works but any will do)
• Dual Eyes by Singular Software (note that Mac version is in beta)
• A Window or Mac Computer

There’s no need for a hollywood-style clapper board or other device that helps the software find a common point in time in the soundtrack. The magic of Dual Eyes is that it’s able to find the commonality between the on-camera audio and the separate audio without your involvement.

Step 1

• Turn on your audio recording device and start recording (e.g. iPhone Voice Memo)
• Position the recorder close to your subject, in or out of frame
• Start shooting video with your DSLR or any other digital video camera
• Feel free to start and stop the video to change angles, no need to stop the audio recording
• Stop recording the video and then stop the audio recording

Step 2

• Email or otherwise download the audio clip to your computer
• Download the camera’s video clip to the same computer

Step 3

• Open Dual Eyes (I tried the new Mac beta version)
• Click “+” and add the audio and video files (multiple video files for one audio recording is OK)
• In the Dual Eyes options menu, select “Replace Audio for MOV and AVI files” to save time
• I also suggest you also select “Level Audio” in the same menu (it didn’t work for me without it)
• Click the big scissor icon to start the sync process

A separate video file will be created with the old audio replaced by your separate audio recording. If you had multiple clips, they will all be synced with the right portion of audio, even if only one big audio file was supplied. It’s quite amazing.

UPDATE: There was a bug with M4A files being recognized as video files but this has been solved in the Mac beta version. Make sure you have build 4301 of the 1.0.0 Mac beta.

Too Good to Be True?

Unfortunately, the bad news is that there’s no free or “lite” version of Dual Eyes. It does work as advertised but it retails for US$149. Luckily, there is a free trial. The Mac beta will last you 45 days which is enough to figure out if you really like it or not.

UPDATE: DualEyes for Mac is now out of beta and offered at a 20% discount ($119) until February 22, 2011.

If you know of a competing software that does something similar, please let me know. I’ll start looking and post what I find here.

UPDATE: Lee Morris from Fstoppers shows effectively the same thing but without any software like DualEyes. He just approximates the sync by doing a clap with this hand. Pretty simple!

Improving Audio Quality

The built-in mic on the iPhone is not a high-grade mic. It’s not even a stereo mic, but neither is the built-in mic on most cameras. Still, getting close to your subject and eliminating camera noise is half the battle.

If you spend the big bucks on Dual Eyes, you’ll inevitably want to get the best audio recordings. If you love the idea of using your iPhone, then search for microphone add-ons which do exist. Alternatively, buy a dedicated audio recording device that’s portable and easy to use. I think I’d do the latter as I’d hate for an incoming email or phone call to ruin my audio track!

Zoom H1

From what I’ve read, the brand Zoom is well respected in the audio recording arena. This past summer they released a $100 entry-level version of their popular “H” series recorders. It’s called the Zoom H1 Ultra-Portable Digital Audio Recorder. See more at B&H.

• Small form factor
• X/Y Stereo Mic
• Records WAV and MP3 up to 24-bit/96kHz
• Records to microSD and SDHC
• 3.5mm I/O
• USB 2.0 Connectivity
• Backlit LCD Display
• Built-In Speaker
• Uses 1 AA Battery
• Threaded Tripod Mount Socket

Zoom H4n

If you have some money to burn, the Zoom H4n Handy Mobile 4-Track Recorder ($300) is even more versatile as it includes XLR inputs for professional mics.

• X/Y Stereo Mics
• Selectable Recording Patterns
• Records WAV and MP3 up to 24-bit/96kHz
• Records to SD and SDHC
• XLR/TRS Combo Inputs
• Built-In Speaker
• USB 2.0 Connectivity
• Backlit LCD Display
• Uses AA Batteries
• Accessories Included

Have you tried to improve the audio on your DSLR videos? Share some tips!