Review: Zoom H2 Handheld Surround Recorder
Pages: 1, 2, 3, 4, 5

The Surround Sound Scoop

Enough with the suspense! What happens if you record to four tracks using the H2's front and rear mics? Is it surround sound?

Well, yes and no. Surround as we have come to know it involves a complicated encoding and decoding process to ensure playback compatibility. Even though many DAWs and plugins support some form of surround mixing, you will still need the proper speaker array and amplifiers, not to mention dedicated authoring software to encode the data and burn DVDs or DTS CDs.

If it sounds expensive and difficult, it can be. But don't despair: you can still cobble together a system that plays back the four tracks. I used a multichannel audio interface, a mixer with both main and auxiliary outputs, and four speakers. Here's how I did it. (O'Reilly Digital Media Editor David Battino discovered an alternative approach that uses less gear, but it requires a Mac and some software spelunking.)

I set up a pair of powered monitors directly behind my usual listening position and connected them to a pair of aux outputs on my mixer. I did my best to calibrate everything so I would hear equal volume from both sets of speakers. Next, I loaded the four tracks into my DAW and set them so one stereo pair ("Front") played back through outs 1 & 2 and the rear pair played through outs 3 & 4 on my MOTU 828 audio interface. By sending the rear tracks to the aux instead of the main outs, I could hear playback in 360°.

Boy howdy, does it sound cool. The first thing I listened to was the thunderstorm recording. In stereo, it sounds like your average sound effects track—not much excitement, not a great sense of place. When I unmuted the rear tracks I found myself reaching for an umbrella! Now I could hear the thunder moving across the sky while the rain drummed on my tin roof.

I have uploaded two short WAV files so you can hear it yourself. Be sure to line up the beginning of the clips in your DAW so they play in sync.

• Thunder, Front Mics (4.2MB WAV)
• Thunder, Rear Mics (4.2MB WAV)

Surround Challenges

Four-track recordings I made in the middle of the blues jam were less convincing, if only because the drums leaked into all four mics and ruined the sense of placement. That's a real problem when the mics are so close together. Recordings where I pointed one pair at the band and used the rear mics for ambience—a standard way to record live bands for surround—fared better, particularly after adjusting the relative front and rear balance.

Incidentally, depending on how you point the H2 relative to your listening position, the left/right balance from the rear mics could be reversed. For instance, in the clip we heard of my band's soundcheck...

• Bagpipe Band (1.5MB MP3)

...the soundstage is correct relative to my position on stage, but is reversed from what the audience would hear; Zoom has posted a firmware update that addresses this issue. Nice!

To check for phase problems between the four microphones, I strummed my ukulele as I walked around the H2 in my studio. Playback on my improvised four-channel system sounded like, well, a ukulele walking around the room. That was a surprise, because I expected the levels to drop dramatically when I got to the sides of the H2 and moved away from the mic's sweet spot:

• Ukulele Stroll, Front Mics (7.5MB WAV)
• Ukulele Stroll, Rear Mics (7.5MB WAV)

I collapsed each of the stereo pairs to mono and listened for audio frequencies dropping out (a clear sign of phase cancellation) as I moved. I then did the same for all four tracks. In no case did I hear any significant problems. Even bouncing the tracks down to a mono track did not hurt them. I don't know how Zoom did it, but they managed to build a recorder that captures 360° of audio without significant phase anomalies. Moreover, they did it for less than the cost of a decent stereo mic!