IMR's Frequently Asked Questions
Question 1: What is the easiest way to play DTS 5.1 surround sound files encoded by Vortex Surround Encoder Pro?
Answer: You can use iTunes to play 44.1kHz - DTS encoded files - to play 5.1 material.
David Battino of O'Reilly Digital Media explains:
http://blogs.oreilly.com/digitalmedia/2008/08/itunes-surround-sound.html
Thanks to clever data compression, it's possible to pack six channels of audio into a stereo WAV file. Played back normally, this file sounds like static. But play it through a DTS or Dolby Digital decoder into a 5.1 speaker setup, and the static expands back to six-channel surround. (This Swedish radio site has a bunch of free surround WAVs to explore.)
You can even burn the encoded WAV file to an audio CD and play it back in most DVD players. But configuring a computer to play these files is not so obvious. First, you'll need a digital audio output; my Mac has a built-in S/PDIF optical output, so I was set. I just connected that to my decoder/speaker setup with a single optical cable.
The unintuitive part is that changing the volume on the Mac collapses the signal back to static. To hear it as Dolby (and DTS) intended, you need to keep the software volume control at 100%. If you use iTunes to play back the files, you also need to disable all other signal processing: EQ, crossfading, Sound Enhancer, Sound Check, and any level adjustment you've made to the sound file in its Info window.
This Apple technote shows all the settings. It doesn't mention the Windows version of iTunes or using external audio interfaces, but I was able to play DTS and DD WAV files from Windows iTunes via an Apple AirPort Express. Pretty cool — wireless surround music!
For more surround shenanigans, see my article “DIY Surround-Sound DVDs.” It includes links to more free surround WAVs plus inexpensive software you can use to make your own.
Configuring iTunes for playing DTS files:
Question 2: What are the standard multitrack audio input formats for video editors?
Answer: To our knowledge, there is no standard for this. Although, Mode 4 seems to be favored and is sometimes referred to as "canonical surround layout."
Mode 4: L R C Lfe Ls Rs Lt Rt
Final Cut Pro has no support for surround mixing in the application itself, but Soundtrack does and there are ways of moving the audio back and forth between FCP and Soundtrack. In the case of an existing surround mix coming into FCP, we have limited support for monitoring through an audio interface. The layout that we support "natively" and expect to find as tagged in the QT movie is what is described above (minus the stereo mix channels 7 - 8).
Sometimes the "Lt Rt" are encoded as Dolby Logic "matrix" encoded stereo -- a pseudo-surround encoding that can still be played as a normal 2-ch stereo mix.
Note that QuickTime supports about 17-different surround layouts, but also allows you to re-assign an audio device's outputs to your preferred speaker set up.
Question 3: When dropping a multichannel QuickTime or AIFF file onto iMovie, does it mix it down to stereo?
Answer: We found a Windows program that encapsulates an AC-3 file in a WAV, which theoretically should make it importable into iMovie. Straight AC-3s don't seem to work.
Question 4: Can any hand held recorder capture surround sound?
Answer: Yes, and it's priced under $200.00 USD! Get one immediately.
Zoom H2 Handheld Surround Recorder:
http://www.samsontech.com/products/productpage.cfm?prodID=1916
The ZOOM H2 has amazing spatial capture with virtually no phase cancellation for that unmistakable ImmersiveAudio(tm) sensation. The H2 is versatile and records in two differnent stereo modes and an contains a remarkable array of useful on board DSP functions.
The H2 hand held recorder, designed by ZOOM of Japan, is distributed worldwide by Samson Technologies