re checking for phases issues with LtRt; the only way I know is to monitor through encode/decode… In my experience the worst material is noisy sounds ie sounds with a lot of white noise content. Many years ago I did a project for a museum installation that was a montage of sound & at one point had a baby in the front and ocean waves crashing in surrounds and the position of the baby sounds in LCR got incorrectly steered all over the place….
I think ambiences are the most improtant area to be careful with, although using any binaural material or sounds with weird use of phasing (eg some synth sounds) would warrant testing.

When I put the elements in to the surround setup that as I concieved them, I really did like the bigness and clearness of the pin impact sound. I ended up gating the channels a bit for cleanliness, and when the gate opened in the ambient track as the pins splatted, the effect was awesome.

The setup was not without issues though. First off, the perspective of the ball rolling did not change much, since its travel tended to start and to stay in the center channel. Second, when the ball passed underneath the stereo mic, I got a short but strange right to left effect (i bowl with a hook) momentarily before the impact of the pins.

That said, I’ll probably archive everything both as stereo bounces and as 5.1 interleaved wav files. The 5.1 archiving will be less for actual unaltered use in film, than for a convenient way to store discreet perspectives on the same event, since each mic is essentially hard panned to an individual channel.

On a secondary note, outside of just matrixing the sounds down to LtRt and listening, are there any other precautions to take so that I can check for compatibility there?

Thanks!

So for example if I had 3 stereo recorders available for a vehicle recording I would be much more likely to capture multiple discrete elements with them than to try & capture it as a single perspective 5.1 recording… That way I can edit & construct whatever is needed from the individual elements, no matter how the picture is cut (and recut) later….

Even recording ambiences with two stereo recorders for me usually involves two people trying to find seperate discrete elements, as opposed to a quad version.

But I am generalising, as with everything it depends on context. Many times recording FX I am doing everything possible to minimise the backgrounds (which is why I rcently bought a Sennheiser MKH70) but I can equally think of times when it would be fantastic to be able to discretely capture the environment/acoustics.

For film, compatability with the LtRt is also important (ie matrixed Dolby Surround) and you have to be careful of phase issues, which may not be apparent when mixing in 5.1, but could be an issue when print mastering the LtRt…

Here’s a more technical question:

when setting up a shoot in the field, how important is it to capture (non-ambient) sounds in 5.1?

I personally find that most of my 5.1 sound design tends to evolve from a series or mono sources that are easy to manipulate in space.

That said, I just finished a bowling alley recording session this week, where I brought enough mics to capture every element of the act of rolling a strike: a KSM32 at the lane where the ball makes its impact, a stereo VP-88 aimed directly at the pins from the front, a 57 up close and personal at the pocket, and a stereo ambient pair in the back of the lane for reverb.

Upon bringing the sounds into a session for editing, I realized that I had recorded a pretty workable 5.1 setup – 57 and ksm32 in the center, VP88 left and right, and ambient in the surrounds. I’ll try that setup tomorrow to see how it sounds, but I recognize now that I only got that type of setup (and sound) by a kind of thoroughness accident.

How often do you explicitly set out to capture NON-ambient sounds in a surround format, and what procedures do you use?

thanks!
-Rene