5.1 Sound

[smarsland]

How would I record 5.1 audio? How much gear do I need? I don't want to go super high-end, but not crappy either.

I've never done it, nor do I know anyone who has.

A friend of mine has a video business and I was considering doing some collaboration with him on some projects.

-s

[Roland]

It depends on what you are trying to record, a live rock concert would requie a very different set-up to a classical string quartet, I certainly would recomend tracking everything seperately and mixing at a later date in a controlled enviroment.

Regards


Roland

[RobAnderson]

Here's a great place to start if you are looking for information:

Hauptmikrofon.de

Among all of the other great stuff on this website, halfway down the page is a paper entitled Multichannel natural music recording based on psychoacoustic principles, Update October 2001

Another good paper is the NARAS guidlines:
Recommendations for Surround Sound Production

Also the "Microphone University" page at DPA has some good stuff on surround sound recording:
DPA Microphones

Also, if you are really hardcore, check out Ambisonics:
Ambisonic.Net - where surround-sound comes to life

The Soundfield mic is used a lot in surround production for video.

[smarsland]

Originally Posted by RobAnderson

Here's a great place to start if you are looking for information:

Hauptmikrofon.de

Among all of the other great stuff on this website, halfway down the page is a paper entitled Multichannel natural music recording based on psychoacoustic principles, Update October 2001

Another good paper is the NARAS guidlines:
Recommendations for Surround Sound Production

Also the "Microphone University" page at DPA has some good stuff on surround sound recording:
DPA Microphones

Also, if you are really hardcore, check out Ambisonics:
Ambisonic.Net - where surround-sound comes to life

The Soundfield mic is used a lot in surround production for video.

Rob.. thank you for all of those.. I will check them all out in detail over the holidays.

From simply an equipment/software standpoint, is there any easy way into this avenue of recording?

[RobAnderson]

At the risk of pointing out the obvious, at minimum you will need 5 microphones of the same make and model (or an ambisonic setup - Soundfield mic or two fig 8's and an omni) and some sort of multi-track recording device - a laptop with a firewire interface is good, but there are a bunch of small four-channel portable recorders (such as the Sound Devices model) which may be easier to use for on-location video work.

The Soundfield mic is nice since it allows you to have a single-point surround setup that will also work in stereo or mono. This is extremely easy and quick to carry and rig when compared to multiple-mic setups. You only need to be able to record four channels, and there is some flexibility in post because you can decode it after-the-fact (think M-S in three dimensions).

On the other hand, some people feel that something is lacking with the ambisonic recordings and prefer to have the ability for spaced mic's. Also, the flexibility of having five mic's to work on other projects may outweigh the simplicity of a single mic for field recording - the Soundfield mic is sort of a one-trick pony.

If you plan on going the 5-mic route and are short on cash, you may want to check out the Oktava MK012's, since these are modular and will allow you to work with combinations of omni's, cards, and hyper-cards without breaking the bank. There are many viable surround techniques and having this flexibility will allow you to tailor your approach to each situation.

[David Rick]

If you look at the article Rob gave the link to, you'll see that an OCT tree doesn't use five identical mics, but rather two hypercardioids and three cardioids. In my experience, the two rear-facing cardioids don't have to be the same as the front center mic. You can even ditch the rear facing mics entirely, if you're getting your room ambience from other mics, or perhaps out of a box.

Michael Williams (he of Stereophonic Zoom fame) has tabulated maybe a couple thousand five-mic arrays that do use identical mics. For minimizing cross-channel crosstalk, I've found that I usually prefer OCT, but I might consider a Williams array if I were actually recording from inside a group and needed 360 degree pickup, which is what he was trying to achieve. Also, the OCT imaging gets a little smooshy right in the center, so if I were doing something were that mattered, I might turn to a Williams configuration as well. Now scrounging up five identical mics can be a challenge. When I first started experimenting with these arrays, I bought five Rode NT-2A multipattern mics. They're not horrible, but they're not Schoeps either. (Now that I actually have Schoeps, I could make someone a deal on the Rode's if anyone is interested.)

One issue with a tree is the amount of visual space it takes up, which can be a particular problem if it is a video shoot. That's where single-point rigs can really help out. The Soundfield is one possibility, but I believe its natural successor for a 3/2 speaker configuration is the Trinnov rig which you can see in my picture. Obviously you need to have friendly banker if you want one equipped with DPA's as you see here.

Surround recording is so much fun that it will be hard to drag yourself back to doing stereo work.

David L. Rick
Seventh String Recording

[RobAnderson]

I forgot to mention this website:


Wendy Carlos Gosurround

I'll have to check out that Trinnov rig - what are the polar patterns and how are they arranged?

[David Rick]

Originally Posted by RobAnderson

I'll have to check out that Trinnov rig - what are the polar patterns and how are they arranged?

The pickup angles and pattern overlaps are optimized for direct mapping to an ITU 3/2 speaker arrangement. I've attached a screen capture of the polar patterns as given in Trinnov's SRP white paper. That white paper and much more are available here: Trinnov SRP.

David L. Rick
Seventh String Recording