Recording Surround Sound

[Tim Burton]

Hi All,
I'm in the process of making a visual impairment documentary and am trying to recreate human hearing by recording surround sound.

Any Tips?

Tim

[K. Forman]

Planet of the Apes stunk!

Just in case you are THAT Tim Burton... ;)

As far as your surround sound, there have been a few threads that have covered some of what you might want to know. If there is something specific you want to know, ask. The 'shotgun-type' general question might not cover your situation.

But in general, surround is usually mixed in a studio, not recorded live.

[Jesse Bekas]

First off I don't know much about the intricacies of human hearing, but from the shape of my ear, I can only assume that we hear sounds in front of, and to the sides of us better than those that are behind (although not by too much). The following is all conjecture throughb logic so..

If you want to record how people actually hear, live, you will need multiple sources (mics), each recording to an individyual track, to be mixed later, in post. Obvously you'll want the mics placed in a pattern that would resemble a typical 5.1 speaker setup, so that when reviewing the audio, the sounds coming from each speaker, are basically in the same physical space as it was recorded. However close this setup gets you to live sound it will still not be a "real" recreation of it. This has to do with things as scientifc as listening room acoustics, and the differences between the direction of soundwaves during recording and later during projection. To actually recreate what a single person hears, you'd need a bevy of cardiod mics all at 0,0 (on an X,Y graph) pointing outward at 45*, 135*, 225*, and 315* (* = degrees), and then an omnidirectional also at 0,0. (Does this make any sense? I may have just lost myself writing it!)

Realize that final sound quality is dependent on microphone placement, and if placed so that the sounds are more real in space, you may be greatly sacrificing quality. The opposite would also be true (high quality, sacrifices "realism").

For example, nobody hears the way most boom mics do (especially when placed above or below actors), but their sound recording method is fantastic for high quality playback.

[Alex Filacchione]

Maybe this will help...

Here is how they do it for music CDs.

First of all, you need audio software that can Mix in Surround Sound. Magix Samplitude can. Steinberg NuEndo can. Possibly Stenberg Cubase SX can, but I don't really know for sure since I haven't used CubaseSX. No clue on Logic Audio. Logic Audio is Mac only now, btw... I don't know for sure, but I would be really surprised if ProTools could NOT do surround!

So, you mic everyone. For example on drums you might have the following mics in a simple setup:

1 mic on the snare
1 mic on the bass drum
2 overhead mics for cymbals and toms

maybe a room mic. This is average. Some people mic drums with only 1 mic (When the Levee breaks by Led Zep - that famous drum sound was one mic - the huge sound is because of the room that it was recorded in). Some (like I suspect a band like Rush) will mic the snares w/ 2 mics (one on top, one from below), put a mic on every tom, bass drum, 2 overheads, and a room mic, etc.

Guitar. Usually a single mic on the guitar cabinet. Maybe a room mic set out a few feet from the amp.

Bass will usually go direct into the board vi a DI box made for bass. Ditto for Keyboards and singers.

Now, you have all of these tracks. Every individual track is mono, except possibly for the keyboard (yes, there are exceptions in everycase, but lets keep it simple). NONE of these tracks have any sense of space as far as panning left & right. Everything sounds as if it were right in the middle. The same goes for surround.

Now, the surround sound part comes all in the mixing. An engineer can sit there and with the mixing of the software virtually place the tracks in a 3d field. You could for example, mix it to sound like you are on stage, standing in the middle, in which case you have the vocals out front, guitar to one side, bass to another, and the drums are panned center, left & right, but BEHIND you. Not that anyone would necessarily do that, but they could. THis is all done in mixing, and all from those same mono tracks.

I guess what I am saying here is that you do NOT have to set up the mics in a typical 5.1 pattern that reflects how you set up a system at home. In fact, that would be a bad thing to do! You don't necessarily even think about surround until after you have recorded and are in the mixing stage. Now you can think "I want this car sound to come in from the back left, and move to the front right", but you just record it normally. Get the car sound. Then when you mix, you place the signal (via surround panning) to the back left. Then as the sound plays, you pan it to the front right. There is your "motion" through the surround field, but the bare, raw sound before mixing is a mono track with no fades or anything of the sort. In fact if you set up 2 mics to mimic the speaker pattern and record that way, you are going to run into all sortso fo problems. There will be phasing problems, and even if you don't run into any phasing problems, you are going to have areas in between the mics where the sound is weaker than when the sound source is close to the mics. Ideally you want the sound to be at a constant level throughout the pan range. Otherwise it will sound like it is moving away and then back rather than THROUGH the surround field!

A lot of times they do surround with effects. THink of Pink Floyds "The Dogs of War". The beginning has this kind of pulsating keyboard sound. In concert, and probably on a DVD-A disc, that pulsating sound slowly circles *around* you, not just left to right. Cool! They justr record that as a mono sound and in the mixing stage they pan it around the speakers.

So, how you actually record it doesn't matter (well so long as you don't try to mimic the surround speaker pattern as described above). However, if you record only using 2 mics, your surround pans, if you take advantage of the surround capabilities, is just gonna sound odd.

For effective surround mixing, you gotta be able to visualise or hear in your minds ear, where you would like to place the instruments in the virtual sound space, and then mix them out that way.

You can do it effectively w/ 4 sources. IOW, you don't need a seperate track for the center channel. Pan everything to center and you'll hear it there. You don't need to do anything for the bass. The .1 in 5.1 (the bass/subwoofer) is not done in recording or mixing, but in playback. 5.1 stereo amps will have a (usually passive, but maybe active on more expensive systems) crossover that basically takes any frequencies below a certain threshold, and sends them out to the subwoofer speaker out on the amp.

So for video, it is the same process.

Hope this helps a little,

Alex F

[Jesse Bekas]

I don't think Tim is trying to record a conventional 5.1 production (where everything gets mic'ed for quality and mixed later), as much as he's trying to record so that he can recreate normal human hearing through a 5.1 speaker setup. (attention to spacial relationships and directionality more than anything else). Am I right, Tim?

[Alex Filacchione]

Ahh, OK. I see. I would still do it the same way though. That way you have much more control. You can position it in the mix, and just turn the volume slightly down in the rear.

Even though he wants to simulate human hearing in recording, I would STILL record it regularly and then mimic human recording in the mix.

The biggest problem will be attmpting anything below or above you.

Alex F

[Tim Burton]

Hi Guys,
just wanted to say thank you for all your help and support, you've all made me think very carefully about what I'm doing and how I'm going to go about it.

cheers

Tim Burton - the poor student one

[Douglas Spotted Eagle]

Tim,
you'll laugh, but if you're looking to create a surround mic on the cheap, go buy a styrofoam dummy head/wig stand.
using self-stick pads, attach 5 mics to the dummy's head. My experiment used very inexpensive computer mics acquired at a cost of 5.50 each from a local computer's discount bin.
Plug them into a sound card that can accept 5 channels on input. I used the Echo Layla with Sony Vegas.

You'd be SHOCKED at how good this stupid experiment worked. Had I not been experimenting with a band that would have my butt for copyright issue, I'd post the wma file.
At 640kpbs, 96K, this is a screamin' cool sound from a very cheap mic setup.
would I recommend it for everything? Nope. But was it fun and functional? You bet.