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Old October 17th, 2007, 12:00 AM   #1
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How to record 5.1 atmos on the cheap?

Hi Everyone!

The title pretty much sums it up! How is the best way to go about recording 5.1 atmos on the cheap? I'm currently working on a documentary, with a lot of observational/landscape shots. Sound will play a big part of the film. The plan is to try and do a 5.1 mix capturing the scene more accurately.

The current plan is to put five Rode shotgun mics on a custom stand pointing in different directions (straight ahead, front left, front right, rear left, rear right) and then capture any really low frequency sound with a Shure Beta 52. The mics will be recorded to three Sony V1's - synced via firewire and slate. I originally hoped to record direct to a laptop, but I couldn't find a firewire interface with enough inputs for the money we have!

This method could introduce all kinds of weird phasing issues - which could be interesting! I guess we'll just have to play around until we get the angles right.

I've had a quick look around Google for alternative solutions - but apart from purchasing/hiring a "surround microphone", this seems like the best option.

Looking around DVi, there seems to be quite a few people doing mixes in 5.1. How do you go about capturing your sounds? Do you just capture dialogue and then do everything else in post with the help of SFX libraries?

Any hints, pointers or suggestions would be very much appreciated!

Best Regards, Chris!
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Old October 17th, 2007, 06:20 AM   #2
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Originally Posted by Chris Hocking View Post
Hi Everyone!

The title pretty much sums it up! How is the best way to go about recording 5.1 atmos on the cheap? I'm currently working on a documentary, with a lot of observational/landscape shots. Sound will play a big part of the film. The plan is to try and do a 5.1 mix capturing the scene more accurately.

The current plan is to put five Rode shotgun mics on a custom stand pointing in different directions (straight ahead, front left, front right, rear left, rear right) and then capture any really low frequency sound with a Shure Beta 52. The mics will be recorded to three Sony V1's - synced via firewire and slate. I originally hoped to record direct to a laptop, but I couldn't find a firewire interface with enough inputs for the money we have!

This method could introduce all kinds of weird phasing issues - which could be interesting! I guess we'll just have to play around until we get the angles right.

I've had a quick look around Google for alternative solutions - but apart from purchasing/hiring a "surround microphone", this seems like the best option.

Looking around DVi, there seems to be quite a few people doing mixes in 5.1. How do you go about capturing your sounds? Do you just capture dialogue and then do everything else in post with the help of SFX libraries?

Any hints, pointers or suggestions would be very much appreciated!

Best Regards, Chris!
Most 5.1 is not recorded on set that way but instead is constructed in post from conventional mono and stereo tracks. Dialog is recorded in mono the old-fashioned way. Music is usually recorded in conventional stereo - sometimes 5.1 might be used for, say, concert footahge where you want to pull some hall atmo into the surrounds but unless the POV of the shot is of a musician in the middle of the group during a performance, having music coming from all directions can be quite confusing. The VLF ".1" channel is almost inevitably routed there from SFX tracks laid in during post. SFX is recorded stereo and panned into the surrounds - check out the helicopter sounds in the opening sequences of "Apocalypse Now" - but only rarely is the original recoding done in surround.

IMHO shotguns are the wrong way to go - they're far too narrow in their acceptance angles. Conventional stereo is done using cardioids or omnis (depending on mic technique) most of the time and surround is stereo on steroids. One common mic arrangement that is workable is a stacked double MS array. A figure-8 mic with the long axis of the 8 facing left-to-right and two cardioid mics, one facing forward centre and the other facing backward centre. This gives you left and right mains, left and right surrounds. The front centre and VLFX channels are created in post.
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Old October 17th, 2007, 08:44 AM   #3
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I too would record in stereo (to get the phase information) then overlay a bunch of recordings to get surround. Steve is right on the money.
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Old October 17th, 2007, 09:36 AM   #4
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Ambiance recording

Get 2 good large diaphragm mics and record in XY wide with the capsules almost 180 degree from each other this will give you the widest stereo spread and with both capsuled being as tight together as possible your phasing issues should be absolutely nil. you extract the sub out from this stereo pair. a beta 52 is good for bass instruments because it can handle LOUD volumes, but is terribly inefficient and your levels would be so low that the noise of any preamp trying to give you good volume would be unbearable. or look at a microphone that Crown makes called a SASSP its very interesting, and made for such projects, not to mention it records grand pianos beautifully. and if you can rent Neumann made a human head like design that included two KM series mics inside the ears , recordings from this design were some of the best binaural recordings I have ever heard, you would swear you were at the location if you were wearing good headphones. but back to real life get 2 condenser mics in a wide XY and you won't be disappointed. just be weary of having the capsules as close together as possible. dynamic microphones are pretty much useless for this.
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Old October 18th, 2007, 11:04 AM   #5
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Go to www.holophone.com, order one of their devices, plug it in and away you go. I'm not being completely serious here but it does look like a fascinating gadget.
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Old October 19th, 2007, 01:54 PM   #6
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Chris,

I often capture sound using a method similar to what you have in mind, with a lot of success. I use a multitrack audio recorder, though - I don't know how well you can synchronize your three cameras, and fractions of a video frame may be significant here.

I agree with Steve that shotguns are not the best mics to use here. Take five cardioids and point them the right way, and you are good to go. As far as the LFE channel is concerned, my advise is to just forget about it. Unless your atmos track has volcano eruptions or explosions or stuff like that, you simply shouldn't have to worry about it. When you play your five tracks, a bass management system will take care of all but the most intense low frequency sounds (i.e., it'll take the low frequencies from the main tracks and play them through the subwoofer). You can experiment with summing up the five main channels, applying a low pass filter and routing that to the LFE channel, but for general atmos recording it will rarely make a difference.

Note that all the above is valid in the context of the atmosphere for nature shots or, say, crowds in a busy park or market place. Things get more complicated when recording music, for example. The other posters have made some valid points on how surround mixes are typically done for feature films, where surround sound is engineered more than it is recorded, but for the purposes you described, I think you are on the right track and you'll just have to experiment with a few details to find out what works best.

If you have specific questions about my setup or workflow, let me know - I'd be happy to share my experience if it helps you.

Good luck!

- Martin
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Old October 19th, 2007, 08:28 PM   #7
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Thanks everyone for your replies! It's very much appreciated!

A couple of days ago we did a test with the shotgun setup. We went around and about with a crazy mic stand with shotguns pointing in all directions and captured audio to three V1P's. We haven't captured anything yet, so I don't know what it will sound like once we play it through a surround system. It's going to be very interesting... I'll let you know the verdict (although I'm sure we all already know what it's going to be!). Either way it was a good experiment and lots of fun!

In regards to why I decided to use five Rode shotguns, that's all I could get my hands on at the time. Also, before reading your posts, for some reason, the use of shotguns made sense in my head. I think I thought for some reason the nature of the microphones would mean I would pick up more of the forest sounds. Obviously lack of sleep was getting to me!

Now, as the title suggested in the original post, I need to do this project on the cheap. That rules out A.J's suggestion, and the SASSP. I'm going to have to try and make do with what I can get my hands on. So!

Can this be done with "stage microphones"? I've got access to Beta 58's, Beta 57's, PG81's, Betas 52's, I have one Behringer B-1 lying around and a Rode NT3. Apart from those, all I've got access to are shotguns! Rode's, 416's, 418's, ME66's, etc. But obviously these aren't right for the job!

I'll follow your advice and just create the VFL/LFE channel in post. The reason I originally used the 52 was to capture the low rumble of trucks going past while we were on a bridge. As you only need the "bass" from this channel, I just presumed all the preamp noise would be removed by the low-pass filter. Not sure if it worked out that way!

Next time, I also won't record to the V1P's! That was a bit of a nightmare (really hard to carry around), and we haven't even got to the stage of capturing and trying to sync. Next time I think I'll only use four channels and record straight to a Deva II (I'll create the centre channel in post using Left + Right) or two Fostex's hard drive recorders.

Just out of interest Martin could you please explain your set-up in more detail? What microphones do you use? On what stand? What multi-track recorder? What software do you edit with?

To be honest, I don't like the idea of just recording a stereo atmos track and then building the surround left + right in post. I would much prefer to have AT LEAST four channel recorded "on the day". I think it will sound a lot more natural. I would ideally love to record the centre channel as well, but that'll mean two recorders which makes life just that little bit more hard.

Again, thanks for your advice and suggestions everyone! It's very much appreciated!
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Old October 19th, 2007, 09:59 PM   #8
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ambiance for surround

The PG81s are going to be your best bet if you can get a hold of 2 or 4 (with 4 you can do a double XY setup with all mics at 90 degree). the center channel is for the most part useless, if you combine L+R to get your center channel all you are doing is collapsing the stereo image not to mention losing your depth ... The betas arent going to work because they are dynamic mics, and are not as sensitive to faint ambient sounds, and just will not capture the detail of your surroundings, they are designed to pick up the sound source from inches not feet. one thing you can do is to use the NT3 as a rear mic with the 81's at 110degree separation in an XY setup. the condensers will pick up the low end as good or better than the 52 (I know you see these 52s on kick drums and bass guitar amps) but they are there because they can reproduce low end at loud volumes, they are still a full range microphone just like a 57 or 58, if you can do these I think you can achieve a very realistic 5.1 even though youll really be creating a 3.1 which will sound just as impressive for ambiance the only time 5.1 sound is required is when you have specifics effects you need to provide in the rear left to right panning. considering your lack of access to more purpose specific equipment ,I think this will be your best and simplest way to achieve what youre looking for. dont fall in to the trap of thinking you need the center, leave that for dialog... if you ever hooked up a surround rig and listened to a movie you notice hardly anything comes out of the center except for voices as well as voices hardly come out of the L and R unless the actor is far off screen and then they are brought into the center as their character moves into the field of view (all done in post) the center was originally created for intelligibility of dialog, as well as placement for the BIG screen. so now all you need is 3 channels of audio, 3 mics, and youre good to go. youre not going to be able to better this without going out in the field with an 8 track recorder a mixer, more higher end mics and alot of other hardware. save yourself the head ache and cheat of some one else's test. oh by the way if youre careful to have all the mic capsules as close together, youll get less phase anomalies. The XYs will give you the L,R and front perspective and the NT will give you the rear, this in conjunction with the XY will give the feel of LR out of the rear. Keep in mind the human head has only 2 ears.
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Old October 19th, 2007, 10:50 PM   #9
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Originally Posted by Chris Hocking View Post
Just out of interest Martin could you please explain your set-up in more detail? What microphones do you use? On what stand? What multi-track recorder? What software do you edit with?
I use four mics to capture ambience or audience (L/R/Ls/Rs). I use SM81s for this purpose - not because I did a lot of research and they turned out to be best, but because I already had them and they seem to work fine. They are on regular mic stands.

As Gerry Gallegos suggested in his post, I treat the center speaker differently. I do a lot of stand-up comedy recordings, where the center speaker is assigned to the recording of the stage mic (from the club's sound board). Narration is another good candidate for populating the center channel track.

I record all this on a multitrack recorder, which until recently was a Tascam FW-1082 connected to a laptop, but has been replaced with the Alesis HD24. Not exactly a portable solution, but there are field recorders that can record four channels or more. I edit in Final Cut Studio, i.e. Soundtrack Pro for the audio.

- Martin
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Old October 20th, 2007, 02:00 AM   #10
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sm 81

Marty you are so right as far as the SM 81s, they are the most underrated mics out there, I had the pleasure of owning 4 to 8 each of the finest small diaphragm recording mics (including SM81's)from Neumann's Km84 (older version of 184's) and 184's ,shoeps, earthworks, AKG 451, 460,480 all the way down to shure BG 4.1 (budget version of the 81's) just to mention a few. which seem to be called PG 81 now. these are great mics. they can get the job done very well. one of the cool things about the 81's is that it was the absolutely BEST Barri tone sax mic I ever heard (the low end was unbelievable), and I had a very nice mic locker. (about $150k us ) one of the things I learned in acquiring this mic collection is that what you think will be the best for a certain situation can become a big surprize as to what works the best. I think these new versions of the BG4.1 (now PG81) will be a great asset to the video industry as they are battery powered and great sounding (SM81 lineage), and very affordable. I do really think the industry could be alot more enhanced by the use of wide XY mic'ing techniques in the L+R track supplemented with the Dialog tracks in the center. or slightly panned to either side depending on video content.
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Old October 20th, 2007, 02:11 AM   #11
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Originally Posted by Chris Hocking View Post
...
Next time, I also won't record to the V1P's! That was a bit of a nightmare (really hard to carry around), and we haven't even got to the stage of capturing and trying to sync. Next time I think I'll only use four channels and record straight to a Deva II (I'll create the centre channel in post using Left + Right) or two Fostex's hard drive recorders.

Just out of interest Martin could you please explain your set-up in more detail? What microphones do you use? On what stand? What multi-track recorder? What software do you edit with?

To be honest, I don't like the idea of just recording a stereo atmos track and then building the surround left + right in post. I would much prefer to have AT LEAST four channel recorded "on the day". I think it will sound a lot more natural. I would ideally love to record the centre channel as well, but that'll mean two recorders which makes life just that little bit more hard.

...!
For general backgrounds, yes, recording in surround would work. But for other sounds besides that - say a fighter jet comes in from behind the audience, flashes overheard and bombs a target on the hills in front - that sort of thing is best positioned into the surrounds in post.

There's some interesting discussion of surround sound mic placement in a technical paper on the Schoeps website here http://schoeps.de/PDFs/oct-e.pdf

I've been thinking about you recording to multiple recorders and the phase issues that will introduce and the more I think about it the more I'd discourage it. Accurate phase relationships between the channels is an important part of the decoding process during playback and relatively minor phase shifts can cause all sorts of annoying things to happen. An evening doesn't go by when I'm watching broadcast TV on my home system when there aren't several instances of 'phase flip' where normal stereo front channels suddenly jump into the surrounds when they obviously should not have. Commercials and station promos are the worst offenders where sound that has been perfectly normal stereo during the program suddenly becomes an echo'y diffuse mass of ugly unlocalized sound filling the room when a commercial comes on. So annoying it sends one scrambling for the mute button on the remote.
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Old October 20th, 2007, 06:07 AM   #12
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i would use 4 wireless mic, at maximum distance allowed from the scene with a track frecording for each (+ the stereo from the cam)
then you can choose to remix in post
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Old October 20th, 2007, 11:13 AM   #13
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If you want to continue editing with a format you can record then using Power Book or Mac Book with Digital Performer and MOTU896HD let you record with up to 8 microphones. Then you can use the same project that you recorded to do totally professional surround mixing and sweetenings. Digital Performer let you do all of the sound processing you need like multiband compressor, limiter, parametric eq, reverberation in the surround format of your choice, 4ch, 5.1ch, 7.1ch, 10.2ch and so on (10.2 would be possible if you add another audio interface with more than 10 ch outputs). Might be more than what you are talking about but that will give you the recording rig with total post production environment.

Dolby Japan always recommend Digital Performer to game companies that want to adopt surround editing environment and my company had sold Digital Performer and MOTU audio interface for Sony PCL's surround theater room in Tokyo.
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Old October 25th, 2007, 08:22 PM   #14
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Thanks EVERYONE for your replies! Very much appreciated!

Gerry, I'm probably going to go with your suggestion and record four PG81's to a Deva II. See how that goes...

Some more questions though - someone off topic however!

I've got a Firewire Audio Interface with 8 outputs. That what I've been using to monitor Final Cut Pro/Soundtrack Pro. However! Is there any tricky way to route "DVD Player" to this device? Or do I need something like a "Griffin FireWave 5.1 Surround Sound Processor"? I don't have a normal surround sound setup - I've currently just got five individual speakers, sub and amps connected to the interface. After I bring the project through compressor I now have no way of monitoring it! To be honest, I'm pretty sure you can't do this - but I'm hoping there is some magic program out there that will do it... Any ideas?

Thanks again everyone!

Chris!
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Old October 26th, 2007, 09:23 AM   #15
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Hi Chris,

I have not verified this information - just did a Google check, because I was curious myself. Here is a post I found that may be helpful for you:

http://www.ehmac.ca/anything-mac/178...-surround.html

Quote:
We tried this at work and the Apple DVD PLayer does not support Surround Sound, but the VLC player does, and it does it well. It also gives you lots of control and testing options for the speakers.

We tested with an M-Audio card (Not sure which model) and the Altec Lansing 5100 speakers and Terminator 2 for the movie.
I'd be interested to hear what you find out!

- Martin
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