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If you are going to use 1 or more remote mics, I'd caution against setting the mix balance at the time of the recording. I'd suggest recording them to separate tracks and syncing afterwards.
I'm quite interested in soccer sound. I've videoed junior soccer matches for the last 3yrs. (Prior to that, I shots stills of them for 7yrs.) I capture a really nice "thunk" sound with the Rode VideoMic (VM), a short shotgun mono mic, when the ball is kicked.
Look at the timing delays involved. I shoot from the sideline in the middle. In the diagram below, the main cam with VM is at "A", and a Tascam DR-2d stereo audio recorder is at "B".
The Tascam has a DeadKitten muff, (originally used with a Rode Stereo VM), over it. This is on a table-top tripod, placed on the far side, facing back at the Main cam. This mic is usually between the two teams' boxes and often picks up the instructions yelled out by either of the coaches, as well as ball sound near it.
Here's a link to the spreadsheet:
https://dl.dropbox.com/s/o6by9e4bma8c47o/Soccer field timing delays.xlsx
In the example above, only "A" is calculated. I usually have "B" the same distance back from the sideline so, for me, its levels and delays are mirrors of "A". If you were to have "A" a much larger distance away from the sideline than "B" is, you'd need to add in some extra columns to calculate it separately.
The field size here was 105m x 68m, measured off Google Maps from a satellite image.
The labels in the 2nd column indicates the distance. So, for example, "A-1" is the distance between "A" (the main cam) and the near mid-sideline.
Sound drops off at 6.02dB for every doubling of distance:
Sound level distance damping decibel dB damping calculation calculator change distance versus sound level apps reduction drop dissipation SPL sound transmission loss free field loss sound and distance - decrease drop fall sound over distance versus dB sound different distances attenuation microphone calculator distance level drop ratio dampening - sengpielaudio Sengpiel Berlin
My calculator uses different reference points for timing delays and levels:
Delays are referenced against the VM on main cam at "A"Levels are referenced against the level which would have been picked up if the sound was coming from centre of the field.So, if the ref blows his/her whistle from the Centre ("2"), the sound will arrive at "A" & "B" 129ms later, the sound pressure levels (SPL) will be similar and here are considered to be 0dB.
Say, the ref blows the whistle at "1". The sound will arrive at "A" 29ms later, with a relative level of 12.9dB. But for the pickup at "B", the distance ("B-1") will be similar to "A-3", so the delay will be 229ms and the level will be -5dB. The timing delay difference between "A-1" and "A-3" of 200ms, (229ms - 29ms), is a significant delay which causes a very noticeable echo, but the difference in SPL of 17.9dB, ( 12.9dB - (-5dB)), usually masks it.
The "A-1" delay of 29ms in this example means that, for main cam, the sound of an event will always lag the video of it by a least a half a frame. Normally in a video editor the video and audio from a camera are grouped (linked). But it is possible to ungroup them, slide the camera's audio track 29ms to the left (earlier on the timeline) and then regroup them again. This temporal offset provides a little extra latitude in helping the captured sound appear to be in sync with the video.
I usually shoot from the fence near the half-way line. When I've been able to shoot from up back in the stands, I've found the pickup of the crowd was far too loud, even with the extra directivity of a short shotgun mic. I got around this large "A-1" by placing the "B" mics down at the fence near "1" so "B-1" was much closer than "A-1". Even with the lower directivity of the crossed (X-Y) cardioid mics in the Tascam, the result was better than relying on the mic on "A" as the main sound pickup.
The VM is mono and quite directional. Since it's mounted on the main camera, it follows panning. This improves the discrimination-against-noise-background at a distance but, by itself, the mono sound reduces the liveliness of the soundscape. So I add in the broader stereo pickup of the Tascam at "B". As already mentioned, this also enable me to more clearly capture the comments of the coaches, which I believe is useful for the players to re-hear afterwards when reviewing the match. Since this stereo pickup is facing "A", the stereo channels are reversed in the mix to avoid confusion.
The combo of main mono mic following the action with the fixed stereo mic adding some spread and ambience to the soundscape seems to work OK. Normally, though, I use 2 more remote recorders. Both are on the fence approx half-way along the side of the penalty box (i.e. about 8m in from each end-line i.e a bit along the side-line from "5").
One is the mics on a static side-on goal cam, fixed in position, zoom (usually 2x), and focus point. I was using its internal stereo mics with an extra home-made wind-muff:
Stereo pickup is only useful in a goal mic to broaden the area from which I can get the sound of a kick from. So I usually either combine both channels or, if the traffic noise or pickup from a game on an adjoining field is excessive, only use the L-channel if it's on the nearside near the R-end of the field. The side of the field on which the goal cam is situated depends on sun position and crowd position. In this example, the sound from the goalcam would be panned hard R in the mix.
I've just got a 2nd VM so I'll be using it on the goal cam in a low-mount position. I'm hoping that the 2x zoom I normally set this camera to, to frame the penalty box area, will be sufficient to keep the DeadCat windmuff out of the top of the frame:
While I only have one side-on goal cam, I use another sound recorder at the same position at the other end of the field. This is a Zoom H4 with home-made wind-muff. Again, the side of the field and whether or not I use just one of its stereo channels, or combine both, varies. In this example, its output would be panned hard L in the mix.
So with remote vs camera int. mics (or ext. mics on cameras) I think you really need to capture them separately and determine their levels in the mix. I often have to reduce or even temporarily mute the output from one of the extra mics due to unwanted crowd chatter, passing of a large truck or the banging of a sign on the fence in the wind. Often this can be done without being noticeable as the output from the other mics will hide its absence.
Also sometimes I need to temporarily increase/decrease the level in the mix of a mic, say to highlight/conceal a particular comment/abuse from either team's coach or from a player. If the sound sources were mixed down at the time of recording this would reduce the flexibility of this highlighting/concealing.
Unfortunately, if using either int. or ext. mics on the camera, you have to work at developing the self-discipline not to verbally respond. Even sub-audible groans or chuckles are usually picked up well. You can temporarily lower the level of the main mic to conceal this, particularly if you're using multiple extra sound sources. Other issues are the ringing of your mobile phone, or people trying to talk to you during a match or ask you a question. I usually use sign language when this happens, but it's hard not to appear rude.
Dan. |
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2-12-2019 02:16:59
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