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Transformers
Colleagues
I have recently fimed a set of nine three-minute movies. These were all shot in a make-shift studio and for a variety of reasons we used fluorescent lighting. We also used consumer cameras which I have to say with huge amounts of light look superb – mainly because everything was shot progressive.
So, and here is the audio part, all worked well except the audio. We used a recording studio mic designed for vocals. A fantastic mic that gave great sound and really transformed the videos. You see all the films were static enough that we could keep the mic out of shot. This was recorded through a good quality mic pre-amp that gave the phantom power and onto a laptop. I had wanted to go out of the mixing desk straight into the audio input of the consumer camcorder. It was only mono. However when we connected the audio sub-system to the camera we just got loads of hum which was made worse because the fluorescent lights are electrically noisy. Back in the old days I would have put a magnetic transformer by the input to the camera but now such things seem to no longer exist. Please tell me then; what do people do now? Any ideas?
Richard Schiller
Working amateur
Panasonic Camcorder 1080p, Nikon SLR with video acquisition 720p, Sony Vegas editing software.
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5 Replies
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Hello Richard and welcome to the Cow Audio Forum.
How about trying a “Way Back Machine”?
But seriously, are you asking what to do with the bad audio you already shot?
There are any number of noise reduction plugins that may help. What system are you editing on.
Question. Did you not hear the noise as you were recording?
Regards,
Ty Ford
Creative Cow Audio Forum Leader
Cow Audio Forum Leader
Want better production audio?: Ty Ford’s Audio Bootcamp Field Guide -
Ty
Thanks for your reply. No; I have great audio from the shoot because I laid down the tracks separately and synced them in the edit. What I was wondering is how one now turns balanced to unblanced nowadays in an electrically noisy environment like that? I still have some transformers around and I can use them if necessary but I need to suggest equipment for the rest of the team to buy and these simple, small, battery and power-supply free devices do not seem to be readily available. So is there a modern method? I would not need to ask if the cameras had balamced inputs but they don’t.
Richard
Richard Schiller
Working amateur
Panasonic Camcorder 1080p, Nikon SLR with video acquisition 720p, Sony Vegas editing software.
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Gotcha.
Well there are the laws of physics and this forum has its share of posts from people who ignored those laws. Sometimes you get lucky, but in your situation, there’s not much range for luck.
Keeping the unbalanced lines short as possible helps. Running from a device via AES, S/PDIF or USB where the audio is already digital helps the the device on the receiving end has one of those inputs.
I’m sure someone has boomed a Zoom H4n, or H1, but I wouldn’t because there’s no way to control the level even if you could wangle a headphone feed.
Regards,
Ty Ford
Cow Audio Forum Leader
Want better production audio?: Ty Ford’s Audio Bootcamp Field Guide -
Afraid the answer isn’t as simple as you would like it to be. There are many variables in play and there are different solutions (and often multiple, equally-viable solutions) depending on the exact situation.
In addition to the “digital solution” as Ty mentioned, use of the old-fashioned “heavy-metal” traditional transformer is quite often a life-saver when dealing with disparate equipment, grounds, levels, RFI, ad nauseum.
There are several products from various vendors like BeachTek and JuicedLink which are made for taking balanced line (mic level or line-level) signals and “munging” them to make them suitable for the 3.5mm stereo mini-phone mic inputs on consumer camcorders (and DSLRs, etc.) Some of these products use traditional “heavy-metal” transformers, and many more modern products use active circuits to achieve the effect of a differential balanced input. Alas many of the active circuit designs are much more susceptible to environmental noise (mains buzz, RFI, etc.)
Some people also keep various ferrite/powered iron torroid cores around to put cables through (sometimes several turns) to minimize the RF before it hits the input. Or those clip-around ferrite “beads”. I would have put a couple of these photos here if I could figure out this bizare web software.
https://195.84.101.101/~goranl/interference/page6.html
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What about the hum eliminator you mention below?
https://www.ebtechaudio.com/hedes.html
I really think the original solution however is the best. Mini-cams can take good visuals with good lighting. Audio is not very good however.
OSX 10.5.8; MacBookPro4,1 Intel Core 2 Duo 2.5 GHz MacPro4,1 2.66GHz 8 core 12gigs of ram. GPU: Nvidia Geoforce GT120 with Vram 512. OS X 10.6.x; Camcorders: Sony Z7U, Canon HV30/40, Sony vx2000/PD170; FCP 6 certified; write professionally for a variety of media; teach video production in L.A.
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