Some things get painfully obvious when you watch internet videos, like how
most attempts at serious productions tend to still get an overall amateuristic
feel to them. And what is it about consumer equipment that makes them seem
bad?
First of all, it should be noted that I'm not talking about content (or
rather, lack there of in most cases), but rather production value of a video.
Small consumer cameras have several faults to them, and some are easier to
correct than others. The main issues being: sensor size (and quality), audio
and the fact that consumer camcorders tend to be way too light for hand held
operation, leading to shaky-cam.
Sensor size and quality isn't an issue that's very easily corrected, as it
involves extra optics and equipment that tend to be rather expensive and quite
bulky. Shaky-cam can be eliminated by either using a tripod, or, if you have
to go "hand held", a floating camera stabilization system, such as a
steadicam. Again, this is very
expensive. The cheapest way to improve the overall perceived quality of the
production is audio.
First, let's get one thing straight: Don't be afraid of redubing audio, it's
done professionally all the time. Most big movie productions film most things
in MOS anyway.
You should too! But, when you do record sync, get a good mic.
A decent shotgun mic can run somewhere between $100-$300, and they'll improve
the quality of your production considerably. But here's where consumer grade
cameras run into problems; A real mic is connected through an XLR cable, and
most of the time also requires phantom powering. Your consumer camcorder on
the other hand, will provide you with a 3.5mm (stereo) mini jack for the mic
input, if you get any at all. (and this obviously doesn't give you any phantom
powering).
The most common thing for people to do in this case, is to invest in an
"XLR-adaptor box", sometimes called a "beach box", no doubt due to one of the
bigger and more know manufactures
Beachtek. But, again, these are quite
expensive. Running from anywhere between $300 to $1000, which is usually
outside the budget of amateur cinematographers. And the cheaper ones wont
provide you with phantom power.
So what better alternative is there, than to create a "free" alternative
(free in this case doesn't cover the cost of manufacture and parts, for
obvious reasons.)
So, what do we want this thing to be able to do?
We want to be able to grab two channels of audio, via XLR. Switchable between
line and mic levels. And selectable phantom powering for each channel. Each
channel should then have independent gain control, and a mono-mix toggle
switch, should you for whatever reason want to mix both channels on the
output. Outputs should be provided as Both two balanced XLR lines, and one
unbalanced stereo TRS line. These should also be selectable between line and
mic levels. A 1kHz tone generator at 0VU for headphone level calibration (and
slating on camera, good stuff to have). A headphone jack with it's own level
control. Two channel VU meter, with momentary on switch to conserve battery.
And, all of this shall be operated from a 6-18V battery power source.
What's been designed so far:
[x] power supply, +48V 20mA [ ] power supply, +/-15V [x] preamp [x] phantom power injector [x] mixer/gain control [ ] 1kHz tone generator [x] output circuit [ ] control panel
What's been built so far:
[ ] powersupply, +48V 20mA [ ] powersupply, +/-15V [ ] preamp [ ] phantom power injector [ ] mixer/gain control [ ] 1kHz tone generator [ ] output circuit [ ] control panel
Project files:
control png 7.3 kB, 2012-01-12 injector png 7.1 kB, 2012-01-12 mixamp png 13.5 kB, 2012-01-12 output png 11.4 kB, 2012-01-12 preamp png 16.9 kB, 2012-01-12 supply png 4.4 kB, 2012-01-12
In the beforetime, in the long long ago..
