At 10:41 PM 7/20/2010 -0500, Rob wrote:
>Opps, I forgot to mention that if the HS700's mic input only has
>auto-gain, the recordings will "pump" and this makes nature
>soundscapes sound pretty bad. If it turns out the HS700's mic input
>is noisy or it only has auto-gain, looks like you're stuck with using
>another sound recorder.
I think this is Ray's original plan as he has a PCM M10 and his original
question was, "How (or can) I use my Sony PCM-M10 with my Panasonic
HDC-HS700 camcorder for better sound quality and if so how? I'd like to be=
able to walk around and record with this configuration."...
However, making a "T" type resistor network to pad down the audio, the
output of the M10 can be made low enough to get under the threshold of
level that causes pumping in the video camera. Whether or not there will be=
enough gain at that point is another issue however using the PCM-M10 ahead=
of the mic input of the video camera allows for control of the mic preamp
gain at the input of the M10 recorder thus controlling the level of the
output going to the video camera. The "T" network is a fixed ratio device,=
it will only reflect the level of PCM-10 output at whatever the reduction
established by the value of resistors used. It doesn't necessarily have to=
be 40 dB, it can be what ever the ratio of resistor values chosen makes it.=
Then the PCM-M10 becomes the controlling device.
As most all cameras are AGC, Auto Gain Control, you may have to experiment=
with the value of the resistors chosen to find the values that work best
with your camera however they resistors are inexpensive, usually between
$.05 to $.20 cents. And if you need more control range, one of the
resistors in the "T" network can be a variable resistor or
potentiometer...
>If the HS700 does have _manual_ audio gain, one way to test/compare
>recorder input noise is to make comparison sound recording in the
>same, quiet location with these two record chains:
>
>AT4022's -> RollsPB22 -> Mic Input M10 (max or near max gain)
>vs
>AT4022's -> RollsPB22 -> Mic Input HS700's (max or near max gain)
I agree with Rob's test, this will give you an idea of what is the best
direction to take wether the camera has manual gain or not. You may find
the simple fix is to use the AT4022 mics with a Rolls PB224 phantom power
module on the video camera itself. That is assuming the video camera
itself uses an audio digitizer with adequate rate.
Another potential gotcha about cameras that I learned recently, if using
the internal camera microphone, its liable to be a monaural mic and the
digitizer runs at a low rate around 11Khz. However, when a microphone
plug is inserted into the camera external microphone input jack, the camera=
switches to a digitizing rate of 44.1Khz and generates excellent audio
recordings...
--
Thanks,
Mitch & Shadow...
http://www.4shared.com/dir/UTASxktL/wildlife.html
Shadow's area: http://www.4shared.com/dir/ecfWjyZb/Shadow.html
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