Posted by jakdedert on 03/31/06 15:13

mv@movingvision.co.uk wrote:
> In message <1143805585.304897.289310@u72g2000cwu.googlegroups.com>, Oleg
> Kaizerman <KAIZERO1@gmail.com> writes
>> pd150 or 170 do not have automatic level control
>> they have fixed input stage with hard limiter around-1 dbfs
>> common mistake .
>> alc its wrong term only
>> the Panasonic 100 also has the same structure but without fixed input
>> stage m the limiter kicks at -6 dbfs till -4.5 (ganged)
>>
>
> Oleg dear chap, you're being pedantic to a fault. Of course the PD's
> have, for all practical purposes, automatic audio level response with
> options for 0db limiter/cut off.
>
> Nevertheless the issue is one of using an external mixer, such as an
> SQN, as a means of over riding, to a significant degree, the cameras
> auto level response using the cameras proportional responsiveness to
> such an input.

There is a significant difference. ALC is exactly what it says:
Automatic Level Control. IOW, it raises the gain for quiet inputs, and
lowers it for louder signals...leaving everything squashed within a
narrow dynamic range. A hard limiter does nothing at all to the signal
until it reaches a preset level, then chokes it off (in a usually
unfriendly fashion).

However, given that the it does nothing until then, it's only a matter
of keeping the input below that threshold to get decent recorded
dynamics. That can be done with a mixer or even a simple level control
between the mic and camera. Some experimentation is in order to stay
below the threshold, but overall, it's good news for the OP.

A 'sort of' ALC can be achieved with a limiter by raising the gain of
the mic to the point that almost any audible sound will hit the limiter
threshold; but it's not true ALC, which is variable.

jak

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