--- In Rob Danielson <> wrote:
>
> At 1:29 PM -0400 9/9/06, Walter Knapp wrote:
> <snip>
> >
> >I operate with 15dB on average for headroom,
>
> I've been monitoring my results in northern woodlands in this regard
> pretty carefully and I agree. If I set the background ambience at
> -15dB, its very rare for an natural event to over-modulate. I set
> both the side and the mid at this level.*
>
> Even with this limited dynamic range and increased headroom of
> digital media, I still regard saturation pretty carefully when
> recording in Hi-SP mode because sufficient** bit depth seems like it
> helps ATRAC efficiency. When the ATRAC original is "thin," I notice
> that my EQ plug is less responsive and there are more spots along the
> spectrum where frequencies seem under-represented. Perhaps the
> slight degradation stems from shifts in ATRAC Hz emphasis with
> content. At what level the degrading sets in, I could not say. The
> -15dB background calibration method is pretty reliable for me, but
> my "safe" level could be higher than some recordists want to risk.
>
> With 16 bit originals, I EQ and convert them to 24 bit sub-masters in
> one step (saving the settings should I question my judgement later
> on). Its during this stage that I tend to notice the differences in
> outcomes. After I get through this demanding school year and
> relocate in LaFarge, such tests will be much easier to do.
>
> *At night, unless I'm close to a pond or other active spot, I'm at
> full pre gain anyway and the natural ambience is well under -15dB
> unless its windy, raining etc
> .
> ** Assuming a modest dynamic range of 15-25dB, shouldn't we be able
> to get adequate saturation and headroom with digital media?
>
>
> >so that's what my mid will be set at (and for some sites it might be
> >as low as 25dB or more, it's
> >based on my estimate of the probability of a louder call). I've found
> >the side to balance right with as much as 30dB below the mid upon
> >occasion, depending on the site, may have used even more at times,
can't
> >remember just now. That's a total possible setting on the side under
> >your system of 45dB down. That is a lot, particularly as I do still
> >record with a 16bit system and don't expect that to change anytime
soon.
> >
> >Wasn't Rob giving us a talking to a little while back about how much we
> >lost recording that low? Particularly in 16bit. About how the lower
half
> >of the range did not resolve as well as the upper half? Maybe should
> >resolve that issue before going down there as a standard practice?
If we
> >record in the bottom 60dB of the dynamic range of a digital recorder
> >will the recording be as good as if we did so in the top 60dB?
>
> Isn't bit distribution/resolution linear up and down the scale? Rob D.
>
> <snip>
> >
> >Walt
> >
>
As far as I was aware 1 bit equals 6dB where ever you were in the
scale? So a 16 bit system has a dynamic range of 16 x 6 which equals 96dB?
As regards the 'line-up levels' one of the most common in use is
-8dB's below peak equals -18dB on a digital system. This gives you a
10dB headroom for those transient peaks most level measuring devices
fail to register.
Phil
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