On Wed, Aug 11, 2010 at 1:35 PM, <fons@email-addr-hidden> wrote:
> Not really, EQ normally being pre-fader. Post-fader meters in a mixer
> strip are useful only of the signal being metered is actually one
> that is physically available on some connector, e.g. as a direct out.
> It would not indicate any overload that occurs pre-fader.
The only time I've seen EQ pre-frader is low-cut on a microphone
preamp. I was using standard "mixing board" definitions of PFL and AFL
per, http://www.mackie.com/support/faq/index.html
......
What are PFL and AFL?
PFL and AFL are acronyms that describe a mixer's SOLO function. PFL
stands for "Pre-Fader Listen" and allows the user to "solo" or
audition the audio in mono at a point in the signal path before the
channel fader. Perfect for a live sound situation where you need to
dial in an instrument before bringing it into the mix. AFL stands for
"After-Fader Listen" and allows the user to solo the channel at a
point in the signal path after the channel fader. This is more
commonly used for recording applications (the signal is also typically
after the EQ and pan controls). The Main Output signal is not affected
by PFL or AFL solo functions, though the Phones and Control Room
outputs are. On all Mackie mixers, the solo function serves as the
preferred way to set input levels.
......
Using a real mixer analogy, here the PFL levels are the current "peak"
levels from the ice1712 architecture diagram I've posted; its values
displayed in the meters present in "Monitor Inputs" and "Monitor PCMs"
panels of mudita24. The AFL levels are available (as I mentioned
earlier) only by "soloing" (aka muting all others) the channel for
which the AFL's are being determined, and looking at the resulting
levels on the digital mixer output.
In this case, Tim E. Real's:
"post-fader meter value = pre-fader meter dB value + slider dB value"
is a trivial computation that could easily be displayed, and would be
helpful to debug situations like "why can't i hear myself in the
monitors" (because mute was on). Having a narrow second meter
displaying the AFL levels (stereo), dynamically shadowing the PFL
displayed, would be a helpful visualization of mixer function. Even
more-so with an automatic fall-off of the side peak-level.
In contrast, it would be less helpful, and potentially more confusing
to have a modal interface that would require clicking a button to see
the PFL's, if only AFL's displayed, or vice versa. Especially for
people that might not be able to tell their AFLs from their PFLs and
just want to see some dancing meters as sings of activity.
> If the signal just goes to a mixing bus (as in the case we are discussing)
> then it's individual level is irrelevant - the level on the mixing bus (all
> signals summed) may be. But in this case you can't overload the mixing
> bus, so even that would be useless.
I think that we are both in agreement that the AFL level meters are
not strictly necessary.
However, they may not be sufficient to provide a good visualization:
having the AFL levels in the meters could help with understanding
what's actually going on, hidden in the hardware. Similar to how
useful it is here
http://osx.iusethis.com/screenshot/osx/traktordjstudio3.png ... My
suggestion would be similar, except that it would either show the
computed AFL value, or it could be switched to display the overall
stereo mix output. With its function made superfluous by that option,
the standalone digital mix meter could go away. Such side-by-side
metering functionality makes it easier to visualize the level of
contribution a given input has to the overall mix level.
> In this case, just individual buttons for L and R instead of the panner
> would be just fine, and you wouldn't need the mute buttons anynore.
The mute buttons are useful since there's no "solo" and one might want
to set levels independently of whether a channel is monitored. The
individual levels are useful because one might just want to use this
thing as a mixer anyways, maybe because you don't have another one,
and because, now that it's adequately metered, it actually performs
the function of "midi-controlled outboard synth submix" quite nicely,
and with better fidelity than an external mixer.
-- Niels
http://nielsmayer.com
_______________________________________________
Linux-audio-dev mailing list
Linux-audio-dev@email-addr-hidden
http://lists.linuxaudio.org/listinfo/linux-audio-dev
Received on Fri Aug 13 00:15:02 2010
This archive was generated by hypermail 2.1.8 : Fri Aug 13 2010 - 00:15:02 EEST
