17 May
2010
17 May
'10
11:31 a.m.
On Sun, May 16, 2010 at 11:12:06PM -1000, Joel Roth wrote:
Yeah, it's old. But it's very cool, and Monty certainly knows his DSP.
On Thu, May 13, 2010 at 12:58:15AM -0700, Ken Restivo
wrote:
They do indeed seem similar in layout. As for the quality of the filters in them, that
varies. But if we're all using the same LADSPA effects, the results should be
comparable.
On Wed, May 12, 2010 at 10:14:41AM -1000, Joel
Roth wrote:
> Some time ago, Julien Claassen forwarded to me the
> results of his exchange with Fons regarding reasonable defaults for
> a three-band mastering network for Nama.
>
> As Fons writes here, the sum of the bandsplitting filters
> is unlikely to add up to the original signal, however
> we did adopt what we believe to be a reasonable compromise,
> with just a couple dB error.
>
> I'm appending the default settings for the LADSPA effects
> we are using. Each of the low/mid/high branches gets a compressor
> and a spatialiser.
>
> +-- low --+
> mix ----> eq ---+-- mid --+-- boost ---> output
> +-- high -+
>
> You could create a similar network in Ardour or any other
> sufficiently flexible software.
>
> eq: Parametric1 1 0 0 40 0.125 0 0 200 0.125 0 0 600 0.125 0 0 3300 0.125 0
>
> low_pass: lowpass_iir 106 2
>
> mid_pass: bandpass_iir 520 800 2
>
> high_pass: highpass_iir 1030 2
>
> compressor: sc4 0 3 16 0 1 3.25 0
>
> spatialiser: matrixSpatialiser 0
>
> limiter: tap_limiter 0 0
>
This is interesting. Never thought of building a
DIY
mastering system out of LADSPA plugins, but I guess it
couldn't hurt.
Hi Ken,
The network here is based on the one used in Jamin.
I'm not sure how to match up the settings you
have here
with the ASCII diagram above. i.e. where does the
spatializer and limiter fit in?
+-- low --+
mix ----> eq ---+-- mid --+-- boost ---> output
+-- high -+
The low/mid/high branches each get a spatializer
and compressor.
The limiter goes on the boost track. Could be a
brick-wall limiter, however the scaling limiter
is OOTB defaut.
And why is the parametric
in front of the three high/mid/low pass filters, and what
purpose does it serve?
Same as any equalizer: for boosting/cutting various
frequency ranges, which may not correspond to the
low/mid/high bands.
Also, I'm assuming that the SC4 has
the same settings for each band, at least for starters.
Yes, zero compression is the default (see Julien's notes
below).
Also, I'm not sure how to route this in
stereo. I thought
SC4 was mono anyway. I'd guess that the compressors for
each band should be stereo compressors, ganged togehter in
some way (RMS?), like perhaps the Calf Compressor is.
In this case, Ecasound is hosting the LADSPA effects.
I believe Ecasound gangs the effect if necessary
to obtain the correct number of channels.
I feel limited here by ASCII art, and also by how
to do
the routing in for example Ardour, which might be really
complex, or maybe in something like Ingen.
Well, you could try installing Nama. Then you get
your mastering network by issuing 'master_on' at
the prompt.
The GLAME settings make sense to me: all 2-pole
filters,
with the lowpass rolling off at 106, the bandpass at 520
and 800, and the highpass at 1030.
Under Nama, if you want to use GLAME plugins instead of the
default filters, you can just substitute the plugin name or
LADSPA Unique ID into the appropriate configuration file
lines quoted above.
(Incidentally, I'm just getting ready to release a 1.0x
version. I've just today uploaded version 1.056 to CPAN,
but it has yet to show up. 1.055 is broken.)
How would these LADSPA filters compare to, for
example,
postfish?
In my untutored opinion, all conventional mastering tools
will use a somewhat similar network and similar effects.
If you understand how to use the individual effects, I
think
there will not be any unfathomable mystery in the aggregate.
The mystery and artistry will be in your own creative
choices.
What I think Jamin does better than the others is that
it allows you to use different mastering parameters (scenes)
for different parts of the song.
Ron Parker is a respected engineer who not only approves of
Jamin but also wrote the mastering with Jamin tutorial.
http://jamin.sourceforge.net/en/tutorial.html
You say you hear some artifacts. Did you ever approach
the author?
Well, Fons kind of sniffed at Jamin-- "you are mastering through a vocoder"--
and I've seen and heard the quality of his code so I tell he knows a LOT more than
most folks about DSP. Meanwhile, the code of JAMIN looks like some cut-and-paste filters
off of a web forum, and indeed their EQ is an FFT. The GUI is pretty and well-organized,
but I'm not sure if what's going on underneath the hood is any good.
My ears are not good enough to hear DSP artifacts-- and to know that's what they are.
I did have some problems in the 6K and 12K range, which I fixed in the mix (my mixer going
straight to the mastering stage in one chain). And I guess I'm just worried that I may
have used a tool that introduced artifacts I can't hear or see, but others will.
It's not a big deal. It's not like millions of CD's are going to get printed
up.
I'm really
starting to wish I'd used postfish
instead of JAMIN now.
Is Postfish current? It's not on the Linux Sound and MIDI
Applications page, and the last journal entry for postfish
I see is 2004:
http://xiphmont.livejournal.com/595.html
# Julien Claassen's Notes on Mastering effect defaults
#
# Eq: All sections are initially off. You can turn them
# on as needed, one at a time.
#
# Bandpass: Default settings are courtesy of Fons
# Adriaensen, who says they will be within 1.5dB of
# flat settings.
#
# Compressor is turned off, with reasonable default values
# set.
#
# Spatialiser and limiter: both initially off so you can start out
# clean and slowly work your way from there.
Thanks!
-ken