On Sun, 2010-11-07 at 03:37 -0800, Patrick Shirkey
wrote:
It think it is a bit more subtle. I have listened
to the mix on several
systems now and have found that the overall levels are not exactly what
I
am hearing when I listen with ardour. That could be partly related to
the
exporter, my sound card which I am mixing on being a high quality audio
device and the general levels being just not quite right. I am working
on
toning down the tracks that have become distorted in the export process.
The subtlety of the differences is < -120dB. This is what the test just
proved beyond any doubt (if in doubt, read DSP basics). The difference
is inaudible and is created only by the imperfections of floating point
calculations (you always loose some precision when operating on floating
point numbers).
The difference you hear is caused by your playback system (maybe the
soundcard?) distorting at higher playback levels. Or, if you are
monitoring the two mixes at different overall volumes, the difference
can be attributed at least in part to how the human hearing is
non-linear:
http://en.wikipedia.org/wiki/Equal-loudness_contours
You might even be imagining the differences. Don't be offended, it's
really easy to hear differences between two things when you're looking
for (expecting to hear) a difference. This is has been researched and
documented countless times. We all suffer from that, nobody is exempt.
In your shoes, I'd measure the playback system and try to pinpoint the
part which is causing the distortion. If you tweak your mix to sound
good with the distortion your current system exhibits, the mix will not
sound like that anywhere else. So to make your mix sound good
everywhere, you have to have a clean setup as a reference.
(Note the word measure: this is the only way to get any sort of
objective results. )
Ideally I would have some very good speakers to do this step but that is
not currently possible for me.
My approach atm is to just bring the levels of the distorted tracks down
until they stop distorting after export. Then when I have found the sweet
spot I will be able to adjust the rest of the tracks to match.
However finding the sweet spot on a 65 minute mixdown is a fairly
laborious process. Hence I am becoming very familiar with the content of
the material and getting a lot of meditation done at the same time. It's
not such a bad deal ;-)
--
Patrick Shirkey
Boost Hardware Ltd.
"This is the basis of the Bohm interpretation of quantum mechanics, which
requires that all particles in the universe be able to instantaneously
exchange information with all others."