[LAD] what does "full range" mean with regard to ambisonics and speakers?

[Jörn Nettingsmeier]

On 08/03/2010 09:38 PM, fons at kokkinizita.net wrote:
> A separte VLF decoder is one of the features I want in the next
> generation Ambdec. The question I'm asking myself is how much
> 'configurability' this requires.

as far as i'm concerned, it would be cool to have some help creating a 
"hybrid" matrix like i described to bearcat, to avoid having to run 
separate ambdecs for tops and subs. the most important thing would be 
another gain coefficient to match the subs to the tops, similar to what 
you already have to tweak the two psychoacoustic bands.

> It's no problem adding the
> filters that would perform a 'perfect' split of VLF and the
> rest. But then you have to consider the response of the units
> themselves - many subs have their own filters, and the LF
> response of the 'full range' speakers can't be assumed to be
> really flat in the crossover region. A really good xover has
> to take into account the response of the two systems it is
> driving. All suggestions are welcome...

i don't think ambdec can do much about it, for the reasons you mention, 
and for the fact that the subs will be physically misaligned wrt the 
tops. so what we need is a delay (already there), and maybe, just maybe 
some "+/-" buttons for the delay to help with a setup by ear, and a tone 
generator that creates test signals in the critical overlapping band - 
these could then simply be tuned for maximum loudness.

> Another question to two (Joern and Fernando) AMB nerds: does
> a multicnannel AMB aware dynamics processor make sense ? When
> would you use it ? I'm asking because one of the plugins I'm
> developing could be exactly that.

oh, certainly. it would be divine to *not* be able to do evil sum 
compression in ambisonics, ever, but sometimes, earthly matters require 
it...

but my favourite solution to this approach would be for ardour to do the 
right thing wrt side chaining (or at least allowing the chains to be 
made manually). i'm told a3 can do it, and i'll be checking it out.

but yours would certainly a welcome addition to my tool chest.

> ATM it's just compression
> (with real RMS response), but the full version will have a
> noise gate as well, Do you need such a thing ? Current plans
> are that the full version will be mono/stereo only.

N-way side chaining would be cool, with just a single set of controls.
the interesting question is how the measuring should be done and the 
orders interpreted. and here we go again, at normalisation and channel 
order ;)