Hi
On 27 September 2012 01:53, Michael Chapman <s...@mchapman.com> wrote:
>
>>
>> - Are identical speakers needed for each speaker of the array, or can I
>> DIY
>> it buy mixing and matching speakers from old hi/fi and found systems?
>
> Don't think anyone would recommend it ... but one has to be
> realistic.
Definitely not to be _recommended_ but, as Michael says, one has to be
realistic. Things to watch out for include not just different sounding
speakers, which DRC would most probably help with,but also polarity
(or, phase as it is generally called in audio, ignoring the frequency
related part of that). Moreover, not just overall polarity which is
easily fixed by reversing the connections. If I remember rightly, some
designs of crossover reverse the phase of (usually) the midrange unit
to get a flatter frequency response. A mixture of some of those, with
some that have non-phase reversing designs would undoubtably mess
things up. If you have to use mixed speakers (and I have Tannoy Lynx's
in the under audience 4 of our Rymer Auditorium 16 speaker rig, the
rest being Diamond V's) it's probably best to use pairs of matching
speakers on the opposite end of a diameter passing through the central
point, rather than, for instance, distributing them randomly or
placing them next to each other.
>> - I was reading that the exact layout of an HOA is not so important,
>> there's tolerance for different configs, unlike traditional 5.1 channel
>> based systems which have specific locations that they should live in.. if
>> so, what is the determining factor for accurate localization? If I rig up
>> my studio with one config, will it translate to a much larger space by
>> scaling up ? (assuming enough power in the loudspeakers?)
>
> The whole point of ambisonics is that it is independent of the final
> rig.
>
Ahh - within limits! The limit being set by the differences in local
acoustics. It is very difficult, for instance, to get sounds to be
closer than the closest speaker in the rig would sound if a mono sound
was fed to it on its own. Moreover, variations in acoustics local to
the speaker (local reflections, resonances, etc) can distort the
reproduced field. This is why Augustine says you should be prepared
for tweaking of the scaled up version, although this is by no means
always necessary.
>> - What are ways of writing original music for this format? I use Logic and
>> Max... does this format need specific compatible syths/instrument with
>> multiple out, or is the source irrelevant and it's all in the host
>> routing?
Again, Augustine has got it right - Logic into Max. Logic (unless the
latest version has corrected the shortcoming) has real limitations in
terms of input and output configurations both in and of itself, but
also in terms of what multichannel plugins it can use, so using it for
dealing withe the stems and then routing those out to Max (or pD or
Bidule or AudioMulch or...) for Spatial processing and output to the
rig is the way to go - or swap to something like Reaper which is much
better in this respect..
>> - What's the easiest way of using my existing stereo samples/recordings to
>> convert them for use and reproduction ? Is this even possible? If I
>> convert, will I then have to manually 'map' movement across the field?
>>
On stereo samples - a good starting point is to pan the two channels
into the soundfield with a 60 degree separation in panning position.
This will preserve the image in the stereo, including its movements
(basically you are creating a virtual stereo pair of speakers). Then
experiment! As I always told my students, it is important toknow and
understand what is the technically correct, but you should be prepared
to throw some or all of that that away if necessary because, in the
end, all that matters is how it sounds to your ears.
All the best - and have fun!
Dave
--
These are my own views and may or may not be shared by my employer
Dave Malham
Music Research Centre
Department of Music
The University of York
Heslington
York YO10 5DD
UK
Phone 01904 322448
Fax 01904 322450
'Ambisonics - Component Imaging for Audio'
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