Re: [Sursound] New Ambisonic VST Plugins

[Dave Malham]

Another possible approach is to use a standard 1st order microphone set in
the far field and add panned in (at third order)  signals from close mics
from each of the instruments. These will need to be delayed to match the
distance to the main POA mic. It might also be necessary to some
second/third order components corresponding to early reflections but this
would have to be experimented with. It won't be perfect but it will be
closer to the output from a true third order mic than using Harpex - and
without the processing artefacts.

   Dave


On 22 November 2013 22:23, Michael Chapman  wrote:

> > �David Pickett �wrote:
> >
> >
> >
> >>> How does one record in third order (or indeed any order above first
> >>> order)?��
> >>> What kind of microphone array does one need, for instance, for 3rd
> >>> order with no height information (WXYUVPQ)?�
> >>> Is there a "native format" method for HOA or is it all extended A
> >>> format, with conversion through matrices?
> >
>
> I don't dispute Eric's very short, but very full summary
> but I think we may be at cross purposes.
>
> Richard Furse's software obviously works with a higher order microphone
> (if anyone has one) but I would suggest his primary motivation was for
> synthesised higher order soundfields. You can obviously create a synthetic
> soundfield of any order you want.
>
> Michael
>
>
> >
> > All excellent questions. �It is not quite as obvious how to record any
> > order of Ambisonics above first order. �It will require some sort of
> > microphone array and post-processing. �One of my favorites is the array
> > described by Craven, Lawe and Travis in:
> > Microphone arrays using tangential velocity sensors
> > P.G. Craven, C. Travis, M.J. Law
> > We introduce a new class of 3D microphone arrays that use symmetrical
> > arrangements of tangential velocity sensors.� Use of velocity sensors
> > allows these arrays to recover spherical harmonics of a given degree with
> > less low-frequency boost than when using pressure sensors only.� As an
> > example we present a symmetrical array of twelve velocity sensors that
> > resolves the eight harmonics of degrees 1 and 2.� A second-order
> spherical
> > microphone can now be constructed by combining this array with one or
> more
> > pressure sensors that provide the missing harmonic of degree 0.
> >
> http://ambisonics.iem.at/symposium2009/proceedings/ambisym09-craventravis-tangentialsphmic.pdf/at_download/file
> >
> >
> > The other practical method for constructing an array that produces higher
> > order spherical harmonic outputs is to use a group of omnidirectional
> > microphones on a sphere, such as the commercially available Eigenmike:
> > http://www.mhacoustics.com/products
> >
> >
> > There are other methods. �It's still early days for this technology.
> >
> > Eric Benjamin
> > -- next part --
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-- 

As of 1st October 2012, I have retired from the University.

These are my own views and may or may not be shared by the University

Dave Malham
Honorary Fellow, Department of Music
The University of York
York YO10 5DD
UK

'Ambisonics - Component Imaging for Audio'
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Re: [Sursound] New Ambisonic VST Plugins

[Dave Malham]

("Third Order Ambisonic") VST
> plugins
> > > from Blue Ripple Sound have been released, along with some other bits
> > and
> > > pieces. They are intended primarily for use with Reaper (Cubase/Nuendo
> > > currently can't host them).
> > >
> > > More details can be found at
> > > http://www.blueripplesound.com/story/new-toa-plugins.
> > >
> > > Best wishes,
> > >
> > > --Richard
> > >
> > >
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> > > https://mail.music.vt.edu/mailman/listinfo/sursound
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> > >
> >
> >
> >
> > --
> >
> > As of 1st October 2012, I have retired from the University.
> >
> > These are my own views and may or may not be shared by the University
> >
> > Dave Malham
> > Honorary Fellow, Department of Music
> > The University of York
> > York YO10 5DD
> > UK
> >
> > 'Ambisonics - Component Imaging for Audio'
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-- 

As of 1st October 2012, I have retired from the University.

These are my own views and may or may not be shared by the University

Dave Malham
Honorary Fellow, Department of Music
The University of York
York YO10 5DD
UK

'Ambisonics - Component Imaging for Audio'
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Re: [Sursound] New Ambisonic VST Plugins

[Richard Furse]

I basically agree with all of this - I just don't think it's that big of an
issue in practice. We don't generally ask engineers to provide their stereo
mixes twice for -3dB and -6dB pan laws, though arguably we should. [Okay,
tenuous parallel.]

HOWEVER, we want these plugin libraries to do what folk need! We actually
already have first order decoders computed for all these layouts, reasonably
aligned with the third order ones - they are already used in Rapture3D.
Putting them into a separate VST plugin library would be tedious but easy.
Should we do this? Would this address everything raised on this thread? IMHO
the biggest argument against it is that these minor worries might sow FUD
among potential ambisonic novices (I can imagine a naïve engineer observing
that "5.1 doesn't have these issues").

Quick vote maybe? If folk email me *OFF-LIST* with "I would use a first
order decoding plugin library like that" and we can get to a count of five
from folk on this list, I'll schedule the work. I'll subtract one for each
email saying "No! Too much FUD!"

How's that? ;-)

Best wishes,

--Richard

> -Original Message-
> From: Sursound [mailto:sursound-boun...@music.vt.edu] On Behalf Of
> Dave Malham
> Sent: 23 November 2013 10:39
> To: Surround Sound discussion group
> Subject: Re: [Sursound] New Ambisonic VST Plugins
> 
> Hi Richard,
>The only problem I see is that straight first order decoding generally
> has a different ratio of W to XYZ components that that used for third
> order, which ideally should be corrected before feeding first order
> material to a third order decoder, otherwise the first order material in
> the mix won't be decoded optimally. Unfortunately, of course, correcting
> this on the first order material in the mix (so that it is right on TOA
> decoders) means that if it is then decoded at first order (say, with an
> older decoder) the decode will be wrong - and unfixable, as we've
discussed
> before on this forum. The only full solution is to keep first order only
> material completely separate from third order so that it can be handled
> separately at the decoder - or, alternatively, say it has to be 3rd order
> always, though I am not sure how this would work out with decoders to
small
> numbers of speakers.
> 
>  Dave
> 
> [...]


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Re: [Sursound] Ambisonic first approach

[Dave Malham]

Before I retired, I intended to remove the ppu's for our Tetramic from
their individual tubes and mount them all into a single 25mm (or there
abouts) tube, with a ST450 standard connector at one end and a mini-xlr
recessed into the other. The mic would then plug directly into this with a
degree of support thanks to the recessing, with rubber vibration isolation.
The larger diameter tube could then be mounted into one of the lovely
Rycote mounts that the ST450 uses. This system would get rid of most of
fragility problems of the existing system and help with any problems of rf
pickup due to having sections of unbalanced cable runs.

 Dave


On 17 November 2013 12:18, Michael Chapman  wrote:

> > On 11/15/2013 07:23 PM, Len Moskowitz wrote:
> >> J?rn Nettingsmeier   wrote:
> >>
> >>> the tetra sounds great, but the connectors are very flimsy.
> >>
> >> The connectors are all from Switchcraft's Tini-Q (mini-XLR) series, used
> >> in many professional products and contexts.
> >>
> >> In the six years since TetraMic was introduced, we've had exactly one
> >> cable returned to us due to connector or cable failure.
> >
> > you are right, i should have phrased that more precisely, the connectors
> > are actually fine, or at least not the biggest problem.
> >
> > the _cables_ are frightfully flimsy (which is a consequence of the small
> > size of the 6-pin miniXLR), and they are very inconvenient to re-solder
> > in-the-field, which i've been forced to do several times, despite
> > handling them with the utmost care.
> >
> > most of these issues were a consequence of the comparably heavy PPUs
> > which cause a great strain on the split when handled or transported.
> > since i've taken to tying the the PPUs to a bundle, i've had no further
> > problems, but i'm still muttering prayers before every important
> > recording.
> >
>
> I tend to put the four (Mk. I) PPUs directly into a snake box
> (4xXLR->-CAT5).
> At least then the mass is so great one takes care, whereas one PPU can be
> optimistically/mistakenly be left in a line ...
>
> Mmmm, what is the new project ... this gets worse than an Apple launch ;-)>
>
> Michael
>
>
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-- 

As of 1st October 2012, I have retired from the University.

These are my own views and may or may not be shared by the University

Dave Malham
Honorary Fellow, Department of Music
The University of York
York YO10 5DD
UK

'Ambisonics - Component Imaging for Audio'
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Re: [Sursound] New Ambisonic VST Plugins

[Daniel Courville]

Le 2013-11-22 12:12, Richard Furse a écrit :

>you should
>also be able to upsample to third order using Svein's excellent HARPEX-B
>plugin, although the public version of that currently generates only
>horizontal components at third order (for compatibility with channel count
>limits in other hosts).

Is there a "non-public", beta, version that outputs the full 3rd order 16
channels?

- Daniel


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Re: [Sursound] New Ambisonic VST Plugins

[Michael Chapman]

> Le 2013-11-22 12:12, Richard Furse a �crit :
>
>>you should
>>also be able to upsample to third order using Svein's excellent HARPEX-B
>>plugin, although the public version of that currently generates only
>>horizontal components at third order (for compatibility with channel
>> count
>>limits in other hosts).
>
> Is there a "non-public", beta, version that outputs the full 3rd order 16
> channels?

Non, (or so I am informed).

Michael

>
> - Daniel
>
>
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Re: [Sursound] Hector bird recording - SoundCloud

[Hector Centeno]

Hello!

Yes, I gave those recordings to Umashankar before I got the microphone
calibrated. I just uploaded a B-format version converted using
Tetraproc and the preset file that Fons made for me after I gave him
my IR measurements. It's not exactly the same fragment but comes from
the same group of recordings. Those birds make indeed very strange
sounds, they are called Urracas in Mexico, were the recording was
done. This is obviously not a pure nature recording since it was done
in the backyard of a house in the city. I placed the mic right under
the tree where the birds were perching.

http://www.hcenteno.net/extras/Urracas_WXYZ.wav.zip

I'll try to get the music recording processed too by tomorrow.

Cheers!

Hector



On Fri, Nov 22, 2013 at 2:41 PM, Eric Benjamin  wrote:
>> Is the W level correct? I am finding myself turning up my W knob 3-6dB
>
> I'm tempted to agree.  Of course it's difficult to be certain.
>
>
> 
>  From: dw 
> To: sursound@music.vt.edu
> Sent: Friday, November 22, 2013 6:21 AM
> Subject: Re: [Sursound] Hector bird recording - SoundCloud
>
>
> On 21/11/2013 19:08, Aaron Heller wrote:
>> I took the liberty of merging them into 4-channel files and putting them on
>> my server, which might be easier to access than the skydive (the UI was in
>> Japanese for me, fortunately I recognized the character for 'down')
>>
>>http://ambisonics.dreamhosters.com/01-Birds_WXYZ-110425_0119.wav
>>http://ambisonics.dreamhosters.com/05-Music_WXYZ-110425_0127.wav
>>
>> They sound quite nice.  In Harpex, you can clearly see the locations of the
>> singers, percussion, and birds.  Impressive!
>>
>> Thanks...
>>
>> Aaron (hel...@ai.sri.com)
>> Menlo Park, CA  US
>>
> Is the W level correct? I am finding myself turning up my W knob 3-6dB
> relative to other recordings before it sounds good..
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