Hi, As you must have realised, Ambisonics does not intrinsically model distance, and is based on a central listening position. In many ambisonic applications you can only pan a sound source around at the same distance. The loudspeakers are ideally all at the same distance from a central listening point. This ”same distance” is unity = 1.0, which is dimensionless.
Sound travels at a finite speed, which has a dimension e.g. m/sec. This makes effective soundfield production in larger spaces, with restrictions on loudspeaker placement, problematic. Sound arrives sooner and louder from near speakers than from far ones. This can be partially corrected by delaying and attenuating the signal to each speaker to match the acoustic time and level of the furthest. Unless this is done in the ambisonic decoder, it has to be done with external processing. User adjustable and storable hardware DSP is the the most flexible way of achieving this, also offering loudspeaker equalisation. Of course this still only fixes the situation at at central listening point. It will help at other positions especially with "in-phase” decoding, but can never be right everywhere. The larger the space, the worse the problem. On top of this is the acoustics of the space. Practically this may require that the final audio content be made in the space with its sound system, producing a recording of the signals sent to the loudspeakers, either directly from a suitable decoder, or after a hardware loudspeaker management system. Wavefield Synthesis is probably the most complete solution to this problem, though it is impractical and unaffordable. Delta stereophony, which could be regarded as stripped down WFS, is probably the next best. Ciao, Dave > On 12 Oct 2024, at 17:00, sursound-requ...@music.vt.edu wrote: > > 1. Re: Ambisonics for larger spaces (carey dodge) > > From: carey dodge <dodge...@gmail.com> > Subject: Re: [Sursound] Ambisonics for larger spaces > Date: 11 October 2024 at 18:37:38 BST > To: Surround Sound discussion group <sursound@music.vt.edu> > > > The IRCAM spat software does all this. > > cheers, > > On Mon, 24 May 2021 at 08:58, Guillaume Le Nost <guillaume.len...@gmail.com> > wrote: > >> Hi Tom, >> >> Scaling 3D speaker setups to larger spaces is a challenging topic. >> If you are willing to consider hardware processing for the larger space, I >> could only encourage you to consider the L-ISA technology from L-Acoustics, >> that my team develops. It would tick almost all the boxes of your >> requirements: >> - software renderer to work in the studio on speakers or headphones >> (headtracked binaural) >> - hardware renderer for real-time, large-scale performances >> - it includes a "scale simulation" mode to anticipate issues you will face >> when in the larger space (timing issues, precedence issues, speaker >> coverage issues, etc.) >> - it is not Ambisonics based, but object-based >> - 3D panning and 3D room engine >> - DAW friendly with control plugins AU, VST, AAX, mac / windows. >> - Integrates with a 3D speaker design software (Soundvision) to accurately >> design your system for the larger space, including SPL coverage, timing >> metrics, localisation metrics. >> >> Have a quick look at www.l-isa-immersive.com. You will find some more >> details on the technology, but also many stories relating to large-scale >> immersive audio projects, such as the Coachella festival, Panorama >> festival, the UAE National Day, the Tate Modern Turbine Hall, etc. >> >> I actually live in New Cross Gate (London), not far from your studio, happy >> to discuss your project further ! >> >> Guillaume >> >> >> Le lun. 24 mai 2021 à 14:59, Mikhail Pozdniakov <mike_...@hotmail.com> a >> écrit : >> >>> Hi Tom, >>> >>> I don't have anything useful to contribute on your set of questions, but >> I >>> did have a few for you: >>> >>> When mixing for this project, did you lie down on the floor of your >> studio >>> to check if the mix works? Going from standing to lieing down will >>> effectively make the listeners inhabit 2pi space with all the glories of >>> proximity effect on bass/lower mids and lack of rear reflections. >>> >>> Also, do you use those KEF 107s in your normal workflow? :) >>> >>> Thanks, >>> Mikhail >>> >>> ________________________________ >>> From: Sursound <sursound-boun...@music.vt.edu> on behalf of Tom Slater < >>> slater...@gmail.com> >>> Sent: May 24, 2021 07:52 >>> To: sursound@music.vt.edu <sursound@music.vt.edu> >>> Subject: [Sursound] Ambisonics for larger spaces >>> >>> Hi everyone, >>> >>> I have a project coming up that requires me to create a spatial mix of >> some >>> music and then transfer it to a much larger space. The details are: >>> >>> The space is circular with a 12m radius and a 3.5m ceiling. >>> >>> We can use a large number of speakers (48 or more) >>> >>> Budget is sufficient to consider all hardware processing options. >>> >>> The audience will be lying down to form concentric circles, facing the >>> ceiling. The outermost circle will be sitting with their back against the >>> wall slightly tilted up. (there is a visual element to the show that >>> requires this audience placement). >>> >>> I will be producing and mixing the music in my studio in which I have a >>> 25.2 dome-shaped speaker layout (8, 8, 4, 4, 1.2). See images of the >> studio >>> here https://callandresponse.org.uk/ >>> >>> I use the Blue Ripple suite of plugins and Rapture 3D Advanced decoder. >>> >>> When transferring mixes from my studio to other venues I usually build a >> 3D >>> model in Sketchup, design the speaker array for the venue and then >> extract >>> the cartesian speaker coordinates from the 3D Sketchup model, build a new >>> decoder in Rapture 3D Advanced and render a polywav for playback in the >>> venue. >>> >>> This has always worked well but I just wanted to see if there was >> anything >>> I could do to improve this method, particularly when transferring to >>> larger spaces. >>> >>> I read about this project at The Royal Danish Academy of Music >>> <https://www.digitalaudio.dk/page2169.aspx?recordid2169=1149> where they >>> used a DAD AX32 as a delay matrix to delay certain speaker channels to >>> create a virtual hemisphere. I guess they then build a bespoke decoder >> with >>> the same speaker positions as the virtual hemisphere and then render to >>> that. >>> >>> I'm particularly interested in the community's experience using hardware >>> delay matrices in conjunction with ambisonics. *OR *instead of >> ambisonics, >>> such as Meyer Galaxy processors and their Space Map Go system, D&B >>> Soundscape, etc. etc. >>> >>> I’m also very interested to hear experiences of using systems like >> SpaceMap >>> Go or D&B Soundscape in conjunction with your favourite DAW i.e. how well >>> have did they fit into your creative sound design and composition >> workflows >>> as studio tools? >>> >>> Thanks in advance everyone. >>> >>> Best, >>> >>> Tom >>> -------------- next part -------------- >>> An HTML attachment was scrubbed... >>> URL: < >>> >> https://mail.music.vt.edu/mailman/private/sursound/attachments/20210524/a701c436/attachment.htm >>>> >>> _______________________________________________ >>> Sursound mailing list >>> Sursound@music.vt.edu >>> https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here, >>> edit account or options, view archives and so on. >>> -------------- next part -------------- >>> An HTML attachment was scrubbed... >>> URL: < >>> >> https://mail.music.vt.edu/mailman/private/sursound/attachments/20210524/aa80ea61/attachment.htm >>>> >>> _______________________________________________ >>> Sursound mailing list >>> Sursound@music.vt.edu >>> https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here, >>> edit account or options, view archives and so on. >>> >> -------------- next part -------------- >> An HTML attachment was scrubbed... >> URL: < >> https://mail.music.vt.edu/mailman/private/sursound/attachments/20210524/05f29970/attachment.htm >>> >> _______________________________________________ >> Sursound mailing list >> Sursound@music.vt.edu >> https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here, >> edit account or options, view archives and so on. >> > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: > <https://mail.music.vt.edu/mailman/private/sursound/attachments/20241011/f62d23d9/attachment.htm> > > > _______________________________________________ > Sursound mailing list > Sursound@music.vt.edu > https://mail.music.vt.edu/mailman/listinfo/sursound > > WHEN REPLYING EDIT THE SUBJECT LINE > > ALSO EDIT THE MESSAGE BODY _______________________________________________ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here, edit account or options, view archives and so on.
