Hi dave - thanks very informative post. My solution for getting speakers close to people without them seeing them is stealth - ie I hide them - since a fair few of my installations are site specific - for example in forests, urban environments there's usually a few good hiding places - and then there's piezo speakers that come in handy. Invisible speakers with no mass ? One day Dave, one day.
On 8 November 2014 13:45, Dave Hunt <davehuntau...@btinternet.com> wrote: > Hi, > > There are obviously severe limitations in trying to make signals appear > close to the listener with ambisonics. As far as I know, all first and > higher order spherical harmonics go to zero at zero distance, the central > listening position, leaving W (omni) only. The ambisonic encoding equations > do not inherently include distance, even though they can be expressed in > x,y,z coordinates, but only direction. Distance is basically unity: sq(x) + > sq(y) + sq(z) = 1. > > We then have to resort to other methods of suggesting distance: amplitude, > arrival time of the sound from the source, the ratio of direct to > reverberant sound, high frequency absorption of sound from distant sources > (only really appreciable in free air beyond 50 to 100m), some sort of > proximity effect leading to an increase in in the level of low frequencies. > > Some sounds have no immediately recognised source, and thus their distance > cannot be judged at all. If they move and the above factors change, > especially if they move past the listener, a meaningful illusion can be > created, as Dave has suggested. The Doppler effect arises through the > variation in the arrival time of the sound from the source, and indicates > the speed of movement of the source towards or away from the listener. > > WFS claims to offer a solution but, as pointed out, is "a lot of speakers > to lug around" and a lot of amplifiers, cable, audio hardware and signal > processing power. Then it's down to hybrid solutions like Gus's " put a > hidden speaker close to them and use Dbap". > > If only we had loudspeakers that were invisible, weightless, required no > power or cable, could be moved and resized at will and be placed anywhere > without support, could be passed through by human beings with no injury, > and were capable of producing high quality sound at any level, etc., we > could do it using one speaker per sound source. > > Ciao, > > Dave Hunt > > On 7 Nov 2014, at 17:00, sursound-requ...@music.vt.edu wrote: > > From: Augustine Leudar <augustineleu...@gmail.com> >> Date: 7 November 2014 16:18:08 GMT >> To: Surround Sound discussion group <sursound@music.vt.edu> >> Subject: Re: [Sursound] The "BUCKET LIST" for Ambisonics? - or only how >> to proceed with Head tracked Binaural listening directivity control ? >> >> >> Hi Dave, >> Is that the one that adds bass to the signals that come closer ? I only >> ask >> because I have never heard an ambisonics composition that successfully >> made >> the sound seem close to the listener which is weird because that's what a >> lot of people assumes it can do - and I have heard a lot of ambisonics >> compositions in the Sonic lab which is is a 48 speaker array in an >> acoustically pretty controlled environment by people from all over the >> world. I've also read papers from Ircam where researchers claimed they >> could get sounds to come a couple of metres inside the array effectively >> but no more - they almost blew up Ircams system apparently when the bass >> of >> the nearfield went out of control. Nonetheless its possible that the >> artists involved didn't have access to the right software for encoding >> such >> NFC-HOA recordings - is there any software around with which I could try >> it >> out ? I would be interested in moving synthesised sounds around with some >> sort of panner rather than replaying recordings. I have had some success >> at >> this with ICSTs panner - as you say with fast moving sources - but I put >> this down to psychoacoustic effects rather than wavefront shinanigans - >> plus as somebody will no doubt point out this is ambisonics equivelant >> pannin. . WFS of course but its a lot of speakers to lug around - so for >> the time being if I want a sound to seem likes its close to someone I put >> a >> hidden speaker close to them and use Dbap - I find ambisonics useful for >> surround sound panning as it seems to fill the holes better - especially >> if >> you can adjust the directivity. Anyway - Id love to give any NFC-HOA >> software out there a test drive if there's any available, >> all the best, >> Gus >> >> On 5 November 2014 03:47, Dave Malham <dave.mal...@york.ac.uk> wrote: >> >> Hi there, >>> It depends what you want to do. If you can limit yourself to fairly >>> rapidly moving sources, then you can get some way towards this even in >>> FOA >>> especially if the replay venue is reasonably dry and the acoustic of the >>> soundscape is somewhat reverberant. With a bit of doppler, the >>> appropriate >>> variance of direct to reverberant field and patterns of early >>> reflections, >>> it will be difficult for the brains of the listeners not to perceive the >>> source as moving past their heads (if that's the path you've set). >>> However, >>> the slower the rate of travel, the more likely it is to fall apart and >>> revert to the source appearing to come from no closer than the reverb >>> radius (usually the surface of the speaker array). If you want to go >>> further, you need to use NFCHOA, (see Jerome Daniel's work). >>> >>> >>> Dave >>> >>> >>> >>> On 5 November 2014 00:21, Augustine Leudar <augustineleu...@gmail.com> >>> wrote: >>> >>> I'm wondering - what is other artists experiences of using ambisonics to >>>> get sounds to appear "close" to the listener - ie proximity or in WFS >>>> focussed sources ? >>>> >>>> > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: <https://mail.music.vt.edu/mailman/private/sursound/ > attachments/20141108/bc23b030/attachment.html> > > _______________________________________________ > 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. > -- www.augustineleudar.com -------------- next part -------------- An HTML attachment was scrubbed... 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