Hi Ben. Thanks for your overview and relating of experiences, Ben. Much appreciated. You said >> We ended >> up piecing together an 8 channel system for a 1700 seat hall that was not >> accurate in the slightest. However, my professor and the sound designer were >> both blown away by the precision of what was essentially glorified panning, >> despite the large hall.
A couple of rwsponses, FYI. One of the things that I think gets lost in all the technical chatter about ambisonics is how "robust" it actually is: Sure, you can get better performance by spending $squillions on gold cabling etc etc but it is surprising how forgiving of abuse it is. Dave Malham will remember and experiment I did in York in 1996 before the advent of (affordable?) 4 track digital recorders - I took did some field recordings with their (ST250, I think it was) onto two unsynced DAT recorders, made a 4ch reconstruction in the studio and on playback, whammo! - up came the soundfield like it had been recorded with precision! On the Dome front - and the number of speakers depends on lots of things - do you have any photos? One I found was not to place a speaker at the very top. Here's some domes I've built and used ambisonics with: http://www.avatar.com.au/worrall/index.php/polymedia-event-theatres + a 3rd one is on the way: http://www.avatar.com.au/worrall/index.php/current-projects/35-polymedia-event-theatre-no-3 I'm working towards a residency in Atlanta later in the year - and they've expressed an interest is spaces and configurations for sonification, so it may be that we can touch base and compare notes/benefit from knocking heads together. cheers, David (W) On 30/07/2011, at 1:43 PM, Ben Bloomberg wrote: > Ok, at the behest of Jörn, I am going to send some links to various things. > Feel free to tear them apart! Also for what it's worth, the setup pictured > in the first article is about the worst sounding rig we've put together. The > speakers are really not that bad, though. I wish we had given them some > other photos. > > http://blog.bowers-wilkins.com/sound-lab/the-future-of-surround-sound-from-mit/ > http://bot23.com/tag/ambisonics/ > > We also had a paper in NIME this year that has a description of our current > project: > http://www.nime2011.org/proceedings/papers/J01-Jessop.pdf > > Ben > > > > On Fri, Jul 29, 2011 at 12:05 PM, Ben Bloomberg <b...@mit.edu> wrote: > >> Hi Everyone, >> >> Well, now that Sarang has spoken up, he's given me the courage as well. >> I've been lurking on this list for several months now. Just to be clear, I >> think you're all high-priestesses!! It's been incredible to read the >> discussion (most of which has been way over my head, but I try to slog >> through) and hear what people have to say. >> >> My experience with ambisonics is odd, having sort of jumped into the deep >> end after suggesting ambisonics as a solution for a school project 3 years >> ago (with little knowledge of math, let-alone spherical harmonics). We ended >> up piecing together an 8 channel system for a 1700 seat hall that was not >> accurate in the slightest. However, my professor and the sound designer were >> both blown away by the precision of what was essentially glorified panning, >> despite the large hall. We used the ICST Max 4.5 externals. >> >> Since then, we've implemented our own parallel processing audiounit/OSC >> based system and we use ambisonics as an abstracted panning system for >> synthetic sound environments on most of the performances we put together. My >> professor loves the idea that we can encode something and play it back on >> any speaker configuration with relatively consistent results (given the >> halls we play are vastly different anyway, usually the ambisonic >> configuration is the least of our concerns). >> >> So my experience is almost purely empirical/trial-and-error. We've done >> systems for 3 people and systems for 2000 people, some very high density and >> some very low density. Mostly we just put up speakers and listen to see what >> we think, or take the live-sound fudging approach of blurring multiple >> systems together for different seating areas. Having taken some more math >> classes, things are starting to become a bit clearer now, but I'm still >> learning (that never stops!). Some of our equipment sponsors have asked me >> to write things about the projects for them, which have ended up on the >> internet and probably contain some mis-information. >> >> That said, I have a two questions and an offer. >> >> First, I'm really interested in ambisonic decoder and encoder weightings. >> From what I read, they provide a means to used fixed-point processing. >> However, playing with them results in vastly different sounding results. I >> made a really simple script to visualize the phase of a signal at the output >> of decoders with different weightings, but I'm not sure I understand what >> I'm seeing or how that has an effect on what we hear. I will try to make a >> comped image of all the plots and send it out. >> >> Second, we will be putting up a fairly large ambisonic system hanging from >> a 20 by 20 foot truss in the next month. I have heard that the more speakers >> you can add to a system, the better it will sound. Is that true? With higher >> speaker counts >20, we've had the best results by removing decoder >> weightings. We seem to hear a better sense of localization for our synthetic >> recordings. I had an idea that this changes the decay rate of "cosines" in >> what is essentially a vector projection, so each speaker occupies a smaller >> slice of the surround field "pie". Is that anything close to correct? What >> would be the optimum number and configuration of speakers for a 20' dome? >> (assuming equipment is not an issue) >> >> Ok, now the offer! Being at a place that has a lot of resources, but little >> time and man-power, I wanted to offer up our inventory of equipment to the >> community. We have about 90 speakers that we keep around for projects or >> touring. If anyone is working on a project that could benefit from extra >> speakers, drop me a line. If we've got the gear free, you're welcome to it. >> It's a mish-mash of Bowers and Wilkins, Duran Audio Axys, and Mackie 824s. >> We drive our systems with MOTU, RME, and SSL MADI interfaces. Also, if >> people are interested in testing things on this 20x20 dome and want to come >> down to Boston (it'll be up in September and October), we'd be honored to >> have you as guests! >> >> Best wishes, >> Ben >> > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: > <https://mail.music.vt.edu/mailman/private/sursound/attachments/20110729/967e0688/attachment.html> > _______________________________________________ > Sursound mailing list > Sursound@music.vt.edu > https://mail.music.vt.edu/mailman/listinfo/sursound _____________________________________________ Dr David Worrall Experimental Composer, Polymedia Adjunct Research Fellow, Australian National University david.worr...@anu.edu.au Board Member, International Community for Auditory Display Regional Editor, Organised Sound (CUP) IT Projects, Music Council of Australia worrall.avatar.com.au sonification.com.au -------------- next part -------------- An HTML attachment was scrubbed... URL: <https://mail.music.vt.edu/mailman/private/sursound/attachments/20110730/8c10d89b/attachment.html> _______________________________________________ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
