we used a much cruder version of this back in 2002 - decoding a hemispherical 32 speaker array to second order, but crossed over the B-format at 90Hz (I think) to a horizontal-only 8-sub array, decoded in 1st order. This was on the basis that we couldn't fly the subs, and anyway, elevation discernment, being largely due to pinnae affects, was not appealed to by the subs anyway. Had to work on the time alignment (the sub decoder was analogue, the mid'n'tops 32 speaker array done in software) and spatial alignment (rotating the subfield to match t'other, in the b-format feed). It worked well, though could have been further refined; it was a one-off installation. But the principle of using decreasing order with decreasing frequency made sense from the point of view of efficient use of transducers.
It made me wonder whether the same principle extends the other way - increasing order with increasing frequency, to make up for the deficiencies in spatial resolution of lower orders at HF. Given that it should now be reasonably 'easy' to align the fields of multiple cells - even having differnt numbers of speakers for each frequency band, there might be less reason to assume that point source speakers are strictly necessary. We're still using speakers designed as stereo projection systems, and it could even be that starting again, thinking about real-world usages of ambisonics, that one could revisit the speaker design theories. Going off on a tangent, it might be that (as others have experimented with, before) that the trasnducer design for the programme material which is 'ambient' (reflected sound, from no particular source, and therefor not requiring precision in phantom imagery) might differ than that for the'virtual sources' ('images') So I experimented with 12 very modest nxt-type flat panels which were rotated thru' 90 deg. to what you'd expect, as it were - that is, they didn't 'face' the centre but were at right angles to it. The results (given the modest set up) were better than they had any right to be - most especially for ambient and distant sounds. I know they used to use multiple dipoles on the walls in cinemas for conveying the surround channels of 5.1 material (they might still do, I never go to the cinema because of the loud, poor sound) - so this seems to be a similar principle. Just a few ramblings cheers Dr. Peter Lennox Senior Fellow of the Higher Education Academy Senior Lecturer in Perception College of Arts University of Derby Tel: 01332 593155 ________________________________________ From: Sursound [sursound-boun...@music.vt.edu] On Behalf Of Jörn Nettingsmeier [netti...@stackingdwarves.net] Sent: 16 October 2015 12:15 To: sursound@music.vt.edu Subject: Re: [Sursound] Advice on new loudspeaker array... Genelec 8010 speakers? On 10/15/2015 10:51 PM, Dave Malham wrote: > One of the things that should be investigated in conjunction with higher > order Ambisonics material would be to "fade down" the higher order > components as the frequency drops, thus spreading the bass over more > speakers, reducing the strain on the individual speakers whilst maintaining > the spectral balance - hey, wasn't that Richard Lee's Powered Integrated > Sub concept from several years ago?? Doesn't help with first order materiel > but.... > <ears pricked up> Intriguing idea, that. So we would apply zero-phase high-pass filters to the second and higher components? Should be nice for a test run, but how to keep latency down for live electronics and A/V sync? How would we phase-align an IIR filter? Allpasses on the lower components? The spectral balance would be maintained despite the filters, since we're in LF, where each new order "takes away" as much as it "adds", so to say. Unlike at HF, where we have to add energies and any such filtering throws the spectral balance of kilter, as Eigenmike users will know... -- Jörn Nettingsmeier Lortzingstr. 11, 45128 Essen, Tel. +49 177 7937487 Meister für Veranstaltungstechnik (Bühne/Studio) Tonmeister VDT http://stackingdwarves.net _______________________________________________ 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. The University of Derby has a published policy regarding email and reserves the right to monitor email traffic. If you believe this was sent to you in error, please select unsubscribe. Unsubscribe and Security information contact: info...@derby.ac.uk For all FOI requests please contact: f...@derby.ac.uk All other Contacts are at http://www.derby.ac.uk/its/contacts/ _______________________________________________ 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.