> > Message: 10 > Date: Tue, 10 Jan 2017 08:42:43 -0000 > From: "Alan Varty" <alan.va...@talktalk.net> > To: "Surround Sound discussion group" <sursound@music.vt.edu> > Subject: Re: [Sursound] The BBC & Quadrophony in 1973 > Message-ID: <26495940C1B04DA6B9C600AD83F69931@AlanPC> > Content-Type: text/plain; format=flowed; charset="iso-8859-1"; > reply-type=response > > I think I am correct in saying the BBC (H) and NRDC (45j) decided to > co-operate rather than have yet another two competing systems on > the 4-channel scene which at the time already had CD-4, UD-4, SQ and > QS in the arena. BBC/NRDC each modified their encoding "towards" > each other and called it HJ.
As I recall, the BBC were getting bad reviews of the stereo produced by matrix H and discussed this with MAG who proposed a compromise. UHJ was a variation within the 5 parameters which define an Ambisonic encoding, mainly a reduction in the centre front phase shift compared with 45J, based on many listening tests. It was known internally as 35JA’, so you can guess there was a whole family of small variations. BBC HJ was defined as a set of tolerance zones on the locus, mainly defined with reference to pairwise panning, I think it coincided with the UHJ locus at four points , so in that sense it was compatible; the exact parameters of both variations were defined by MAG. In subsequent tests the BBC made, primarily using SFMs, they also used our encoders, so I suspect drama productions such as Gilgamesh and Inferno Revisited are actually UHJ. Geoffrey _______________________________________________ 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.
