Many of us in The current discussion participated in an earlier discussion about The importance of head tracking around 9 months ago, so that is more or less understood :-)
Best regards Bo-Erik Den 6 dec 2015 19:48 skrev "Stefan Schreiber" <st...@mail.telepac.pt>: > Fons Adriaensen wrote: > > On Sat, Dec 05, 2015 at 06:06:08PM +0000, Stefan Schreiber wrote: >> >> >> >>> Fons Adriaensen wrote: >>> >>> >>> >>>> * The hedgehog is at least twenty times as big. >>>> >>>> >>>> >>> Hardly... >>> >>> >> >> Depends on which picture you look at, but OK, let's say ten times >> (see Fig.12). >> >> > No, Fig. 12 very obviously is something different. > > Since both microphones >> layers are identical they are working as an A/B configuration also in the >> vertical axis. >> > > > The supercardioid hedgehog is pictured on p. 19 and labelled as such. I > wrote this, the dimensions are the ones I have cited. > > >> >>> The OZO's will >>>> be omni over most of the frequency range and turn into >>>> something like subcardioid only at very frequencies >>>> (above 4 kHz or so). >>>> >>>> >>> And how can/could you know this? >>> >>> >> >> Basic theory really. >> >> No matter what type of mic you place behind such a tiny hole, it will >> pick up the pressure at that tiny hole. So apart from >> diffraction effects the result will be omni. >> >> > > But the pressure will come from -90º to +90º, at least mainly? If so, the > capsule "view" is 180º, not 360º. (Case as shield) > > It's not too difficult to compute the diffraction caused by >> a solid sphere. You can see the resulting polar patterns for >> 16 cm diameter sphere here: >> >> <http://kokkinizita.linuxaudio.org/export/sphere16.pdf> >> >> > > Serious question: Is this not (more or less) a cardioid response?! > > > Even if the OZO isn't exactly spherical, the results will >> be similar. >> >> It's also interesting to look at the result of taking the >> difference signal of two diametrically opposed capsules: >> >> <http://kokkinizita.linuxaudio.org/export/sphere16-diff.pdf> >> >> This produces a usable fig-8 up to 1 kHz or so (with lower >> frequencies requiring additional gain). Above that, chaos >> takes over. Using more mics (e.g. the four frontal ones >> minus the four at the back) will not improve things. >> >> > > But if it IS a hedgehog based mike, this is no issue. > > Which doesn't mean my theory is proven, but also no argument against > here... O:-) > > Probably it would be helpful to ask Nokia, in any case. > > Best, > > Stefan > > Note that such a fig-8 pattern is a component of any first >> degree directional pattern and also of most higher degree >> ones. If can't be obtained then the same is true of any >> pattern of which it is a component. >> >> Caio, >> >> >> > > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: < > https://mail.music.vt.edu/mailman/private/sursound/attachments/20151206/cdd8f043/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. > -------------- next part -------------- An HTML attachment was scrubbed... URL: <https://mail.music.vt.edu/mailman/private/sursound/attachments/20151206/038c0aef/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.
