Interestingly, he dinosaur size geese (John Leonard's recording "when geese go bad") was played in a field, speaker radius 15-20 metres. And the passing motorbike was impressively large, too.
AS a rule of thumb, I've always found that one needs to bear in mind the speaker array radius when deciding on the source-mic relationships. Even in a not-very-reverberant outdoor setting, there seems to be some perceptual constancy for speaker distance - this could be using visual, prior knowledge, auditory-only or combination cues. We've observed the same thing for movement plausibility, with recordings of rolling balls. They have to change angle only as much as the rolling sound (which gives reasonable speed cues) would allow, for a particular speaker distance (range). So, if you want to 'scale up' to a bigger rig, then you need to re-pan (where discrete mic recordings are used) - the perceptual understanding of speed draws on far more than change-of-subtended-angle - and when the cues clearly conflict, the mediated nature 'leaps out' at you. Dr Peter Lennox School of Technology University of Derby, UK tel: 01332 593155 e: p.len...@derby.ac.uk -----Original Message----- From: sursound-boun...@music.vt.edu [mailto:sursound-boun...@music.vt.edu] On Behalf Of Dave Malham Sent: 31 May 2012 09:26 To: Surround Sound discussion group Subject: Re: [Sursound] Chasing flies with ambisoinics? Hi Fons On 30/05/2012 18:24, Fons Adriaensen wrote: > On Wed, May 30, 2012 at 02:10:22PM +0100, Augustine Leudar wrote: > >> but anyone listening carefully would have heard a fly about 1 foot high ! > This magnification effect has been reported many times. > I wonder how much it has to do with playing back at too high > levels. We do associate LF energy and size. Too much of it > and the source 'must be' big. That's certainly important - kind of the other end of the scale of quite but distorted sounds can be interpreted as very loud sounds but with a distant source. For sound sources with perceivable angular extensions which are perceived as single objects (pianos, geese and steam loco's have been mentioned in the past), there is an even stronger cue in that for the angles to be right the perceived size of the object is set by the perceived distance which can in turn be modified if the reproduction space reverberation is dominant over the recorded reverberation. Whilst familiarity with the source can overlay some of this , even in York, where we are so familiar with geese ** that there's an informal ban on students recording them, we still find it difficult to hear anything other than Peter Lennox's giant geese when an Ambisonic recording is played back in a reverberant room. Dave ** At present I can see half a dozen Canada geese with young outside my window and some Greylags out on the lake - and I can hear a lot more! . PS - I gather you guys in Parma might be getting pretty shaken up by the earthquakes in Northern Italy - hope all is well there. -- These are my own views and may or may not be shared by my employer /*********************************************************************/ /* Dave Malham http://music.york.ac.uk/staff/research/dave-malham/ */ /* Music Research Centre */ /* Department of Music "http://music.york.ac.uk/"; */ /* The University of York Phone 01904 322448 */ /* Heslington Fax 01904 322450 */ /* York YO10 5DD */ /* UK 'Ambisonics - Component Imaging for Audio' */ /* "http://www.york.ac.uk/inst/mustech/3d_audio/"; */ /*********************************************************************/ _______________________________________________ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound _____________________________________________________________________ The University of Derby has a published policy regarding email and reserves the right to monitor email traffic. If you believe this email was sent to you in error, please notify the sender and delete this email. Please direct any concerns to info...@derby.ac.uk. _______________________________________________ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
