Subject: Re: spatial separaton From: Al Bregman <BREGMAN(at)HEBB.PSYCH.MCGILL.CA> Date: Thu, 1 Feb 2001 20:42:23 -0500Dear Peter, The trick is to find an experimental framework that is rich enough to capture meaningful aspects of the pattern of sound that occurs in everyday life, but is simple enough that answers can be obtained. Al ----- Original Message ----- From: Peter Lennox <peter(at)LENNOX01.FREESERVE.CO.UK> To: <AUDITORY(at)LISTS.MCGILL.CA> Sent: 1-Feb-01 1:57 PM Subject: Re: spatial separaton ... ... > In fact this discussion touches on the question I asked earlier of the list > for opinions on "sound fields" as against "sound environments"; what we > actually perceive are the latter, but what we use to conceptualise > perception are the former. Perceptual segregation in the former is > relatively poor, compared to that in the latter. In 'real' environments, > some classes of information are manifested only in richly varying conditions > through space and time; controlling variables in experiment design using too > strict parameters might well negate exactly those classes of information > which facilitate what we actually mean by "perception", as against the > simpler 'stimulus-response' type reflex which is manifestly not what we mean > by perception. Given that even the simply defined 'precedence effect' has a > substantial 'soft' component (Moore, Brian, AES16th .,1999), richer > hypotheses are needed. Simply enriching 'bottom-up models with a leavening > of 'top-down-ness' is not enough. > Are there any experimental psychologists out there? > > > > regards, > ppl > > Peter Lennox > e-mail: peter(at)lennox01.freeserve.co.uk > or:- ppl100(at)york.ac.uk > > > ----- Original Message ----- > From: "Ward Drennan" <ward(at)IHR.GLA.AC.UK> > To: <AUDITORY(at)LISTS.MCGILL.CA> > Sent: 01 February 2001 10:26 > Subject: Re: spatial separation and ASA > > > > > In other words, > > > in cases where two signals were partially segregated by factor X, > > > adding a difference in location would strengthen the segregation. > > > > By separating spatially, you'll get a change in signal to noise ratio at > > the two ears that will inevitably help. I think the work of Plomp (1976, > > Acustica 34, 200-211) on speech intelligibility sheds some light on > > this. In an anechoic environoment, spatial separation of two speech > > sources gives a 5 dB advantage for speech intelligibility. If the > > environment gets very echoic though, the advantage drops to 1 to 2 dB. > > Note that head shadow plays a big role here. If you were to low-pass > > filter the speech (limiting mostly to interaural timing cues), I bet the > > advantage would drop to 2 or 3 dB in the anechoic and be non-existant in > > reverberation. > > > > Perhaps there are some more studies showing this? Speech has a number of > > segregating cues, but can anyone point to more constrained studies that > > show this, maybe with only one factor X? > > > > >We know that spatial > > > differences do play an important role in SEQUENTIAL grouping.). > > > > Perhaps because of the integration of consitstant interaural cues over > > time yeilding a clearer 'picture' of the scene? > > > > > My point about spatial information was not that it was very weak > > > but that it was only one of a number of cues for sound > > > separation. To this should be added the idea that it may need > > > those other cues in order to be effective itself. > > > > > Yes, perhaps the human is better at Auditory SA than the machine, > > because people are especially good at integrating all the information. > > > > Best Regards, > > Ward Drennan > > > > Peter Lennox > Hardwick House > tel: (0114) 2661509 > e-mail: peter(at)lennox01.freeserve.co.uk > or:- ppl100(at)york.ac.uk >