[ossrp-control] Re: What Is A Screen Reader?

Hi Rich,

Yes, 3D sound over headphones is often better than that through speakers. Using a Head Related Transfer Function (HRTF), that combines the Interaural Intensity Difference (IID), Interaural Time Difference (ITD) and the spectral cues that our brains use to localise sound positions, you can create 3D Sound using headphones. We all have individual HRTF maps, and so a general HRTF, one that's been created by taking the average of a series of measurements, won't initially give as accurate a representation as naturally occuring 3D sounds would, but there's a growing body of neurology research suggesting that given time our brains adapt to the new HRTF mappings whilst retaining the old ones at the same time.

One reason for the difference in localisation ability between speakers and headphones is reverb. There's growing research suggesting that it's not just the IID and ITD that our brains use to judge the distance of a sound source from us, but that reverb also plays an important part. Barbra Shinn-Cunningham from the Boston Hearing Research Centre has suggested that IID and ITD alone only provide accurate distance perception when a sound is one metre or less away from a listener. Durand Begault, of NASA's Advanced Displays and Sensory Perceptions lab, describes inside-the-head localisation of sound, where sound appears to be coming from inside the region of the listener's head, in one of the chapters. He goes on to suggest that adding reverb externalises the sound, in other words makes the sound appear as though it's located outside of the listener's head, and my own research with Microsoft's DSound has drawn the same conclusions. So, reverb is obviously an important factor in determining a sound's distance, and using headphones you have more control over reverb than you do with speakers as a result of there being no natural reverb present from the walls, ceiling and floor of the room in which the listener is located.

Will
----- Original Message ----- From: "Rich Caloggero" <rjc@xxxxxxx>
To: <ossrp-control@xxxxxxxxxxxxx>
Sent: Friday, June 03, 2005 9:11 PM
Subject: [ossrp-control] Re: What Is A Screen Reader?


Yes, using multi-channel sound seems like it would be useful, or
alternatively a good 3D positioning scheme which encodes 3D sonic
information in stereo to be listened to via headphones...  I don't think
this is precise as vission, but it could certainly fill in the gaps so to
speak.

If you want to check out a game which uses this technique, check out the
game "Shades of Doom" from www.gmagames.com
There are other games which claim to do this, but in my humble opinion, this
is the only one which truly works and does it right!

-- Rich

----- Original Message -----
From: "Veli-Pekka Tätilä" <vtatila@xxxxxxxxxxxxxxxxxxxx>
To: <ossrp-control@xxxxxxxxxxxxx>
Sent: Friday, June 03, 2005 3:19 PM
Subject: [ossrp-control] Re: What Is A Screen Reader?


Hi Rich,
Thanks for mentioning the shortcuts for traversing doc items on the Mac
side, that are different depending on the orientation of the doc. Yet
another feature that can easily require some notion of screen layout.

Usually in Windows, the direction stays the same regardless of physical
layout. For example, take opening sub-menus. Sometimes if there's not enough
space on the right, I've noticed the sub-menu may open at the left side of
it's parent or originating menu. Yet the logical keyboard shortcut to open
it is still the right arrow key. Also, I think the graphical arrow symbol
always points right.

Speaking of screen reader demos in presentations, I've got good experiences,
too. It was actually a course about scientific writing but I chose problems
of current screen readers from a user point of view and had a 15 minute
screen reader demo at the end with Supernova. The sighted people who were
present found the example helpful especially the bits about inaccessible
bitmapped text.

By the way, I've got enough sight to get some sparse layout info even
without magnification. Yet I cannot easily read text under say 28 pt, so I
use Supernova's magnification extensively. Also, apart from vague
recognizable shapes, I don't benefit much from icons either and would rather
turn them off to have a minimalist visual layout.

I also like the idea of being able to navigate freely in a certain direction
using virtual focus, view finder or whatever the screne reader specific
navigation mode is called. Though I do think that it might be very hard for
a totally blind person as it relys on layout information that the screen
reader doesn't ordinarily convey. Howabout conveying it with Torihara's
speaker matrix?

http://www.csun.edu/cod/conf/2002/proceedings/100.htm

I find the idea fascinating and do have a real multi-channel sound card. An
unconventional speaker setup in which up is really up rather than forwards
might work well. Howabout using pseudo-surround sound with headphones as in
some games, is that feasible?

Just my two cents.

With kind regards Veli-Pekka Tätilä (vtatila@xxxxxxxxxxxxxxxxxxxx)
Accessibility, game music, synthesizers and programming:
http://www.student.oulu.fi/~vtatila/

Rich Caloggero wrote: 
This sounds interesting, but again there should be a way of disabling
such a "feature" when not wanted.

When looking at VoiceOver for the Mac recently, I ran into a situation
similar in spirit to this type of "directional navigation".  If the mac
start menu was placed along the bottom of the screen, left/right arrows
move you through its items; if its placed along the side of the screen
then up/down moves you through it.  However, not knowing this, I spent
about half hour trying to figure out why I couldn't access the items on
the menu the way I had the day before. It was only when I got sighted
help that I learned of this "feature"! I'd turn it off in a minute,
unless I were in a program (such as perhaps a layout program or something
where position really does matter).

Interesting to speculate here, but I suspect that if we survey all the
blind folks on this list, we'd find two camps: those of us who are
totally (or close to totally) blind and have never had (or remember
having) sight will not want (or feel overwhelmed by) such "features";
those who currently have some sight, or who remember having sight will
find this kind of thing helpful and useful.  Our senses do actually
modify our neuro connections, especially in a very young brain. So, if
one has sight up to about age 7, the brain has been shaped by it. Folks
who have lost their sight before this age, or who have never had it will
most likely have a very different set of connections, i.e. their brains
will be wired differently.

-- Rich 

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