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Problem with binaural perception.

post #1 of 12
Thread Starter 

Recently, I've decided to try and use stereo convolver plugin for fb2k with my modded Fostex T20RP. I've written a somewhat similar post in appropriate thread, but here I have a different question.

 

While trying different samples from IRCAM demo sound page (http://recherche.ircam.fr/equipes/salles/listen/sounds.html) I've noticed that I'm consistently unable to localise any sound in 10:30 to 03:00 region (12:00 being dead ahead). When sound source passes 10:30 boundary, it gets mirriored to 7:30 position and moves to 03:00 position in the rear hemisphere rather than front. There were also some cases with zero frontal localisation at all, with sound either mirrioring to rear hemisphere moving out of head, or even moving straight through head from ear to ear.

 

I have also tried to listen to "Holophonics - Matches" on youtube (http://www.youtube.com/watch?v=HprNPCRyP40), which had exactly the same effect. No problem with top-down localisation and localisation in the rear hemisphere at all.

 

I've thought that this may be due to headphones not having enough angle conflicting with my ears' shape, and posted about that in T50RP thread. However, since then, I've tried it also on SHP2700 headphone, also doing stuff such as lifting HP's up to 10 cm from ears, angling them, rotating them around the head so right earpiece is near 01:00 and left is at 7:00, etc, but the effect was always the same: complete left-right, top-down and distance localisation in read hemisphere and almost no localisation in front.

 

So it seems that the case is me. I've got no speakers, but tried to localise some other sound sources and seems that indeed I have problems locating sounds in front-right sector. However, I am probably now suffering from cognitive bias and cannot rely on what I feel.   Though I'm rather sure that somewhat reduced high-frequency hearing on right ear is not a bias product (not extension, it's roughly equal to left ear (tried that once on headphones using SineGen), but level (in real life perception, not by test). However, that difference is slight.

The only objective measurement I have is that my left ear's pinna is parallel to head and doesn't stick out, while right one sticks out. Also I have had recurring otitis on left ear and have to use some drugs on it about once in a year.

 

So the question is: are there any home-reproducible scientific methods of determining hearing's spatial resolving capability? Or at least not home-reproducible, just for information. I've tried googling a bit, but haven't found anything straight out yet.

 

Thanks!

post #2 of 12

Are you using the stereo convolver plugin during this test?  Have you tried it with the plugin off?  Are you sure it's off?  

 

It would be simple to verify at home that your actual ability to localize is working. Close your eyes and have a friend try some randomly positioned finger snaps, see if you can tell where they come from.  I'm betting your localization ability is working just fine.

post #3 of 12

Afaik, these test sounds were created using real persons. If the anatomy doesn't match yours then some things aren't going to work. Don't worry.

 

 

Do you have a swivel chair? You could close your eyes and do a couple of turns so you don't know which way you're facing and play some sound through a speaker or even headphone. Then point in the direction the sound is coming from and open your eyes. ;)

post #4 of 12
This is a common problem if the HRTF being used isn't matching well with the listener. Try different software and see if anybody uses something similar to your ears. You might be SOL though.
post #5 of 12

Even the worst HRTF mismatch still will localize in a generally correct way. You just won't get the really solid imaging, and center front vs center back may not work well. The OP complaint sounds very much like a wayward plugin in use.  He can easily test is own ability to localize sounds, but that hardly ever goes bad without some other severe hearing issue, typically one ear suffering a severe loss, which would scramble normal stereo too.

post #6 of 12
Thread Starter 

xnor,

The chair test was what I tried to do, but there was too many clues that'd help the brain localise the sound. I couldn't get consistent result and was a bit frustrated.

 

jaddie,

I was silly not to think about something as simple as that :) Perhaps due to frustration. Indeed, I was unable to localise snaps in front-right sector - they all seemed directly right to me. No problem with localisation in any other sector though.

 

I was listening to "Matches" and IRCAM sounds using browser, so there was no plugin. :)

 

Draygonn,

What does SOL mean in that case? English isn't my native, and haven't found anything possibly related in Wiki, sans for being out of luck. :)

post #7 of 12
Quote:
Originally Posted by Nevod View Post

 

jaddie,

I was silly not to think about something as simple as that :) Perhaps due to frustration. Indeed, I was unable to localise snaps in front-right sector - they all seemed directly right to me. No problem with localisation in any other sector though.

 

I was listening to "Matches" and IRCAM sounds using browser, so there was no plugin. :)

 

Draygonn,

What does SOL mean in that case? English isn't my native, and haven't found anything possibly related in Wiki, sans for being out of luck. :)

If you're having trouble with only one or two directions, it's probably a HRTF issue.  Yours is just different enough from what was used in the recording that one particular direction isn't working.

post #8 of 12
Thread Starter 
Quote:
Originally Posted by jaddie View Post

If you're having trouble with only one or two directions, it's probably a HRTF issue.  Yours is just different enough from what was used in the recording that one particular direction isn't working.


I meant I have the same  problem  IRL, not just with headphones. So it's me, not the recording. 

post #9 of 12

from tech support:

Click "Start" then select "Restart".  

 

Oh, wait...it's you...

 

 

Seriously, that's a very odd problem to have.  Have you had your hearing tested?

post #10 of 12
Thread Starter 
Quote:
Originally Posted by jaddie View Post

Seriously, that's a very odd problem to have.  Have you had your hearing tested?

Nope, never had any real complaints about it. I didn't even ever noticed I have localisation problem, as in the most cases visual clues allow me to pinpoint sound location (I hear sound in the proper direction with eyes open) and in the cases I didn't I also haven't thought about it much - when you hear some car blowing horn, you try to find it, not to think why you didn't discern direction from just the sound. :) 

I'll try to go for a check surely, though not asap, as it doesn't have any real practical implications for me..

post #11 of 12
Thread Starter 

The good thing about all that is this time I did set up the stereo convolver correctly. Made the sound much less bright and more comfortable. Noticed some details that were hard to notice otherwise. Have some suspicions about IRCAM's equalisation though, not explained well enough on their site.

post #12 of 12

It is possible to have difficulty processing different aspects of sounds Here is a reference link to APD.   http://en.wikipedia.org/wiki/Auditory_processing_disorder

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