1. distance, m (log scale) -25o 0o +25o C50, dB left right L-shaped12
left
right
-25o 0o
+25o 10
2.5
C50, dB
L-shaped
corridor
room 1l08
room 155
room 157

2. Some further data on ‘wide-band scn’ contexts
scn is speech → noise
operation is performed on the wide-band signal (unlike the vocoder manipulations)
reverse polarity of a randomly-selected half of the samples, then apply a speech-shaping filter
‘noise before’ conditions:
room impulse response (BRIR) applied after the scn operation
in this condition of Watkins, 2005, expt. 4:
no effect of test-word’s reverb.

3. L-shaped room, as before
This experiment
similar except:
‘to click on ‘ part of the context stays as speech in ‘noise before’ conditions
monaural (left ear)
stressed (slow) test-words and context speech
looks at the effect of a context-length (685 ms) gap preceding the test-word
4 observations per stimulus from each of 6 listeners
L-shaped room, as before

4. category boundary, step
context’s distance, m
category boundary, step
.32
10. 5 10
no gap
test dist.=10. m
test dist.=.32 m
gap
speech
noise (before)
compensation effect with speech
gap reduces the effect, but it’s not entirely eliminated
effect is marginal or absent in noise (before) conditions
no influence from ‘to click on’

5. as reverb increases, mean increases
Temporal envelopes of context and test-word in an auditory (gammatone) filter, fc= 4.2 kHz
as reverb increases, mean increases
but this effect is if anything more apparent with the noise context
noise (before)
speech
0.32 m
10. m
amplitude re. max 1
time, s

6. Is temporal structure of reverb pattern important?
8-band vocoder, one channel:
if scn comes after the BRIR operation
temporal structure is scrambled
e.g. as measured by autocorrelation:
consider a single reflection
scn flattens its combfilter spectrum
forwards reversed
gammatone gammatone
speech → → scn → →
BRIR

7. category boundaries higher than in mismatched
context’s distance, m
group 2 1
4-,8-band
mismatched
matched
unprocessed
speech
test dist.=10. m
test dist.=.32 m
.32
10.
category boundary, step 5 10
mismatched, both groups
matched, group 1
matched, group 2
test word
context
category boundaries higher than in mismatched
could well be an inverse filter effect
if even bands have more info about the [t] …

8. Inverse-filter effects with wideband (smother) temporal envelope?
replace speech input with wideband scn
8-band vocoder, one channel:
forwards reversed
gammatone gammatone
scn → → scn → →
BRIR

9. Band importance experiments using compensation effect, rather effects of reverb on the test-word.