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Finding directional transfer functions by means of in-ear signal sampling.

Calculating hrtfs for signals from various directions

Directional signal sampling

In order to find directional HRTFs for our test subject, we first had to make recordings of the signals as heard by the test subject coming from different directions. In order to do this, we placed our microphone in the ear to be tested, as shown below.

In-ear microphone setup for the left ear

We then played our chirp signal at the test subject from various directions with the speaker at the same distance as in the initial channel characterization. As in the initial channel characterization, we sampled twice for each direction and averaged the two results. After sampling for that particular ear, we then switched the microphone to the other ear and sampled the same directions for the other ear.

The five sampling directions used to find HRTFs

Hrtf calculation

In the initial channel characterization, the transfer function H Channel ( ω ) size 12{H_ ital "Channel" \( ω \) } {} was the only thing acting on the chirp signal. Now, with the microphone situated in the test subject’s ear, both H Channel ( ω ) size 12{H_ ital "Channel" \( ω \) } {} and the directional HRTF for that particular ear H Directional ( ω ) size 12{H_ ital "Directional" \( ω \) } {} act on the chirp signal. In other words:

H Channel ( ω ) IN ( ω ) H Directional ( ω ) = OUT ( ω ) size 12{H_ ital "Channel" \( ω \) cdot ital "IN" \( ω \) cdot H_ ital "Directional" \( ω \) = ital "OUT" \( ω \) } {}

Since we already calculated H Channel ( ω ) size 12{H_ ital "Channel" \( ω \) } {} and IN ( ω ) size 12{ ital "IN" \( ω \) } {} during the initial channel characterization, and we can find OUT ( ω ) size 12{ ital "OUT" \( ω \) } {} for each particular ear/direction combination by taking the fft of our recorded outputs, we can therefore calculate H Directional ( ω ) size 12{H_ ital "Directional" \( ω \) } {} using the equation:

H Directional ( ω ) = OUT ( ω ) / [ H Channel ( ω ) IN ( ω ) ] size 12{H_ ital "Directional" \( ω \) = ital "OUT" \( ω \) / \[ H_ ital "Channel" \( ω \) cdot ital "IN" \( ω \) \] } {}

Questions & Answers

how do they get the third part x = (32)5/4
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ninjadapaul
20/(×-6^2)
Salomon
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ninjadapaul
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ninjadapaul
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Salomon
I'm not sure why it wrote it the other way
Salomon
I got X =-6
Salomon
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ninjadapaul
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ninjadapaul
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ninjadapaul
Commplementary angles
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Kim
The answer is neither. The function, 2 = 0 cannot exist. Hence, the function is undefined.
Al
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Kristine 2*2*2=8
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Differences Between Laspeyres and Paasche Indices
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No. 7x -4y is simplified from 4x + (3y + 3x) -7y
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. After 3 months on a diet, Lisa had lost 12% of her original weight. She lost 21 pounds. What was Lisa's original weight?
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I start with an easy one. carbon nanotubes woven into a long filament like a string
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AMJAD
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Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
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Stotaw
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
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Prasenjit
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Damian
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Prasenjit Reply
At high concentrations (>0.01 M), the relation between absorptivity coefficient and absorbance is no longer linear. This is due to the electrostatic interactions between the quantum dots in close proximity. If the concentration of the solution is high, another effect that is seen is the scattering of light from the large number of quantum dots. This assumption only works at low concentrations of the analyte. Presence of stray light.
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the Beer law works very well for dilute solutions but fails for very high concentrations. why?
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Source:  OpenStax, The science of surround sound. OpenStax CNX. Dec 18, 2010 Download for free at http://cnx.org/content/col11254/1.2
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