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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

where we get a research paper on Nano chemistry....?
Maira Reply
what are the products of Nano chemistry?
Maira Reply
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
learn
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
learn
Google
da
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Bhagvanji
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
revolt
da
Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
Nasa has use it in the 60's, copper as water purification in the moon travel.
Alexandre
nanocopper obvius
Alexandre
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
Hafiz
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
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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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