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36

Yes, we can. By means of bone conduction we can hear up to 50 kHz, and values up to 150 kHz have been reported in the young (Pumphrey, 1950). However, it is indeed generally agreed that 20 kHz is the upper acoustical hearing limit through air conduction. The reason for this is debated, but the transfer function of the middle ear ossicle chain is a suspected ...


12

A quick diagram to point out to people who may not know what Eustachian tubes are (#2). In order for the aromatic molecule to reach the olfactory bulb, it would first have to get through the Tympanic Membrane (#22) [a.k.a. - Eardrum]. The Tympanic Membrane is water/airtight unless pierced. So, while it's plausible that an aromatic molecule could travel ...


12

The only sensible answer to these questions is "sometimes". The reason: even a simple monotone must be described by both frequency and amplitude. Any frequency can cause harm with enough amplitude, and any frequency can be harmless when the amplitude is low enough. If you want to actually quantify the damage, you'll need something like an equal-loudness ...


7

If all the processes through which a signal passes are linear, then it makes sense to speak in terms of a maximum useful-content frequency. If a signal passes through non-linear stages, however, it is possible that frequency content which would in and of itself be above the range of hearing, may interact with other frequency content which is also above that ...


7

There is no direct link between the capillaries in the sinuses and the ear. The Eustachian tubes drain the middle ear (between the eardrum and the inner ear) into the nasopharynx, the part of the throat that is just behind the nose. The para-nasal sinuses drain into the nasal passages themselves at different points. The sinuses and middle ear constantly ...


7

Although tinnitus is usually described as a ringing in the ear, there's a whole range of tunes, buzzes, whooshing sounds, humming and hissing sounds that are described of as tinnitus. The sounds can either genuinely be there or be perceived to be there. If it is genuinely there it suggests muscles ate at play or some blood vessel disease if the sounds are in ...


6

I will provide an answer in 2 parts. The first part is a theoretical approach based on the absolute possible minimum (my original answer). The second part focuses on experiments in the peripheral auditory system (added edited answer). PART I: Absolute theoretical minimum (original answer) As you inquire about electrical signals in the auditory human system ...


6

As quoted from the wikipedia page on Earwax: Cerumen [earwax] is produced in the outer third of the cartilaginous portion of the human ear canal. It is a mixture of viscous secretions from sebaceous glands and less-viscous ones from modified apocrine sweat glands. The primary components of earwax are shed layers of skin, with 60% of the earwax ...


6

If you are talking about sound damaging the sound sensing organs in the ear, analogous to an ultrasonic heavy metal concert, I've found an interesting report just on this topic. For ultrasonic components above 20 kHz, the limits were set to avoid hearing damage in the audible (lower) frequencies. One-third-octave band levels of 105-115 dB were observed ...


5

It is related to Eustachian tube. It links the back of throat and the middle ear and allows air pressure to equalize in the middle ear. When you yawn air pressure goes up in this and it bends the ear drum and causes impair hearing (notice, just impair and not stop). Yawning also helps to open Eustachian tube.


5

@MCM gave a succinct and accurate description of how a healthy and "normal" person will not be able to smell via olfactory sensing trough the Eustachian tube. Here is an interesting concept in which the brain is able to confuse senses, or alternatively, use sensory input as a metaphor for interpretation via another sensory output. This is a condition known ...


5

+1 for giving a solid answer to @AP, but being older I've had friends who have had tinnitus and I'd like to add some notes to try to flesh this out a bit. I don't think tinnitus is the result of nerve damage usually. Nearly everybody experiences episodic tinnitus at one point or another. When exposed to a loud sound or a blow to the head can cause it. ...


5

Yes, of course they can. What happens when your ears feel 'full' like on an aeroplane is that the air pressure in the middle ear is different from the air pressure outside. When you 'pop' your ears, you push open the Eustachian tubes that connect the middle ear to the throat and make the pressure equal. No matter what the air pressure, the air still conducts ...


5

Acoustically, we hear better in the 2-5 kHz range because our auditory canal resonates in that range (specifically, around 3 kHz). Our ear looks something like this (U Miami): The auditory canal is part of the outer ear, which amplifies sound so that it can be converted into electrochemical signals by the middle and inner ear. We hear better in the 2-5 ...


3

Preamble. There is a lot of misunderstood science here and you are more than right for questioning the lecturers interpretation of these energy values; something the other answers do not discuss. The problem arises from a dodgy reference and a lot of conjecture. In summary. Light and sound cannot be compared energetically in a biological context. Our ears ...


3

This phenomenon is called Ototoxicity, which literally means "toxic for the ear". Mostly the cochlea or the auditory nerve are affected and almost all these cases are connected to medications as gentamicin or cisplatin. The reasons for this are that the cells are either driven into apoptosis or necrosis. This is caused by destroying mitochondria and ...


3

Short answer Hearing threshold is 0 dB SPL at 1 kHz, and pain threshold is around 125 dB SPL at that frequency. Background Loudness thresholds depend on acoustic frequency (pitch), as depicted in the following figure: Loudness contours in human. Source: Stanford Uni When expressed in dB sound pressure level (dB SPL) the threshold of pain is approximately ...


2

Copied from my comment: It just means a sound that starts at a low frequency and goes up to a higher frequency like a whistle sound. Perhaps someone can give you an example sound file and/or a spectrogram representation of it.


2

Taken from "24/192 Music Downloads... and why they make no sense": Sampling rate and the audible spectrum I'm sure you've heard this many, many times: The human hearing range spans 20Hz to 20kHz. It's important to know how researchers arrive at those specific numbers. First, we measure the 'absolute threshold of hearing' across the entire ...


2

Apparently some (small amount of) tinnitus is caused by, or at least associated with, otoacoustic emissions. This paper covers the link if you are interested. If you want a great talk that generally covers the molecular mechanisms behind hearing, I highly recommend this one by James Hudspeth. This covers a ton of material, including otoacoustic emissions, ...


2

Humans do not have the ability to move their outer ear in response to sound. Many animals can do that, and use it to determine the source of the sound waves. Thus, human outer ears are equipped with many "hills and valleys". It does not provide amplification (because the waves can lose their energy bouncing around the ridges), but rather gives the brain more ...


1

Basically you are asking: (1) does the low-pitch noise affect my hearing sensitivity; (2) has the noise aggravated hearing loss acquired earlier in life; (3) if the noise can induce stress and (4) if the noise may cause tinnitus (kind of a hidden question). (1) Is the ventilator noise damaging?: Noise-induced hearing loss typically occurs at high sound ...


1

I am not an ENT doctor, but I think the following diagnoses would suffice to determine each of the conditions: Blocked Eustachian tube: Complaints would be of sudden onset and likely associated with a common cold, or ear infection. Providing the patient with standard decongestant should provide quick relief. Ruptured eardrum: Patient should have subtle ...


1

Inner hair cells (IHC) do not fire action potentials themselves. It's the auditory-nerve that synapses with IHC that generates action potentials. The firing rate of the auditory nerve can be as high as few hundred Hz with a refractory period as short as 1 ms or so (depends on the animal). However, it is important to note that the signal is not sampled at ...



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