question: How do earphones separate sound in vertical space?
comment: There are a couple of reasons that we can hear what direction a sound is coming from: •Left to right is the simplest, we can pick up the slight delay from the sound taking a little longer to get to one of our ears and figure it out from there •The other directions are because of the unusual shape of our ears - in getting to the eardrum the sound will bounce around in various different ways depending on where the sound is coming from, and our brains have had so much practice at listening to those echoes that it knows exactly what direction just from that exact echo. Binaural recordings are literally just recording the exact sound that gets to your eardrum, and so it tricks your brain into thinking that it echoed off your ear to have come from that exact spot instead of coming from your headphones.
passages: Directional sound perception is based on the delay between the same sound reaching a person's left and right ears. In stereo speakers, the sound from one speaker reaches both ears, although at different levels, and with a delay between one ear and another, since the speaker is placed away from the center. In headphones, this "crossfeed" does not occur, so the resulting stereo image is different from what is heard from speakers. A crossfeed signal processor attempts to recreate the stereo image heard from speakers by mixing some signal from the left channel into the right channel, and vice versa.
   Thaler is a pioneer in the field of spatial sound and 4D music creation, having launched SoundSphere Studios, CineSphere, and Lysten 360 Sound Systems in 2019 with partner Steven Boardman. He is developing educational initiatives in 360º sound at post-secondary facilities in Canada and Colombia, with curriculums focussed on industry transformations taking place in the worlds of spatial sound capture, music creation and 4D sound transmission.
  
  Section::::Biography.
  
  Section::::Biography.:Early Years.
   Section::::Professional career.:Research and development.
  
  Chahine took part in research and development of algorithms related to 3D Sound at Ralph Kessler's Pinguin Inc. in Hamburg, Germany. He has been invited to give guest lectures at the SAE Institute Berlin and consulted by Focusrite for his professional opinion on new products within the audio engineering market.
  
  Section::::Professional career.:Live music production.
   The ILD arises from the fact that,a sound coming from a source located to one side of the head will have a higher intensity, or be louder, at the ear nearest the sound source. One can therefore create the illusion of a sound source emanating from one side of the head merely by adjusting the relative level of the sounds that are fed to two separated speakers or headphones. This is the basis of the commonly used pan control.
   A consequence of this duplex system is that it is also possible to generate so-called "cue trading" or "time–intensity trading" stimuli on headphones, where ITDs pointing to the left are offset by ILDs pointing to the right, so the sound is perceived as coming from the midline.
   BULLET::::- In the X-Y techniques, the microphones would ideally be in exactly the same place, which is not possible – if they are slightly separated left to right, there may be some loss of high frequencies when played back in mono, so they are often separated vertically. This only causes problems with sound from above or below the height of the microphones.
  
  BULLET::::- The M/S technique is ideal for mono compatibility, since summing Left+Right just gives the Mid signal back.
  
  The equipment for the techniques also varies from the bulky to the small and convenient.
   Section::::Technical derivation.:Localization of sound in virtual auditory space.
  
  A basic assumption in the creation of a virtual auditory space is that if the acoustical waveforms present at a listener's eardrums are the same under headphones as in free field, then the listener's experience should also be the same.
  
  Typically, sounds generated from headphones appear to originate from within the head. In the virtual auditory space, the headphones should be able to "externalize" the sound. Using the HRTF, sounds can be spatially positioned using the technique described below.
   Binaural recordings are made specifically to be heard through headphones rather than loudspeakers. When listening to sound through loudspeakers, the left and right ear can both hear the sound coming from both speakers. By distinction, when listening to sound through headphones, the sound from the left earpiece is audible only to the left ear, and the sound from the right ear piece is audible only to the right ear. When producing binaural media, the sound source is recorded by two separate microphones, placed at a distance comparable to that between two ears, and they are not mixed, but remain separate on the final medium, whether video or audio.
   In order to meet the challenges of real-time 3D sound synthesis. Our approach using strategically placed speakers to simulate spatial sound is proposed. Instead of focusing on attaching sampled sound to objects,this method uses eight speakers to simulate spatial sound. The system is shown in figure "Sound field reproduction" on the right. First, a sound is captured using a cubic microphone array in the original sound field, as shown on the left in figure. Second, the captured sound is played by the cubic loudspeaker array in the reproduced sound field, as shown on the right in figure. As a result, the 3D sound field captured by the microphone array is reproduced by the loudspeaker array. Thus, as shown in figure, the listener, who is in the loudspeaker array, feels that sound is moving above their head when sound is moving above the microphone array. This method lowers the accuracy but raises the efficiency compared to the previous two methods. Here one specific implementation of this method,wave field synthesis, is introduced below.
   Section::::Technology.
   BULLET::::- Zoom Corporation's integrated recorder, the H2n, has a firmware update that enables it to generate horizontal B-format files directly. They have now also released a recorder, the H3-VR, with a tetrahedral microphone arrangement for full first-order Ambisonics.
  
  BULLET::::- Audeze make a tetrahedral microphone using their planar capsules.
  
  BULLET::::- Nevaton have announced the Nevaton VR, a tetrahedral first-order Ambisonic microphone with very low self-noise.
   A pair of HRTFs for two ears can be used to synthesize a binaural sound that seems to come from a particular point in space. It is a transfer function, describing how a sound from a specific point will arrive at the ear (generally at the outer end of the auditory canal). Some consumer home entertainment products designed to reproduce surround sound from stereo (two-speaker) headphones use HRTFs. Some forms of HRTF-processing have also been included in computer software to simulate surround sound playback from loudspeakers.
   BULLET::::1. The bank of HRTF impulse responses are now be converted into a filter bank of some sort (e.g. minimum phase filters). Any desired sound can now be convolved with one of these filters and played to a listener over headphones. This creates the perception of an externalised sound source. This approach has obvious advantages over the "dummy head technique", most notably the fact that once the filter bank has been obtained it can be applied to any desired sound source.
  
  Uses for VAS in science
   There are multiple arrangements for drum overheads, which are often based on personal preference of the musician, engineer, or producer. These include "A-B" spaced pairs (where two directional microphones are suspended above the left and right clusters of cymbals), "X-Y" coincident pairs, where the two directional microphones are centred on the drum kit with their capsule are very close without touching, and angled across each other at 90°. Coincident placement give a wider stereo image than spaced pairs, and some engineers prefer it for this reason.
   There are two microphones in each AirPod: one at ear level, facing outward, and another at the bottom of the stem.
   "In Ear" headphones or earphones using balanced armature technology were launched in November 2007. These headphones use patented Contour Ear Gels, invented by Mark Blanchard of Klipsch Group, which are anatomically designed to accurately fit inside the human ear canal. These oval shaped silicone tips reduce ear fatigue by minimizing pressure to any one area of the ear canal wall. The patented ear tips are designed to be inserted in the ear canal to acquire an air seal for noise isolation and a proper frequency response.
   Perhaps most innovative at a conceptual level is The Sonic Mess Kit. This is made from a cinema film reel cover. The edge (lip) is scored to allow two sets (courses) of rubber bands to be strung across. The two courses are at different depths in the lid and are mostly perpendicular (a right angle) to each other. Parallel to the lower course is a spring, divided into three segments. The tension of each rubber band and spring segment can be individually adjusted.
   In the late 1960s, Aiwa and Sony offered headphones with a pair of microphones mounted on the headband around two inches above the ears. These allowed pseudo-binaural recordings to be made.
   Three or more microphones are suspended above the speakers by means of a cable and stand. The microphones are pulled back, switched on, and released over the speaker, and gravity causes them to swing back and forth as pendulums. As the microphone nears the speaker, a feedback tone is created. Different lengths of cable will swing at different speeds, creating an overlapping series of feedback squeals. The music created is thus the result of the "process" of the swinging microphones.
   Section::::Recording methods.:M/S technique: mid/side stereophony.
  
   This coincident technique employs a bidirectional microphone facing sideways and another microphone at an angle of 90°, facing the sound source. The second microphone is generally a variety of cardioid, although Alan Blumlein described the usage of an omnidirectional transducer in his original patent.
   There are some complications with the playback of binaural recordings through headphones. The sound that is picked up by a microphone placed in or at the entrance of the ear channel has a frequency spectrum that is very different from the one that would be picked up by a free-standing microphone. The diffuse-field head-transfer function (HRTF), that is, the frequency response at the ear drum averaged for sounds coming from all possible directions, is quite grotesque, with peaks and dips exceeding 10 dB. Frequencies from around 2 kHz to 5 kHz in particular are strongly amplified as compared to free field presentation.
   Once recorded, the binaural effect can be reproduced using headphones. It does not work with mono playback; nor does it work while using loudspeaker units, as the acoustics of this arrangement distort the channel separation via natural crosstalk (an approximation can be obtained if the listening environment is carefully designed by employing expensive crosstalk cancellation equipment.)
   After beveling or rounding the edges, fine-tuning adjustments are made. If a bar is flat, its overall pitch structure can be raised by removing material from the ends of the bar. Once this slightly sharp bar is created, the secondary and tertiary tones can be lowered by removing material from specific locations of the bar. Vibraphones are tuned to a standard of A=442 Hz or A=440 Hz depending on the manufacturer or in some cases the customer's preference.
   3-pin XLR connectors and quarter-inch (¼" or 6.35 mm) TRS phone connectors are commonly used for balanced audio signals. Many jacks are now designed to take either XLR or TRS phone plugs. Equipment intended for long-term installation sometimes uses terminal strips or Euroblock connectors.
   3D audio effect
  
  3D audio effects are a group of sound effects that manipulate the sound produced by stereo speakers, surround-sound speakers, speaker-arrays, or headphones. This frequently involves the virtual placement of sound sources anywhere in three-dimensional space, including behind, above or below the listener.
  
presuppositions: Earphones seperate sound in space.
corrections: It is more the ears themselves that do the seperating the sound. However the sound can be designed in a way that makes it seem like it comes from different areas.
raw_presuppositions: Earphones seperate sound in space. Earphones seperate sound in space.
raw_corrections: It is more the ears themselves that do the seperating the sound. However the sound can be designed in a way that makes it seem like it comes from different areas. It is more the ears themselves that do the seperating the sound. However the sound can be designed in a way that makes it seem like it comes from different areas. 