question: how come when I’m on a call and it’s connected to a speaker, the other person can’t hear themselves despite their voice being the loudest thing in the room
comment: Telephone devices use "echo cancellation" techniques to prevent people hearing themselves like this. It's hard to do well, especially in environments where the hardware is moving about. Devices listen for echoes of their outgoing signal to work out their delay and volume so they can subtract it from future incoming signals. Some devices do it better than others, and some listening environments can be more difficult to handle than others, so the results will vary. For example, in a room with many hard (reflective) surfaces, the echo from a speaker can travel directly back to the microphone, and also be bounced off the walls back to the microphone. So there can be multiple echoes, each with a different delay and volume.
passages: Some users of the iPhone 4S reported the random appearance of echoes during phone calls made with earphones in the initial release of iOS 5. The other party in the call was sometimes unable to hear the conversation due to this problem.
  
  Section::::Reception.
   It is the case that a "stereo system" with external speaker attached by long leads to the main unit (holding the audio electronics) can be troubled by EMC problems which are caused by the speaker leads acting as a dipole antenna.
  
  One method of curing this is to add a ferrite choke to the speaker leads close to where they enter the main unit.
  
  Section::::Audio equipment.:Rectification in the audio equipment.
   Echo can also be an issue for PSTN integration. Common causes of echo include impedance mismatches in analog circuitry and acoustic coupling of the transmit and receive signal at the receiving end.
  
  Section::::PSTN integration.:Number portability.
   In quiet conditions, speech discrimination is approximately the same for normal hearing and those with unilateral deafness; however, in noisy environments speech discrimination varies individually and ranges from mild to severe.
   These acoustic technologies must also remove or reduce the noise levels so that the caller is well understood. A person making a call from a handsfree device who is in a busy restaurant or while driving will introduce large levels of noise into the call. This situation is complicated as the software must not only remove the noise around him, but must transmit his voice clearly and loudly to whoever is connected to him. 
   Section::::Earwitness memory.:Verbal memory: voice recognition.:Direct hearing vs. devices.
  
  Whilst many earwitness accounts are attained directly and 'in-the-moment', many will be acquired over a telephone or over other communication devices. Whether the earwitness hears a conversation or other auditory information in person or hears it over a communication device could impact their rate of accuracy. However, contrary to this prediction, research has found no significant differences between the accuracy of voice identification when the voice was heard directly or over a mobile phone, despite the sound quality seeming poorer in the latter.
  
  Section::::Earwitness memory.:Verbal memory: voice recognition.:Emotion.
   The amount of masking will vary depending on the characteristics of both the target signal and the masker, and will also be specific to an individual listener. While the person in the example above was able to detect the cat scratching at 26 dB SPL, another person may not be able to hear the cat scratching while the vacuum was on until the sound level of the cat scratching was increased to 30 dB SPL (thereby making the amount of masking for the second listener 20 dB).
  
  Section::::Simultaneous masking.
   Ambient noise levels can impede both collections of the initial and subsequent voice samples. Noise reduction algorithms can be employed to improve accuracy, but incorrect application can have the opposite effect. Performance degradation can result from changes in behavioural attributes of the voice and from enrollment using one telephone and verification on another telephone. Integration with two-factor authentication products is expected to increase. Voice changes due to ageing may impact system performance over time. Some systems adapt the speaker models after each successful verification to capture such long-term changes in the voice, though there is debate regarding the overall security impact imposed by automated adaptation.
   BULLET::::- Seeming lack of awareness of other people's personal space and moods since brain is hyper-focused on deciphering auditory information in lieu of non-verbal social cues.
  
  BULLET::::- Lack of sound depth: any background noise (in the room, in the car) is flat and wrongly interpreted by the brain. The effect is similar to what happens when trying to hear someone speaking in a noisy crowd on a mono TV. The effect is also similar to talking on the phone to someone who is in a noisy environment (see also: King-Kopetzky syndrome)
   In a quiet environment when speech from a single talker is being listened to, then the MOC efferent pathways are essentially inactive. In this case the single speech stream enters both ears and its representation ascends the two auditory pathways. The stream arrives at both the right and left auditory cortices for eventual speech processing by the left hemisphere.
   Interference, for example, is seen in certain EVP recordings, especially those recorded on devices which contain RLC circuitry. These cases represent radio signals of voices or other sounds from broadcast sources. Interference from CB Radio transmissions and wireless baby monitors, or anomalies generated through cross modulation from other electronic devices, are all documented phenomena. It is even possible for circuits to resonate without any internal power source by means of radio reception.
  
  "Capture errors" are anomalies created by the method used to capture audio signals, such as noise generated through the over-amplification of a signal at the point of recording.
   Subvocal speech recognition deals with electromyograms that are different for each speaker. Therefore, consistency can be thrown off just by the positioning of an electrode. To improve accuracy, researchers in this field are relying on statistical models that get better at pattern-matching the more times a subject "speaks" through the electrodes, but even then there are lapses. At Carnegie Mellon University, researchers found that the same "speaker" with accuracy rates of 94% one day can see that rate drop to 48% a day later; between two different speakers it drops even more.
   The most common situation in which a mix-minus is used is when a telephone hybrid is connected to a console, usually at a radio station. The person on the telephone hears all relevant feeds, usually an identical mix to that of the master bus, including the DJ's mic feed, except that the caller does not hear his own voice. Because the feed being returned to the telephone has an identical mix, minus only one input, it is most efficient to employ a mix-minus as opposed to creating and mixing for a new independent output bus..
   "I’m a big woman...so I could actually shoot a heavier bow than some of the smaller women I competed against. And I think, I’ve never had the best hearing, so when people were distracted by things around us, I might not have necessarily ever heard them. Not that I have bad hearing, but people would say, Didn’t you hear that? Or, Didn’t that bother you? I don’t know that my concentration was so good that I could block everything out, but I think sometimes I just didn’t hear things that other people heard, that they were distracted by."
   On June 25, 2018, it was announced that Showtime had given the production, now untitled, a series order consisting of eight episodes. Additionally, it was announced that McCarthy and Sherman had co-written the first episode together and that Jason Blum, Alex Metcalf, Marci Wiseman, and Jeremy Gold would serve as further executive producers. On August 23, 2018, it was announced that Kari Skogland would direct the first two episodes of the series. On October 5, 2018, it was reported that Russell Crowe and Liza Chasin would serve the production as additional executive producers and that 3dot Productions would serve as a further production company for the series. On October 30, 2018, it was announced that the character of Megyn Kelly had been cut out of the series. The role had yet to be cast and reportedly only appeared in a few scenes. Sherman commented on the removal saying, "Megyn Kelly was a peripheral participant in Ailes’ downfall. It was Gretchen Carlson and her lawyer Nancy Erika Smith who drove the events that led to Ailes' ouster...By the time [Kelly] spoke to investigators, Ailes’ fate had been sealed. Any dramatization that makes her a central character in Ailes' takedown is pure fiction."
   The human brain must also solve this problem in real time. In human perception this ability is commonly referred to as auditory scene analysis or the cocktail party effect.
  
  Section::::Applications.
  
  Section::::Applications.:Cocktail party problem.
  
  At a cocktail party, there is a group of people talking at the same time. You have multiple microphones picking up mixed signals, but you want to isolate the speech of a single person. BSS can be used to separate the individual sources by using mixed signals. In the presence of noise, dedicated optimization criteria need to be used
  
  Section::::Applications.:Image processing.
   These equipment are typically at the edge of the core networks that acts as a gateway between mobile core networks (IP based) and digital PSTN networks. Mobile core IP networks carry voice encoded in the form of one of the GSM/UMTS codecs (e.g.: GSM AMR). When this has to be carried over a G.711/PCM based PSTN network, the gateway equipment transcodes from GSM/UMTS codec to G.711 PCM samples. This results in a certain loss of voice quality.
   After a six-year hiatus, the band reformed in 2012 with only bassist Will McGinniss returning from the original line-up. The new Audio Adrenaline was fronted by Kevin Max, formerly of DC Talk, as the new lead vocalist. This new line-up released a new studio album titled "Kings & Queens" in March 12, 2013. In June 2014, Max stepped down as lead singer of the band. He was replaced by Josh Engler, a former member of the band Abandon until February 2015 when Adam Agee of Stellar Kart was offered and accepted the role.
   Phasing problems usually become evident in walk-around environments, and are of less concern for a seated audience, unless the interference pattern is so dense that it is perceived by small head movements.
  
  Section::::General considerations.:Loudspeaker occlusion.
   In contrast, the dynamic range of patients with SNHL is often narrowed by both an increase in the threshold of audibility and a lowering of the ceiling of tolerance to high-intensity sounds.
  
  This compaction of dynamic range leads to recruitment, an abnormal growth in loudness as sound intensity increases. 9,10
   What sounds normal for someone with normal hearing may be too soft for someone with recruitment, and what is too loud for someone with normal hearing is also too loud for the patient with recruitment. In effect, the range of sound intensity that a patient with recruitment can tolerate is much narrower. Further adding to the difficulty, recruitment is observed in those frequencies that are most impaired—in the high frequencies, which also carry critical information for speech understanding.
   Speech perception is not necessarily uni-directional. That is, higher-level language processes connected with morphology, syntax, or semantics may interact with basic speech perception processes to aid in recognition of speech sounds. It may be the case that it is not necessary and maybe even not possible for a listener to recognize phonemes before recognizing higher units, like words for example. In one experiment, Richard M. Warren replaced one phoneme of a word with a cough-like sound. His subjects restored the missing speech sound perceptually without any difficulty and what is more, they were not able to identify accurately which phoneme had been disturbed.
   An effective hybrid would have high trans-hybrid loss, which means that relatively little of the incoming audio would appear on the outgoing port. Too much leakage can cause echoes when there is a delay in the transmission path, as there is with satellite, mobile phone, and VoIP links. This is a result of a talker's voice traversing to the far-end hybrid and returning to his own receiver with insufficient attenuation. ITU-T Recommendation G.131 describes the relationship of echo delay vs. amplitude to listener annoyance. At 100ms, 45 dB return loss is required for less than 1% of test subjects to express dissatisfaction.
   The device was met with criticism when it first launched as it did not have a shuffle feature. Shuffle functionality was added in September 2017 via a software update.
  
  Section::::Reception.:Connectivity.
  
  Users setting up their Mightys with the mobile app experienced connectivity issues. The company released software updates to address these connectivity issues.
  
  Section::::Reception.:Software Releases.
   Many modern speakerphones must first be calibrated to the acoustic characteristics of the room in which they will be used. During this calibration phase, they may make a variety of noises including ascending tones or chiming sounds. This calibration may be automatic or manually invoked by the user, and it may need to be repeated if the speakerphone is relocated within the room. A failure to be properly calibrated can be indicated by the occurrence of echoing, ringing sounds, or feedback.
  
  Section::::Handset vs. base speakerphone.
  