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Whenever you have a speaker and a microphone in the same room, there is always bleed from the speaker into the microphone. However, when those speakers are tin

Whenever you have a speaker and a microphone in the same room, there is always bleed from the speaker into the microphone. However, when those speakers are tiny little things pointed directly into your ear canals, the amount of bleed that makes it into the microphone is so small as to be completely negligible. For regular in-room speakers, the amount of bleed depends on the relative placement of the speaker and microphone, the directionality of both, the volume of sound from the speaker and the sensitivity of the microphone. For most people on videoconferencing calls, the amount of bleed is going to be quite substantial. The reason it's sometimes a big deal and sometimes not is because of echo cancellation software. But echo cancellation is a hard problem when you don't know the precise physical characteristics of the setup: the relative placement of the speakers and mic, the frequency response curves, and the amount of round trip latency. You have to attempt to detect what you think is an echo rather than a direct sound source, and then try to cancel it. That often fails. But because it sometimes works, people who hate headphones take that as license to never wear headphones. And since it doesn't affect them, they often don't realize how much they are wrecking the experience for everyone else.

adrianmonk 6y ago
> For regular in-room speakers, the amount of bleed depends on the relative placement of the speaker and microphone, the directionality of both, the volume of sound from the speaker and the sensitivity of the microphone. And on how much reverberation there is in the room. If there's a tile floor, a brick wall, and no furniture with upholstery, sound is going to find some path from the speakers to the microphone no matter the placement and directionality. If you have carpet or a rug, maybe a couch or bed, etc., then some of the sound will get absorbed before it can get from speakers to microphone.
bscphil 6y ago
> The reason it's sometimes a big deal and sometimes not is because of echo cancellation software. But echo cancellation is a hard problem when you don't know the precise physical characteristics of the setup Sort of. Software can approximate good echo cancellation for most conversations just by bringing down the mic volume when someone else is talking. Most meetings aren't supposed to have people talking over each other the whole time. Add to that the fact that most laptops have decent echo cancellation now and you can frequently get away with it. It's still something of a tragedy of the commons scenario though. If one person is creating an echo, then the speakers on the speaker's computer will play that echo while they are talking, which will get fed back it to the microphone, creating still more echo. That's when you really start to get major problems, but it's avoidable if no more than one person is using speakers.

adrianmonk 6y ago

> For regular in-room speakers, the amount of bleed depends on the relative placement of the speaker and microphone, the directionality of both, the volume of sound from the speaker and the sensitivity of the microphone. And on how much reverberation there is in the room. If there's a tile floor, a brick wall, and no furniture with upholstery, sound is going to find some path from the speakers to the microphone no matter the placement and directionality. If you have carpet or a rug, maybe a couch or bed, etc., then some of the sound will get absorbed before it can get from speakers to microphone.

bscphil 6y ago

> The reason it's sometimes a big deal and sometimes not is because of echo cancellation software. But echo cancellation is a hard problem when you don't know the precise physical characteristics of the setup Sort of. Software can approximate good echo cancellation for most conversations just by bringing down the mic volume when someone else is talking. Most meetings aren't supposed to have people talking over each other the whole time. Add to that the fact that most laptops have decent echo cancellation now and you can frequently get away with it. It's still something of a tragedy of the commons scenario though. If one person is creating an echo, then the speakers on the speaker's computer will play that echo while they are talking, which will get fed back it to the microphone, creating still more echo. That's when you really start to get major problems, but it's avoidable if no more than one person is using speakers.