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Equipment used: I just bought a cheap Bluetooth handsfree from china: http://www.miniinthebox.com/mini-stereo-wireless-v3-0-headset_p1187467.html

Explanation: This works perfect for me, and i don't notice any problems at all. The problem is that for people calling me, or i am calling hears them selves in an echo with about 1 sec lag.

I cannot hear this echo at all, but for everyone i talk to with the handsfree set hears this echo.

If i mute the mic, then the echo disappears.

My question is this: Is it possible to remove echo by using any software or android setting?

I think that there should be two ways of doing this:

1. muting my mic while the other part talks. (nearly like an automatic walkie talkie)

2. cancelling what is sent from the other part, and don't send the same sounds back to the other part again.

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    Do you resolve your problem? I have same problem with you. You can download my probject at drive.google.com/… Please let me know the best way to ignore it. I tried to turn of MIC but it is not successful
    – John
    Commented Jan 3, 2015 at 8:31
  • user8264, is this a android application? do you have a link for the APK?
    – patchie
    Commented Jan 6, 2015 at 12:19
  • YOu can download apk at dropbox.com/s/77zyc8vrlnjz9r2/AudioDemo.apk?dl=0
    – John
    Commented Jan 6, 2015 at 13:34
  • user8264, What does this application do?
    – patchie
    Commented Jan 7, 2015 at 15:08
  • It will record sound from headset device and play/record in application in real time. The problem is that the sound has echo during playing
    – John
    Commented Jan 7, 2015 at 16:29

2 Answers 2

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This is pretty hard to do with software, since there are delays in the audio stream. The transmission from you phone's BT to the headset can take up to 200ms, and the same for the reverse. Therefore before sending the audio from the mic to the recipient, up to 400ms of audio would have to be sampled and cancelled, assuming that the BT connection is stable.

Usually this is done in the BT headset itself, but, as you said, it's a cheap Chinese headset, so the circuits for this have been left out.

As far as I know, the only settings in Android regarding noise cancellation support only on-board noise cancellation mics.

As for the muting solution, some phones use compression to boost the mic strenth, which will raise the noise levels when the person is silent. This would cause the mute to be always on.

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  • Yes, thats true, but the cellphone should be able to cancel this by software i think.
    – patchie
    Commented Jun 27, 2014 at 12:46
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    Android has a builtin NoiseSuppressor class, yes, but this is not designed for BT communication. It would have to create a 400ms dynamically scaled buffer for the incoming audio to be filtered from the mic signal, sync it to the weak echo and/or insert timing information to the audio, and then process the cancellation, creating more delays to the sound.
    – aleksikallio
    Commented Jun 27, 2014 at 13:01
  • @onik: Thank you for your suggestion . I have same problem about echo sound, although I am using good device. I tried to remove noise(success) and echo sound(not success). I used " AcousticEchoCanceler.create(mRecorder.getAudioSessionId()); "YOu can see my project at drive.google.com/…
    – John
    Commented Jan 3, 2015 at 9:05
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Yes, it is possible. Try turning down your volume.

I spent more than a week but couldn't, but suddenly I had a call from my friend and he said it echoes. I couldn't do anything, so I just turn down the volume unknowingly and he said the echo disappeared.

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