Brain Bulletin #36 - How to Hear Better on Your Cell Phone in a Noisy Room

What do you do when you can't hear on your cell phone because the room is too loud?

You put your finger in the other ear. It doesn't work very well. There is a better way, and it has to do with how your brain and phone work together. I was surprised when I tried this. It works remarkably well.

The way to hear more clearly is to cover the mouthpiece when you are listening to the other voice.

You will hear just as much noise around you but you will be able to hear the voice on the phone much better. Try it. It works!

Why does this happen?

The reason it works is that your brain has a special ability to separate signals from each other. Sometimes this is called the "Cocktail Party Effect". In a party you often have to make out one voice and separate it from all the other voices and general sounds coming from many different directions. You brain shines in this situation. It takes the voice in the left ear and the general room noise in the right ear. It looks like this:

voice > left ear > BRAIN

This is called source separation. Electronic circuitry and communications technology cannot do this. Yet it is easy for your brain.

Now you, your telephone, and a noisy room. The phone makes your brain's job much harder because while you are listening to your friend's voice on the other end of the lineyour phone feeds in general room noise in through the mouthpiece. The phone, through its circuitry, mixes in the general room noise with the signal from the other phone. It looks like this:

voice plus distorted room noise > left ear > BRAIN < right ear < room noise

This is a problem for your brain. The phone has mixed the room noise and your friend's voice into one source. Source separation can't happen now. When you cover the mouthpiece you stop this mixing from happening. Your brain can now do its job and recreate the "Cocktail Party Effect". Your friend's voice is much clearer!

Why do phones do this? It turns out that years ago the makers of phones found that mixing the callers own voice with the signal from the other voice gave more of a feeling of talking live. Engineers call this "full duplex". This is great until the room gets noisy.

Can you hear me now?

In the next Brain Bulletin we will look at whats really going on in your brain.