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May 31, 2011 13:08:19

Posted By Peter Bentley

I'm now supervising research projects on iPhone apps, and one of my students, Ariel Elkin, has found some very interesting information about iPhone microphone frequency responses. See these pages for details:

Microphone frequency response for the iPhone 4

Microphone frequency responses for the previous iPhone:

What these curves say is what my feedback for the iStethoscope app has been suggesting: the original iphone had a poor built-in mic, the 3G had a very impressive mic (look at the low frequencies), the 3GS had a worse mic (iPad similar), and the iPhone 4 is slightly better than the 3GS.

Perhaps the most surprising result is that the inline mic provided with the white earphones may be better than we thought. According to those charts it should be better than all of the built in mics! The problem may be with the earphones themselves - they can't play the low frequencies back properly, so you just can't hear what the mic records. So one option if you're using a device with a worse built-in microphone compared to the iPhone 3G is to use the inline mic from the white headphones to gather the sounds, then use better headphones to listen to what you just sampled. Of course if you're using an iPad you can plug a USB mic into the camera connection kit and have great quality sound that way. Reports suggest that you can't do the same with the iPhone, however.

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Categories: iPhone Apps

iStethoscope works with the iPad 2

May 22, 2011 12:46:41

Posted By Peter Bentley

After a little queuing in USA, I was able to purchase a new white iPad 2. It's a lovely device and I'm using it more than I was expecting to. Another unexpected bonus is that my iStethoscope Pro app works perfectly on this device. Admittedly it's rather awkward to use the built-in microphone, but it's quite possible to use the inline microphone with the white iPod earplugs. Also, if you happen to have the camera kit for the iPad, you can plug in a USB microphone and use that. (Note you may have to alter the amplification and filtering settings to suit your specific microphone.)

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Categories: iPhone Apps