Author Topic: iPhone 3Gs with LF roll off on the mic input  (Read 7025 times)

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Riley Casey

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iPhone 3Gs with LF roll off on the mic input
« on: August 05, 2009, 03:59:16 PM »
Apparently the new 3Gs phones incorporate a steeper high pass filter on the built in mic and mic input jack input than the previous iPhones.  Are there any plans to issue an update to the Signal Scope app to account for this change in the hardware?

FaberAST

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Re: iPhone 3Gs with LF roll off on the mic input
« Reply #1 on: August 05, 2009, 04:11:42 PM »
Quote
Are there any plans to issue an update to the Signal Scope app to account for this change in the hardware?
In short, no. The lowest frequency signals are essentially driven into the noise floor by the iPhone's high pass filter. "Compensating" in software cannot bring back signals that are already lost, and it won't improve the SNR for those frequencies which have not been totally lost.

It's unfortunate that Apple decided to apply such a filter in the iPhone 3GS (and a less destructive one in the iPhone 3G). Ironically, for flat headset mic input response, the original iPhone is the best option (see the blog).

Ben