How reduce background noise while recording in iphone?

I am planning to compare two audio files. i have recorded two voices and compared them using cross correlation. since the presence on bac开发者_运维知识库kground noise while recording the resulting correlation value is always near 0.5.If i give any recorded waves from internet , i am able to get the correct value. So how can i reduce the background noise while recording.Please guide me .Thanks.

Is there any possibility to reduce noise from the recorded .wav file?

Not really a good way to remove background noise while recording other than simply turning down the recording mic. It seems that you're already exporting the data, so instead of attempting to eliminate it at the source, it'd probably be easier for you filter it out, this is a quick tutorial on how to eliminate background noise using Audacity

Try using a noise-canceling microphone and an anechoic chamber (or really quiet studio).

You can also try filtering out all frequency bands that are not of interest (e.g. are outside the human vocal spectral range required for recognition or your comparison).

There is a special kind software to remove background audio noises. Audacity for PC might be one of the most popular (it is open source by the way). Also, you could do that entirely on iPhone with the Denoise app.

Basically, recorded audio contains a lof of individual sounds and some of them are harmful (a.e. buzzing lamps, street noises, mic issues, etc.). A very popular approach to suppress harmful sounds is to calculate frequency spectre of harmful noises and supress "harmful" frequencies throughout the whole audio duration. In both, Audacity and Denoise you do that by selecting a "noise only" fragment. All sounds in that fragment are considered to be noises and are suppressed in whole file.

If you need to incorporate this feature into your app then you could have a look at the Audacity sources. Please let me know if you need more details.