# Upsampling a recorded sample.

Discussion in 'Homework Help' started by Monica1986, Apr 23, 2009.

1. ### Monica1986 Thread Starter New Member

Apr 23, 2009
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Hi guys I am new to this forum. I wanted a bit of help on the following question I got for homework.

A sample of a women singing is recorded at a sample rate of 20,000Hz; the digital recording is then played back, but the sample rate parameter of the playback function set to 44,100Hz. How will her voice sound ? Explain whether her vowels will be understandable, and whether the song man still be recongnisable.

I was thinking of the lines of the Nyquist theorem. As the sampling rate must equal twice the highest frequency component. So roughly the highest frequency should be about 40,000Hz. But after upscaling the sampling rate the highest frequency is still the same. So this causes aliasing ? I am not sure about the vowels tho ? any help would be great !

Cheers Monica

2. ### Audioguru New Member

Dec 20, 2007
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I think the sounds will playback at a little more than double their original frequencies.
Like chipmunks. The rate of the words will be speeded up too.
The playback will last less than half the recorded time.

3. ### Monica1986 Thread Starter New Member

Apr 23, 2009
3
0
thanks Audioguru, can you explain why there frequencies double ? isnt the question just talking about the sampling rate ? Tbh your answer does sound right actually , I am just a little confused ....

4. ### Audioguru New Member

Dec 20, 2007
9,411
896
Hi Monica,
Your playback sample rate is too fast so the playback time of everything including duration and frequencies will also be too fast.
Like a tape recording that is played back too fast.
Try it.