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Re: Wavetable example?

From: Ray Bellis <ray@bellis.me.uk>
Date: Sat, 21 Jul 2012 22:20:12 +0100
Message-ID: <500B1D0C.7000003@bellis.me.uk>
To: public-audio@w3.org
On 21/07/2012 21:13, Peter van der Noord wrote:
> Can anybody give a quick and short example of the creation of a
> wavetable? I did some reading about wavetables, and as i understand
> it, you can specify the harmonics for the wave-cycle, but i'm not sure
> how it works and what the params do exactly

If you set the cos wave to [0, 1] and the sin wave to [0, 0] you just 
get a pure sine wave.

If you flipped those two around you still get a sine wave, but it's 
rotated 90' in phase.

If the waves are [0, 0, 1] and [0, 0, 0] you get a sine wave at double 
the harmonic frequency.

For each component "n" in the two tables the amplitude of the frequency 
(f * n) is proportional to sqrt(cos_table[n]^2 + sin_table[n]^2)

The phase is atan2(sin_table[n], cos_table[n])

At least that's how I understand it :)

Ray
Received on Saturday, 21 July 2012 21:20:36 GMT

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