Hey, I'm implementing a flanger effect as part of a guitar effects processor on an ADSP-21364 development board. A Flanger effect is produced by adding a single delay to the current input sample, the length of the delay is dictated by a sin wave which i have in aa lookup table. This implements a comb filter. My problem is that on top of the desired output I am also getting a 'police siren' like sound which is a sin wave produced by the imperfections involved when the sin wave calculates a non-integer delay. I have tried to overcome this problem using linear interpolation which was an improvement but not a complete solution. I then implemented a 4-point cubic interpolation algorithm which didn't seem to improve things much more. My question is, can anyone suggest a decent interpolation algorithm suitable for this audio application? Many thanks Ronan

# flanger effect, audio interpolation

Started by ●February 15, 2006

Reply by ●February 20, 20062006-02-20

Do you have a sample program? Perhaps you need to stabilize the comb filter, i.e. multiply the delayed value by some factor smaller than one? omalley.ronan@gmail.com wrote:> Hey, > > I'm implementing a flanger effect as part of a guitar effects processor > on an ADSP-21364 development board. A Flanger effect is produced by > adding a single delay to the current input sample, the length of the > delay is dictated by a sin wave which i have in aa lookup table. This > implements a comb filter. > > My problem is that on top of the desired output I am also getting a > 'police siren' like sound which is a sin wave produced by the > imperfections involved when the sin wave calculates a non-integer > delay. > > I have tried to overcome this problem using linear interpolation which > was an improvement but not a complete solution. I then implemented a > 4-point cubic interpolation algorithm which didn't seem to improve > things much more. > > My question is, can anyone suggest a decent interpolation algorithm > suitable for this audio application? > > > Many thanks > > > Ronan >