Hi Kaukomedia. May I ask what you are trying to achieve here? Are you filtering the final block to get rid of resampling artifacts? I am currently investigating replacing the linear interpolation in the SynthesiserVoice renderNextBlock-method with a juce Interpolator (lagrange), but I cannot make it work due to the fractional ratio issue. (LagrangeInterpolator sounds weird when I try to implement it in SamplerVoice)
Did your solution give you better results for resampling?