Decorrelation (spatial audio)

coralie's icon

Hi everyone,

Does anyone knows of techniques / tools used for the implementation of decorrelation of signals in space in Max MSP? I read a few papers about the principle, which consists of randomizing the phase and the spatial location (I might be wrong about the last, it's been a while I didn't look into the papers) of the spectral components (partials) to get a diffused spatial image of the sound source in space. Some of the researchers who used these techniques mentionned randomization filter banks, but I don't think they used MaxMSP.

Thanks!

Coralie

tep's icon

Hi Coralie,

The Hoa library provides a hoa.decorrelation~ object.

"hoa.decorrelation~ allows you to delay the differents harmonics depending on the harmonic number to decorrelate the harmonics and generate a diffuse soundfield."

goodparleyandorfing's icon

You should be able to do it by sending a mono signal to two allpass~ filters that have decorrelated or random phase responses. Let us know how you get on, I have been meaning to try this

coralie's icon

Merci Tep, c'est super. En plus je travaille avec un encodeur et décodeur ambisonic (ça fait plaisir de parler français quand on vit loin de chez soi)...
Hi Tep, great, just what I need. PLus I use ambisonics encoding and decoding.
Thanks goodparley, You could look at the above solution, I'm sure it is the right one.

Coralie

Shauk Khan's icon

Hi everyone

so far what i understood the way to decorrelation is to pass a mono signal through a set of all pass filters, set at different frequencies. I want to decorrelate my signal in the band of 250-20000 Hz. Does any one have an idea how many all pass filters should i use and what should be the setting. I looked in the internet and did not find any good theories to suggest me, so if you could suggest me some papers or research articles, that would be a great help also.