Where do these noisy artifacts in the sound of the CloudBank come from?

Question

Hello dear friends!

I really/still enjoy working with the incredibly good sounding CloudBank. There I use wavetables recorded in realtime for the Grain Wave and Grain Env. In the case of Grain Wave I use a Memory Writer which cyclically creates 4096 samp long records (Trigger = 1 and Cycle is checked). So I can record permanently morphing wavetables.  But I found out that if I just record an unmodified sine wave and let it read by the Cloud Bank, some noisy artifacts appear in the sound of the Cloud Bank.

What is that and how can I avoid it? Thanks in advance :)

 

Here is an example.

In the left sound, I have only set the sine wave as a grain wave in the CloudBank and in the right sound I use the memory writer to continuously record a sine wave which is then read by the CloudBank.

The artifact effect can be listened to especially in the lower octaves and at full velocity - at least with MemoryWriter.
In the example on the left, where only a sine wave is used as GrainWave in the CloudBank, the artifacts are not noticeable. I also suspected that there might be sync problems.  In the course of this I tried to solve the problem by changing the CaptureDuration, by adding a SwarmSmoother (e.g. TimeConstant = 1 or 2 samp , Damping =1) and in SimultaneousRead mode in the MemoryWriter - unfortunately without success.

 

Comments

Could you please upload your Sound so we can hear what you're talking about? My first guess is that it is a synchronization issue (that the memory writing is not synchronized with the start of new grains), but this is impossible to check without seeing how you've implemented it. Thanks!

Answer 1

Hi Knut,

Thanks for sending the example. In the CloudBank, if you set the GainEnvelope to Gaussian, and for Interpolation, select Linear, it gets rid of the artifacts.

Comments

Thanks a lot!
Is this also possible with other Grain Envelopes like the exponrev used by me? Or is there maybe another way to remove the artifacts?

---

The exponrev wavetable has a discontinuity at the beginning (it jumps from 0 to 1 in a single sample) so it has, basically, an infinite bandwidth which is probably what you are hearing as "artifact". You could try something like FilteredPulse or you could compute your own envelope shape that has a fast attack but is more continuous. It also has to go to zero at the end, since each grain "rests" on its final sample when it is not playing. So any envelope that has a nonzero value at the end turns into a constant amplitude scale (you will hear that grain constantly).