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What is really happening in a RE analysis and how can I achieve 'consistent' results?

+1 vote
Hi all,

I've been obsessing over cross-synthesis lately and I have been using the RE analysis a lot. At this point, I've read everything I can find about it in Kyma X Revealed as well as in Kyma itself but I want to understand better what's going on so I can arrive at some more consistent results.

Often I get radically different sounds from the analysis on my voice as the RE, even from almost identical recordings and identical settings in the tool. In other words, sometimes my voice sounds like it's playing back at a slower rate than recorded and sometimes at the same rate as recorded etc. Is this typical and I should just continue to experiment with the parameters or is there a way to better predict the results?

Thanks in advance for any thoughts or suggestions!
asked Nov 14, 2018 in Sound Design by will-klingenmeier (Adept) (1,270 points)
The fact that you are hearing playback at different rates makes me wonder whether there is a difference between the original files you are analyzing (Are some mono and others stereo? Were they originally recorded at different sample rates?) The example produced by the RE tool also has a !Rate control. Could it be getting accidentally set differently each time?
Thanks! Turns out I did need to take a closer look at my files, sample rates and settings. Just curious though- When I load a 96khz file in the 'sample' prototype and my Kyma session is at 48khz, Kyma must convert it because I don't hear the sample played back at half speed. I figured this would be the same elsewhere in sounds but I guess not in this case? Is that a characteristic of the RE Analysis tool or something else?
What are chirps in the playback typically a sign of? I notice that often I have a chirp sound and I can't pinpoint what's causing it. I've tried adjusting the parameter settings but that doesn't seem to help.
The most likely cause is that the bandwidth is so narrow that it easily goes into oscillation. I would try reducing the input amplitude and try re-analyzing with fewer bands. The RE is extremely sensitive to input amplitude (listen to the EX file on its own to get a sense for how much to attenuate the input).

1 Answer

+1 vote
Hi Will,

If I understand your question correctly I also had this issue. In my case it was due to a mismatch between the length of the Wavetable you’re using for the REResonator and the TimeIndex feeding the ReResonator  - these have to be matched each time you load in a new RE wavetable file - unless they are all the exact same length of course. Otherwise you’ll end up with a wavetable file being read at a different speed than the corresponding RE wavetable file length

To make sure that the length of the TimeIndex feeding the REResonator is exactly the same as the length of the wavetable used by RE. Shift-click the disk icon on the right side of the “Wavetable” tab to get the information popup where you can copy the exact length in sec of the RE wavetable file.
In the Timeindex tabs I usually write :
Trigger : X s tick
OnDuration : X s
where X is the exact length of the RE wavetable used

Aside from this (and as SSC remarked) - make sure your RE files are all the sample sample rate as the sample rate you're using in the Audio settings.

Hope this helps!


answered Nov 26, 2018 by koenraad (Practitioner) (330 points)
Thank you! This too was a factor in my results. I appreciate you taking the time to provide a thoughtful and accurate response.