"Flatten real time processing" NOT WORKING

I am warping the event and it is perfectly fine on time until I flatten the processing. Then the resulted event is off.
I use Mpex poly complex, but tried other algos with no success. Any ideas? Is this a known issue?

To show you the issue I created 3 versions of the same track.
As shown on screenshot attached,
the upper is the non processed material,
the middle is the time warped prior to processing,
and finally the lower one is the flattened.

Check especially the bars 12.2, 12.3, 12.4!!! And it’s the whole project like that.

I even tried without free warping tool just auto audio quantization

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By flatten you mean, bounce selection?

No, I mean -Flatten Realtime Processing-
The action to optimize the sound quality of the processing, or apply offline processing.
From manual:

So as stated in manual

Any loop that was previously stretched in realtime plays back exactly the same, but the warp
markers discarded.

So why isn’t it playback exactly the same? Big words Steinberg

ah, good to know.
What happens if you bounce it? Is it the same issue there?

Bouncing works, but you don’t get the intended result.
You 're bouncing the event with the real time algorithm (quality),
thus beating the purpose of using the flattening process for higher quality algorithms (MPEX), so to optimize the quality of processing.

So anyone? Is this a bug? Is it a known issue? Will this be addressed?
It is a basic function of the DAW that is not working as it should, making it useless.
It must be reported to Steinberg

Yeah I see, just wanted to know. Because I always bounce and never had an issue there.

Seems like it is indeed a problem with flatten, I am gonna try to reproduce it later on my side.

Just out of curiosity: You tried to trash the prefs, and reproduce it in an empty project without plugins, just to be sure, its not influenced by that? (I know, thats very unlikely, but just to be sure)

Would you mind sharing the exact steps to reproduce it?
I tried to reproduce it here, but it seemed to work.

Yeah correct, I tried it before and after the prefs trash. More I tried on a different machine with same results.
Project is new, no plugins or so.

  1. record
  2. make new track version
  3. edit event’s hitpoints on editor
  4. create warpmarkers from hitpoints
  5. quantize audio
  6. manually readjust using freewarp
  7. make new track version
  8. flatten realtime processing using MPEX poly complex

And just tried again without messing with the warping at all , just quantized audio, to check.
though quantization it’s warping tbh

  1. make new track version
  2. edit event’s hitpoints on editor
  3. quantize audio
  4. make new track version
  5. flatten realtime processing using MPEX poly complex

Same mess, not to say a bit more…

upper: original
middle: quantized
lower: flatten

There is also a lever drop after the flattening, you can even see it on waveforms too.
The first two (upper and mid) are the same in level, the lower is smaller.
The flattened is It’s -0.8dB lower on RMS, -4.9dB on peak meter…go figure…totally unreliable. I am really disappointed

Care to know if other users have this issue, though I tried on two different machines…
FWIW the audio event is 3-4 minutes long.

Sorry, I had work to do, so I could not test it before.

I tried to reproduce it, but I can only chose “Realtime” when flattening and in my Audio Pool I only have Elastique and Standard algorithms to choose. I can choose MPEX Poly complex as standard algorithm for timestretch, but when flattening it shows still only “Realtime”.

So where are you able to choose MPEX Poly complex?

EDIT: Even with “Realtime” the flattened version looked different, but the timing was the same (flip the polarity and listen to both together). So this seems to be a graphical issue, that the unflattened version has when displaying the waveform after applying some processing.

When you get to Audio->Realtime processing->Flatten Realtime processing I get the pop up to choose between the algorithm, realtime is the default and I can choose all of the MPEX solo and poly algorithms.

If you reproduce these steps try to alter just a few hitpoints from the left pane hitpoint editor and don’t go to far, meaning move them just a bit, because if the stretch factor is too big then it can only flatten using realtime algo , I think…
Also choose low quantization value like 1/16 or 1/32, depends on the hitpoints and off times.

Don’t mess with the warping at all. It is not necessary for the flatten to screw up timing, it also does it without, heh


  1. edit event’s hitpoints on editor
  2. quantize audio
  3. flatten realtime processing using MPEX poly complex

Thanks for your time and efforts.

Yes, you are right. It only works, when you don’t go too far as you say.

And I could reproduce it now. But in my case I did not even have to quantize it. I just used free warp and flattened straight away using MPEX Poly Complex and there you go.
So to sum it up:

  1. use free warp (don’t go too far)
  2. flatten realtime processing using MPEX algorithm (does not really matter which MPEX algo)

This is my outcome:

Well this confirms an actual problematic process within Cubase which makes the whole purpose of the process useless.
What’s the best way to raise steinberg’s consideration on this issue?

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If instead of flatten you bounce do you get the same problem?

Tj99 asked that too some posts back


I’d suggest to open a support ticket. This way a SB employee will check it and hopefully transform it into an official bug report (could take some time though). I usually waited about 2-4 weeks.

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I just noticed, that this seems to be an old issue. Multiple years and versions ago, other people already mentioned this behaviour. Time to fix it.


I’ve opened a support ticket yesterday and I got a fast reply from my country’s official distributor today saying that they will forward my case to Steinberg along with this topic relevant to my issue.

Hopefully this major issue which doesn’t allow users to benefit from the MPEX algorithms for crucial processes, such as audio time correction (warping), will be swiftly resolved.

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Several updates later still “Flattening process” is useless. That’s too sad.
My support ticket was never answered or didn’t get any info about it.