Old 05-24-2019, 05:45 AM   #1
Skaven252
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Default Spectral Edits above project sample rate

If you have a 48k project into which you import 192k material (for example, down-pitched ultrasonic recordings for krazy sound design stuff), and would like to apply spectral edits to the items, Reaper won't let you apply edits to the frequencies above the project sample rate; and the item's spectral display is limited to the range of the project sample rate even if the item's source rate is higher than project sample rate.

You can switch the project to 192k to apply the edits, then switch it back to 48k, but the spectral edit windows get skooshed above the item frame, out of reach. And the edits may be lost altogether.

Would it be technically feasible to support spectral edits before the resample-to-project stage in the pipeline?
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Old 05-24-2019, 05:54 AM   #2
Justin
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Hmm any spectral edits above the output nyquist frequency would be moot anyway...
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Old 05-24-2019, 06:06 AM   #3
Skaven252
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Quote:
Originally Posted by Justin View Post
Hmm any spectral edits above the output nyquist frequency would be moot anyway...
Nope. If the source wav is at 192k, and you disable the "Preserve Pitch when changing rate" setting, and slow down the sample to 0.25 playback speed (for example), the sample is pitched down before resample-to-project and the ultrasonic frequencies shift into audible range.

Currently it's not possible to apply spectral edits above that range, before the sample is downpitched to 0.25 speed. Even when you downpitch the sample to 0.25 speed in Reaper, the spectral edit view doesn't display frequencies in the sample above the project rate, even if they are there.

So currently you have to switch the Reaper project to 192k, apply the spectral edits, then switch back to 48k. But this causes odd problems.

There's a workaround: open the wav in a wav editor and just set its nominal sample rate to 48k (no resampling) before you import it to Reaper. But pre-resample-to-project-rate spectral edits would help to avoid this step and keep the source material at the original rate it was recorded at.

Last edited by Skaven252; 05-24-2019 at 06:55 AM.
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Old 05-24-2019, 07:50 AM   #4
guycalledxan
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Hej Justin,

This is something I discovered while working with "Skaven" on some content this afternoon.

I'd been working with a 192k file of me eating spaghetti, pitched down heavily for some monster noises. It was pitched by just stretching it out on the timeline. I keep adjusting different bits to find an interesting pitch for that section of the recording. I would plan to affect the timing of transients (with timestretch) after I've chosen my edits based on modified frequency content I like.

But the recording had some (inaudible) noise from some nearby electronics that became audible after pitching down.

I'm about 6 weeks new to Reaper, with only about 10 working days logged using it on a project (migrating from a mix of Cubase/Vegas/Abelton). So there's a bunch of reaper-specific tricks and workflows that I'm learning from the other Reaper users here.

First I went old school and tried to notch out the noise (image 05.png). But every time I affected the pitch with stretch, I'd have to re-do the notch.

Then Skaven pointed out that I might be able to add a spectral edit that would follow the frequency range I wanted to remove, up and down, as I stretched and edited the clip.

That's when we found a few problems.

1) First was that the spectrograph showed the frequency domain of the source clip, not that of the stretched clip, as I'd hoped/expected. You can see that as the noise became audible through the down-shift, it'd be helpful to have it visible at the right relative range in the spectrograph (images 01 and 02). I added image 04, to show that as the clip stretches and the frequency content changes, the spectrograph image - and the spectral edit canvas - remains the same.

2) Then, after I'd set the project settings to 192, setup the spectral edits, and reverted the project to 48 (one of Skaven's suggested workarounds), the edits behaved weirdly. They moved to the top of the clip, but were offset oddly, and they stopped removing the frequencies I'd set them on (the noise audibly returned) (images 02 and 03).

Overall, the spectral edit feature-set is amazing. This use-case(s) contains a few things that I guess weren't originally in the requirements capture. Addressing most of the above would probably count as 2nd-pass feature work and useability improvements, rather than bugs. The strange behaviour in (2) might be an issue.

(I'm also new as to how else to communicate feature requests to you)

For now, I can cope by consolidating/freezing/rendering my pitched clips and then attacking the noise, clip by clip. But I can imagine a better workflow.

The process of working with high frequency recordings to find weird sounds for sound design is becoming more common, as the equipement (mics and digital hardware) become more affordable. I'm not really expecting to ever look back now I've switched to Reaper, so it'd be nice to see the above addressed at some point on the mid-horizon.

Hope this was useful info.
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File Type: zip reaper_spectral_edit_bug.zip (1.27 MB, 7 views)
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Old 05-26-2019, 05:58 PM   #5
Justin
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Noted, I see the use cases... but sad to say it's unlikely to happen given the way things are put together... so keep rendering or gluing your stretched takes (or editing the samplerate of the source media) before you spectral edit, I guess?
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