Oversampling oddities

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Oversampling oddities

Post by blinddrew »

At the last virtual SOSage meet we actually got into a brief discussion about music production (I know, right?) and Martin Walker (I think) linked to a video about the plugin oversampling available in Reaper now: https://www.youtube.com/watch?v=GjtEIYXrqa8

Being a curious sort I dragged up a nascent project that just had half-a-dozen or so tracks and ran a back to back test with all the plugins running at 44.1 and then oversampled to 88.2.
I was actually really quite surprised at how obvious the difference was, as if a gossamer veil had been lifted between me and the speakers.

So this arvo I pulled up a much more complex work in progress and went through a fairly laborious process of doing the same thing*.

Three things were apparent on this, firstly was a recognition that I really need to do a lot more work on this mix.
Secondly, and more relevant to the thread, was a repetition of that 'lifting a veil' effect.
Thirdly, and this is the oddity bit, the loudness of the oversampled mix went up by 0.3 LUFS. I don't know why this should be but I wonder if a fast acting compressor at low frequency might be letting more of an initial transient through?
Image

Anyway, I loudness matched the two files and auditioned again and there is definitely a clear sound improvement in the oversampled file.

The downsides to this oversampling are two-fold (as far as I can see):
1) CPU usage went from 14-15% to about 25% (on a 65 track project with over 100 plugins).
2) Render time went from 1 minute to 5 minutes.

But that seems a fair price to pay for the sonic improvement from my perspective, so if you're a Reaper user, and you've got CPU capacity to spare, I'd seriously recommend having a look at the video above and experimenting.

For the cynical amongst you I have uploaded the two versions of the track to soundcloud. I doubt you'll hear the difference in the web-player but they're downloadable as 24bit wavs to load into your DAW. You'll probably need to drop the oversampled file by about 0.3 dB to match the loudness.
No oversampling: https://soundcloud.com/blinddrew/fat-ro ... MjaRMXN2Y9
2x oversampling: https://soundcloud.com/blinddrew/fat-ro ... zkNrs8N5YO

* there were a few things like M/S decoders and simple delays that I didn't oversample because, as I understand it, it wouldn't make a difference.
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Re: Oversampling oddities

Post by Hugh Robjohns »

The very small change in LUFS value is almost certainly due to the slightly different responses of dynamics processing between standard and oversampling modes.

The 'removed veil' thing is a common response -- I hear it too.

But do you think any average listener would notice or complain without the direct A/B comparison? Genuine question of your opinion.
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Re: Oversampling oddities

Post by RichardT »

This is my experience working at 96 kHz - without doubt things sound clearer.
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Re: Oversampling oddities

Post by blinddrew »

Hugh Robjohns wrote: Sun May 15, 2022 10:06 pm The very small change in LUFS value is almost certainly due to the slightly different responses of dynamics processing between standard and oversampling modes.

I assumed that there would be some effect on dynamic but I was surprised to find it that high (accepting that 0.3 LUFS is not exactly 'high' ;) ).

The 'removed veil' thing is a common response -- I hear it too.
But do you think any average listener would notice or complain without the direct A/B comparison? Genuine question of your opinion.

Good question. On its own I'd say probably not* but I do think we're into 'aggregated marginal gains territory' (as British Cycling used to say).
This 'veil' is something that I still consistently notice when comparing my mixes with commercial ones. So if this is a little step towards narrowing that gap, at the small cost of a bit of extra CPU, then I think it's worth adding to the toolbox.
Plainly there's still a barrel of other stuff I need to keep working on, but if I can keep making these incremental improvements then in total they might sum to something that is noticeably better than what I was doing before.

I hope. ;)

* I haven't tried listening to the files on a 'normal' set of headphones yet. I was slightly surprised that I could still hear the difference even via the soundcloud web player.
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Re: Oversampling oddities

Post by blinddrew »

RichardT wrote: Sun May 15, 2022 10:17 pm This is my experience working at 96 kHz - without doubt things sound clearer.

Hmmm. It might be time to rethink my recording approach. But as I have about a dozen projects on the go at the moment I might leave that to the next album! :D
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Re: Oversampling oddities

Post by James Perrett »

If you don't want to go through all your plug-ins and individually change all your plug-ins you could just set your project sample rate to be 96kHz. Reaper will automatically upsample all your sources and you can render to whatever sample rate you need to at the end.

I've been doing this since Reaper started using the R8brain conversion algorithm a few updates ago. I wouldn't say that I've noticed a massive difference doing this but every little helps.
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Re: Oversampling oddities

Post by blinddrew »

James Perrett wrote: Sun May 15, 2022 10:45 pm If you don't want to go through all your plug-ins and individually change all your plug-ins you could just set your project sample rate to be 96kHz. Reaper will automatically upsample all your sources and you can render to whatever sample rate you need to at the end.

I've been doing this since Reaper started using the R8brain conversion algorithm a few updates ago. I wouldn't say that I've noticed a massive difference doing this but every little helps.

This would be a much smarter way of doing things compared to what I have done today... :headbang:
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Re: Oversampling oddities

Post by James Perrett »

If you are lacking in processing power then it may make more sense to only oversample with certain plug-ins but it is far easier to set the whole project to oversample.
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Re: Oversampling oddities

Post by Martin Walker »

blinddrew wrote: Sun May 15, 2022 6:44 pm At the last virtual SOSage meet we actually got into a brief discussion about music production (I know, right?) and Martin Walker (I think) linked to a video about the plugin oversampling available in Reaper now: https://www.youtube.com/watch?v=GjtEIYXrqa8

Being a curious sort I dragged up a nascent project that just had half-a-dozen or so tracks and ran a back to back test with all the plugins running at 44.1 and then oversampled to 88.2.
I was actually really quite surprised at how obvious the difference was, as if a gossamer veil had been lifted between me and the speakers.

Yes, 'twas me, and I've done a lot of Reaper tests since then, and heard some distinct improvements with some plug-ins.

Personally I'm going to carry on doing individual per plugin oversampling, as for me it's mainly the preamps/distortion plug-ins that benefit (Airwindows and Soundtoys' Decapitator in particular), while the TDR compressors I use tend to already have their own integral oversampling options.

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Re: Oversampling oddities

Post by Tomás Mulcahy »

Yes I think it’s better to test each plug-in for aliasing. DDMF has an app to do it. It’s quicker than doing blind AB listening tests and it’s definitive. I’d consider using something other than saturation to achieve certain sounds. Because that’s the hardest effect to do with minimal aliasing.

By the way, the TDR plugins are incredibly good.
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Re: Oversampling oddities

Post by blinddrew »

Sorry, DDMF? :?:
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Re: Oversampling oddities

Post by muzines »

blinddrew wrote: Mon May 16, 2022 11:17 am Sorry, DDMF? :?:

https://ddmf.eu/plugindoctor/

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