Increased gain on Resampled files with convolution enabled [Resolved]

Roon 1.3 build 208 Core on Debian and Intel i5 NUC

I have the following set up in DSP:
Headroom Management: Enabled, Clipping Indicator: Enabled, Headroom Adjustment: 0dB
Sample Rate Conversion: Max PCM rate (Power of 2), Minimum Phase or Linear Phase
Convolution: single 192kHz filter made with Audiolense, but split to L and R 32bit float, Roon resamples as needed

44.1 (and 88.2) material gets upsampled to 176.4, 48 and 96 to 192kHz

Problem is that a Redbook file is MUCH louder when resampled to 176.4 than played with it’s native 44.1. Maybe as much as 8 dB or more.
The same goes for 48 and 96kHz material resampled to 192kHz.

Note: this is with convolution enabled. With convolution disabled resampling seems to behave correctly.

I have not checked the exact difference in loudness, but I believe there is variable gain depending on what one resamples from (i.e. less from 96 to 192 than 48 to 192).
Volume leveling is not used (I think) I’ve turned off both Audio Analysis in Settings->Library.
Either way there is no clipping. The native 44.1 is very low in level as the convolution filter is attenuating quite a lot.
I’ll add @support here. Hopefully not too busy …:slight_smile:

Hi @ogs – we’d like to look into this further. Can you post some screenshots of your signal path and DSP settings?

I’d also like to get a look at the convolution file – can you upload it to Dropbox (or similar) and send me a link? If you don’t have Dropbox, just let me and @Eric know and we can help you upload the file directly to us.

Thanks!

Sure @mike and @Eric. I’ll get it done this evening. I have indications that this is related to using 32bit convolution filters. When I use 64bit filters the levels are normal I think. I’ll double check this tonight.
I do not use Dropbox or similar so I’d need advice on uploading directly to Roonlabs.

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You might be onto something with the 32 bit filters Olav. I’ve heard this, but I’m not sure what bit depth my filters were.

Hi @ogs ---- Thank you for the follow up. I have sent you a PM with instructions on how you can upload the content to our servers.

-Eric

I’ve uploaded files. I believe it is the resampling that makes the level difference.The three 192*.zip files only contain a 192kHz filter so Roon will resample for other resolutions. The level differences are quite clear. The *-all.zip has a filter for each sample rate and there are no level differences. I’ll do the screen shots in a separate post.

Files uploaded:
06.03.17-all.zip
192_L-R_headerless_pcm32.zip
192_wav_32.zip
192_wav_64.zip

Here are three screen shots:

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Hi @ogs ---- Thank you for the follow up, my apologies for the wait here. Confirming that the content has been received and is with our tech team for evaluation. Your patience is appreciated while we look into this issue for you.

-Eric

No problem @Eric The only worry I have is that my trial will run out before a solution is found. Then I can not test…
Luckily it does not prevent me from enjoying Roon as I can easily work around and ignore these issues.

Hi @ogs ---- Thank you for your patience here. We have been able to reproduce the behavior you’ve reported in house and we believe that it has been fixed. This is pending our next release.

-Eric

Thanks @Eric, good that you could reproduce it. I’ll look out for the next release and report back here.

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This seems to be fixed in 218

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