DRC Convolution and conversion to DSD

Core Machine (Operating system/System info/Roon build number)

Latest Roon build; Windows 10 Pro 64 bit; i7 server, Xeon board

Network Details (Including networking gear model/manufacturer and if on WiFi/Ethernet)

Ethernet network, Linksys 1900ACS router
Audio Devices (Seicify what device you’re using and its connection type - USB/HDMI/etc.)

USB direct from core sever to Kii Control

Description Of Issue
I’m using Audiolense convolution filters in Roon. I have five installed: 44.1k, 88k, 96k 176k 192k. I understand that for PCM convolution, the respective convolution filter for the sample rate of the file being played back is used. In the signal path displayed in Roon it says “2 paths, 33k taps” are being used for each of those sample rates during convolution.

Today I tried setting up convolution with the sample rate conversion in Roon DSP also set to 128 DSD. The signal path now says the signal is being converted to 352.8k, and the convolution is “2 paths, 66k taps”, after which the signal is converted from 352.8k to 5.645 Mhz and modulated to DSD 128.

Just curious: since I don’t have a convolution file written for any rate of above 192k, and definitely not one for 352.8k, how does Roon actually do the convolution? What’s the process?

Hello @danny2,

In scenarios where one does not have a convolution filter with the same sample rate as the content, Roon will automatically resample the convolution filter to match the content before applying the convolution to the audio stream. As you double the sample rate of a FIR filter, the tap length is doubled as well.


Just to make sure. Is this what’s happening to my DSD playback as well? I have convolution filters for 44.1-192.

Hello @ComputerAudiophile,

Correct, the convolution filter is being resampled to the DSD rate before being applied to the audio stream.

If you’d like to know more about how Roon handles native DSD DSP operations I’d recommend reading this post from @brian :


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