Guide · Roon DSP
Roon room correction: how convolution in MUSE works, and where the filter comes from
Roon applies room correction through convolution in MUSE, its DSP engine: you give it a filter, a zip of WAV impulse responses (one per sample rate, with a small configuration file), and Roon plays every track through it, zone by zone. Roon does not measure the room or compute that filter itself. You build it with a measuring program such as REW and a filter designer, or with a tool that does both, like audiolaz Room, which measures with a phone or a calibrated microphone and installs the filter in MUSE for you.
Updated by Alexandre Besson, who makes audiolaz. audiolaz Room is in beta.
In Roon
Zone, MUSE, Convolution.
Convolution is set per zone. In Roon, open the zone’s volume control, then MUSE (the DSP engine), and switch on Convolution. Roon asks for a filter file: a single WAV, or a zip that holds one impulse response per sample rate and a configuration file that tells Roon which file goes with which rate and channel.
Two settings matter next to it:
- Headroom Adjustment. A correction filter cuts most frequencies but may boost a few, and boosts can clip. Roon’s headroom lowers the level before DSP. Set it to the filter’s largest boost, or a little more; Roon’s clipping indicator shows when it is too small.
- Sample rates. A filter is built for one sample rate. With a file per rate in the zip, a 44.1 kHz album and a 192 kHz one are both corrected properly.
Roon’s MUSE also has a Parametric EQ and a Procedural EQ. They are good for a few known bands; convolution is the tool when the correction comes from a measurement of the room.
The filter
Three ways to get one.
- By hand: REW, then a filter designer. REW (Room EQ Wizard) is free and very capable. You measure with a calibrated microphone, read the curves, design a correction (REW’s own EQ, or a tool like rePhase for FIR filters), export WAV files and zip them for Roon. You control every decision. It asks for a few evenings the first time and a computer next to the system.
- With audiolaz Room. It runs on a computer of yours (Mac, Windows, Linux, a NAS or a Raspberry Pi) and is driven from the phone’s browser. Three measurements at the seat with the phone or a calibrated USB microphone (UMIK-1, UMIK-2, Dayton iMM-6C), a minimum-phase FIR filter built for those speakers and that seat, four sounds on top (Neutral, Balanced, Warm, Analogue), then the presets installed into MUSE, each sound one preset, with “No correction” at the same level. Less to decide by hand; the expert settings and a target curve of your own are there if you want them. Roon is one of its sources; its corrector also takes AirPlay, Spotify Connect, UPnP and every app on a Mac (every source).
- Another tool’s export. Any program that writes WAV impulse responses can feed Roon: some correction systems export a filter, and a convolution file for headphones works the same way.
ROCK and Nucleus
The filter, without the desktop app.
Convolution runs on the Core, so it works on a ROCK or a Nucleus like anywhere else. The awkward part is loading the file: Roon’s help says it must be done from Roon on a Mac or a Windows computer. Without one at hand, each new filter is a trip to someone else’s machine.
audiolaz Room installs the presets into the Core itself: on a ROCK or a Nucleus through the Data folder that Roon OS shares on the network, on a Linux Core with its password typed once (then forgotten), or directly when Roon runs on the same Mac or PC. Roon restarts once, about 40 seconds without music, and the previous settings are kept in case a step fails. The guide shows each case.
Check
Measure again, compare at one level.
- With the filter on, measure again at the same seat. The response should follow what was predicted; if not, check that Convolution is on in the right zone and that nothing moved in the room.
- Compare with the filter off, at the same level. Switching Convolution off also removes the headroom loss, so the uncorrected version plays louder and tends to sound better for that reason alone. A “No correction” preset at the same level avoids that trap.
- Listen to music you know, for some days. Tighter bass is usually obvious at once; the rest takes longer.
Plainly
What convolution will not do.
- It corrects one listening position well; a metre away, less so.
- It cannot fill a null where two sound paths cancel. Good filters leave nulls alone and cut the peaks.
- It does not replace acoustic treatment, and it does not make a weak speaker good.
Questions
Short answers.
Does Roon convolution add latency?
Some: a convolution filter needs a block of audio before it can play it. For music the delay does not matter. For video it can, which is why lip sync is measured with the picture, not guessed.
Do I need a filter for each sample rate?
It is best: one impulse response per rate in the zip, listed in its configuration file. audiolaz Room writes them from 44.1 to 192 kHz in its zip, and up to 384 kHz when it installs the filter in Roon itself.
Does convolution work on a Nucleus or a ROCK?
Yes, it runs on the Core. Loading the file normally needs Roon on a Mac or a Windows PC; audiolaz Room installs it without that step.
Can I use a REW filter in Roon?
Yes, as WAV impulse responses, zipped with a configuration file or as a single file. audiolaz Room also imports a REW target curve.
A question this page does not answer?