DSP: What it does and how to use it in Roon 1.8

Time for the professional Roon team to answer this

The only advice on using DSP that I can find is a thread started in 2017 going into great depth about running a microphone software to calibrate it with.

However that tells you nothing about setting up the DSP: what do different elements of it do and, not do, and in particular how do they interact.

Any thread of that age becomes impossible to read with so many divergent posts. Yet the fact it’s still going shows there is a need for information about the subject.

I am simply trying out Roon in order to access its DSP in order to reduce some room modes with excessive low bass. This is an issue that probably affects most users.

If I have two parametric EQ filters one with simply a low frequency shelf of -6 dB at say 100 Hz and then another parametric EQ with a low shelf of say -3 dB at 70 Hz, does that effectively produce -9 Db below 70 Hz. similarly if I use one of the filters that makes an adjustment aimed at a particular frequency, what again is the cumulative effect; also on these what does the Q adjustment do: I can see it makes it wider or narrower but again it’s a question of how different filters interact when they overlap.

How do the various filters affect the processing load; how do you make it most efficient?

DSP is a complicated subject and as far as I’m concerned the only reason to consider using Roon which expects one to spend considerable money on it, over a period, for software and quite possibly hardware, so it does not seem unreasonable to ask for some proper instructions. All I could see was a suggestion that I have a play and have fun with it. It’s real use is to correct poor quality sound caused by room effects which is a painstaking and detailed exercise. It is certainly not fun but some sensible instructions would make it more effective and bearable.

I am finding my two adjustments and tuning them by ear is making a big difference so I would be interested in learning what more subtle things can be done at which point I might buy a microphone to do the calibration.

Can the roon team provide a clear and definitive answer to my question please

Yes I read this before posting my question. It describes the features but not the benefits. Or the only ones are irrelevant. I don’t have headphones, have excessive bass not insufficient, I don’t need a cool curve or whatever.
Pay attention to headroom it says but with no guidance, and what’s clipping?

This article perfectly illustrates how not to do it. It’s written in marketing tones and avoids real detail. Either it assumes the reader already understands the principles or doesn’t care.

I would love someone to explain how it works: 1s and 0s leave Qobuz ‘s server and get converted in my DAC. They do not go anywhere near my computer so does the computer tell the server to modify the 1s and 0s it emits?

I don’t think the DAC modifys its output but maybe I’m wrong. Thanks.

FAQ: What is signal path?

FAQ: What kind of processing is Roon doing to my audio?


Thanks. I saw those and I can understand the logical chain.

Mine is source Qobuz, bit correction to 64, two bands of parametric eq, both low shelves that partially overlap, recorrecton to 32 bit streamer/DAC then analogue to speakers.

Router is ethernet into Streamer. Computer in different room.

Yes I read that thanks but I’m doing more in the way of room treatment not correction. Just removing some bass. Not convinced correction is sophisticated enough yet and tends to give a precise listening position which is impracticality restricive. Would really want to understand what it does not just how to set it up before being tempted that far

You can apply broad listening correction which will not be as precise at any given listening position, but may be better in some rooms as you move around or you can apply multiple separate corrections and switch between them as needed. I generally find a well measured and applied correction at a main listening position can provide a significant improvement everywhere however.

Even on my sofa I use the DSP to alter relative L+R levels and timing so that if say lying on sofa reading (which puts your head much nearer to one speaker) is also very useful to restore a correctly timed and balanced stereo image for off center listening. The room correction I apply at my main listening position is also still a huge improvement all around the room.

I think you could gain quite a bit of understanding of the problem domain playing with the room simulator in the REW app. Even using that without a microphone to inform you of the room mode frequencies can be a useful aid in applying filters by ear. Shelving filters are not really the ideal choice. They are good for simulating tone controls (bass, treble) and can even be used to simulate Quad’s tilt control which can be very useful for restoring a more natural sounding speaker/room response following flattening by full room correction (ie a good house target curve).

1 Like

Thanks that’s helpful. I expect to try a mic eventually but first I want to understand how the eq software works before becoming hostage to it

I am not sure what you mean by becoming hostage to it.

For most of us who have successfully applied room correction in Roon then the opposite is true, its liberating. No longer are we having to generally mess with anything due to bad interactions between the frequencies in a specific track and the speakers in the room and the room’s walls etc.

Once its all setup correctly and with a desirable overall response curve, then its pretty much forget it and just enjoy the music.

The need or desire to fiddle is usually a good sign something is wrong. These days I have no need to fiddle with the sound. Sure there are still poor recording around that may need some enhancement to sound right next to better recordings (usually a basic bass + treble smile curve will do it, or sometimes a just gentle high pass at 30Hz for poorly mixed sub bass and I have a couple of stages setup with these I can switch in if really needed), but mostly I never need to fiddle anymore.

Thats reassuring. Thanks again

I’m happy to use Roon DSP as a tone control - mostly at the bass end of the freq although I sometimes pull down treble slightly or a specific region in the 3.5K area when the loudness wars are too much.

I did try REW with a measurement mic several years ago and gave it up - too complex for me. If I go there again - it’d more likely be with something like DIRAC.

I’d be happy to pay a small fee for someone with the mic and software to come and set up the DSP function. Needed for bass correction. South of UK. Is there anyone out there, or recommendations? Cheers

https://www.homeaudiofidelity.com/ did a very good job for me.
You take the measure yourself using his tool with a mic, send them. Easy to use with Roon.