Any plans for convolution and parametric EQ? [Released in Roon v1.3]

This may have been discussed elsewhere on the forum. If so, I apologise for not using existing threads.
I use room correction (Audiolense, stereo only) and need convolution capability for playback. Currently I use either JRiver via it’s UPnP server + upmpdcli/MPD or LMS with the BrutefirDRC plugin. To use Roon as player I’d need Roon with convolution. As Roon now supports playback on Squeezebox/Squeezelite (that is fabulous!!) and HQplayer I am considering a subscription, but not without convolution. I know HQplayer supports convolution, but have not checked if I can set up this with the combination of Roon and HQplayer


I haven’t heard of anyone actually using it and haven’t any experience myself, but in principle I can’t see any reason why the convolution engine in HQP couldn’t operate on an input stream from Roon. If the EQ data file for your existing program is supported by HQP (RIFF (WAV) format FIR impulse responses) then it could be easy to test. Be interested to know what kind of CPU load you experience with convolution and upsampling to DSD.

Thanks Andrew!
I’ll see if I can find time to test this. Problem is that I have no experience at all with HQP. Convolution in HQP is taking place in the main program, not NAA as far as I know. I’d need to run Roon on a separate PC away from the stereo. Think microRendu at the amp (Devialet 250) and Roon (+ HQP) some where else.
It would be easier if Roon had a convolver or maybe VST support.

VST/AU support would help a lot of people with whatever plugins they need. I use Dirac for example, so Roon adding a convolver wouldn’t help me in that case and I’d reeeeaaaaaalllllly love to run Dirac properly within Roon.

Out of interest, do you have access to a pre-production microrendu, or you’re just thinking it would suit your needs when available? I was thinking the same same for my Devialet, but again the only tricky aspect is Dirac room correction - it just doesn’t fit with Roon and RoonSpeakers as things stand. And I really don’t want to live without it.

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Hi Ogs,

Convolution in HQP does take place in the main program. The NAA is little more than an Ethernet/Wi-Fi in and USB out buffer.

You can run HQP anywhere on your network and send it input from Roon. Roon asks for an IP address for HQP and defaults to “localhost” being the same machine for Roon and HQP.

As at November last Danny indicated there were no current plans to add VST plugins.

VST/AU have a very annoying technical limitation:

Both plugin architectures allow plugins to provide user interfaces for configuration, and apps that support plugins generically must display these interfaces. The way that the VST/AU folks chose to do this requires that the user interface be displayed in the same process where the plugin is loaded.

This is a big problem for Roon, since for many users, the server and the UI are running in different processes (RoonServer vs Roon) or different machines, and often not even on the same platform.

It’s frustrating that the vendors of these plugin systems didn’t think bigger, or consider that architectures other than “standalone app with UI” might exist one day.

Anyways, that’s why, as much as we’d like to do it, I don’t think VST/AU are in the near future for Roon.

I think supporting user-provided convolution filters is a good idea. It’s not technically very difficult. We have convolution (FIR) filters in the app already as an implementation detail of our sample rate conversions.

There’s a detail or two that I need to understand better about how other products handle this feature from a product standpoint, and I think I would want a faster convolution implementation than we currently use so that longer filters would be practical, but these aren’t big problems.

Technically, you could also do use a convolution feature to accomplish parametric EQ in conjunction with a filter design tool like this.


Hi Steve

no I do not have a microrendu, but as you suggest I think it would work very well with my Devialet amp. Dirac is certainly interesting. The very reason you mention - Dirac not exporting filters - is why I have avoided it.

@brian, what you write here is very encouraging! I will follow this development closely. I see myself as a lifetime Roon user with convolution in the app! I may even subscribe to Tidal although I’d prefer Qobuz for music selection.

@andybob I’ve checked HQP once more. It seems to require some sort of desktop environment even if I use the headless version for normal playback. Most of my PCs are headless Linux boxes so this is not ideal. In addition HQP looks to be quite complicated. Not that I could not handle it, but if Roon comes with convolution at some point I think I’ll wait for that.
Thanks for the information. It is very helpful

Hi Olav,

I think it is fair to describe HQP as complicated. There is an embedded version of HQP that can be used on a headless Linux box with a Rigel compliant Android controller, but that adds a further layer of complexity.

I haven’t yet delved into room correction, but have sometimes felt my system has a bit of a mid-bass dip. How would you describe the change you experienced from using room correction ?

@andybob The listening space is in our living room. Speakers have a nice symmetrical set up, but placement is dictated by practicality and is far from optimum. I have unpleasant room modes in the bass range and quite large L-R differences in sound stage. Room correction takes care of all this. From my listening seat the sound is simply wonderful without any of the un-corrected irregularities. I’d probably play very little music if I did not apply correction.

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That’s a real shame…… but good to know.

Dirac for me is just amazing and IMO more inline with Roon in terms of a design/usability mindset - it makes RC a much more realistic proposition for ‘average’ users, with a nice interface all you pretty much need is a mic and follow the instructions and you’re done. It keeps the advanced stuff behind the scenes.

In my setup it fills in missing bass and mids, and lowers the upper frequencies, all of which made my system seem too bright for the past few years since I moved house, and just seems to balance everything out so it sounds ‘just right’. It also does a slight delay (45ms) on one side to balance my offset listening, but seems to leave everything sounding great throughout the room. It deals with a lot of reflections too (so I’m told), and has a nice selector for 4 favourite target curves.

I love it, its had the most positive effect in my system over any other hardware or software I’ve purchased in the past 3 years (since I moved house) - including the Devialet, Hugo, and various other amps etc. I don’t think I’ll ever go back to no-room correction… If you have a good hifi in a modern lounge type setup like I do (rather than a dedicated listening room), I would be surprised if RC didn’t make your system sound better. The only downside is situations like this, where you have to work out how to integrate it.

I know there are other much more advanced Room Corrections out there (in terms of ‘options’ and configurations at least), but not only do they generally require Windows, they’re also a LOT more complicated from the users perspective.

So I guess it means continuing using the Dirac’s virtual sound card, which rules out RoonSpeakers for me - which was the one thing I was really excited about….

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Unless, perhaps this could be a case where Dirac and Roon get together and combine it without using VST/AU? :wink: Well, it doesn’t hurt to ask, and it worked for HQ player users……

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I have no experience with Dirac, but people seem to be using it with Roon:

Yes, @music you can use it with Roon as things stand now. I do this.

Roon outputs to a Dirac virtual soundcard, which then passes the processed signal to the output device. It works. (actually there’s a slight bug on OSX not remembering the output device, but that’s more of an inconvenience).

The problem comes for those wanting to take advantage of RoonSpeakers and networked endpoints. This rules out Dirac, as once you send to the Dirac virtual sound card, Roon is no longer ‘looking after’ the data, and since there’s no feedback loop, there’s no way to send the processed stream back to Roon for delivery.

The only way it would work with RoonSpeakers or RoonReady devices (as far as I can understand it) would be:
-apply Dirac via VST/AU plugin - which has been ruled out for now by Roon / the VST system architecture
-Roon to create a ‘Roon Virtual sound card’ so that the output from Dirac can be piped back to roon - no idea of this is technically even possible
-Dirac to be integrated into Roon directly. Oh, we can dream……


My comments were on the topic of integrating with VST/AU generically.

Integrating with a particular VST/AU could be feasible provided that it exposed its configuration parameters in a way that let us manage the user interface for configuration. In context of some sort of business relationship, it’s conceivable that that might be feasible.

I too would prefer a direct integration of Dirac+Roon (regardless of the underlying API layer used to connect the two). Virtual sound cards are clumsy and architecturally limited.


I dont think Dirac have their own forum, but I know they interact with the CA ‘Room Correction and DSP’ forum, so I posted the notion there, and will also contact Dirac direct just to express one customers interest!

I have the files for VST & AU for Dirac if you would like a look?

@hifi_swlon : One of these boxes could serve you well:

If I ever get around to spending more time tinkering vs. listening, I’ll order the D version myself.