HAF - Home Audio Fidelity (Room Correction / convolution filter creation)

Hi All,

I would like to share with you a young company providing with high quality room audio correction available on Roon.
This is HomeAudioFidelity: https://www.homeaudiofidelity.com/
You will find more details about the technology embedded in this solution.

From my point of view, this is the best solution I have implemented so far. Previously I was doing my own corrections using Rew and Rephase but with this solution the results are far more efficient with a very nice soundstage, deep, large and coherent.


Hi @Sylvain74,

The linked website didn’t say how to use this service. Can you give some more detail about how you found the company, what they did and how much it cost ?

The information is all present on the website but a number of people have tripped up on the websites’ navigation, which may be dependent on the browser and device used.

On an iPad, select the ‘menu’ icon in the top left hand corner which will present a choice of language. Select the expansion (+) icon at the end of the appropriate language for a subsequent drop-down list.
Do NOT select the language as this will simply display the home page again.

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Ah, thanks Alan. I wasn’t hitting the +. Unusual design.

Hi Andybob,

It seems that the website navigation is a bit confusing depending on the support used to browse it.
Anyway please find hereafter the links to directly access the page.
Home: https://www.homeaudiofidelity.com/english/home/
Technology: https://www.homeaudiofidelity.com/english/technology/
Requirements: https://www.homeaudiofidelity.com/english/requirements/
Pricing&Contact: https://www.homeaudiofidelity.com/english/pricing-contact/

I met the creator on an another forum when he shared with us his room correction. Then he proposed to be like beta tester to validate and get feedback about the technology he implemented.

A good feedback from a use on Computer Audiophile

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Interesting approach. I read the technology page and the comments about constant directivity reminded me of a paper written in 1971 by Ted Jordan (published in Wireless World) where he argued much the same thing.

Somewhat ironically the Geddes paper (from which the chart showing ideal polar response is taken) ends with this conclusion:

"The take-away information from this last figure is that once one has a well designed loudspeaker, there is no need for electrical EQ and in fact it is likely to make things worse. Acoustic problems can only be solved acoustically, and once that is done, nothing more is possible.”

This is what Ted Jordan aimed to do. I have to admit some bias - I use Jordan Eikona speakers - but my ears confirm that the theory works.

Happily reporting I am very pleased with the set of filters built for me by Home Audio Fidelity (HAF). The science behind is solid and indeed works : the multichannel filter is not only doing the “standard” Dirac/Acourate/REW/Rephase equalisation and phase adjustments that I know well, but also boosts the reverberant field where it lacks, allowing the brain to feel it more natural and improving the depth and precision of the sound stage. In my case (reverberant living room, no room treatment allowed by the landlord…) the result is spectacular. Wow.


Looking forward to getting some filters made.

Couple questions:

Did you go for the cross-talk option?
What ‘house curve’ did you go for?

Oh, and had you previously used Acourate or similar?

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@hifi_swlon thanks for reminding us that there is also a thread open on the Devialet users forum to discuss HAF filtering. https://devialetchat.com/showthread.php?tid=4492

For the French speaking see also the thread on forum-hifi.fr http://forum-hifi.fr/thread-2781.html

Couple questions:
Did you go for the cross-talk option?
What ‘house curve’ did you go for?

Yes I went for the cross-talk option which in my case further improved the sound stage on acoustic records. There is little difference with the standard MOD filter on non-acoustic recording, just a feeling that there is a little bit more “air” in the room. Also no loss of details or tone. So after several tries swapping MOD filter and MOD_XTALK filters, I decided to keep the MOD_XTALK active all the time. You can make up your mind anyway with the sample files that Thierry will provide in the (free) evaluation phase. Make sure that you get at least 2 files of different genre (you can also submit your own file).

I had previously used home made REW/Rephase filters, there were comparable with Dirac to my ears (but I had tried Dirac some months ago so I might be wrong). I am pretty convinced the HAF filters outperform Dirac in my case, but in order to be sure I have re-downloaded Dirac and plan to run a face to face against HAF filters. This I cannot do fairly in Roon as there is no way to use the Devialet Air driver (by far the best connection to the Devialet) with Dirac :roll_eyes:. My setup for the test will be :

  • conf 1 : JRIver (no convolution) → Dirac → USB → Devialet D200
  • conf 2 : JRiver (with HAF convolution) → USB → Devialet D200
    Stay tuned :slight_smile:

EDIT: regarding house curve I asked Thierry for an “acoustics standards” one, flat until 2KHz then slowly going down at 2dB/oct. Playing with Roon DSP EQ it is easy to change afterwards if you want more bass, or a steeper slope in the treble, or something else. I played a bit with the EQ but at the end always went back to the initial correction suggested by Thierry. Also note that Thierry can also adjust the filter to your taste after you buy (for free). This was not required for me.

I wanted to bump this service as a few users on Devialetchat are reporting great results and may be useful for Roon users that want to try but don’t have the technical knowledge and/or desire/time to mess with filter creation.

Essentially you take measurements, and send them to Thierry, who is apparently highly knowledgeable in the field and creates filters for you using his allegedly proprietary software.

I have no affiliation, but it’s of particular interest to me as I was deliberating whether to buy Acourate to make better filters than my REW PEQ ones, or try and find such a service. I will almost certainly try a test with him as soon as I can make fresh measurements. It is a paid service just to be clear.

There’s a thread on Devialetchat where Thierry has also contributed, and some measurements (including with correction) have been posted:

And his website is here:


A silly question most likely as I know nothing about this but how does one make the measurements to send to Thierry?

In Noddy does DSP terms please.


In the simplest setup you get a calibrated mic like the umik-1 (about £100 plus a cheap mic stand from eBay/Amazon), which is USB, and you connect to your computer. You then run a free program called REW, which outputs sound ‘sweeps’ via USB to your DAC, while the static mic simultaneously measures the response (which REW captures).

You do this multiple times - for your hero position, plus others around it, and you save them all as a REW file containing the measurements.

The sweeps are varied, but generally people use a log-sweep which goes from low frequency to high frequency. As the curve is known, what the mic records shows how the sound is distorted from this known curve due to your speakers and room interaction - in all bar the most perfect dedicated and treated listening room or sound studio, what you get back will be quite different to what REW sent the DAC. In fact I was amazed how bad mine was when I first saw it, but most people’s graphs show the same - the sound’s all over the place.

There’s a lot if info out there which will be helpful to read but not really necessary - if you want to give it a go there are a few guides here on this forum and plenty of people can walk you through it. It’s not rocket science but it’s worth taking time and doing a few practice runs.

If your room isn’t perfect, and you can’t (or don’t want to) treat it acoustically, you’ll probably benefit. For many people - like me- with hifi in a domestic setup it’s a far from ideal room, the benefits are huge, taking from a system I dont like listening to, to one I really do.


Hi @hifi_swlon
I’m a newbie about convolution.
If i understand correctly this simplest measurement setup bypass player DSP (Roon or HQP).
I’m currently using such DSP (mostly DSD conversion and upsampling with filter and modulator),

Is convolution applied before or after other processing in the signal path ?
If after, how to get measurements taking in account DSP if any ?

Hi volpone.

This is probably beyond the scope of the home audio fidelity filter creation discussion, but yes you need to disable any other DSP to make measurements regardless how you do it, but in this example REW is the only player active.

If you feel you need to take into acvont upsampling and DSD conversion, that’s probably another topic in itself… things are more complex when DSD’s involved. :slight_smile:

Thank’s @hifi_swlon,

I’ve no feeling about best practices to get adhoc measurements. I understand your point about DSD “more complex” but why a new topic ?

I’m not alone using DSD upsampling and tempted to try HomeAudioFidelity convolution filter files to get room correction.

Yep, it’s better to perform measurements without any other processing. Still you can run convolution in conjonction with the other DSP if you want, Roon will take care automatically of the upsampling of the correction filters.

For measurements : the easier is not to use Roon but directly connect the computer with the microphone to your amp. USB, analog, optical, doesn’t really matter. It this is not convenient for you (for example you don’t want to crawl behind your amp to plug another cable…) you can still play the sweeps from Roon after adding these two sweep files to your library. They are tagged Artist/Album = Home Audio Fidelity. Just make sure all DSP is off during the measurements. Then just record the sweeps in REW, making sure that “wait for timing reference” is ticked.


See previous comment below from Thierry to myself regarding DSD:

"Regarding DSD, there is no convolution possibility on such raw format : all players usually convert to PCM & apply filters at high sampling rate (I have created filters at 384 kHz for HQplayer for instance)

Kind regards,

I’m not alone using DSD upsampling and tempted to try HomeAudioFidelity convolution filter files to get room correction.

You can upsample to DSD after the convolution if you want, see example.