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

Yeah I am thinking maybe get a USB Phono stage and use a computer to stream it as flac and have Roon pick up the URL. Some have done this but its a complexity I am looking to avoid if possible.

So maybe the new Arcam SA30 is calling me. It has Dirac built in, and a mc phonostage so saves on another few boxes. Decisions, Decisions.

Having just done REW with @Magnus’s help (thank you!) (and now done to 500 Hz as you suggested) I found the process very manageable. Moving mic measurements with RTA is the anchor point to make REW easy and effective (along with ofcourse first having tried to make your speaker placement and room function as best you can within whatever limits you have in your home.)

Just out of curiosity, can one not use Dirac completely in software on your Roon endpoint, without needing a special amplifier? Wasn’t that supposed to come at some point?

People have asked for Dirac but never been any mention from Roon themselves to my knowledge. I would imagine the licensing is quite expensive and would likely put the cost up some.

Wow, so, Dirac is only available in HW, and for example that MiniDPS SHD still requires a DAC attached before you can send the output to your amp. So, your going digital (from your network - from Roon? Because it has Volumio running…) to the SHD which does Dirac but outputs only via SPDIF and AES-EBU, so that limits your DAC choice, or you need connect yet another device like a Pi and then output the DAC of your choice.

Very complex and expensive. In order to use Dirac. Is Dirac so insanely much more amazing than the most direct, simple and efficient use of REW / HAF filters convolved directly in Roon?

Dirac is available as software and until recently could be linked to by Roon. The new version of Dirac has complicated this process.

If interested, you could try This thread which links to others etc.

Thanks for the link. From there I take it, having a VST Host that Roon can talk to is the issue. Mentioned was using FB2K via the Squeezebox API to do that (Roon(LMS) => squeez2upnp => foobar2000(as VST host w/upnp plugin) => dac). Atleast that is free and completely in software, but wow is that alot of work compared to REW / HAF.

That does appear to be unnecessarily complicated and that’s before you consider the cost. You could have several expertly crafted HAF filters for the price.

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I still cant believe how much HAF’s filters have changed my system. It really is to coin an audiophile phrase, a veil has been lifted. Its makes listening so much more pleasurable and I can stop thinking about the hifi and more about the music.

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I’d go so far as to say his filters have made my speakers sound better than they are. No real rush to upgrade them.

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I have recently been reading the thread on room correction with DSP and that lead me to the thread on Home Audio Fidelity. I have used Roon with the Direct Stream for a couple years and only recently used a house curve here and there, usually running flat.

I was intrigued as once I got the Utopia’s and BHA-1, I spent a lot of time listening to them. I like the presentation of speakers, and believe it gives me a better soundstage with the music coming from in front of me. My room and equipment did a good job with this, generating a nice acoustic image with some depth laterality outside of the speakers. What the Utopias really had over the room and speakers was resolution and timing. In comparison the room and speakers sounded slightly smeared, which I attributed to problems with phase, crosstalk and resonance. The room was finished to improve acoustics and has some treatments as detailed below.

I decided to demo HAF as others wrote of it being a great improvement over their own efforts with REW, rephase and other software. I am retired and have a medical background and liked the idea of measuring things and trying to fix problems.

I contacted Thierry, downloaded REW and his software for HRTF measurements, bought a UMIK-1 mic and a Sound Professionals MS-TFB-2-USB binaural mic. I read and reread the forum threads. I used Thierry’s procedure to take measurements and a modification of Magnus technique for the room measurements with the UMIK (the girl picture). A $25 mic stand was very helpful. I made measurements no further than 30cm lateral to sweet spot as 99% of the time its just me listening and my wife really doesn’t care. I waited for her to take the dogs out for a while and turned off the air conditioner. I had already placed tape markers on the couch to indicate where to measure.

The measurement process was not difficult and took maybe 30 minutes after I had run through it once.

I sent the measurements to Thierry for HRTF as well as a FLAC of Jeff Buckley “Mojo Pin”.

The next day I heard back from him with the modified test track. I listened several times and AB’ed with the original. I was overall impressed and wished I could hear more. Thierry offered to modify another track but I didn’t think it necessary. I heard improved spatial definition with a slightly wider and deeper soundstage. The vocal was much more natural sounding and the bass and kickdrum better resolved.

His method had made my already good system even better. So, I sent him payment and got the files to plug into Roon’s convolution filter within an hour or so.

The next day I had a couple hours to listen to what I wanted and AB the HRTF filter/no filter.

After a few cuts I was convinced that this was a great improvement in the sound of my room. Differences were particularly apparent with well-recorded vocals and acoustic instruments. I listened to a Bartok String Quartet (24-96), the strings sounded much sweeter and natural, losing a mild harshness they had before. Miles Davis (DSD) showed a natural sounding trumpet and sax, along with bass and drums which sounded in the room. In both cases the spatial presentation was enhanced significantly with precise, focused locations, improved depth relationships and a wider soundstage.
Tool “Lateralus” (24-44) was revelatory, I’ve listened countless times but never like this. Maynard’s vocals were crisp and defined. The bass, guitar and drums all with improved definition and pacing.
Further tracks only reinforced these impressions and continued AB’ing always showed the filters to be an improvement. I go to occasional small venue live performances and dabble in electric bass. I have had symphony season tickets and heard live string quartets. My wife had a piano for years.
The filters gave the room/speakers a sound approaching the Utopia’s in resolution but with the more natural presentation of speakers. I heard things I hadn’t before and heard instruments and talking or a dropped glass well lateral to the speakers.
The improvement was less than new speakers but more than new amps or possibly DAC. There is no comparing the minimal difference interconnects and cables make. I need to rip what hard music I have that I can’t stream so I can play it through Roon and filters.
It is the best few hundred I have spent on my audio hobby including the mics.
Thierry is great to work with and responds to questions in a timely way. I need more time to try the HAF room correction filter alone without HRTF. The HRTF just sounds so good.
After seeing the graphs of the measurements it is clear the room has a tremendous influence on the sound and the response curves are hugely different than what the speakers measure in an optimized lab setting. I was always hesitant about altering the signal path or deviating from flat response. I think most of us are fooling ourselves if we think that is what our gear and rooms are giving us. The proof to me was in the listening and I am very happy with the difference Thierry and Home Audio Fidelity have made in my life.

PS Audio Direct Stream (Snowmass 3.06 firmware) Roon streaming Qobuz, Tidal and pulling ripped CD’s and DSD’s from a Synology NAS.
Bryston SP3 (latest firmware) running in 2-channel analog bypass mode
These have power via Tice Power Block III
Bryston 7B-ST monoblocks
Aerial Acoustics 10T (second generation) on spiked stands.
Marantz sa-7st
Focal Utopia through Bryston BHA-1 (for comparison)
All interconnects are balanced (Bryston between the electronics and Wasatch Cable Works between SP3 and 7B-ST’s). 2 foot run of biwired Wasatch Cable Works between each 7B-ST and its driven 10T. Don’t remember what the WCS stuff is exactly, higher end from them as I recall (supporting local economy and they were well reviewed).
ASC Bass Traps in front corners, 2x ASC half-rounds on ceiling, an ASC flat-trap on each sidewall.
Half-Rounds and flat-traps placed using a mirror to optimize cross-channel rejection to sweet-spot.
Basement room with a 7 foot ceiling. (1 x 1.6 x 2.6 : height x width x length). Front wall and right side are foundation walls with concrete up to approximately 5 foot level. Double studs and drywall. Rear wall and left side are interior walls with double studs and drywall.
Room layout fairly symmetric other than asymmetric media drawers/cabinets on back wall (center and left) with equipment rack at right back wall. There is an Aerial Acoustics SW12 subwoofer a few inches inside and slightly behind the left 10T. There is an Aerial Acoustics CC5 midline between the 10T’s. There is an Aerial Acoustics LR3 on each sidewall, roughly lateral to sweet spot. Center and surrounds driven by a Bryston 8BST (2channels bridged for the CC5).
All listening done in stereo with only 10T’s. All equipment moved from my old house which had a larger room. This results in a little crowding up front to accommodate the SW12, CC5 and 7B-ST’s (located on stands behind the CC5). The room obviously does double duty for home theater but majority of time is spent with 2-channel music without subwoofer.


Another satisfied customer! I can’t recommend enough a decent cheap microphone stand for taking measurements.


To get the filters to work correctly on a Marantz SR7012, I would imagine I need to set the AVR to Direct or Pure Direct mode so the receiver doesn’t try to do room correction via Audyssey?

Yes I would imagine of your using Roons DSP you need an unmolested signal path to get best results.

Yes. You absolutely have to do this. Some AVR’s don’t have a direct passthrough option – hope yours does.

For anyone using a UMIK-1 mic with REW, which calibration file should I use, 0 deg or 90 deg?

I’ve been in touch with Thierry and finally ready to take my measurements using REW, which is all new to me. He has been very helpful with my noob questions. Couldn’t get his simplified method using his software to work, he wrote in an email the following:

“It seems you have a more serious issue preventing loading my pd program to your MacBook. And this is why you don’t hear any sound when using the remote control. There is a quite simple procedure using REW as recorder and Roon as player for the test signals : the procedure is described below and you can find the test signals as attachment.”

In the referenced procedure he sent step 2 is Configure your microphone. I wasn’t sure what that meant, and he said go to the MiniDSP site and download the calibration file for the UMIK-1. There are two calibration files and the site says:

We provide two calibration files to be used depending on your application.

  • For stereo system (e.g. 2ch dirac live, single speaker measurement), use the 0deg file and point the UMIK-1 at the speakers
  • For multichannel system (E.g. 5.1/7.1) or a surround application where multiple speakers are spread out around the room, use the 90deg file and point the UMIK-1 at the ceiling.

In an earlier email Thierry said “You can put the mic toward the ceiling as it is easy to keep this orientation while changing the measurement position.”

Does this mean I should use the 90 deg calibration file? I asked Thierry in an email last week but haven’t heard back yet.

Yes, the 90-degree calibration file is for when the UMIK-1 is pointed to the ceiling.

Thanks, and it’s okay to use the 90 deg for HAF measurements, even though it says that calibration file is “For multichannel sysyem…” ?

Yes, if Thierry says so. My (limited) understanding is that the vertical rather than horizontal orientation means the mic is less sensitive to whether or not it’s directly pointed to the speaker whose response you’re measuring.

Sounds good to me, that’s what I’m going to use, want to do this today! I’ll probably run into more questions anyway when I start REW and try to use it :rofl: