My great experience with Home Audio Fidelity room correction software

I have recently been reading the thread on room correction with DSP in Roon Forums 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 DAC Firmware. 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 audio system.

PS Audio Direct Stream with Bridge II (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.


Thanks for taking the time to share your experience with HAF. It’s very high on my to-do-list. Now even higher. It’s just hard for me to find that hour alone at home to do the measurements.

A question: you wrote, that you used the UMIK for measurement but requested a HRTF model - but aren’t these done from measurements via the binaural mics? Thanks for clarifying! And: please share your findings from the HAF/HRTF comparison!

You are correct about the binaural mike being needed for the HRTF measurements.
The UMIK is needed to measure the room for the room correction. Both sets of measurements are used to generate the file for the final HRTF correction. I have been listening to HRTF the last few days since getting the filter from Thierry. I have to get more experience with the straight room correction filter. Thierry also sent me a filter using his head model cross talk rejection which I don’t have much experience with.
The thing is that the HRTF filter is so amazing I find it hard to listen now without it. When I turn it off there is an immediate contraction of the soundstage and the music sounds less natural. I am quite impressed.
I will take some measurements when I get a chance with the UMIK in REW to compare with my original measurements. I see this as being academic as the listening is a great improvement and that’s what matters. The binaural mic I can use with my DSLR to record audio with video as the quality is better than the camera mic. The binaural recording gives an amazing soundfield in the playing around I have done. Plus the mic is less obtrusive than the larger Shure mic I bought. People would think you are wearing earphones and listening to something.


The binaural mic can be used for the room measurements but the UMIK is superior as you download a calibration file for your individual mic. The expense is nominal compared with what I have invested in audio equipment. I am amazed about the great improvement the filters have made.

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Got it now - you need both measurements. Thank you.

A bump for Thierry’s work at HAF. I’ve run his xtalk filters for ~3 years now and just added Room Shaper to the processing arsenal.

I can’t have enough bass traps to do any good but this little plugin really improves the decay time in the <600Hz region without any audible negative impact. If there is a downside it’s somewhat involved to setup depending on one’s digital system and the induced latency is a bummer but required as these alterations are in the time domain.

This is definitely in the icing on the cake category though. Everything else should be well sorted first otherwise the improvement may be lost.

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