AuraEngine: Perfectionist off-line mega-tap digital filtering - with hybrid-phase transient detection & blending.

As you know, while digital oversampling filters have been around for ages (4x oversampling available back in the '80s), audiophiles probably got more interested in digital filters thanks to Bob Stuart, and Meridian by 2009 talking about "apodizing" filters. DACs started allowing different filter options. And spin-offs like MQA took things too far utilizing poor designs through the 2010's (and still looking for a reason to exist).

Years ago now, I spent quite a bit of time talking about digital filters across articles like this and contemplating things like pre-ringing here. There were also discussions of using the intermediate phase setting as a compromise. And we even ran a blind test to compare strong pre-ringing vs. no-pre-ringing minimum phase settings.

While I think I've exhausted my time exploring such things at the base level, ever-more-precise filtering options have been available for audiophiles to use. HQPlayer has many realtime software-based playback settings including DSD transcoding. Companies like Chord/Rob Watts have taken their stand on using ultra-tap-length linear phase filters (to the point of extreme IMO).

Off-line upsampling of high precision can also be achieved using software like Pan Galactic Gargle Blaster (PGGB) in 2021 -  I see they have a PGGB+ version now with DSD and up to "ludicrous" 256-bit processing.

Well friends, it's 2026 and the other day I was contacted by Toxa Dev about his new ultra-accurate upsampling system called AuraEngine (current version 1.2.2) available on Github; full source code published and freely released for non-commercial use. You can also download and run the pre-built Windows portable app here. Notice that there are three downloads available: Starter 1M-taps, Standard 10M-taps, and Reference 30M-taps. Pick your level of obsession err... weapon against weak upsampling!

Magic Beans Audio: True Target. DSP correction fine tuning, concepts, and effects.

In my previous post, I discussed target curves and gave examples of curves you might want to consider when implementing DSP correction in your sound room.

While the use of full-range target curves is not uncommon, as discussed, there are those who advocate against doing so and would insist that only partial corrections in the bass frequencies up to the Modal+Transition Zones should be applied. There are of course some good reasons for this line of thinking which will be addressed.

As you can see in the comments last time, I had a long discussion with Joe Mariano (aka Joe N Tell) of Magic Beans Audio about his product called True Target. I continued my discussions with Joe via E-mail and he provided access for me to the Pro version which allows export of the curves to Room EQ Wizard in order to have a deeper look under the hood at how the system works.

The picture above was taken right before one of my measurement sessions with Magic Beans highlighting some "tools of the trade" used to perform the tuning.

Let's talk about the Magic Beans* True Target app. 

[Standard version regularly priced at US$249 should suffice for the vast majority of users, Pro version US$399 allows up to 128 channels and unlimited daily calibrations.]

Room Target Curves - then, now, and options to try...

Be it resolved that there is no such thing as achieving sonic perfection - technically at least based on objective ideals, but "perfect" can also be a subjective state of mind.

In domestic homes, we're simply not going to be able to achieve near-perfect rooms. Likewise, no sound system will be absolutely transparent although the digital electronics side will get much closer to "perfect" than analogue playback and loudspeakers. Furthermore, beyond what we can say about our domestic playback systems, despite all the care and detail-orientedness put into a recording studio, they're not identical even if they followed published standards (like ITU-R BS.1116, or EBU Tech 3276), and besides, is there ever such a thing as a perfectly engineered recording? Or a perfect performance from our favorite artists for that matter?

While perfection might be out of reach, let's not turn away from the pursuit of what is reasonably accurate which is something we can all do to some extent whether it's choosing better-engineered gear, working on small room acoustics, or using DSP to improve frequency response and/or time-domain performance at our listening position. Regarding the specifics of DSP room correction, let me refer you to previous articles covering various methods here, here, here, here, and here.

The intent of this post is to focus on the topic of Room Target Curves which we define and apply when doing EQ and DSP correction. Let's explore a little history, what they are, what they look like and considerations for what to try at home.

SUMMER MUSINGS: True audiophile aspirations; recent events in the audiophile culture - end of Atkinson's Stereophile measurements, YouTube influencer legal drama.

Through my years as an audiophile, I've come across articles in magazines and online talking about hobbyist "aspirations". At audio shows, and seemingly each new issue of magazine we read, we're introduced to the latest and greatest piece or gear, the next "must have" item to consider in this never-ending path of upgrade to satisfy luxury consumeristic appetites.

Given that it's "Summer Musings" season, let's take some time to think about what I think is the most important aspirational item in all of the audiophile hobby - your room. And since in the last month there have been other events happening in audio news, let's also talk about the fact that John Atkinson has retired from doing measurements for Stereophile magazine, and the interesting legal drama around the case of an "influencer" (Michael Gefteas/The Greek Audio Geek) and social media.

SUMMER MUSINGS: "Final" ceiling absorption 😉. AI-assisted summary of Floyd Toole's thoughts on early reflections treatment & discussion on this.

Hey guys and gals, it's July and thus time to enjoy some summer jams, BBQ, and family time ahead. And of course getting into the "Summer Musings" season here on the blog!

Let's "shoot the breeze" and talk about a couple of things in this post related to discussions over the last while with room treatments and acoustics you might want to consider for your own space.

First, as you can see in the picture above, despite the self-proclaimed statement that I was "done", I just had one more little addition to add. I cleaned up and optimized my seating area a little and realized that the rear ceiling panel wasn't exactly overhead. So I added an extra 2' x 4' x 0.8" PET panel immediately overhead above the main listening position. [I also spent some time optimizing the height channels and DSP recalibration along the way.]

Ceiling Absorption Panels (AudioSilk branded PET material 2'x4'x0.8", doubled thickness).

With the recent discussions about room acoustics and treatments, I thought it would be good to continue on this theme and move forward with the next logical step for my listening space. Let's talk about ceiling sound absorption as you can see installed in the picture above.

For years, I've been thinking of doing this but really didn't want to put something up there that could damage the walls. I definitely would prefer not to drill holes unless absolutely needed. Recently, I had some positive experiences with 3M's Command Strips when I put up some picture frames and artwork around the home. These double-sided tape strips were designed to be removable without damaging painted walls. Looking around at options, it seemed that this could be a reasonable ceiling installation solution within weight limits.

On Amazon, there are various options for acoustic absorbers these days. I settled on a package of 4 sheets of 0.4" thick x 2' x 4' AudioSilk-branded polyethylene terephthalate (PET, non-toxic, non-irritant, made typically from recycled plastics like bottles) absorber panels at a good price (~US$110) along with some strong 2-sided tape for doubling up the panels for thickness and of course the 3M Command Strips to stick it up on the ceiling.

On Envy, "Cope", and just plain Reality in Audiophilia. More GR-Research/Danny Richie drama.

After writing the articles looking at room acoustics over the last month, I thought this would be a good time to discuss another observation about the psychology and culture of the audiophile hobby and some of the claims that people make.

As I noted last time, room treatments like the IKEA Mittzon absorption panels are far from the exciting products highlighted in magazines each month or even popular forum topics commonly discussed. While they do review realistic, non-controversial room treatments once awhile (like this), I would find it shocking if one day I opened an issue of The Absolute Sound and saw an article reviewing the Mittzon panel!

Sound Absorption: IKEA Mittzon Floor Standing Panel (+ GIK Acoustic panel).

Greetings audiophiles. Finally, I'm back home in Vancouver after my Asia trip. I love traveling but there always comes a time to look forward to "Home, sweet home." And music to listen to in my personal sound room of course!😌

In this post, let's talk about perhaps one of the most boring things you could buy - a sound absorption panel. Made all the more pedestrian because this one comes from IKEA. At a retail price of US$230 each for the smaller (but IMO adequate for my home audio) 27.5" x 61.75" x 3.125" panel, the IKEA MITTZON Floor Standing Acoustic Screen is inexpensive and easy to find. There is also the larger 35 3/8" x 61.75" model if you prefer for just a little more - US$250.

While this may look boring, I must admit that as I've experienced more and dare say, "matured" in this hobby, the most interesting upgrades do not have to be high-tech active gadgets, bear fancy brand names, or the stuff that seems to capture the latest hype.

No friends, always remember the most important components that contribute to sound quality! Digital technology in particular has reached levels of performance where diminishing returns are quite easily reached these days. Make sure to explore other "domains" and products in your search for high fidelity audio.

Audiophile Malls Asia: Highsun/Haiyin Plaza - Guangzhou, China. (And thoughts about China and the global order.)

Last time, we talked about Seoul's Yongsan ETLand, so moving along in my Asia trip, let's check out another audiophile mall, this time in Southern China, in the city of Guangzhou. I've been in this city before (as per 2016 post) but not at this exact location, the Highsun/Haiyin (name used interchangeably) Plaza.

It looks like in the last 10 years, this place has really become quite concentrated with many audiophile stores.

Audiophile Malls Asia: Yongsan ETLand - Seoul, S. Korea

I don't know about you guys, but I'm like one of those husbands/boyfriends/partners who sit outside surfing the web at women's clothing stores. So while "the girls" were out shopping and getting pedicures in Seoul, I decided to take a couple hours' detour to the Yongsan ETLand which is about a 10 minute walk away from the massive Yongsan subway station (take Exit 3).

I suspect in the Western world (North America and Europe), it's quite rare to find a good concentration of stores selling hi-fi hardware any more, if even this was ever the case. Unless one is fortunate enough to have a large dealer in town, audio shows seem to be the only place left to see a large number of brands under one roof. However, as you might remember for past articles (like this, this), in Asia, the concept of an "audiophile mall", or "hifi-mall" still exists, so let's document some of these places in 2026... this time, we take a peek in Seoul.

Small Room Acoustics: Example of impact with (ultra) high-end speakers in Stereophile. (On AI audio writers, and Asia vacation pictures. 😊)

Last time, we discussed small room acoustics and audiophile listening rooms. In that article, I used an idealized loudspeaker with flat frequency response from 40Hz up. As I'm still traveling, away from my gear, I figured for this article, let's look around published data in audio articles to examine room effects and consider what this means.

One widely available and consistent source of objective data over the decades comes from Stereophile. While there are clear examples in the magazine where they perpetuate the "woo" in audiophilia, I appreciate that they do provide measurements for audiophiles who can read graphs and consider the technical performance of devices beyond subjective claims of how "great" something sounds, at some point in time, to someone, in some nebulous-quality sound room.

So let's take a look at a very recent Stereophile article - this one reviewing the Marten Mingus Septet Statement Edition loudspeakers - and consider the effects from room acoustics. Clearly, at an asking price of US$200k/pair, we're in the zone of "ultra high-end" luxury audio hardware. These speakers would be way above and beyond what the vast majority of audiophiles (never mind "music lovers" at large!) would ever spend.

Audiophile small room acoustics: complex and essential.

In the post "What are the most important audio components?" a few years ago, I said that we need to understand the various audiophile "domains": audio hardware, room acoustics, quality of your music, and of course personal mental engagement. Each of these have a part to play in the achievement of and personal judgment around sound quality.

Of those domains, it's hard to speak about personal mental engagement as this is a highly individual exercise (and related to one's auditory acuity). The quality of the music we listen to again is related to not just personal preferences (like genre) but also what mastering quality and variants like hi-res, multichannel, and on what format (SACD, vinyl, etc.) the record label makes available of our favorite albums.

It's always tempting of course to get excited about audio hardware - the latest toys. For example, recently, I heard that Andrew Jones has another ported box speaker design with paper/fabric drivers, this time with a coaxial tweeter+midrange that's based on field coils / electromagnets, paired to the permanent magnet woofer at something like USD$34k. While I'm sure this could be a compelling design for many, I think we can also recognize that these days, as equipment fidelity has improved significantly to the point where a simplistic "high price = high quality sound" equation no longer works, it's maybe wiser to direct our attention to the other domains.

This then leaves the very important issue of sound room acoustics, an area that we can all to some degree optimize (see also previous discussion on the sound room). I have heard it said that the sound room is the "foundation" from which we build our hi-fi sound system. As with any project, without an adequate foundation, no matter how great the rest of the system may be, you can only achieve a ceiling of performance dictated by the limits of that foundation.

In this post, let's dive a bit deeper into the importance of typical domestic small room acoustics and general principles around achieving good sound quality.

MUSINGS: On high-end audio component prices, inflation, April Fools and peak "greedflation"?

 

Let's consider how over the last while even audiophile magazines have wondered about the High-End Audio Industry's escalation in suggested retail prices for their products.

A year ago, Stereophile attempted to answer "Why Hi-Fi Prices Have Risen". To be fair, I think Jim Austin in the article made some good points about inflation, tariffs, etc. I'm glad that the article also acknowledged the fact that for years now, each generation of "high-end" audio products seemingly have also been just getting more expensive, untethered from inflationary expectations.

Grab a nice beverage, have a seat. Let's talk about prices in audiophilia. Is it true that the "high end" has become much more expensive?

[Some of these thoughts will trickle into the psychology of other luxury products beyond audio. Also, we'll be talking about dollars and cents in this post. Since most audiophile goods are priced in US dollars, let's use that through this post, with early April 2026 currency conversion as needed.]

Crosstalk Cancellation/Ambiophonics: Updated CTXMatrix Lite with standalone processor & 60° speaker angle support.

Significant changes in the UI from the previous CTXMatrixBeta release.

I want to remind 2-channel "immersive sound" lovers about the potential for using stereo crosstalk cancellation (XTC) / ambiophonics playback to enhance the 3D soundstage. You might have already heard of uBACCH in the audio magazines and on forums - why not try a similar effect for free (or through a small coffee donation)?!

You might recall, last year STC contributed a post on CTXMatrixBeta DSP for Windows. Well, it's great to see that he has continued to develop the software with updated user interface and abilities, this latest edition renamed CTXMatrix Lite, currently at version 1.3. It now includes a standalone processor which I'll spend some time discussing in this post, along with the 64-bit VST3 plugin as shown above that can be used in JRiver, Audirvāna and DAW software like Reaper.

Furthermore, there is now a VST3 plugin for Linux. Since I primarily use Windows for my music listening and processing, I'll stick with the Windows variant here with the hopes that some of this will be applicable. In my discussions with STC, he's aware of interest from Mac OSX users.

Perhaps the most important update in the last few months is that there is now improved support for standard ~60° stereo speaker angle (typically, the recommendation is 20-30° in ambiophonics). As a result, one should have a much better experience with the effect on most set-ups. In particular, hopefully more desktop computer music lovers will give this a listen without needed to move the speaker position and explore what you might be missing in your existing music library.

[If you run a miniPC streamer in the sound room like I do, CTXMatrix can easily be used like with HAF X-talk Shaper DSP discussed a couple years ago.]

Do HDMI cables make a difference for IIS/I2S/I²S-HDMI audiophile DACs?

It's taking a bit longer for my testing of the inexpensive I²S/IIS/I2S-HDMI DDC boxes due to some unexpected results which I'm chasing down currently; hopefully that gets resolved or understood soon.

In the meantime, let me address something that folks might be curious about related to this topic of the I2S-HDMI interface... Does the HDMI cable make a difference to the sound quality?

As with much of audiophilia wherein some members of the culture have the belief that "everything makes a difference", obviously this is not the case and I do not recommend this kind of mindset. There are many things that don't make much, if any difference (as discussed here and here) based on experience and understanding principles of the technology.

Since I have not seen measurements examining the effect of HDMI cables on I²S performance from a DAC, let's do some testing here.