Pacific Audio Fest 2024: Part I. [And expensive speaker cables unanimously turned down in a blind test?! 😕]

This is the third year for the Pacific Audio Fest which first started in 2022, basically after the COVID-19 pandemic reopenings. I think the first 2 years of the show were quite similar in size but this third show is clearly a smaller event with fewer display rooms and less stalls in the Marketplace. Correlated with that, I also noticed fewer headphone set-ups to try out.

To be honest, while I think this probably was disappointing for some, I only had a couple of days to visit anyways so this actually worked out driving into Seattle on Saturday morning, stayed a night, and got home by later afternoon Sunday having felt like I spent enough time in each room, even visiting a few of the rooms a number of times to compare.

So, let's have a peek at some audiophile eye-candy and consider the goods out on display this year. Let's be honest, one of the most important specs whenever doing any shopping is the asking price. Unless specified otherwise, all prices are in USD.

The show ran from September 6-8, 2024 at the SeaTac DoubleTree Hilton which is the same as in previous years. I spent the 7th and 8th "hitting the rooms". Let's go!

AS WE HEAR IT: Moving forward as audiophiles & a plea for higher dynamic range music (to Epica). [Plus highest DR Oasis - Definitely Maybe.]

Well, this weekend is Pacific Audio Fest 2024 and I figure since it's nearby in Seattle and they've decided to make it every 2 years (next in 2026), I'll pop down for a look and listen for a couple days. It's fun staying incognito for the most part as a "more objective" audiophile even if this might not be the prevailing culture at these shows to get a sense of how the megabuck systems perform, what's potentially exciting, and observe the trajectory of the hobby. Given the busyness of work these days, I'll just take my time this year on the show reports with pictures, sharing some thoughts over the next couple weeks.

For this post, it's time for an "As We Hear It" article based on reader E-mails.

I. First Watt Amplifiers & Progressing as Audiophiles

June 26, 2024

Hi Achi:

Your blog took me here (ie. E-mail address) and thanks for all your wonderful work to make the audiophiles' world a better place. Here is my little story.

I have been an audiophile for as long as I can remember. But only recently decided to get serious about the equipment side of things. Thanks to the YouTube channel called Audiophiliac by Steve Guttenberg, I quickly decided to get a pair of Magnepan speakers. That was wonderful, due to planar construction, the transparency and soundstage is amazing. 

Part II: Fosi Audio V3 Mono Amp; Class D + PFFB, TI TPA3255 - Retail box with single 48V/10A power supply and filter. [Power, Distortion, and Subjective Impressions.] And on rejoicing over "Solved Problems" in audio.

Gotta love those Nordost-like flat speaker cables from AliExpress. The 90° locking banana connectors are a bit on the large side however. 😉

As we saw last week in Part I, I started reviewing the Fosi Audio V3 Mono amplifier, early August 2024 retail release, in the form of the stereo with 48V/10A power supply kit. We've already had an extensive look externally and inside the device, seen the benefit of PFFB for load invariance as well as discussed a couple of the issues I ran into (inverted polarity and the ground noise with 2 amps connected to one battery).

This time in Part II, let's proceed deeper into the measurements to explore the amount of power this little amplifier can provide, some details on distortion characteristics, and as usual, ending off with subjective impressions and summary of the product.

Part I: Fosi Audio V3 Mono Amp; Class D + PFFB, TI TPA3255 - Retail box with single 48V/10A power supply and filter. [With initial measurements.]

Over the last few months, I've been hearing a lot about this Fosi Audio Mono V3 (~US$140) amplifier which is typically sold as an individual unit with 48V/5A power supply, or as dual amps with 48V/10A supply, DC filter, and splitter cable (currently ~US$280).

I have already seen a number of reviews and YouTube videos typically with the pre-release product supplied by the company; honestly guys, many of the reviews seem superficial with essentially "Trust me, bro!" opinions rather than presentation of facts. For this review, let me grab the 2 amps + single 48V/10A kit from the Amazon retail pipeline to have a look at the final product. This review is not sponsored by Fosi Audio. With measurements, I believe this would be as bias-free as a review can be.

As you might already be aware, this inexpensive amplifier represents an evolution of their TI TPA3255 Class D "chip amp" product line. The company incorporated community feedback and developed this as a monoblock design (through Kickstarter funding, as usual due diligence needed when participating in crowd-funding) with no volume control so as to optimize resolution, accepts true balanced (XLR/TRS) input, and also incorporates Post-Filter Feedback (PFFB) to lower output impedance (increase damping factor) for load independence.

The company publishes a power rating of 240W into 4Ω, 1% THD; 120W into 8Ω. That should be more than enough for most reasonably efficient speakers of normal load, in normal smallish listening rooms.

Let's take a good look...

SUMMER MUSINGS: What are the most important audio components? Domains / dimensions of the audiophile pursuit.

The other day, I came upon another common question we run into within the audiophile forum communities. The thread topic on the Steve Hoffman Forums read: "What is more important? The quality of the source devices or the quality of the amp and speakers?"

Among the pages, in response to the question, there was this one listing items as such:

1 (tie). Source material, i.e. the recording, the mix and master, etc.
1 (tie). Speakers
3. Your hearing
4. Analog source playback device
5. Your room
6. Your mood
7 (tie). Digital source playback device
7 (tie). Amplification

A good list to start with! Let's spend some time in this post thinking more about this, adding more details, and broadening it out. Clearly, this (and variants of this) topic is one of those "classic" big-picture questions that demand a more nuanced and complete take. Specifically, let's make sure to contextualize the response with what I believe are relevant dimensions or domains to include.

2.5Gbps Ethernet in the Sound Room... (D-Link DMS-106XT & GigaPlus S25-0802 2.5G Smart Switch). And a quick peek in the Headphone Bar & Red Cat Records.

On occasion, I get a kick out of reading the audiophile media's review of ethernet switches. These are perhaps some of the most hilarious pseudo-infomercials out there as companies try to justify their highly expensive network switches in the hopes of capturing the interest of the few audiophiles who still somehow do not realize that there's no benefit to these devices (even Paul McGowan agrees, imagine that!).

Feel free to check out the reviews of such things like the Silent Angel Bonn NX Pro Ethernet Switch (asking US$4000!), or filters like the Network Acoustic Muon Pro (asking £1,329.17!). There are also now Chinese companies that make these things for audiophiles - Gustard N18 (US$370 - only 2 ethernet ports + 1 gigabit SFP) and N18 Pro (US$530 - 5 ethernet + 1 gigabit SFP) for example; sure, they're cheaper but that's still quite a bit for what you get which is just a nice looking ethernet switch with integrated power supply and an essentially meaningless 10MHz clock input! (Timing is essential inside the DAC for precise conversion to analog output, not the network switch.)

A few years ago (2020), I talked about the Netgear Nighthawk S8000 as a great choice for a high quality ethernet switch which affords features including port priority. Hey, it's still a great little switch and I see that sometimes there's still stock available on Amazon.  Over the years, I've upgraded my home network beyond 1Gbps (and update here) so I figured let's find faster switches to try out for the sound/media room.

Here are two easily available and not expensive options: the D-Link DMS-106XT (US$200), with 10GbE high-speed port to connect to your main network plus 5 x 2.5GbE ports for downstream devices with user-defined port priority, and the very inexpensive GigaPlus S25-0802 2.5G Smart Switch (US$80), an 8-port 2.5GbE switch with 2 x 10Gbps SFP+ for those who want to use fiber networking, or possibly 10GbE RJ45 multigigabit transceivers (some very inexpensive like this).

Both are fanless - essential for the sound room.

AudioVero Acourate v3.1 - room correction with bass pre-filtering and Inter-Channel Phase Alignment (ICPA).

After writing the post on Audiolense recently, I thought it would be good to have another peek after a few years now at AudioVero's Acourate (€416 non-EU countries); the latest version 3.1 released in June 2024.

For years, Acourate has been the room-correction filter toolbox I've used (at least since 2016, updated 2019, plus discussion on partial correction in 2021). Now that it has been half a decade plus a pandemic (!) since the step-by-step 2019 update, let's look at the latest version which has brought with it changes in the user interface as well as the Inter-Channel Phase Alignment (ICPA) feature released in version 2 which I had not discussed previously.

Before getting started, a big thanks to Mitch Barnett of Accurate Sound for his YouTube video a couple years back using Acourate 2 showing the technique around pre-filtering and ICPA. I've taken inspiration from his video, applying it to my home set-up, and converting those steps into a written blog format for the current Acourate version. If what I'm doing here is not clear, make sure to also check out the video since Mitch might have already covered your questions/issues there.

Let's get started!

SUMMER MUSINGS: Defining "subjective" and "objective" audiophile evaluations.

Hey everyone, I thought I'd make a "quick" post in response to this comment in the recent "SUMMER MUSINGS: On the perils of subjective opinions in High-End Audio (dCS v. GoldenSound)" article:

SY 24 July 2024 at 13:07

Could I beg and plead with you to join me in refusing to misuse the term "subjective" to mean "uncontrolled?" Something can be subjective and absolutely valid and rigorous (e.g., subjective reactions made with basic ears-only controls) or subjective and absolutely invalid (e.g., subjective reactions made with peeking, preconceptions, and non-auditory inputs).

Subjective =/= uncontrolled. So much fuzzy thinking has arisen because of that conflation of terms.

Greetings SY,

Sure! I agree with you that "subjective" (when referring to audio hardware reviews specifically) is simply a reference to the form of evaluation and does not imply whether the evaluation is valid or invalid, nor whether controls were applied or not. Certainly some subjective opinions are clearly valid if the difference is obviously detected by the listener. I trust no audiophile worth his street credibility would have difficulty telling the difference between AM mono and FM stereo sound quality for example and will accurately point to the stereo FM playback being of higher fidelity.

Indeed, subjective reviewers listening under controlled conditions also can produce highly valid reports. I hope I have not confounded that over the years. For clarity, let me expand the position in some (pedantic) detail for those who like reading this stuff. 😉

SUMMER MUSINGS: On the perils of subjective opinions in High-End Audio (dCS v. GoldenSound).

Every once awhile here in audiophile-land we see our share of drama.

There was MoFiGate a couple years back when vinyl collectors panicked about DSD256 data corrupting their precious analog remasters, Tekton (Eric Alexander) v. Erin recently due to legal threats for calling into question a speaker design, we've seen silly hyped Pono/Neil Young claims a decade ago, and of course the painfully prolonged MQA episode which was just a mess (as summarized years ago).

Well, in the last week we have something a bit different; the dCS v. GoldenSound lawsuit threat due to unhappiness about a YouTube DAC review from late 2021. I'm not going to rehash the stuff here because there were clearly many missteps in dCS's communications as explained in GoldenSound's video and here's the dCS response where the company "fully acknowledge that some of the emails shared by GoldenSound were unacceptable and we addressed and acknowledged this in subsequent communications".

I trust they'll figure it out between the various players on the two sides. As with the domestic conflicts of others, I'm not particularly interested in the details as to who said what unless personally involved. Likewise, some of the technical details regarding the external clock, DSD resampling, seem to be side distractions from the concerns around the review; no need to spend time with these minor digressions.

Instead, I was more curious about that original dCS Bartók DAC/headphone amp YouTube review by GoldenSound that came out on December 31, 2021. What was it that made dCS or their representatives so upset? Is there something about the review itself we can/should learn from?

Seating variations, multi-seat correction & multichannel DRC. The audio "sweet spot".

A look at the rear of my room and the sofa seating - surround speakers, LP rack for a little bit of diffusion room treatment. For best practice, it's important to not sit too close to the back wall. I have 3' between the couch and the LP rack, and the rack is about 17" deep before that back wall. 

Before putting the UMIK-1 microphone away after using Audiolense XO as discussed last time, I thought it would be interesting to explore in greater detail what happens with frequency response and time-domain performance as we sit off the "sweet spot" where the measurements were collected and correction calculated for.

In the image above, I've put a meter stick on my listening couch to identify the seating positions 1 and 2-feet to the right and left of that sweet spot so I can take detailed measurements of what happens to the sound coming from the 5 main speakers at those positions with and without DSP turned on.

Multichannel Digital Room Correction with Audiolense XO. And "What's your budget?".

As you might recall from over the years, I strongly believe that one of the most important things one should try as an audiophile seeking high-fidelity - after having a decent sound room, and getting good equipment - is to consider the use of room correction. It could be as simple as frequency-domain EQ correction for larger bumps and dips (as discussed with the Behringer DEQ2496 hardware back in 2013-2014, device measurements here), or the much more sophisticated frequency and time-alignment of filters created by software like AudioVero's Acourate (and 2019 update) capable of much higher resolutions.

The power that one has to optimize and customize the sound runs well beyond most hardware upgrades other than wholesale speaker replacements and changing sound room! The change one can expect with room correction dialed in is astronomical compared to all the snake oil tweaks, cables, hi-res DAC/streamers, even amplifiers you might want to throw at your system.

These days, I've increasingly been converting multichannel content over to my Roon server, typically 5.1 SACDs and DVD-As but also Bluray rips, ideally lossless TrueHD with 7.1 channels. Unfortunately, Roon is currently unable to decode codecs like EAC3-JOC (lossy multichannel/Atmos) or TrueHD (lossless, based on the MLP codec) so the content typically gets transcoded to multichannel FLAC-compressed PCM which can handle up to 7.1.  

Although Acourate can be used for multichannel filter creation, the manual procedure here is unfortunately quite involved and more than most audiophiles would like to get their hands dirty with! Which is why today's post is going to be about multichannel digital room correction using Juice HiFi's Audiolense XO (€390, currently version 6.21). I see that there is the less expensive Audiolense Surround which I suspect could be enough for many users, and if all you need is 2-channel stereo, there's Audiolense 2.0.

MEASUREMENTS: Nordost-like flat silver-plated copper speaker cables. And, comments of a "high-end" cable insider compared with an apologist?

Cables are fun to play with! They look different, there are all kinds of brands available, and for some audiophiles, there's a sense that the sound has been "changed" if not "improved" when trying products at different price points. All without lugging big and heavy speakers or amplifiers around which makes the upgrade easy especially if one believes that the change can be equivalent to such component swaps! Speaker cables in particular would be the most interesting because they carry complex musical signals of potentially high current and voltage for longer lengths. (Digital and power cables are least interesting for me for obvious reasons - here's my summary post of cable measurements over the years.)

I've already talked about a number of different speaker cables in the past; most recently here, here, and here. Notice that morphologically, all of them have been "roundish" cables so I thought it would be fun to try something flat and measure to demonstrate the LCR changes that this kind of design provides.

Looking around AliExpress, I found the cables above - China-made Nordost-like speaker cables - I bought the 2.5m pair with locking gold-plated banana plugs for less than US$100. There are similar products found on Amazon but you'll need to shop around for a good price.

I think the design of these are probably most similar to the Nordost Heimdall 2 cables which currently retail for about US$2,500, 2m pair.

The E1DA Cosmos Stack: ADCiso and 2 APUs. An example of bad multichannel - Neil Young's 'Harvest' on DVD-A (2002), fixed in new Atmos mix.

E1DA Cosmos ADCiso Grade A center.
Cosmos ADC Prototype I've been using over the years to the left.

Readers here probably are aware that over the last few years, I've been using the E1DA line of devices, the Cosmos ADC, APU, and Scaler typically paired with PC-based software like Room EQ Wizard for most of my measurements, especially for the highest fidelity products like DACs. As a hobbyist exploring objective performance, there's obviously no need to spend thousands of dollars on devices like the Audio Precision (here's a peek inside the APx555B top-of-the-line model, around US$30k). Not enough return on investment unless one is doing professional product design and testing.

As usual, over time things evolve around here and since I needed an extra ADC for work-related purposes, I bought one of the newer E1DA Cosmos ADCiso Grade A to replace the prototype that Ivan sent me back in 2021 which I will repurpose elsewhere.

This post is mainly an update and comparison, refer to the original article on the Cosmos ADC for more details.

"High-End" DAC Blind Listening Results - PART III: Subjective Descriptions

In this last part of the "High-End" DAC Blind Listening Survey write-up, (see Part I, Part II) let me document the more qualitative aspects of the responses I received from listeners. These come from the comments section where listeners described what they heard. You'll also get to see in context some of the descriptions of the hardware used in the evaluation.

Comments will be posted verbatim other than removing any identifying information and names unless the person specifically says it's OK. Not all comments are posted, only the ones with a fair amount of subjective experiential content or description of evaluation procedure. It's interesting knowing which city/country some folks are from so I'll leave that information if mentioned.

So as not to neglect those who said they heard no difference (yet I know many spent a good amount of time on the test), let's start with that group of respondents... I'll add some comments/responses along the way.

"High-End" DAC Blind Listening Results - PART II: Results & Analyses

I imagine that the banner graphic above must be so bizarre for some audiophiles! How is it even possible that the audio output from something cheap like the Apple USB-C headphone dongle could be mistaken for the way more expensive Linn digital streamer devices that cost orders of magnitude more?!

Well, of course we can! And if we are to honestly appreciate the difference in sound output between the very cheap and very expensive (we can buy a lot of other stuff, services, and experiences for US$20,000!), IMO, as audiophiles, we must open our minds to such comparisons. The hi-fi audiophile pursuit is not a cult; everything is up for empirical examination regardless of company, price tag, or which heroic personality is attached to said product.

Last week in Part I, I unveiled the identity and discussed those DAC/streamer devices. Let's proceed today with looking at the data from the recent 2024 "High-End" DAC Blind Listening Survey which collected listener impressions for 6 weeks; plenty of time I trust for those motivated to download, listen, and offer their subjective opinions.

As usual, let's go through the data broadly and then let's see if the results can provide some answers for specific questions around audibility, preferences, and listener subgroups. I'll group these questions and evaluations into a number of Sections.

Grab your favorite beverage, have a seat, this is a pretty long one... 🙂