The "Measurement Of Amplifiers Rig" (MOAR): Standard Tests, Loopback results, and the AMOAR Score.

While I'm not a huge fan of acronyms, sometimes one just needs to make something up for ease of reference; hence the "Measurement Of Amplifiers Rig" or MOAR ;-) for short to refer to this system which I'm going to attempt to characterize today:

Running loopback tests.

As you can see, it's a conglomeration of hardware components which will allow me to collect amplifier measurements relatively quickly and I believe with good quality results based on my own testing over the last number of weeks (in fact I've been mulling over much of this for months even before the Linear Audio Autoranger was fully up and running). A hobbyist project to be sure, and one that audiophiles and DIY folks can come up with variants of and try out.

Of course, a measurement system isn't just about bits of hardware but also the software that can be used, the thought behind various tests we can run, and most importantly, a standard procedure that can be followed to ensure that devices are measured consistently and can be reliably replicated here on my test bench and elsewhere with similar equipment. As with most testing, I wanted to find a way to quantify performance, consider what is reasonably "true to life", borrow from tradition for comparison purposes, as well as emphasize aspects I find important. Hence this post will hopefully provide adequate details around a "standard battery" for what will be posted here in the days ahead.

RETRO-MEASURE: Klipsch Forté I speaker impedance. (And it looks like Qobuz responds to Amazon...)

Well guys, I'm still working on the Autoranger amplifier test system looking at standardization of the measurement technique and settings which is a pretty big job still, so this week I thought I'd show you some data I grabbed a few months back while working on the speaker impedance measurements series (Part 1, Part 2).

Every once awhile, I'll drag up an old device for a quick measure. Previously it was stuff like my old Sony SACD player, or the old laser disk player. This time, I went over to my dad's place to have a listen and measure his main speakers - the Klipsch Forté (original first version) made back in the 1980's until the early 90's I think.

Front and Rear of Klipsch Forté from the 1980's. Note the large 12" rear passive radiator.

I thought it was good to have a look at this device since there's been buzz lately about the latest model Forte III (Stereophile review, Darko review, Darko bought a pair). Also, a couple years back I ran into this Stereo Review article by Julian Hirsch on these speakers from 1986 as an example of what SR tests looked like back in the day:

It's Alive! The Linear Audio Autoranger MK II...

And the kit is now alive just in time for Halloween the other night. :-)

For those still wondering what this is, you can check out Jan Didden's video of the Autoranger MK I from 2017 and his demo of how it's used:

On Audiophile Forums. Disagreements on MQA. (And Redscape preview...)

I thought for this post it might be good to talk about audiophile forums.

A couple weeks back, some of you expressed frustration with the Audio Science Review Forum, the opinions of the host there, and general MQA disagreement. Over the years, like probably many of you, I've had my share of participating in forums, disagreements with views expressed and the bickering at various venues. All in good fun however and nobody needs to get too perturbed... It's only a hobby, right?

I've read posters say that MQA is "the gift that keeps giving" :-). No doubt it's a topic that has provided for much discussion around here and elsewhere!

However future audiophile historians ultimately judge this time in our hobby, I think MQA will have its place as a controversy that divided the community deeply. I don't think this is a bad thing in that it has provided many opportunities for us to discuss and perhaps be enlightened by what is true vs. false, shown a divide between mainstream press with close industry ties vs. independents, objective vs. subjective testing, faith in (specifically one) authority of digital audio vs. skepticism. And this has played out publicly probably in its most dramatic fashion on audiophile forums these years.

Gone Building... Linear Audio Autoranger MK II.

Linear Audio Autoranger Mk II "quarter kit". Attenuator board (yellow-gold), Control/Display board (green-blue), SilentSwitcher power supply board, metal case, USB-A connector, and programmed microcontroller in the anti-static bag.

Hey guys, during the summer, I got the above kit from Jan Didden at Linear Audio. As you can see on the front, this is the Linear Audio "Autoranging Attenuator" - also known as the "Autoranger", standard 10kΩ version.

2019 Update: Basic Acourate DSP Room Correction (using Dayton Audio EMM-6 mic, and other related bits...)

As I mentioned last time, I changed the tweeter in one of my speakers resulting in a significant adjustment to the frequency response in the 2-5kHz range. This means it's time to update my AudioVero ((acourate)) (current version 1.9.12, 286€) room correction filters for late 2019. Looking back, I haven't posted on this since 2016! My, how time flies.

Given that it has been awhile, picking up Acourate again for some measurements required that I dig out my old notes and review the previous procedures again. As such I figured that it was time to write an update for a reasonably "quick and dirty" measurement which basically took me an afternoon to perform with excellent results. If you've tried Acourate, you'll know that this program is very powerful but can take a bit of time to figure out the interface and get comfortable with the process.

Okay then, let's get going with a quick but detailed summary while it's fresh in my mind and provide some pointers the next time I might have to do this again maybe in a few years :-). We'll then end this post with a few other related subtopics that came out during the measurements...

Paradigm Signature S8 v.3 Tweeter Replacement. A word about importance of speakers (+ rooms). (And a link to a HDMI cable blind test.)

Paradigm Reference Signature S8 v.3 tweeters.

I mentioned in late August with my "Speaker Impedance - Part 2" post that I noticed a variance between the right and left speaker impedance from my Paradigm Signature S8 v.3 that I was going to track down.

While an ohm here and there might look innocuous on the impedance curves, sometimes this could be indicative of a significant imbalance between speakers. Since I'm a bit obsessive about these things, let's get down to the "nuts and bolts" of the speaker and have a closer listen and look at the frequency response in that frequency region...

MUSINGS: "Democratization", "Doublethink", MQA, and the Audiophile. Becoming "Post Hi-Res Audio". And some issues with vinyl...

“Doublethink means the power of holding two contradictory beliefs in one's mind simultaneously, and accepting both of them.” 

“Freedom is the freedom to say that two plus two make four. If that is granted, all else follows." 

“For, after all, how do we know that two and two make four? Or that the force of gravity works? Or that the past is unchangeable? If both the past and the external world exist only in the mind, and if the mind itself is controllable – what then?” 

"In the end the Party would announce that two and two made five, and you would have to believe it. It was inevitable that they should make that claim sooner or later: the logic of their position demanded it. Not merely the validity of experience, but the very existence of external reality was tacitly denied by their philosophy."

--- George Orwell, selections from 1984 (1949)

It's sad sometimes reading how some (many?) in the audiophile press present products to consumers. Apparently, they'll stop at nothing to push a product even to the point of destroying their own credibility. It was bad enough a few years ago in 2017 when Robert Harley called for a "revolution" and that MQA represented a "paradigm shift"; making a mockery of the idea of paradigm shifts. And now recently he's "doubling down" to bring disservice to the idea of "democratization", linking it with the likes of MQA, in the article "From The Editor: Hi-Res Democratization" (The Absolute Sound, online September 6, 2019). Specifically, he seems to believe that those who oppose MQA is somehow fighting against the democratization of high-resolution audio for audiophiles! Really?

Upgrade to AMD Ryzen 9 3900X Workstation Computer. (And Amazon Music HD/UHD opens to lossless and "hi-res".)

Being post-RMAF 2019 with all that talk in the last week or two with "high end" audio stuff, I figure I'll switch gears a little and take a look at computer tech instead.

One of the least enjoyable things I do every few years is to update the machines I use for work and the various ones I have here at home. While I don't enjoy the basic IT stuff and all the software installations that typically come with new computer builds, it's a good way to get updated on the machines out there, practice reasonable parts selection, and appreciate the price of the technology. Back in 2017, I updated my workstation here at home to an AMD Ryzen 7 1700 CPU which still is a very impressive processor for general use. But time marches on and my office workstation is really itching for an upgrade which hasn't happened since around 2014 and feels even slower than my laptop.

The idea then is to transition the Ryzen 7 over to the office and let's build an even more powerful workstation here at home where I do most of my writings and media encoding. Furthermore, let's try out one of the newer generation M.2 SSD drives that promise even higher transfer speed...

So, the result of a bit of online shopping:

Parts:

AMD Ryzen 9 3900X 12-core CPU (MSRP US$500, current scarcity higher price)
MSI X570-A Pro motherboard  (~US$150)
EVGA Supernova 750 G3 80+ Gold 750W power supply  (~US$130)
Corsair LPX 32GB (2x16GB) 3200MHz DDR4 RAM (~US$160)
ADATA XPG SX8200 Pro 1TB M.2 Solid State Drive (~US$150)
Corsair Carbide 100R Silent mid-tower case (~US$70)

MUSINGS: Rocky Mountain Audio Fest 2019 - Reflections...

Assorted RMAF 2019 items... Dr. AIX book, demo disks. Collectable MQA brochure and the beautiful 135-page Wilson Audio catalogue! :-) In retrospect, should have also grabbed a T-shirt.

Beyond memories and photos - many of which already shared on Day 1, 2, and 3, the picture above are a few items I've kept from RMAF 2019 now that I'm back home in Vancouver. Each room that one goes into, one can pick up all kinds of interesting pamphlets, specifications sheets, colorful brochures. Most of these I have discarded as these days almost everything can be readily found online and in updated form.

RMAF 2019 Day 3...

As it has been said, Day 3 of audio shows tend to be a quieter day. It was no exception this year at RMAF. The picture above is from the "Headspace" ballroom down one of the lines of booths where headphone-related vendors display products and demo for the visitors. This picture was taken around 10:30 in the morning shortly after opening at 10:00. While number ebbed and flowed through the day, it wasn't difficult to find plenty of headphones to try and devices to play with as I wandered in and out through the day.

Since I did indeed start my day in the "Headspace" exhibits, let's start there and listen to a few interesting products...

RMAF 2019 Day 2...

Alright guys and gals, let's continue with the sights and sonic impressions from Day 2 of RMAF 2019!

Here's a picture of Colorado Ballroom C where the seminars are presented. Bob Hodas was presenting on room acoustics this afternoon and I suspect this is one of the best attended sessions:

I was able to catch most of the presentation. There were a few useful tidbits I suppose, and I imagine it will be up on YouTube for all to see at some point. Hope he would have been a bit more concrete with the equipment he uses and provided more basic discussion on what he's looking for from the measurements he does.