MUSINGS: Increasing the Dynamic Range of compressed audio with DSP... (And is this why vinyl DR is higher!?)

Sadly, the good doctor's diagnosis applies to too many of the recordings we listen to these days.

I mentioned last week a recommendation for July Talk's Touch album at the end of that post. There are a number of catchy and enjoyable tracks on there... However, if we put this album through the foobar DR Meter, unfortunately, we see an album with really nasty dynamic range compression - DR4. Yuck.

Hmmm... Is there any way to change that?

MUSINGS: The 3 Main Home Computers 2017 (Workstation, Server, Gaming) & Thoughts on Gaming Consoles (like the upcoming Xbox One X)...

In the heat of summer, it is nice to get some time off to fix up around the house and do something that I typically take no pleasure in - rebuilding computers and reinstalling the OS & software! It requires a level of "Zen and the Art of Computer Maintenance" that I can only muster up every few years :-).

If you're like me, at home, you might have a little cadre of computers for work and personal purposes. As painful as it is, every few years, I'll update the OS, maybe tweak the hardware here and there (everything from cleaning up cables, vacuuming out dust, updating motherboard firmware and drivers, and the occasional refreshing of the heatsink compound). Updating a less "mission critical" machine like a HTPC or game machine (such as previously discussed) is not a big deal because in my view, that won't affect the others. However when I update the powerful main Workstation, I try to reuse the parts for some of my "lesser" machines; can't let perfectly good high speed CPU, RAM, and motherboard go to waste.

MEASUREMENTS: SMSL A6 as DAC (Part II)

SMSL A6 Integrated Amp - playing through USB 24/352.8kHz signal. Notice the matte/satin finish of the aluminum case. Probably need to wipe it down once awhile if dusty.

As I mentioned last week with the initial review of the SMSL A6 integrated amp, this is a versatile device. It features an AK4452 DAC first released in 2015 which though not "top of the line", does perform very well with a potential 115dB SNR and is part of the "Velvet Sound Architecture" range of "Premium" DACs. For those keeping track, currently, the flagship DAC from AKM is the AK4497, capable of 5-channels and rated at 128dB SNR; they call this series the "Verita" which competes with the best of the ESS DACs like the ES9038Pro previously discussed in the Oppo Sonica DAC measurements and review. By the way, another claim to fame of the AK4497 is that it has a "volume bypass" mode which allows the DSD data to bypass the internal delta-sigma modulator; a more direct processing path... As usual with new features in otherwise mature technologies, whether this is audibly better is probably up for debate.

Today, what I wanted to test out with the SMSL A6 are the RCA and headphone outputs from this device. As usual, along the way we'll have a peek at jitter results, the antialiasing filter being used, and check out the various inputs - USB compared to the S/PDIF variants of TosLink and coaxial.

REVIEW: SMSL A6 integrated amplifier - Part I: Overview and Subjective Listening (and briefly about USB cables)

SMSL A6 at home in my living room system with Tannoy Mercury Mx2 speakers. Doug MacLeod's Break The Chain (2017, Reference Recordings 24/176.4 downsampled to 88.2kHz, DR16) playing over Logitech Media Server.

For many years, my father's audio system consisted of various CD players, a Sony turntable and vintage pre-amplifiers. This then fed a tube pre-amp which then sent the signal to either a tube-based Onyx SP3 Melody amplifier or vintage solid state Pioneer amplifier to feed his Klipsch Forte speakers which have been cleaned and refurbished with new crossover parts over the years.

In the last 5 years, I've supplemented his system with various DACs for the CD player, and most recently got him a streaming connection with my Logitech Media Server based out of my home server using a Logitech/Squeezebox Touch.

This set-up sounds very good. The classic Klipsch speakers really do throw up a fantastic soundstage, have quite a smooth sonic signature (though a little mellow for my taste), is extremely sensitive, thus easily powered by low-wattage amps.

He has gradually transitioned to almost exclusively digital streaming, finding the convenience indispensable compared to spinning disks (whether of the polycarbonate or vinyl variety). As much as the tube and large integrated amps sound great, over time some of those components have needed maintenance and I figured it would be nice for him to try out something much simpler than manually turning on/off multiple devices every time he wants to hear good sounding audio. Thus, the purchase of the SMSL A6 integrated DAC/amp.

MEASUREMENTS: The AudioQuest Dragonfly Black MQA filter set...

Good movie from the 90's!

Just a quick note while we're doing the MQA blind test!

A few weeks ago I posted on the Dragonfly Black and the MQA filter impulse responses. I noted that based on Måns Rullgård's work, although there are potentially 32 filters available when "Rendering" with upsampling to 192+kHz, I only showed 0-8 in that previous post.

Well, using the same kind of impulse response diagram previously (captured using my Focusrite Forte 24/192 ADC), here's the AudioQuest Dragonfly Black "full monty" of impulses...

INTERNET BLIND TEST: MQA Core Decoding vs. Standard Hi-Res Audio

Introduction:

Well my friends, the time has come... Yes, it's another Internet Blind Test!

As a "more objective" hobbyist blog, within these pages I try to demonstrate facts, figures, and opinions as best I can with the hopes that it educates the typical "audiophile" out there who loves music and wants to at the same time understand the hardware and technologies used in the world of high-fidelity. I do this for fun with the hopes that in time, as a group we can be "more rational", each of us better able to adjudicate what makes sense, what works, and what ultimately has either very little worth or should even be considered worthless "voodoo".

Over the last few years, as you've no doubt noticed, a number of my posts have been looking at MQA and the claims made. I'm not going to rehash much of that here (feel free to start on this page and check out the links at the bottom accumulated over time). As we've come closer to understanding details like the filters used and how the "Rendering" works, there is one very important piece that remains rather nebulous.

This last piece has to do with claims of time domain "de-blurring". The idea that some kind of DSP has been used to affect the sound quality, ultimately "improving the analogue-to-analogue performance" from the studio to one's own DAC output (ostensibly using various techniques including measuring and aligning impulse responses of the devices used in production and playback). How this works is of course proprietary and hidden in the encoding system which we as end-users have no access to.

MEASUREMENTS: MQA Filters on Mytek Brooklyn & Thoughts on USB Doohickeys

Hey folks... It's summer and I'm in and out of town doing a bit of R&R mixed with the day job.

I sent my friend with the Mytek Brooklyn and Fireface ADC a package of the MQA "Render" tagged files for testing. As you can see above, that's what the MQA filters look like with the Mytek Brooklyn serving as "Renderer" for the impulse responses. If you look at the top row, we see that the Brooklyn's standard digital filter at 24/96 is the same as what MQA uses for playing back 96kHz "original" unfolded PCM. This is different from the Dragonfly Black DAC presented a couple weeks back where the standard filter at 24/96 is a much sharper one and would shift to the weaker MQA filter only when it detects the MQA Render tagged data.

MEASUREMENTS: AudioQuest Dragonfly Black 1.5 - PART 2 (On "MQA Rendering")

AudioQuest Dragonfly Black - "rendering" MQA playback. Dragonfly logo turns purplish...

For those keeping track, the story of MQA has slowly evolved over the last few years. Initially, it was supposed to be just a technology incorporated into DACs that would take an encoded file (typically 24/44 or 24/48) and almost "magically" transform this data into the "original" high resolution (equivalent to 24/192+) sound while maintaining standard PCM playback compatibility. This was the case with the first products like the Meridian Explorer 2. Over the years, it appears that concessions have been made. Software decoding rather suddenly was introduced in early 2017 with TIDAL's support for MQA; branded as "MQA Core". At around the same time, DACs were classified as either "MQA Decoders" for components that can handle these 24/44 or 24/48 files start to finish (Meridian, Mytek DACs), and "MQA Renderers" which require the computer software perform initial "unfolding" to high-res samplerates (88 or 96kHz) followed by some kind of final processing to the sound performed by the DAC presumably to allow the sound to be more "accurate" to the studio production, or "authentic" (whatever that means).

With the recent firmware upgrade to version 1.06, the Dragonfly Black DAC now belongs to this latter category of "Renderer". As far as I am aware, it is the first of these kinds of devices to be released without "Decoding" capability.

MEASUREMENTS: Audioquest Dragonfly Black 1.5 - PART 1 (General)

Four USB mini-DAC's (back to front): Light Harmonic Geek Out V2, Audioquest Dragonfly Black, SMSL iDEA, AudioEngine D3.

As I showed a couple weeks ago, I have in my possession one of the Audioquest Dragonfly Black DACs for testing. I'm actually borrowing it from a friend so it's not going to be in my possession for long... Long enough for me to listen and run some objective testing to see what the "deal" is.

I think it's useful to show these test results on the Dragonfly because AudioQuest clearly has a healthy advertising budget and promotes it quite heavily on audiophile sites with ads in magazines as well; as such it's a bit of a "standard" even though a number of other alternatives exist. For example, a few weeks back, I showed the measurements for the SMSL iDEA which I thought performed objectively amazingly well for such a small device although I had some issues with seamless connectivity to Linux / Android. As you can see in the image above, I have tested a few others of these kinds of  DACs already including the AudioEngine D3 measured in 2014, Light Harmonic Geek Out V2 in 2015, and also the previous revision Dragonfly v1.2 in 2014 which I don't have on hand any more (it was given as a gift to a friend).

MEASUREMENTS: Oppo Sonica DAC (ESS Sabre ES9038Pro based device)

My Raspberry Pi 3 "Touch" on top of the Oppo Sonica DAC - notice the DAC can handle up to PCM 768kHz (and DSD512 / 22.4MHz).

A few weeks ago, I published the preview of the new Oppo Sonica DAC and noted some issues I ran into with unusual jitter and digital filter measurements. Thankfully, Oppo was able to correct the issues within a week with the beta firmware and I see that the official firmware incorporating the improvements is now out - Sonica-33-0511 on the support website (May 15, 2017 date).

With it becoming official, I figure it was time for me to run and post results of objective tests on the device. This should give us a taste of both the capabilities of this Oppo Sonica DAC as well as look at what the "latest and greatest" ESS Technology ES9038Pro 8-channel DAC chipset is capable of... Although I have not seen it specified anywhere, my assumption is that the stereo configuration in this device ties 4 of the DAC channels for each of the stereo pair.

MUSINGS / MEASUREMENTS: Thoughts on Vinyl LP Fidelity... (And thoughts on Sgt. Pepper's 50th Anniversary Remix.)

Alright... Let's not get worked up about the cartoon :-).

I know, the debate between vinyl and CD (digital) remains one of the greatest "wars" of the audio world; not that it should be a big deal IMO... As usual in most audiophile conflicts, there are many words spilled about the topic, but it is rare to see "data" or actual direct comparisons. For example, look at Wikipedia's entry for "Comparison of analog and digital recording" and we see no actual illustration to demonstrate differences.

Years ago, I wrote a little about this here (and I think it's only fair that I have a digital-preferring Batman cartoon). As you know, over the years there are all kinds of vinyl evangelists going around touting the superiority of LPs over CDs and digital overall (and vice versa although I'm not sure the digital camp is as evangelistic). Here's a nice example of all the awesomeness that is vinyl based on someone's opinion.

As I've said before, I agree that there are some great qualities about having an LP collection. So long as you have the space for the non-biodegradable collection, the beauty of the artwork is wonderful. It's comforting and collectable memorabilia. And likewise the sound can be alluring in the same romantic way. For some, the ritualization of the playback process can bring with it that sense of security and physical engagement as well.

MEASUREMENTS: SMSL iDEA USB DAC / Headphone Amp (ESS Sabre ES9018Q2C + XMOS XU208)

In 2015, ESS revealed its latest generation of DACs at the CES show. One of the interesting new products revealed was the SABRE9018Q2C, a tiny 5mm x 5mm SoC claiming very high audio quality out of an integrated DAC/headphone amp operating with low power along with the ability to decode a wide range of sample rates.

I was contacted by ZugZugOrc on Computer Audiophile to have a look at a recently released USB DAC he wanted to buy for some measurements based on the above chipset. So we made an arrangement where he sent the package to me to have a look at and subsequently after I'm done, I would send it off to him to use :-). Thanks Zug for the opportunity!

Here's the device - the SMSL iDEA (can be found on Amazon for ~US$86 currently), a mini USB powered "stick" based on the ES9018Q2C "audiophile-quality" mobile DAC capable of accepting up to 32/768 and DSD512!

SMSL stands for  "ShuangMuSanLin" Electronics Company based in Shenzhen, China. I was sent the black one, but the device is also available in red.