Friday, 14 February 2014

MUSINGS: Saturday AM B&W Nautilus Listening

Under immense market forces and thin margins for the majority of consumer electronics, it is no wonder that the specialist brick-and-mortar stores have gradually disappeared over the years. Big box stores are everywhere these days it seems (Best Buy and Future Shop here in Canada), and the proliferation of internet "stores" like Amazon has clearly taken centre stage for the consumer on the prowl for the best deal available. In some areas like the AV receiver market, I believe market forces have clearly resulted in marked improvements over the last 10 years in sound quality and meaningful features representing great value (think HDMI support, room correction, proliferation of lossless formats like TrueHD and DTS-HD MA). For audiophiles, I believe the main hardware developments in the last 10 years have to do with the quality of external DACs and software for better integration of computer audio into the sound room. The ascent of Class-D amplifier technology has been substantial as well but I doubt many audiophiles see a need to migrate to these amplifiers purely by virtue of this characteristic (unless of course you need higher efficiency, smaller size, cooler operation, etc...). Likewise, speaker technology has advanced especially in the material sciences used for drivers, but I think it's hard to justify new purchases based on this factor since there are so many other variables in the overall sound quality (like your room!).

I don't blame the small audiophile stores for pursuing to sell gear that have big mark-ups. Things like cables easily come to mind and it's certainly in their interest to promote these products and give them ample "rack space" for potential customers to peruse especially if there are manufacturer incentives - I just hope there is balance between the concept of aesthetics and sonic performance being presented. Likewise, magazines have to sell copy and attract advertisers, what other option do they have? And you can bet again the power of the manufacturers/advertisers in promoting products even if said product is of unlikely benefit for the customer. Without adequate financial viability, there is no business.

In Vancouver, there are probably only about a handful of hi-fi stores left where you can even have a hope of sitting down to listen in anything remotely resembling a decent listening room. Thankfully they still do exist and on occasion, it's nice to visit to check out (and of course purchase) the products, perhaps demo the exotic gear, and interact with knowledgeable salespersons (ok, salesmen - who am I kidding?!) who clearly show a passion in the hobby and in what they sell.

So, on a relatively cooler Saturday morning last week, I headed over to Hi-Fi Center (along Seymour just north of Dunsmuir) to have a look and listen to one of the most recognized speakers ever. I, like many of you probably have seen pictures of the Bowers & Wilkins Nautilus speakers over the years but had never actually heard one. 2013 was the 20th year anniversary of this flagship product from B&W so they've been doing a tour through a number of cities since last year and it was finally time to hit Vancouver. The well done presentation with Q&A was made by Murray Cardiff, Canadian National Accounts Manager for B&W.

Now that's an interesting looking speaker - in "Maserati Gray". WAF was alas poor for me but I suppose YMMV.
For those who may not have looked into the specs and history, here's the deal with the Nautilus (I haven't seen any formal detailed review/measurements to date):

- First released in 1993 - no substantial change to the design / sonic characteristic since. Check out this video, and part two for more (also check out the epic background music)! I don't know how many speakers can be said to not at least have a "Mark II" by now. According to Murray, about 4 units are produced per month for sales worldwide; not surprisingly many to Asian countries. Manufacturing facilities in UK and China.

- Current list price in Canada - CAD$70k a pair (includes external crossovers discussed below). I wonder whether there has been any price appreciation; I think the list price at release was ~USD$60k.

- The shell of the speaker is made of a composite material. Each complete speaker package is about 200lbs based on the specification sheet - evenly split ~100lb for the speaker itself and the granite base it's "standing"/bolted on. They stand (only) about 4 feet tall.

- 4-way driver configuration - 12" (300mm) bass driver (with characteristic mollusk shell spiral tube), 100mm lower mid, 50mm upper mid, and 25mm tweeter. Notice the tapered "transmission line" behind the upper 3 drivers. They're absorbent-material filled terminating with a small opening in the rear. Frequency response widely quoted as -6dB from 10Hz to 25kHz. Crossover points: 220Hz, 880Hz, and 3.5kHz. The speaker impedance is rated 8-ohms, no specification provided for sensitivity (somewhat meaningless anyhow in a set-up like this with external crossovers and separate amps as discussed below).




- All driver domes made of aluminium. This gives away the >20-year old design from the perspective of material sciences.

- There are no internal crossovers for the 4 drivers. You see the non-detachable blue speaker cable coming off the base. Another clue to the 20-year old design is just how thin the cable appears to be for something that contains 4 pairs of wires; a pair for each driver. The wires themselves are multi-stranded silver, and examining them closely, I don't think they're thicker than 16AWG and come in a standard 10' length (30' length also available). Of course this is technically not a problem at all for such a short length of speaker cabling but might surprise those who expect garden hose sized wire gauge for high-end gear!

Bare silver multi-stranded speaker wires connecting amplifier to speaker (red & black).
- External active crossovers connected between the pre-amp and amplifiers. I presume the technology inside hasn't been upgraded since 1993, so not likely DSP-based digital crossovers. (In fact I hope not given the state of digital converters back in 1993!)

For the demonstrations, Murray used a combination of standard 16/44 and some hi-res played off a MacBook Pro through a full Classé (owned by B&W Group) pre-amp / stereo amp rack:



You see the black 2-box active crossover just below the computer. Below that with the LCD screen is the Classé CP-800 preamp which functioned as a USB DAC for the MacBook (it got a good Stereophile review, ~18-bit measured dynamic range, very low jitter). Below are 3 stereo class-D CA-D200 amplifiers, each 200Wpc powering the tweeter, upper and lower mid drivers. Obviously that stacking arrangement highlights a major benefit of the class-D amps - they stay cool. Finally below is the large class-A/B CA-2300 amplifier delivering 300Wpc into 8-ohms for the Nautilus woofer - I noticed a good sized fan on the back which stayed quiet.

Unfortunately, I was not able to play a CD I had brought with familiar tunes. Nonetheless, there was a good selection of music on the Mac already and the demonstration ran through a selection of familiar music - Paul Simon (from Graceland), Sting (from The Last Ship), Aaron Neville (from Warm Your Heart), Lang Lang (Rachmaninov No. 2), Rose Cousins (Canadian girl from Halifax), Beatles, Daft Punk ("Lose Yourself In Dance" off Random Access Memories), Oscar Peterson (We Get Requests). There were also a number of classical pieces I wasn't familiar with.

As usual with these demos, it's very hard to judge the sound given the importance of the room and the music used. On the whole, it sounded very nice. Good frequency reproduction from top to bottom. The upper end was very detailed and it was easy to discern low-level details including tape noise on analogue-sourced tracks and things like musicians taking breaths during classical performances (if you listen for such things!). I'm still a believer in a good subwoofer to tighten those lower registers however. Unfortunately, no hip-hop or rap was on offer in the demo so it was difficult to determine just what isolated beats down at 20-50Hz would have sounded & felt like. Another nice quality was the fact that the system could be pushed to high levels in a moderate sized room without a hint of strain with peak transients.

I was struck by the soundstage. The stereo effect was good even somewhat off center and this set-up certainly conveyed good horizontal and depth dimensions. I've seen comments from Nautilus owners describing excellent sound due to minimal rear reflections and folks placing these speakers against walls and other reflecting surfaces. Some of this may also be a reflection (pun intended) of the external active crossovers doing an excellent job with subtle parameters like time/phase alignment.

I heard a few of the attendees mentioning that the sound was fatiguing... Well, what can one expect when a good amount of the demo music was dynamically compressed?! Seriously, IMO, if these speakers did not convey the harshness of some of the tracks, then there'd be something wrong since that's just what the recordings sound like. Having said this, I did wonder if there was a bit of "ringing" from the aluminium tweeter which may accentuate the fatigue effect in some of the tracks (especially synthetic material like the Daft Punk)... I cannot be sure of this, just an impression. Obviously B&W has advanced over the years to using diamond tweeters while other companies like Focal, TAD, Magico, Ravel and Paradigm Reference are using pure beryllium to achieve higher breakup frequencies significantly above the audible spectrum. I suppose the use of class-D amplifiers could have an effect (likely not) - just don't tell me silver speaker wires sounds "bright" unless there's evidence of such a thing :-). B&W recommends at least 100W for these drivers and given the amplifier demands, I cannot imagine many folks running these with tube amps. I suppose NOS DACs and various upsampling DACs with rolled-off filter settings could tame the upper end at the expense of accuracy of course.  As I mentioned earlier, I have never seen a full review on these speakers and would be very curious what measurements look like.

The System
After the Nautilus demo, I got to wander around the store to check out some Totem speakers, and had a listen to the D'Agostino Momentum monoblock amps (yes, very pretty!). Also managed to put my test CD through the paces with this B&W 802 Diamond system:

As you can see, it's powered by a McIntosh MC302 300Wpc stereo amplifier. SACD player was also McIntosh. Really nice sounding as well, definitely goes deep although I noticed some low bass accentuation in that room (sounds nice and punchy but I would have used some EQ to tone down the bottom end a little). I had a listen to these speakers last summer in Singapore at The Adelphi, coming away with a similar impression of the excellent sound quality. I'd certainly be very happy with these at home :-).

Okay, time to wrap up! I'd like to thank Hi-Fi Center again for the opportunity to listen to the Nautilus - a classic icon of the audiophile world. To be in continuous production for >20 years in these days of perpetual upgrades and engineered obsolescence is quite a feat for anything; much less an electronic device. This opportunity is also a testament to the value of having good "brick and mortar" specialty stores where the knowledgeable, enthusiastic and friendly staff can answer questions and provide informed suggestions. Sadly, an almost extinct species in this day...

Friday, 7 February 2014

MUSINGS: Golden Earism (& The Philips Golden Ears Challenge)

Don't you love the term "golden ears"?

I wonder historically when this term was first coined. I suppose it must have been in the murky distant past of times immemorial when primitive man glazed upon the yellowish gleam of Keynes' "barbarous relic" and began ascribing all manners of idealistic properties. Or not...

The other day, a forum poster brought up this link from What HiFi? about Hi-Res audio. Yeah, it covers the basics, but I did want to add an item #5 in terms of "factors to consider":

5. You must have good enough ears to appreciate the difference hi-resolution makes.

I know this can be touchy for some folks, but it is what it is. Our ears (and brains), like all the other sense organs (and cognitive domains) do not have infinite resolution. And like everything else, time is not on "our" side. At 42 years old this year, my ear's "frequency response" only goes up to about 15-16kHz at normal amplitudes. Do I really have the need to go for files with sampling rates of 88kHz+? Honestly, I don't think so... But as I've expressed elsewhere, this is about perfectionist audio so I'm certainly happy to have access to my favourite music using the most accurate technology available (I'm still of the opinion that 24/96 is more than I'll ever need in terms of the technical specs).

If you haven't seen it yet, recently, our friends at Philips have come up with a very cool website called the Golden Ears Challenge. Just enroll with your E-mail address and get going with some ear training. Log off and it'll keep your place in the test. Seriously, if you believe your equipment and ears are up to the task, take the challenge! I suspect some audiophiles will be surprised at the limits of their hearing ability.

I took the Challenge using the ASUS Essence One on my desktop with a pair of venerable Sony MDR-V6 (<$100) studio monitor headphones. I figured, if the V6 is good enough for Roger Waters, it's good enough for me!

I suppose better headphones like my Sennheiser HD800 and being in my much quieter audio room downstairs could have made tasks like hearing high frequency extension or detection of minor amounts of reverberation easier, but the computer desktop was more convenient... Remember to make sure the DAC is set to native 44.1kHz and something like Windows Mixer isn't upsampling.

The Bronze level wasn't difficult at all unless one has hearing issues, I suspect.


Silver level was achieved in one sitting. I think the test music samples were encoded with 320kbps MP3 and it wasn't too hard to differentiate between 320kbps and 128kbps lossy compression - as usual, listen especially to the treble and see if you can hear the loss of detail, more "brittle" rendering, and slight "chirpiness". I found it more challenging detecting small amounts of reverb down at dry/wet ratio of 0.15 later in this test.


Here's the "coveted" Golden Ears achievement :-). You get an E-mail to confirm.

Not bad, took my time over a couple of nights in between some virtual paper work. Achieved with a little patience and using the same ASUS Essence One / Sony MDR-V6 combination. The most time consuming part was getting the Boost/Cut Identification Test right at the various frequencies (63, 125, 250, 500, 1k, 2k, 4k, 8k, 16kHz). A frequency boost at 16kHz with real music was barely audible for me. Tests like the bass boost really benefits from headphones capable of good bass response so I suspect an open unit like my AKG Q701 would not be the best headphone to try this on.

As of this writing, here are the overall statistics for this test:



Not bad, looks like I'm one of 117 who have completed the Golden Ears level so far out of 925 who finished the Basic level (12.6%). Objectively, Golden Ears aren't that rare :-).

Anyhow, I highly recommend giving this a try yourself... I believe that anyone can have an opinion about equipment fidelity just like everyone has the right to have an opinion on what music they enjoy. But it does require good ears technically if one is to claim discernment of small differences between pieces of gear. I think for many, engaging in tests like this one would be very educational if not eye opening in terms of limits of one's hearing. Furthermore, I think doing challenges like these should be mandatory for those who engage in "professional" audiophile hardware reviews focused on audio fidelity. (And those championing technical specifications based on 'articles of faith' like 24/192 over 16/44... errr... who's that Pono guy again?)


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PS: Remember that JPlay software I measured awhile back which made no difference (actually there was a bug in that version which makes it even worse)? Looks like they've returned with a line of "JCAT" hardware! USB cable for 299Eur, SATA for 349Eur! How about Cat 5e (!) for 349Eur - man, they didn't even bother trying for Cat 7; at least the AudioQuest "audiophile" ethernet cables did! Reminds me of sellers on eBay trying to scalp some bucks by listing items at huge mark-ups with "Buy It Now" to catch shoppers who have never tried "The Price Is Right". This time around, they don't seem to claim sonic superiority of these products - merely "help you create the ultimate PC audio transport and get the most out of JPLAY".

Considering that a high quality SATA-III cable with fastening clips (which this one doesn't even seem to have!) runs for about the equivalent of <$4Eur at my local computer store, these guys are charging at >8700% mark-up presumably for that JCAT logo stamped on, silver plating and teflon coat (of course unless you're pimped out and have a window into your computer case, these will be hidden from view)... Sorry J-Dudes, but IMHO, The Price is Gluttonously Wrong. Why don't you guys show us in what way these are better than good quality generic SATA-III 6Gb/s cables first? (As if there's even a plausible explanation.)

Saturday, 1 February 2014

MEASUREMENTS: Power Cable Redux. The Synergistic Research Tesla T2 SE, T3 SE and PowerCell 4.

As promised over the last months, I've been wanting to borrow some expensive cables to measure to see for myself if I can both objectively and subjectively experience a difference. I've measured power cables before with my ASUS Essence One DAC's output but it just so happened that recently a friend decided to "go deep" into the world of audiophilia and purchased a little "family" of Synergistic power cables to try out:

What we're looking at here is a "tree" of Synergistic gear :-). Plugged into the wall is a "Tesla T3 SE" cable connected to a "PowerCell 4" (basically functions as a 4-outlet power bar). Coming out of the PowerCell on top are 2 "Tesla T2 SE" cables and an Audience power cable (not evaluated here). The blue lights come from the "Enigma Bullets" which I'll address a little later. My friend has been listening with them for >6 months so there's no issue with new cable "break-in".

As has been expressed by others, it's hard to make a case for power cords... The AC in our homes are connected through tens/hundreds of miles of cabling of various gauge. Within one's abode, it's interconnected with multiple outlets (unless of course you hire an electrician for a dedicated line) usually through 14AWG copper wires for most 15A circuit breakers here in Canada. Could the last few feet be significant?! Does running fancy cables like those above really improve sound quality? Here's a chance to have a look and listen...

I. A Look at the Synergistic Tesla T2 SE (5'), T3 SE (5'), and PowerCell 4

For the purpose of these measurements, I wanted to keep it convenient for my friend - the way it's configured as already attached to the Oppo player:
Oppo BDP-105 <-- Tesla T2 SE <-- PowerCell 4 <-- Tesla T3 SE <-- Wall outlet

I'll spend some time talking about the T2 SE since it's the cable directly connected to the Oppo. You can have a look at the manufacturer's information at their website if unfamiliar with this cable. Although not the "top of the line" AC cord, this unit has most of the "headline features" which supposedly provides benefits. It's got some kind of silver & copper conductor construction, "Tricon" and "T2" (?) geometry, high quality "G 07" IEC plugs... Then there's the "Quantum Tunneling" - some kind of 2 megaV pulsatile "treatment" that transforms "the entire cable at a molecular level" (what molecule(s) they did not say...). Check out some more pictures here.

Finally, we have the well advertised "Active Shielding". The claim here seems to be that using an electrically active (DC current) shield improves noise level and some how "greater frequency extension from top to bottom." We are of course not graced with any charts/graphs/details as to how this was determined.

To make things even more "enigmatic", we have these "Enigma Bullets" a.k.a. "Active Shielding Modules" capable of "tuning" the sound! They screw into the pigtails hanging off the male ends of the power cables. Silver = "open and airy", Black = "warm and rich", Grey = kinda in between. Hopefully the pictures below clarify the description:
Despite the huge calibre of the T2 SE cable, it actually feels rather hollow so it's hard to tell what wire gauge is being used inside.

Here they are, the "Bullets":
Cute, solid-feeling metal pieces with an electrical connector on one end and a little LED (the blue light shown in the 1st picture) on the other. They get warm plugged in to the DC source so I whipped out the multimeter and got 1400-ohms resistance for the black one, and curiously 1200-ohms for BOTH the silver and gray ones - not sure if this is supposed to be the case.

The "DC power" end of the "Active Shielding" is connected to what basically is a wallwart ("Mini Power Coupler") - here's a picture of them (2 for T2 SE, 1 for T3 SE) connected to the power bar:
Notice the $399 MSRP Synergistic "Quantum Line Strip" QLS-6 - power bar, no surge suppression - also "Quantum Tunneled"!

Of interest, you'll notice that one of the wallwarts had a sticker that fell off over time! Here's a close up of the label underneath:
A basic wall plug AC adaptor, 24V 300mA switching power supply you can order bulk from ENG Electric in China or Taiwan. Unless I'm mistaken, asking price for one of these is $125 (here)!

Here's the manufacturer's page on the PowerCell 4. It functions as a 4-outlet power bar. I don't think there's any surge suppression on it. It felt surprisingly light weight to me. I have no idea what they mean by a "magnetic cell" or what benefit that affords (?are there magnets in there?). Also, the comment about "The PowerCell 4 also improves picture quality on any display, with darker black levels, better color saturation and a more 3 dimensional picture, simply amazing" should be objectively assessable.

Finally, between the wall outlet and PowerCell 4 is the hefty Tesla T3 SE power cable. Again, here's the manufacturer information page. Looks to me that the main difference is the higher number of conductors (ie. thicker overall effective wire gauge) compared to the T2 SE above. You can read more about this PowerCell & T3 SE combination in this subjective review.
T3 SE cable plugged into wall. Notice its own lit "Enigma Bullet" and you can see the "Active Shielding" winding wrapped around the main power cable.
I could not find a price list all in one place... But the MSRP is something like this as of January 2014:
- Tesla T2 SE cable - $650/5ft (here)
- PowerCell 4 (North American) - $1,250 (here)
- Tesla T3 SE cable - $900/5ft (here)
----- Total MSRP for the set = $2800 USD

 

II. The Test

My friend lives in a multilevel condo and I figured that if indeed an expensive AC cable system is capable of cleaning up the noise coming through the outlet, then this is the kind of environment to demonstrate an advantage!

Of course, the comparison must be to a generic IEC cable, but lets make the generic AC cord even more disadvantaged - I'm going to add a 12' length of inexpensive extension cord to it. Measurements will be taken off the RCA output from an Oppo BDP-105 which he uses (the Oppo is an excellent USB DAC based on previous tests a year ago). This also gives me an opportunity to show a few measurements beyond my usual ASUS Essence One / Transporter / TEAC UD-501 trio of DACs.

Here then are your test "subjects":

A. Synergistic Research Tesla T2 SE to PowerCell 4 to Tesla T3 SE plugged into the condo wall plug:

B. Generic 6' 18AWG IEC AC cable I got 'free' in the box with something (black) + Generic 12' extension cable (white) into condo wall plug:


Test Setup:
Win 8.1 i5 Ultrabook --> shielded USB --> Oppo BDP-105 (powered with either A or B above into outlet) --> shielded (Tributaries) RCA --> EMU 0404USB --> shielded USB --> Win8 AMD X4 measurement laptop

- Newest Oppo USB driver (1.61)
- Latest RightMark Audio Analyzer (6.3.0)

 

III. Results

As usual, I'll measure at 16/44 to make sure the results cover standard CD-quality output. Then I measured 24/96 to get an idea of "high-res" performance. The tests were run under 3 conditions: Synergistic system without Active Shielding (wallwarts unplugged), Synergistic system with Active Shielding using Gray "Bullets", and finally the generic IEC cable + extender. (Note that in the labels I used "T2SE" but in fact the whole Synergistic chain was measured including PowerCell 4 and T3SE.)

16/44 (standard CD resolution):

Frequency Response
Noise Level
IMD + N
24/96 (high-resolution):
Frequency Response
Noise Level
IMD + N
As you can see... The expensive Synergistic power cords + PowerCell made absolutely no difference to the Oppo's analogue output compared to an absolutely generic power cable attached to extension cable for both standard resolution 16/44 and hi-res 24/96 test signals. Inter-test results were essentially exactly the same in all 3 conditions. No evidence here that the Active Shielding made any difference either.

For those who might wonder about jitter...

Again, no different. (Of course one cannot expect a power cable to affect jitter nor J-Test to be too anomalous through an asynchronous USB DAC.)

IV. Conclusion

Within the limits of the testing equipment - the EMU USB0404 as ADC - there is no difference using the Synergistic power cords with the Oppo BDP-105 compared to a generic 18AWG IEC power cable with extension cable in a multilevel condo building near the heart of the city.

Although the USB0404 isn't to be used professionally as test gear, as previously shown, it is a capable "measurement" device able to demonstrate very tiny effects like the -90.3dB LSB test, effect of digital filters, and slight differences between similar SPDIF digital transports; all of which I believe would be below the threshold of hearing for the vast majority of people. As such, I do believe the results above to be accurate and reflect reality when it indicates there is zero difference.

Could these fancy cables improve the sound from other devices like power amps or older technology like tube gear? I don't know... Remember though that tube equipment have much higher noise floor in general so even if this cable could lower it, the difference would likely be irrelevant. As usual, if power cables could substantially improve sound quality, why has there not been good evidence after all these years? I've often wondered why cables like these are not subjected to objective measurements like speakers, DACs, pre-amps, etc. in magazines like Stereophile using their fancy measurement devices? (Heck, many of these cables cost substantially more than good components!) Furthermore, right on Synergistic's web page, we are told that the "Active Shielding" lowers conventional parameters like noise floor and frequency response ("this closed circuit design not only improved subjective performance, but also made our cables measureably (sic) quieter, thus improving detail with greater frequency extension from top to bottom..."). So where are those measurements, and under what conditions? Peripherally, gimmicky marketing terms like "Quantum Tunneling" as it refers to the process they use really should be better explained (seriously, any time a company starts referring to Quantum-anything in the macroscopic world, it's best to be cautious). Finally, if sonic improvements can be made with a cable, did Oppo not bundle one they've tested to be optimal despite all their other engineering efforts?

Subjectively, I have heard my friend's system with the Synergistic cabling and with the generic power cable (as well as other systems with fancy cables but not to this degree of testing). To be honest, there's really not much to say subjectively with any certainty doing a tedious A/B/A trial. Do I think the Synergistics make the sound better? I'll go with the objective results and say this is most unlikely... Without a special setup, it's essentially impossible to do an accurate A/B comparison since there would be too much delay between cable switches, Oppo boot up, then start playing a song to really make any reliable comparison based on auditory memory of mental markers for high-fidelity. If audio qualitative differences were big enough, of course this could be a trivial task, but for at best tiny differences as in this case (if any), I do not believe this is possible based on research into the limitations of echoic memory. Good to see the measurements at least did not show any worsening using the exotic cables. All I can factually say is that the Oppo BDP-105 sounds great (and measurements demonstrate this high fidelity) through his system irrespective of which power cable(s)!

When it comes to power cables in my home system, my internal wiring is standard 14AWG copper and that's the "best" it's ever going to get in terms of power distribution. I don't see how passive wires can do anything for noise floor or "control resonance" or such beliefs. I'm quite happy with generic shielded 18AWG IEC cables for low power devices like the DAC, pre-amp, DSP equalizer. For higher power devices like the monoblock Emotiva XPA-1L and Onkyo AV receiver I have 16AWG shielded generic cables. I do not believe I hear a difference between the 18 and 16 gauge cables with the amps (in fact at one point I had an 18AWG cable on one monoblock and 16AWG the other and notice no stereo imbalance, noise, etc... even at high volumes) but I guess at least it makes me feel good that I did a little more to feed the neurosis :-).

As usual, please feel free to drop a link if you come across other tests on cables such as these; especially tests which have shown significant differences.

Recommendations:

- I've been listening to Eric Bibb's Blues, Ballads & Work Songs (2011) recently and I'm enjoying this Opus 3 SACD (was listening to the PCM layer on my friend's system the night of the Synergistic testing in fact). Easily accessible and great resolution!

- Mark Waldrep (aka "Dr. AIX") runs a nice blog at Real HD-Audio. Opinions and insights from a respected figure in the high-fidelity/audiophile world who clearly "keeps it real". If you haven't, I would highly recommend having a listen to some of AIX's recordings; especially in multichannel and the samplers provide a taste of his work. He posted an amusing recent anecdote on the use of a standard 75-ohm cable for digital audio at CES 2014. Also calling out the snakeoil on these "treatment" products sold through Blue Coast Records  - I wonder if they work better in PCM vs. DSD :-) (Dr. AIX's blog post). Respect.

Enjoy the music... And keep it real, folks :-).

PS: A big thanks to my friend for offering and helping with the testing - he has of course reviewed this write up for accuracy.


Saturday, 25 January 2014

MUSINGS: The Audio PC / Music Server / HTPC (Basics, My PC, and Some Generalization)

I'm in the process of finishing up some measurements - I think many will find it interesting in the days ahead. I'm going to let that article percolate a little first however. This week I thought I'd spend some time discussing/considering the computer system for media consumption; a bit on both the hardware and software aspects, and hopefully putting together bits and pieces I've done over the past year in the process. As you can imagine, there's quite a lot to cover...

In the hopes of a reasonable summary, here are the 3 main component functions of computing devices (almost everything is a 'computer' these days) in the media room:

1. Media Client or "Media Player" or "Transport (to a DAC)": The computer acts as a "front end" to feed your DAC/receiver/amp and or TV/monitor. Of course you can also have a good internal sound card (like the ASUS Essence STX), and I presume few are using the motherboard's sound output (usually of comparatively poor quality). You interact with the computer with whatever player software to control which tracks/files are played, how to "fast forward", "stop", "pause", etc. in much the same way as the disk spinners. Specialized "computers" may have hardware controls for this like a play button on the front panel of the chassis, maybe a specific remote control unit rather than using a generic keyboard. On-screen display on the monitor/TV can be as simple as a web-based interface like the Squeezebox server or the customary GUI of something like iTunes, foobar, JRiver, etc.

This transport/playback task can also be delegated to streaming devices of course (which are essentially little computers inside). For example, the Squeezebox familyMeridian Sooloos, Cambridge Audio streamers, Naim NAC-N, Linn DS, Bryston BDP-2, LUMIN etc... That's the higher end, but on the low end, you have things like the WDTV Live previously measured. These devices usually need to be connected to some kind of server for one's music (although some devices like the Squeezebox Touch can act as its own miniserver) and many can access Internet based streaming media like the hundreds of Internet radio stations around the world, Spotify, MOG, Pandora, SiriusXM, maybe Beats Music in the days ahead.

Although audio streaming may be all one needs, for those who "want it all", the pinnacle of the media room computer is the HTPC (Home Theater PC) with both audio and video playback capability. The HDMI interface has become the de facto digital audio-video cable to do it all. Multichannel 7.1 hi-resolution audio is essentially universal these days with modern HDMI interfaces, and 24/192 sample rates can be sent to a decent modern AV receiver with no problem. Some AV receivers will also accept DSD. IMO, multichannel PCM is preferable because DSP manipulation of the audio stream is an essential part of getting multichannel right... Good bass management (some SACD players are able to do this in DSD), channel reassignments (eg. 5.1 fold down to 4.1 system), room corrections, are all easily done in the PCM domain and would require a DSD-to-PCM conversion step if you're sending out a DSD bitstream. This limitation of DSD is a big one in multichannel and unlikely to be solved any time soon... If ever...

As for video with the HTPC, it's trivial to achieve 1080P. 4K resolution can be reached with the current HDMI 1.4 specification. As of early 2014, I suspect the market feels little compulsion to buy the current generation of 4K TV's and one would achieve little benefit apart from early adopter bragging rights (and spending quite some money in the process!). First and most painfully obvious, there's no content nor even a clearly announced means of media distribution (it looks like 4K/UHD Blu-Ray is still in development). Second, I'd suggest waiting for the wide availability of HDMI 2.0 which would allow 60Hz 4K frame rates (I see that Sony has released firmware for certain TV models already, DisplayPort can already achieve 4K/60) since there does at least seem to be some push towards >24fps movies and if I'm getting a "next-gen" TV, I'd want that. At this time, the real benefit I see from 4K is finally being able to watch 3D in full 1080P on a passive display. I'm waiting for one of those to hit an affordable price range in the 80+" size & HDMI 2.0 :-).

2. Media Server: This is the "back end" where you store your music (videos, movies, pictures). In this day and age with easy connectivity, there's nothing to keep the server in the media/listening room. Many people have opted for NAS storage and since there's a CPU inside the NAS unit, it could also run server software like Logitech Media Server, or the scads of UPnP/DLNA servers. In fact, in a home where there's wired ethernet throughout the house, you can easily have the server computer or NAS on a different floor/room. In my experience, a gigabit network can transfer data just as fast as many inexpensive high-capacity hard drives (50-100MB/s is normal with gigabit ethernet using standard Cat5e cable). A great benefit to this is that you can keep the playback machine (computer or streamer) simple, low power, cool and silent without having a bunch of hard drives running in the same enclosure while listening to your music or watching movies.

3. Mobile Control Apps: Although not specifically the computer itself, the ability to use one's smartphone or tablet computer has been a great boon to the usability of digital media playback. No longer do we need to turn on the TV to select albums, or select video. These days, I still use iPeng and SqueezePad on my iPad to control my Squeezeboxes (Logitech Media Server). Squeeze Commander works fabulously on the Android devices. Cover artwork adds to that overall presentation.

However you want to mix-and-match the functions above, there are a myriad of options based on what OS you choose, which server software, and how the media is being played. The hardware itself can be any combination of devices like NAS, laptop, desktop, network streamers, etc. It is this fantastic flexibility that can be a source of frustration to those starting to enter the computer audio world. Commercial companies are obviously interested in capturing part of the market with devices such as the Aurender computer systems, Sooloos Music Server System (see Streaming products). Not surprisingly, these turn-key products are usually Linux based, low power, relatively slow (often Intel Atom CPU, sometimes ARM based), and generally quite a bit more expensive than something one can put together with standard commodity parts. The greatest thing about true technological innovation in the marketplace is the deflationary price pressure - take advantage of it if you can! Have a look at Computer Audiophile for some ideas on building one yourself.

As a "case study", I figure it might be of interest to show the system I'm currently running...

I basically have an all-in-one box that's a server to my Squeezebox devices all over the house, a digital audio transport to my TEAC UD-501 DAC, as well as full HTPC functionality to the ONKYO receiver and 55" LG TV for movies and videos.
Hmmm... Maybe should clean up a few of those cables in there. Logitech Unifying receiver sticking up front for the keyboard.
HTPC quietly doing it's thing in the corner... The smaller box beside the computer is a CyberPower CP1500PFC UPS. Keyboard is the Logitech TK820 with touchpad.

Main hardware components:
- Fractal Define R3 midtower quiet case (2 quiet case fans - rear exhaust and front to cool HDs)
- Seasonic X-400FLII fanless 400W PSU
- ASUS F2A85-V Pro motherboard (HDMI 1.4)
- AMD A10-5800K APU (integrated AMD Radeon HD7660D GPU)
- CoolerMaster Hyper 212 Plus CPU cooler
- 16GB (2 x 8GB) Kingston Hyper X Blu DDR3 RAM
- SiliconImage Sil3132 port-multiplier eSATA card
- 128GB OCZ Vertex 3 SSD boot drive
- 2 x 3TB WD Red for music library
- 1 x 2TB WD Red for video/movie library
- 1 x 1TB WD Green for web server data
- 1 x 1TB WD Green for misc data backups
- LG BH12LS35 Blu-Ray reader/writer - playing the occasional Blu-Ray & audio ripping

OS: Windows 8 Pro / 64-bit

The AMD A10 CPU has worked well for me in the past year. In fact, I undervolt and underclock it slightly to 3.5GHz to keep it cool and quiet with the CoolerMaster CPU heatsink/fan. I haven't measured, but the CPU power consumption would be substantially less than 100W.

Notice that the HTPC isn't built with necessarily the newest generation hardware components. In fact, much of this was put together more than a year ago. Unless some "disruptive" killer app were to be released that needs much more computing power, I suspect this would be all I need for the next few years (clearly the push to upgrade is slowing). Audio processing doesn't take much power. At times I will turn on SoX minimal phase upsampling à la Meridian for the Transporter (see VirusKiller's thread), other times play with JRiver's PCM to DSD conversion à la EMM Labs, or try out a convolution room correction filter with foobar - never has the AMD A10 felt underpowered for these tasks. With a better audio room since moving into the new house in late November 2013, I've been quite aware of the slight noise the computer makes. Recently, I replaced the power supply with a fanless model (the Seasonic 400W) which lowered the noise a bit.

At this point, the computer is still slightly audible on account of the spinning hard drives (softer than the Panasonic Blu-Ray player in use). The problem with upgrading the room significantly (my ambient SPL is <30dB(A) at night) is that you also have to get the other parts up to spec as well ;-). I guess I can look at moving the hard drives used for video and web serving over to another computer on the home network to drop a few more dB's.

I have 6TB of space for all the music (all backed up on another machine over the gigabit network). The library consists of stereo PCM CD's (~3000+ albums) and hi-res downloads and rips (~250 albums). I have some multichannel 5.1 music (~100 albums) in PCM format taken off my DVD-A/SACD/DVD/Blu-Ray/DTS-CDs. All the PCM music encoded losslessly as FLAC.

Finally I have a small ~30 album collection of DSD stereo music which I know are either sourced from genuine DSD recordings or analogue transfers (ahem... no Norah Jones Come Away With Me type faux DSD, thanks). These DSD recordings are stored as .dff because I like lossless DST (Direct Stream Transfer) compression. As I noted months ago in my SACD/DSD Musings, I do not like the fact that one currently cannot have both tagging and compression. Without compression, DSD files are unnecessarily large, wasteful, and ultimately inelegant IMO. DST compression brings them down smaller than the size of average 24/96 files and I make sure that the filenames I choose can be easily parsed for album, track number, artist, and title. I don't have many DSD albums on the server so it hasn't been difficult. Despite the ongoing hoopla around DSD, I remain sceptical that DSD will have much traction unless a simple foundational issue like a fully featured, modern, file format is addressed. (Actually, I just suspect there's not going to be maintained traction simply because DSD doesn't bring much to the table...)

I'm not going to say much about the video playback since much of it is just family videos with some Blu-Ray rips I made for demo purposes when people come by to visit. The AMD A10 APU has a built-in graphics processor and the HDMI out of the motherboard works well to send multichannel 24-bit audio and 1080P video to the AV receiver.

Player Software:
I see audiophiles can really get heated about this. For those who have been around this blog for awhile, you'll know that I did not measure any difference between bit-perfect software players whether with Windows or Mac OS X using the TEAC DAC. This was the same for PCM and DSD. Furthermore, the "audiophile" player JPlay made no difference and in my opinion risked audio errors with extreme settings like unnecessarily low buffer space. Since I do not claim to have particularly "golden" ears (I'm in my 40's now), I likewise hear no difference between these players.

On my HTPC, I currently have 3 audio "servers"/players running:

1. Logitech Media Server (aka Squeezebox Server back in the day). All my stereo PCM music is streamed out to the Squeezebox units I have scattered around the house. In the listening room, I have the Transporter on the rack. BTW I do have a few 24/192 albums in my collection, but for most DVD-A rips where I have the physical copy, I usually downsample to 24/96 anyways. There are many "fake" 24/192's out there (just like 44kHz upsampled DSD) and even for those that are genuine hi-res recordings or analogue transfers, there's rarely content related to the music itself above ~40kHz (not that anyone would be able to hear it!), so I figure there's no point wasting space.

Because I have 16GB of RAM, I've set up a 4GB RAM disk (free one for personal use) and modified my configuration for LMS to put the database there. Really speeds up library searches - almost instantaneous.
Logitech Media Server (LMS): Some Billy Joel or Benny Mardones anyone? :-)

As mentioned above, I use SqueezePad, iPeng, and Squeeze Commander to control the server.

2. foobar2000: Fantastic, flexible, free software I keep running 24/7. The library keeps track of all my multichannel PCM music and the default output device is to the ONKYO TX-NR1009 multichannel receiver via HDMI using WASAPI. FoobarCon Pro is my preferred controller software off my Nexus 5 or 7; cool that it also has panels to view artist bios and track lyrics so you can sing along as the surround sound plays :-).

Foobar playing 24/96 5.1 Crowded House DVD-A rip.

3. JRiver Media Center 19: Again, I keep this running 24/7. Works beautifully and fully featured with a huge number of customizations and options. Although it has many advanced features like the ability to realtime upsample PCM to DSD64/128, I'm actually not using this for any of my PCM playback... JRiver is dedicated to feeding the TEAC UD-501 all my DSD music in native ASIO! As I mentioned above, .dff files cannot be tagged natively but JRiver can keep an internal database and has the ability to parse the filenames to "recreate" the album data, sort artists, tracks, etc. Furthermore, it decodes DST without any problems even when in the past I found issue with foobar's DSD decoding plugin. Nice :-). I don't think there's another software package that will do all this in such a hassle-free fashion with a lovely presentation at a very reasonable price (~$50USD).
A peek at the DSD library in JRiver using filenames and path to reconstruct tagging information.

JRiver provides the free Gizmo app on the Android for playback control. It works well but functionality is more basic than something like the Squeezebox controllers above. However, the really cool part is that JRiver can transcode and play music and videos to said Android device via Gizmo. A reminder that JRiver isn't just for music but works well as a full-featured "Media Center" for all your A/V needs.

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So that's a glimpse into how I'm currently using my HTPC. Perhaps some of this could be useful for your setup as well.

Now about audiophilia and computer audio...

To close off this blog entry, let's talk about the computer in an audiophile setup; specifically achieving excellent sound quality. I know many people believe that all kinds of arcane software tweaks such as turning off unused processes like printer services, BIOS tweaks, etc. are necessary to ensure good sound (something like this). Much of the OS tweaks probably do no harm and some of these recommendations may have been useful at one time (like a decade ago); I just don't think much of this is relevant any more or makes any difference. As far as I can tell, jitter under high CPU load is not an issue even with a simple TosLink off a motherboard as I showed here so I hope nobody falls for the "it causes jitter to be worse" explanation unless demonstrable at the level of the DAC output. Others in the past speak of using low power CPU's for audio (I haven't seen as many proponents these days). For me, the good thing about a more powerful machine is a speedier user interface, faster file scanning for the server, and also the opportunity to use DSP like convolution room correction filters without the machine breaking a sweat. Of course, you'd want a more powerful computer for video playback. Some others even advise against using lossless compression. Seriously, does anyone still actually believe a processor unintensive task like FLAC lossless decoding will cause enough electrical noise/interference to make it sound worse than a WAV file especially played off an external DAC!? (I certainly hope ideas like this will become just as bizarre as the belief in greening the edges of CD's 20 years ago.) Sadly, over the years, various audiophile magazines have promulgated much speculation and disinformation without checking facts or consulting with common sense (much less science/engineering).

Let's keep it simple - IMO, the main ingredients of a good computer audio setup:

1. Keep the computer sonically quiet! As few fans as possible if not fanless. Laptops are great for this - something like a MacBook Air or Ultrabook would be fantastic for example given how quiet they run. If you can, relocate noisy hard drive servers to another room with wired network (I consider wireless too unreliable for my taste and can be strained by high-resolution data rates).

2. Keep the computer away from your audio gear to reduce EMI/RF from entering the analogue path.

3. Get a good DAC. External units are great because they can be placed with your other components and isolate the computer as in point 2. Make sure you're using the best driver especially with PCs such as bit-perfect ASIO instead of going through the Windows Mixer to ensure bit-perfect output. Also, jitter has more to do with the quality of DAC than anything you fool around with on the computer side. From my measurements posted around here over the last year (eg. look at the TEAC UD-501 PCM results), a good modern asynchronous USB (or ethernet streaming) is generally better than SPDIF (coaxial/TosLink) due to lower jitter (J-Test results better but for the most part I doubt it's audible).

4. Things to not sweat about: cables - just make sure your power cords and interface cables work and look good enough to you in your room. IMO expensive cables may look good and convey a sense of authority, but please do not equate aesthetic value (eg. jewellery) with function (ie. "better" sound). Specific make/model of computer - again, this is aesthetic and so long as it runs your choice of OS, you're good. (No, I do not consider Apple computers as somehow better sounding.) OS - Mac, Windows, Linux, whatever so long as your server/player software runs well on it. As I showed here, different laptops and OS's connected to the same asynchronous USB DAC results in exactly the same analogue audio output. While I can't vouch for every computer, so long as bit-perfect output to the digital interface is assured, there's no need to fret. Player software - Again, see my bit-perfect measurement posts here, here, and here. Find one that has all the features you need and achieves bit-perfect output.

If you have the above down pat, then by all means tweak to your heart's content! Just don't break anything...

I just realized I've been building my computer audio library since 2004 (10 years already!). For those new to computer audio, I suspect all of this could sound overwhelming (and I'm sure I missed some important points). Stick with it, play around with it - it won't take long to pick up. No matter what I do with the computer setup, without doubt, the most time consuming bit of all has been to make sure all the music is tagged properly and named in a consistent fashion (try Mp3Tag). Keeping the directories clean, using the same filename for cover images, and ensuring bit-perfect rips (try dBPowerAmp CD Ripper) do take time and effort; this is as expected since it's all about the music, right? Despite all the effort, high-resolution digital audio is as good as it gets for the audiophile who values high fidelity and the convenience in accessing all your music with a few search keystrokes is undeniable.

It's a great hobby with many avenues to explore. Just don't forget to listen, and enjoy the music :-).

PS: Backup regularly.

Friday, 17 January 2014

DEMO & MEASUREMENTS: What does a bad USB (or other digital audio) cable sound like?

Okay, so the other day I was installing my new BenQ BL2710PT monitor (reasonable monitor for a decent price) and as I was rummaging through my old cables, came across a very old USB 6' cable that I probably got free when I purchased an old Samsung laser printer back in 2001 during the transition from USB 1.1 to early USB 2.0.

This cable is the thinnest, most flexible, likely most poorly shielded USB cable I have; in other words, about as "bad" as it gets when connected to a quality USB DAC which expects to operate in high speed USB 2.0 mode without completely failing... Behold the "Bad Cable":


Plugging this cable into my desktop ASUS Essence One provided the opportunity to demonstrate just what a poor USB cable does to the sound... I'm sure this is "old hat" to those who have experience with digital audio, but for those who haven't, have a listen...

I recorded 1 minute of a freely available track from Jason Shaw called "Pioneers" from here off the Essence One fed into my EMU 0404USB to the usual Win8 laptop using a good quality cable versus the flimsy one above.

Good USB 2.0 cable - well shielded 12', ferrite core on both ends of this specific cable:


"Bad" USB cable as pictured above - poorly shielded against interference and incapable of transmitting at bit-perfect high-speed data rate to the ASUS Essence One:


Even though SoundCloud recompresses the uploaded FLAC audio, I'm sure you can appreciate the obvious errors in the "Bad Cable" sample. (You can press play back & forth between the two samples to A-B them if you want.)

What you're hearing is what happens with digital error (ie. not bit-perfect), similar to watching digital TV with the occasional data error leading to macroblocking and bad pixellation as in this sample found off Google (notice the blue stripe due to digital error):

It's worth noting a few characteristics of this poor cable as it pertains to sound:

1. Poor digital cables leading to digital errors sound like brief pops or occasional static (assuming they do not completely malfunction). They're similar to the errors you get when ripping a CD without something like EAC or equivalent. Sometimes, you'll hear very brief dropouts. Depending on the data packet disrupted, occasionally they will occur in only one channel but not possible for this to happen consistently in a single channel. Remember that although asynchronous DACs have the capability to buffer, hence improve timing and lower jitter, they do not (at least not in the case of the Essence One with the CM6631 USB interface as far as I can tell) necessarily error correct or ask for a packet resend. The more data error, the less the amount of "normal sounding" music will be heard. Obviously if the data error occurs every few minutes, it might be difficult to detect, but if it happens frequently, it's not subtle.

2. A poor digital cable does not result in overall level changes in the song... This is not like analogue distortion that can consistently alter the volume level or change the dynamic range uniformly or periodically.

3. Similar to the above point, poor digital cables are not capable of changing the overall tone of the sound. There is no such thing as a digital cable capable of acting as a "tone control", making certain sounds "brighter" or "warmer". A passive digital cable is not capable of acting with some kind of frequency filtering mechanism.

4. Poor digital cables do not consistently do anything to the soundstage. A poor digital cable cannot make a voice or instrument sound "distant" or move it "forward", or pan the soundstage to the left or right as a whole or in relation to other components of the music.

5. Bad cables cannot cause speeding up or slowing down of the data transfer. Poor digital cables therefore cannot cause sporadic or consistent timing issues like warble (speed up/slow down pitch changes), "pacing", or rhythm problems.

6. The concept of cable "break in" makes no sense with digital audio cables. If it carries data accurately when plugged in then the only problem that can happen in time is corrosion at contact points or reactions such as oxidation of the metal over time. This can only lead to transmission errors as demonstrated above, not some magical improvement due to "break-in".

7. I was reminded here the other day about the measurements with a poor RCA cable I used as coaxial SPDIF last year. Indeed, if you use a very poor, unshielded RCA cable paying no attention to the expected 75-ohm impedance specification with an SPDIF digital interface that's not galvanically isolated (eg. coaxial SPDIF of the ASUS Essence One in that case), noise can be introduced into the system. However it does not take extravagantly priced cables to make things right (an inexpensive 6' <$20 decent shielded cable from a reputable company will do). As always, noise can be introduced into the analogue domain with any electrical connection (or just being careless like putting your DAC right on top of a noisy desktop computer), so it's not really an issue with the digital system itself.

You might be curious how the 2 USB cables measure in terms of jitter...


Surprised? As you can see - not much difference at all! If you monitor the realtime FFT for the J-Test, you will see errors "popping up" with the bad cable due to bad data transfer, but in between, the jitter plots are essentially indistinguishable! This is expected... For an asynchronous DAC like the ASUS Essence One, jitter rejection is handled very well by design and there's nothing the passive cable can do about that.

Now I'm sure there will be a number of folks who disagree and hear various effects in the list above (see here, here and here for some interesting perceptual accounts and/or creative writing). The thing is, where is there decent evidence to show that passive digital cables (and I'm talking here not just of USB but also the SPDIF variants like coaxial or TosLink) sound different if they're error free (a.k.a. bit-perfect) and built to specifications (assuming no issue with analogue noise as in item 7 above)? I've never seen manufacturers come up with anything of substance... Or hobbyists/DIY guys show/demonstrate verifiable claims... As usual, I'm happy to change my mind if some kind of objective evidence exists since I personally have not subjectively heard a problem except as demonstrated above with digital errors.

(Digital cable summary from a number of months back for those who might have missed it. Recent post on EETimes blog on this.)

Recommended album:
- Have a listen to Babatunde Olatunji's posthumous 2005 album Circle Of Drums. This is one of the best Chesky albums I have heard. The drums sound fantastic with wonderful tonality and sense of 'space' around the instruments; a lovely exploration of African drums and rhythm. Unless you believe you can hear the difference between 16-bit noise floor and that provided by SACD, IMO there's no need to buy the SACD because it appears to be a 44kHz PCM upsample (here's the Master List). There is a multichannel mix on the SACD which sounds OK but derived from post-processing. An impressive sounding and quite enjoyable record for those interested in world music nonetheless!

Relax and enjoy the music!

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Addendum (January 20, 2014):
For the sake of completeness in answering Frans' comment below, here is the J-Test result with the TEAC UD-501 using the poor USB cable vs. good one:


The TEAC uses quite a different asynchronous USB implementation than the Essence One. It appears to utilize a TMS320 DSP processor rather than "off-the-shelf" USB interface like the CM6631(A). I'm wondering if this interface is actually more robust since the digital errors were even less obviously audible.

In any case, using a different DAC, the jitter test remains unchanged; two examples now of how an obviously poor USB cable does not appear to affect the jitter from asynchronous DACs in terms of the analogue output (which IMO is the only important measure since that's what we hear!).