November 2009

Audiolics Anonymous Chapter 121
Audience AU24 AC Power Cable And High Definition Downloads
Article By Dr. Bill Gaw

  Welcome to the first of my eleventh year of monthly tomes. How time flies when you're having fun! What a cliché, but its true. Writing these columns has become a joy rather than work, but for some reason this month I'd developed writers block. Thus, this dumb opening.

Anyway, last month I received an e-mail from John McDonald of Audience, makers of the aR line of power conditioners I've written so many good things about in Chapter 96, Chapter97 and Chapter118. Even after three years of trying various other fixes for AC line noise, they are all still being used in my system as the main power cleanup equipment. I've not found anything out there to match their ability to clean up the atrocious AC coming into my house. At the time of purchase they came with Audience's High Resolution Power Cord because their AC input uses a locking Neutric plug. Since no other cable manufacturer uses this special plug, I could not try other AC cords to see if there would be an improvement in noise reduction. Mr. McDonald suggested that I might wish to try a pair of his new and improved...

Au24 Power Chord
On my aR2-T and aR12 power conditioners. Why not I figured? (As a semi-retiree, I have to start worrying about my budget and how much I can slip past the other half. Gone are the days when a minor improvement can be bought for an exorbitant amount. My Scot blood has always pushed me toward high value products, but now that's been heightened.) How much better could one cord make the conditioning?

The two power cords arrived about four weeks ago. Unhappily, my aR2 unit had a 20 Ampere Neutrik plug on it and both cords had 15 amp plugs, so one went back and was replaced with the proper Neutrik.

First off, like its lesser brother, the Au24 is of average thickness for a high end 10 AWG cord, but unlike most, is ultra-flexible. While I don't recommend putting narrow bends into it which could damage the crystal structure of the copper, they could be easily coiled up or wrapped around objects. It is constructed of 684 individual woven strands of high purity OHNO mono-crystal copper, very unusual for AC cords. My speaker cable, sourced from Japan, is made of the same stuff, as is their high end interconnect and speaker cable, and its great stuff for transmission of music due to its single crystal per strand, without breaks in the structure, which cause the electrons to have to jump gaps. While I can understand why this would be important for transmission of music waves, I don't know how it could effect noise reduction on the AC line. Perhaps Mr. McDonald can answer that in the follow-up. They use high quality Marinco and WattGate plugs and with use on their conditioners, Neutrik Powercon connectors. They  even include a tube of Caig Deoxit solution to clean both sides of the connections of oxide buildup.

You may ask (especially if you are one of those objectivist(( you know who you are)) always complaining on the web about high end tweaks that are unscientific) how a 6 foot piece of cable can do any good considering all the miles of crappy aluminum and copper wire between the generator and the equipment. It's because of those miles of crappy cable that that six foot piece can make a difference.

Unhappily, our 60 Hz. electricity is inundated with all sorts of noise, from factory machinery to digital computer noise feeding back on the lines, to RFI picked up by that miles long antenna, to junk added in your own house from appliances, and its getting worse every year. In addition, the junction between the house outlet, the equipment and the AC cord can add significant noise and resistance to the flow of electrons, and the AC cord itself can act as an antenna both picking up and radiating RFI. A great AC cable, rather than adding to this grunge which changes the sine wave into something possibly approaching a square wave, can act as a filter to this noise. At the same time, with proper shielding of the cable it can be prevented from releasing RFI noise into the listening room or receiving such from its surroundings and thus to the equipment. On the other hand, the cord must not add any resistance to the electron flow.

So what can a great cord do to your system? By helping to remove AC line noise and not acting as an antenna, it makes it much easier for the power supply of each piece of equipment to produce a flatter DC current. Most of our equipment works on various voltages of DC produced by the combination of the input transformer changing the 60 Hz. 120 volt-current to various lower or higher voltages and amperages, and the power supply which attempts to produce a perfectly flat DC current for each of those voltages without any AC ripple. The more ripple, the more distortion that will occur to the music.

It is theoretically impossible to produce perfect DC as one would need an infinitely large supply, so our equipment tries to get as close as possible under the engineering and financial constraints. Thus, the cleaner the 60 Hz. sine wave that enters the equipment, the closer the final current will be to flat DC. It is also theoretically impossible for a single piece of equipment to remove all of the junk traveling on and distorting the 60 Hz. sine wave, even an AC-DC-AC converter. Their problem is, again, producing perfectly flat DC and then producing a pure sine wave without  adding high frequency distortions.

Thus every layer of conditioning that doesn't add any artifacts will help to relieve the system of noise. The ideal of course, would be to have a huge number of battery banks putting out the various DC voltages required by the system through power cables with perfect RF isolation and zero resistance, but for most of us that is an impossibility, although I've seen a couple of systems that come close. For the rest of us we will have to put up with the AC line noise or use various conditioners and cables to minimize the effects on our systems. The positive effects relate to a cleaning of the low volume, background information, include a widening, deepening and opening of the soundstage, the so-called removal of curtains,  with an increased accuracy of the relationship of the fundamentals and overtones, giving increased clarity of the bass and midrange and smoothing of the treble. Negative effects relate to increased resistance and impedance and inductance and capacitance effects leading to slowing of the bass, and smearing and darkening of the soundstage.  Thus the best of the conditioners and power cords will do the least damage with the most improvement.

Unhappily for the sake of my bank account, the Au24 cable works synergistically with the aR Power Conditioners to maximize the benefits to a significant degree. Like with most significant improvements, it could be heard by my wife in the neighboring room without my even asking. (This test procedure is called WET, for Wife Evaluation Testing, which occurs when she comes into the room and asks what I've bought now for the system that I didn't let her know about, which causes a cool sweat (WET) on yours truly as I try to figure out how to tell her the cost.) Compared to the standard power cord that comes with the units, there is a tightening of the bass signifying improvement in the resistance of the cable over the standard unit. In addition, there was a slight increase in ambiance information, and a slight decrease in high frequency noise. Thus, the cord does act synergistically with the aR Power Conditioners to decrease the AC line noise entering the system and mucking up the sound, better than their regular cable, as they should considering their cost of $2200 for a six footer compared to $674 for the original.

The aR Power Conditioners are by far the best I've had in my system and I've had a crap load as you can see if you've reviewed my previous articles. This new cord adds sufficiently to their function that I'm going to purchase them from my meager audio funds by selling some equipment that's been lying around. If I were you though and had a finite amount of moolah, I'd purchase the Teflon or T version of the conditioners first, and then go with the Au24 cords later. For those who want the best, get the whole shebang together and save yourself the worry of not knowing what's best.

Happily for my bank account, I could not test them on the rest of the system as all my other equipment inputs are IEC plugs so I couldn't see if they worked better than my other high end AC cords. And I'm not asking Mr. McDonald for some of the IEC cords as my bank account won't allow the possible repercussion of their being better than what I've got. Guess you'll all have to go and try some of them yourselves.

Now a few words from Roger Sheker, Chief Engineer for Audience:

Bill, 

The reason why a quality power cord, being only the “last six feet” of power transmission, makes such an audible difference is problematic from a scientific point of view. This is not because the claim is invalid but from a lack of available data. As far as I know, no real research has been published on this subject. It is the same old “how do you measure how much better it sounds” thing. The meager research I have done on things that can be measured has lead me to believe that lower DC resistance is the key factor with reduced inductance coming in as an important second. The sonic improvement means afforded by lower DC resistance is rather obvious as peak currents can be very high. Even a little resistance will limit power delivery and degrade regulation, this is quite audible. Inductance would appear to have an equivalent effect but relating to the higher frequencies and HF noise in general. It is the old weakest link thing with the average power cord having higher DC resistance than even standard home power wiring. This same higher resistance can also degrade the ground connection integrity leading to a higher noise floor. All of these factors will negatively affect dynamic and sound field perception. Audience Au24 Power Chords have very low DC resistance, very low inductance and relatively high capacitance. This combination yields a cord with very low characteristic impedance. This lower impedance design has a real advantage in making additional shielding both unnecessary and undesirable, thus allowing for a much more flexible cord to be produced. Conventional shielding only affords electrostatic shielding while our lower impedance design also affords electromagnetic shielding by canceling out these undesirable signals. Facing this lower impedance, air borne RF noise sees practically a short circuit and this gives it a very difficult entry path. This same consideration is equally true of any equipment generated noise trying to escape. Lower DC resistance and lower impedance both afford a more intimate connection to any filtering or power conditioning system making it considerably more effective. For easier understanding it can be seen that the noted improvements are much the same as using all shorter power cords (in our case, much shorter).

I have not gone into what differences various types of insulation materials make but will state that the same materials that make a better audio cable also improve a power cord's power transmission ability. I am sure it also is for much the same reason as the audio signal is very much present in the power cord. The Audience PowerChord is made from multi strands of the very finest OHNO wiring with audio quality insulation. This insures our signature neutrality is maintained while providing the noted power transmission improvements.

Roger Sheker
Chief of product design

HDTracks.com
I have a confession. I've become a computer audiophile nerd. Over the past few years I've come to the conclusion that the computer will become the center of every audiophile playback system. When built to audiophile specs with high grade power supplies, high end sound and video cards, audiophile quality recording and playback software, and HDMI or balanced analog output, they can come close to the best audiophile products out there, and replace several pieces of equipment in one chassis. If you don't believe me, there are several now being sold by high end companies that have been written as producing the best sound out there.

My contention is that you and I can produce a unit that is equivalent to the best out there for less than the price of a pair of audiophile interconnects, and have written about withi Chapter106 and Chapter119. Also, over the past two years, all of my analog tapes and vinyl, my CDs and DVD-Audios have been transcribed to digital hard drives for a total of about three Terabytes of information, as described in the above articles. Thus all of my audio software takes up less than 1 cubic foot of space compared to two wall fulls of space. Once that was completed, I began looking for more music to listen to and came upon way over 5000 stations of off-the-air broadcasting being transmitted over the web in various levels of quality from very poor 64 mb. MP3 to 320 mb. WMA audio files that sound better than anything I've heard over FM radio.

But as an avid collector, even that wasn't enough for me. 5000 stations, several thousand recordings on hard drives, and I still wanted more. While there were many sites selling MP3 quality files, some legal and some not, which sound far worse for some reason than those mentioned above from radio stations, and several selling 16-bit/44kHz CD quality music, there are several now from various companies selling 24-bit/88kHz or 96kHz downloads.

One, 2L Records, was mentioned previously within Chapter106 has superb 24/96 and 24/192 downloads of their recordings in both 2 channel and surround that match perfectly their SACD, DVD-Audio and Blu-Ray discs when played back on the same computer. While there are others, all only sell from their own catalogs. Other companies getting on the high bit bandwagon include Linn and Reference Recordings.

Which brings us to today's second topic; HD Tracks. The company is the brainchild of Dave and Norm Chesky, of Chesky Records fame. They were some of the first to do vinyl and CD recordings to high end standards way back when I first got into high end audio, and are keeping the tradition up by being the first company to offer high bit rate downloads from most of the companies offering them on disc. At this point they have close to 4000 CD quality albums and over 120 high definition from companies such as Telarc, Chandos, Naxos, Pentatone, Harmonia Mundi and many others. The average album price is $15.98, but one can purchase either separate tracks for $2.98 to $3.98 or separate symphonies on albums for somewhat more than half the cost of the album. I asked for a mix of classical albums, and they graciously offered to send me several. I therefore picked five albums from different companies of both symphonic and small groups. The following were obtained:

Harmonia Mundi Beethoven III
Pentatone Brahms Symphonies
CSO Bruckner 7
Chandos Carmina Burana
Reference Recordings Exotic Dances
Bruckner Orchestra

See HDtracks by clicking here.

First, my sore points. 

 1. The down-loadable files are encoded in FLAC, a lossless codec. As the average decrease in downloadable digits was only 15-20%, and the download times on my high speed FIOS line was less than 30 minutes per album and not all software players will recognize FLAC files, and high enders are usually wary of any form of lossless encoding except possibly for MLP for DVD-A, I find it unnecessary. This is mitigated by the fact that they do steer you to MediaMonkey, a decent playback software that also allows you to play several hundred web radio stations through it. I understand that there are people out there with slower high speed lines, but the average download speed registered during the 30 minute time was a little over 600 mb/sec. obtainable for everything except phone modem. While Windows Media Player and Windows Media Center could not play them, the CICS Player and FOOBAR do an excellent job, with the CICS player sounding just a shade better as it downloads the files from the hard drive to RAM, eliminating much of the jitter inherent in reading files from a disk, and can upconvert the 88 and 96 to 172 and 192 kHz files for playback.

2. Even with albums that were originally produced for surround, only 2 track downloads are available. For instance, the album The Nordic Sound from 2L Records can be purchased from them in 2 channel for about the same price, but also in 24/96 surround for $19.95 or in their original 24/192 surround files for $24.95. (A bargain by the way compared to Reference Recordings atrocious pricing of their 24/192 HRX downloads for $45. Money-grubbers.)

3. Aiming even higher, Chesky is selling discs of some of their recordings as 24/192 computer files but not offering the higher bit rate programs on the web site. 24/192 to me captures everything I can hear from the best vinyl and is finally hopefully good enough to silence the analog-only purists. While a download of such an album may take over an hour, it would be worth it.

Now for the Kudos.

1. The downloads, at least from the five albums I've listened to, two of which I have the discs on, are superb. I asked for a mixture of five classical recordings from different labels, and four of them sounded great. The fifth, a Harmonia Mundi recording of Beethoven Symphony # 3 with the Helsingborg Symphony, had a strange buzzing sound on the left channel with three different downloads and using three different playback programs; obviously a problem with the files.

2. The SACD of the Chesky Bruckner Orchestra Spectacular was played back in stereo through the HDMI output of my OPPO player and a CD of  the Exotic Dances on my computer's Blu-ray drive and also loaded to its hard disc, and the files were played through the HDMI computer output decoded by the Integra 9.8 pre-pro. The Bruckner recording on SACD was not one of my favorites, being somewhat dark, but the files were actually a little clearer and more enjoyable. The Exotic Dances was far superior on the files, as would be expected if they were true 24/96 from the original tapes and not upsamplings from the CD.

3. While I didn't have the other three recordings on disc for comparison, they all sounded superb in two channel, and, using the Integra pre-pro to pull out the ambiance information and project t it to my surround system, they sounded almost as good as 5.1 DVD-Audio and SACD discs.

So there you have it. Audiophiles finally have a way of downloading high quality high bit rate files from one source for a reasonable price cut compared to purchasing the discs and having to pay shipping costs or gas to get to the store. With more and more households going with high speed web lines and storage costs coming down exponentially, hopefully the days of the mp3 download will be finite.

Plus, unlike SACD or DVD-Audio discs, the files can be copied for use on several of your computers or to finger drives or DVD-A disc for playback on car audio systems. Just remember to back them up so a hard drive failure doesn't wipe out your entire collection. For those who need a disc, DVD-A's can be produced on your computer from files using either Cirlinca DVD Audio Solo (about $65) or my favorite DiscWelder Bronze ($99) from Minnetonka Audio. But I won't guarantee they'll sound as good as the files played back through your computer's semi-pro sound card.