I recently stumbled across a source of DRM-free music that I hope represents the future of music distribution. Pristine Classical sells music, mostly classical, but some jazz and blues also, in a variety of forms, ranging from MP3 downloads to physical CDs. The prices are not very cheap, especially since they are in Euros, but no protection or DRM is attached, so you can back them up or trade them with your friends forever. (A reminder of the futility of DRM is in this Ars Technica article about how Microsoft will turn of their MSN Music license key servers at the end of the year. Your licensed (not purchased) music will still run on the computer it is licensed to until something changes - i.e. OS upgrade, hardware change, etc. I’ve never had a Windows computer be this stable for more than a year.)

Pristine Classical was started in 2005 by Andrew Rose as a offshoot of his Pristine Audio business of restoring and remastering of old records and tapes. He has apparently made deals with the copyright holders of some of these classic works so that all recordings are fully legitimate. The age of the recordings go from about 1955 back to the early electrical recordings of the late 1920s. As such, you won’t hear stereo spectaculars, but the recording quality of the late 1940s and early 1950s recordings can be quite good, if only mono. An added plus is that the details of each restoration are explained for each recording. A particularly difficult restoration is explained in the notes for this 1950 Decca recording.

An outfit that sold only MP3 downloads would frankly not interest me, since I consider the sound degradation too significant, even for vintage recordings. However, Pristine Audio recently has started offering FLAC lossless encoding on many of their recordings, in a 44.1K/16-bit format. Not only that, but they have just started offering 48K/24-bit FLAC versions that reflect the resolution of their original restoration. These are nearly twice the cost of the ordinary FLAC versions, but would offer the ultimate quality. My own experiments with resolution and sample rate show that higher bit resolution is a bigger improvement than higher sample rate.

I bought several of the classical FLAC recordings while I was on the road (I still don’t have high-speed internet at home), and when I got home played them on my main system. So-called restoration of old records can sometimes take the life out of the recordings, but Pristine’s restorations were tastefully done. No major clicks or pops and the surface noise is low, but the details are there. On the whole, I liked the restorations.

The Pristine Classical site is rather cluttered and busy, but that is partly because they offer many versions and services, including cue lists and color CD insert printouts for each recording. The following screen capture shows the general pricing structure:

With our poor dollar-to-euro exchange rate, the prices seem a bit high, but considering you are getting the full musical and sonic equivalent of a CD, with the cue lists and cover art, and no DRM, it isn’t so bad. I’m impressed with their offerings, and hope they do well.

One of the more eye-catching features in a lot of home-built “extreme” tube audio amplifiers are mercury-vapor rectifiers. Their hazy blue glow that is modulated by the current draw of the amplifier adds to the organic life that attracts people to vacuum tube amps. But concerns about safety have polarized the audio community, with some fearing that their homes may become EPA hazard sites! And, do mercury-vapor rectifiers have a sonic benefit in tube amplification? This article will try to answer this question. A follow-up article by my friend, Wally Chan, is a well-researched look at the safety of mercury-vapor tubes in the home. (note: This picture taken by and supplied by Lynn Olson.)

Physics & History

First, some history and definitions. Part of the breakthrough in technology that allowed radios to be run off of home AC power, rather than storage and dry batteries, was the development of inexpensive rectifiers. In the high-power industrial field, conversion of AC to DC was traditionally done with motor-generator sets, but these are expensive, noisy, and unreliable. High-vacuum rectifiers became available in the 1920s, but the early ones (e.g. 207, 81) had high voltage drops, making them inefficient. However, once the physics of gas discharges was understood, the low voltage drops in a gas discharge could be used to make a more efficient rectifier. Mercury vapor gives a voltage drop of about 11 volts, essentially independent of current flow. The first mercury rectifiers were large “pool” rectifiers that used a hot arc discharge from the surface of the mercury pool to generate the electrons and ions needed to conduct current through the rectifier. The smaller ones took the form of large glass bulbs with glass arms coming out of the sides for each anode. The larger ones, handling thousands of amps, were built into water-cooled metal tanks. On a large industrial scale, these were very efficient, and used right up until the time they were replaced by silicon rectifiers in the 1960s and 70s.

For smaller scale operations, hot-cathode mercury-vapor rectifiers were developed. These used oxide-coated cathodes and were processed like high-vacuum rectifiers, but a small amount of mercury was added before the glass bulb was sealed. Once the tube is warmed-up, the mercury vapor allows conduction as soon as the voltage from plate to cathode reaches the ionization potential. If a metal grid is placed between the cathode and plate, a thyratron is formed, where conduction can be inhibited by a negative voltage between the grid and cathode. Once conduction starts, in either a rectifier or thyratron, it doesn’t stop until the anode voltage falls below the ionization voltage. The thyratron is analogous to the silicon controlled rectifier (SCR).

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Wally Chan is a retired manager from Tandem Computers (now part of Hewlett-Packard) with a strong interest in science and engineering. I asked Wally what he knew about the hazards of mercury as used by audio enthusiasts and he came up this well-researched report. - J. Atwood

Mercury Vapor Rectifiers: Breakage in the Home

by Wally Chan

Mercury quantities and releases from household and industrial uses should be minimized because of the cumulative poison effects [1] [2] [3] [4] [5]. One uncommon specialized use is the mercury vapor rectifier, containing approximately 10ug of mercury vapor at 25 microns pressure (60 degrees C) and a total of .5 g of liquid elemental mercury [6]. If totally absorbed into the body, .5 g of elemental mercury has resulted in death, and approximately 1 to 4 gm is regarded as a lethal dose. But what risk occurs in practical circumstances from broken mercury vapor rectifiers?

In older homes, traces of mercury vapor are emitted from mold growth inhibiting paint additives [7], as well as from past thermometer and other spills. To control chronic exposure risk to continuously exposed householders, especially the young, an ATSDR recommended upper limit for mercury vapor in residences is 1.0 ug/m³ for elemental mercury [8]. This is a tighter limit than the OSHA occupational upper limit .1 mg/m³. The 10 ug of mercury vapor from a working rectifier, if suddenly released into a reasonable sized, multiple m³ volume room, will be well under these safety recommendation limits. However, there is still the question of evaporation of the remaining .5 g of liquid mercury into the room air. It turns out that vapor production is slow enough that chronic exposure over many years is the primary concern.

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… from viruses! (with apologies to M.L. King). I finally tracked down the source of the malware on the ClariSonus site. An earlier version of Wordpress (the open-source software this blog uses) had been cracked so that the database could be edited. This was fixed in the latest release of Wordpress (2.3.3), but I hadn’t updated it in a while. Someone inserted an “iframe” with a link to a bad site into the “Thai Trip, Part 3″ posting. I removed this foreign code, and things are back to normal. The site has been running Wordpress 2.3.3 since early February, so hopefully this won’t happen again. However, I’ve learned more about site maintenance and the importance of keeping up with new software releases.

I apologize to anyone who has been inconvenienced by this malware intrusion. (You do have anti-virus software, don’t you?)

- John Atwood

I’ve gotten several reports of this site setting off virus warnings. I was unable to find any viruses myself and McAfee SiteAdvisor reports the site as OK. However, I haven’t upgraded the underlying WordPress software in a while, so last night and this morning, I did a full back-up and completely reloaded the site from scratch with WordPress version 2.3.3. If you noticed that ClariSonus was down during that time, that is why. There have been some changes in WordPress which have caused a few things to look strange- I will soon fix them, if I can.

If anyone still gets a virus report or sees problems with the site, please e mail me at atwood (at) one-electron (dot) com (you put the address together - this helps avoid spam). I will try to track down the problem.

One other thing: As I mentioned in a previous posting, my main computer crashed right after Christmas. After putting in a new hard drive, it worked for about two weeks, then crashed again, this time with signs of flakiness in either the motherboard or power supply. This was an old Pentium 4 system, so I decided to upgrade. I purchased and recently received an Apple Mac Pro. I’ve switched a lot of my software over to the Mac, but I can still run Windows using the Parallels program. So far things are working well, but I am still sorting out and getting used to the new software. My “music computer” is still a Windows machine, and I don’t have any immediate plans to change it.

Update: (Feb. 10) - The specific complaint against the site was that Trend Micro’s PC-cillin flagged this particular file: www.wp-stats-php.infc as containing spyware. With the clean-up I did yesterday, this file no longer exists, so at some point Trend-Micro will take ClariSonus off it’s spyware list.

Update II (March 10): - I’m still getting reports of a “worm” malware virus on the ClariSonus site.  I am able to see it using Avast! anti-virus software.  If your anti-virus software is up-to-date, you should have no problem.  I have reloaded the site again, but the virus was present immediately upon opening the new site.  I may have to work with my ISP or in the worst case change ISPs.  I’m working on this.

- John Atwood

This is a contrarian view of loudspeaker dispersion. I’ll start by saying dispersion isn’t directly audible, unlike frequency response variations, energy storage in the time domain, or nonlinear (IM and harmonic) distortion. That isn’t to say dispersion characteristics aren’t audible - they are, but not in the way usually described in the literature.

Let’s start with a visual metaphor - imagine a multicolored mirror-ball, with red representing 20~100 Hz, yellow 100~300 Hz, green 300 Hz ~ 3 kHz, and blue 3~20 kHz. This mirror-ball is a visual representation of the loudspeaker, with most of its energy coming from the front. The front portion of the mirror-ball is close to white, and the rearward portion is deep red. Along the side, there are twinkly fine-grained yellow, green, and blue colors - these are diffraction artifacts, many of them visible only over a few degrees. Move just a little bit, and you’ll see a rainbow of colors shimmering off the cabinet edges, as well as interference fringes between the drivers.

When you sit in front of the mirror-ball, it is close to white (representing flat response) but there are twinkly multicolored artifacts coming from the edges of the loudspeaker enclosure (diffraction). As you walk around the loudspeaker there are a rainbow of twinkly multicolor diffractions artifacts, until you reach the dead center of the rear of the speaker and see a red glow from the center surrounded by the multicolor diffraction artifacts coming from the edges.

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Lynn Olson recently pointed me to an article in Rolling Stone magazine that digs deeply into the problem of MP-3-quality sound and poor dynamic range in recordings. This six-page article goes deeper than the articles I mentioned in two earlier posts (What Happened to Dynamic Range? and More on Dynamic Range). Also covered are the tweaks that are done in the recording or mastering studio, such as correcting the pitch of a singer’s voice. I won’t go into the excruciating details, but recommend this article, especially since it has a nice on-line bibliography and a selection of “Good” tracks (such as Bob Dylan’s Modern Times) and “Bad” tracks (such as the Red Hot Chili Peppers Californication) so you can actually hear the differences.

With speakers getting more accurate, and high-resolution audio getting better and cheaper, the fact that recordings are being trashed while mastered and then get squeezed through MP-3 lossy compression can only be seen as a dramatic disconnect. We can only hope that a new generation comes along that appreciates and demands good sound.

I was going through one of my alumni magazines this morning and came across a short article that really needs to be on the record in the audio community. It is the story of Winston Nelson, who worked as a research assistant for Harvey Fletcher (of Fletcher-Munson curve fame) while as a student at Columbia University. The story is here.

In 1933, Fletcher, while working at Bell Labs, set up the famous stereo experiment where a live concert performance in Philadelphia was carried by phone lines to Constitution hall in Washington, D.C. By using proper stereo techniques, the illusion of a live orchestra was maintained. Several years later, Fletcher repeated this, but used 4-track film to optically record Leopold Stowkowsi playing Stravinsky’s Firebird Suite. In 1950, Fletcher brought the film and equipment to Columbia and Nelson repair the equipment and get the demo going again. The only place available was in the basement of Philosophy Hall, next to Major Armstrong’s FM lab. Here is Nelson’s description of what happened:

“After a semester’s worth of work, one late afternoon in December 1950, I finally reconnected and fixed all the necessary parts and tried for a test run. I loaded a 35mm reel of the Philadelphia Orchestra’s recording of Stravinsky’s Firebird Suite into the film reader, crossed my fingers, and turned on the system.

The music that burst forth was unbelievable! The deep bass sound from three huge speakers literally made my necktie flutter. When the music ended, I could hear voices up on Amsterdam Avenue. When I looked up through the air well, I saw a crowd of people looking for the source of this amazing, beautiful sound. They must have been as befuddled as that first audience in 1933, no doubt convinced that a live symphony orchestra was playing in the bowels of Philosophy Hall. The revived system was able to perform just a few demonstrations before some irreplaceable parts gave out the following spring.”

The sound must have been stupendous! There is no record that the film of the Stowkowski performance was transcribed to magnetic tape, then just available. Still, this is the kind of experience sound lovers die for. The full story is here.

This post is late for several reasons, but the main one is that I had a gall-bladder attack and subsequent operation a little over a week ago. Anyone who has been through this (or appendicitis or an attack of kidney stones) knows that this is horribly painful. My post-op recovery didn’t go very smoothly, with my digestive system completely locking up. The hospital stay was highlighted by neglect and incompetence (and likely high costs - I haven’t gotten the bills yet). My post-op problems didn’t come to a head until two days after I was released, and, despite considering re-admitting myself on Christmas morning, my good friends Howard and Vallerie Stanley, where I stayed for a few days, contacted some nursing friends, and found that I really just had to walk to get the system going again. This worked, although it’s taken several days for my digestive system to become even semi-normal. Everything still tastes funny, and there is still some abdominal soreness.

This isn’t the forum for politics or problems in America, but my recent brush with the medical system really showed me how dysfunctional the medical system is here. The financial incentives are all wrong: the doctors and hospitals don’t care how much things cost - “insurance” covers it, while the insurance companies try to save costs by denying payment. I noticed a lot higher use of technical gew-gaws compared to the last time I was in for something serious in 1991. However, many mistakes were made. Doctors are virtually absent and even RNs (Registered Nurses) are spread very thinly. The only ones who seemed motivated were the medical equipment salesmen and the doctors who were trying to get you to come to their “for-profit” specialty clinics. No wonder costs are completely out of control. This is a fertile area for discussion and change - but I’m tired of it right now.

The second reason for lateness is that, shortly after I arrived home, the boot hard-drive in my main PC crashed. This is only the third drive crash I’ve had in over 12 years, but it is always traumatic. Fortunately, I keep my working files on other drives, and had backed up some system files, so the data loss was minimal. However, I had to diagnose and then replace the bad drive, and rebuild a new version of Windows XP (rolling in all the latest updates using nlite), do the tedious install, then, once up, spend literally two days downloading updates to Java and Norton antivirus, among other things. (Keep in mind, I am still on a 28.8k dial-up line). My convalescence has caused me to become careful and mindful, rather than pissed-off, plus it is the perfect excuse for not getting things done! As a result, the computer crash hasn’t felt as bad as it would if I was in a crunch.

While not being Christian, I don’t mind vicariously enjoying the holiday season. As John Michael Greer says:

“As human beings, we’re all far enough from the luminous center of things that we have to take meaning where we can find it; if someone can grasp the eternal renewal of spirit in darkness through the symbol of the midwinter birth of Jesus of Nazareth, I can’t find it in myself to object. From my perspective, though not from theirs, of course, we’re celebrating the same thing.

Nor, for that matter, do I turn Scroogelike at the thought of gifts, big dinners, and too much brandy in the egg nog. I can’t think of a human culture in the northern temperate zone that hasn’t found some reason to fling down life’s gauntlet in the face of winter with a grand party. Whether it’s the Saturnalia of the ancient Romans, when cold grim Saturn turns back just for a moment into the generous king of the Golden Age, or the Hamatsa winter dances of the Kwakiutl nation of Canada’s Pacific coast, when the cannibal giant Baxbakualanooksiwae, “Eater of Men at the River Mouth”, is revealed as the source of mighty spiritual gifts, this sort of celebration reflects a profound set of realities about our life in the world. Besides, I’m fond of brandy, and egg nog, and a good party now and then, too.”

In that spirit, here are a couple of fun music-related Christmas links:

The Twelve Composers of Christmas by Michael Monroe (suggested by John Nunes, requires Javascript)

White Christmas by Irving Berlin, sung by the Drifters (suggested by Lynn Olson, requires Adobe Flash player)

These are a little late for Christmas, but maybe save them for next year. Oh, and have a great new year!

I’ve come across the closest thing to a pure play for good audiophile sound: The Tape Project. Run by Paul Stubblebine, Dan Schmalle, and Michael Romanowski. Paul and Michael both run mastering studios and Dan is well-known as “Doc Bottlehead“. Their product are reel-to-reel tapes directly recorded off of running master tapes which are recorded from the original session or mix tapes. These aren’t the mass-produced quarter-track tapes of the 1960s, but a pair of half-track 15 ips tapes on 10″ reels recorded on custom-modified Ampex ATR-100s with Tim de Paravicini tube electronics. There are currently ten released “albums”, mostly jazz and classical. These don’t come cheap - each album lists for $329, but cost $200 each (shipping not included) if bought in a subscription of six per year. A rich man’s plaything? Perhaps, but the cost is not out of line if compared to $30 to $150 audiophile LP pressings. Also, unlike some pirated master tape copies that are floating around, these are fully licensed recordings.

Some years ago I had a chance to hear first-generation copies of jazz master tapes at an audiophile’s home, being played back on an Ampex 351, and the sound quality was staggeringly good. When compared against the CDs of the same album, the CDs were dismally bad. There was an aliveness and “presence” from the master tapes that seems to get lost on even the best LP or digital recording system. Analog tape certainly has its defects and limitations, but well-done professional-quality tapes seem to capture the realism of a live performance the best.

The obvious question comes up “how do I play these things on my home system?”. Some people still have their semi-pro TEAC, Sony, Akai, or Technics tape machines left over from the 1970s or 80s. They could probably use refurbishment by now. A lot of professional tape machines have been dumped on the market over the last 15 years by radio stations and college music departments as they “went digital”. I picked up a pair of Ampex AG-440s in decent condition about 8 years ago for $400. These still usually need work - anything from a re-alignment to new heads to electronic repairs. The Tape Project has a solution, though - they offer various services and equipment ranging from a $500 alignment and tape path update to a complete package of a refurbished Technics RS1500 with custom Doc Bottlehead tube-type playback electronics for $6,500, plus nearly everything in between.

With the faltering of the two high-resolution digital formats, SACD and DVD-Audio, there isn’t much else for us hes-res fans to fall back on other than audiophile LPs. These can be excellent, but are fragile, fussy, and a really high-quality playback system can cost upwards of $10,000! I’ve been aware that the fanatics in the pro-audio community have been keeping analog tape alive, but this is the first time I’ve seen pro-quality tapes offered to the public. I’ll have to finish the rebuild of my AG-440C and try these out!

This should really be called “notable person”, since this posting is about James Boyk, ex-lecturer and -pianist-in-residence at Caltech. Over the years he has written many articles and a book or two, listed in here and here. He combines clear, insightful writing with his skill as a musician, performer, teacher, and technologist. Lynn Olson first pointed out Boyk’s sites to me.

I strongly suggest you peruse James Boyk’s bibliography or curriculum vitae to see to incredible range of his interests, but here are a few articles that caught my interest:

• There’s Life Above 20 Kilohertz! - An analysis of of the spectra of musical instruments, showing that their harmonics go clearly above 100KHz, and argues that recordings should capture these harmonics.
• Audiences of the World, Arise! - “Bad acoustics don’t just get in the way of a good performance. They actually make bad performances.”
• Rules of the Game - a framework for evaluating sound reproduction.
• The Music of Sound - “We may never succeed in reproducing live music’s combination of power, delicacy and beauty, nor its ability to involve us emotionally; but in the attempt to do so, we will learn much, not only about audio but about our perceptions and ourselves.”
• In Love With Sound - “The Los Angeles Times Magazine asked for a personal essay about “sound, music, noise and our culture. The result was so personal that they felt they couldn’t publish it.”

James Boyk - what an interesting man!

On this last part of the Thai trip story, I’ll describe my visits with some Thai audiophiles, introduced to me by my friend Kamon. After exploring the shops in downtown Bangkok, we took a taxi to the edge of the city. Instead of high-rises and dense side streets, the there is a more relaxed feeling, with more stand-alone houses and greenery.

We first stopped at “Music Labs”, a small shop that sold vintage audio equipment. We were met by Mr. Pae, who I had met during an earlier trip to Thailand in 2001. Mr. Pae has been building tube amps and winding his own transformers for a long time, but is now retired from the business. Here are Mr. Pae and Mr. Ood, who runs Music Labs, in front of the shop:

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