For those who always complain that music recorded in MP3 sounds terrible when play in regular sound systems. NY Times had the following article on devices that can help. To put it simply, it’s how to nicely convert between analog and digital signals. And the vacuum tube amplifier may be back because it can do a better job of filling in those lost bits.    - Ji Yan-Sheng
 

The iPod and the Vacuum Tube Sing a Warm Duet
By Anne Eisenberg
April 15, 2007

IPODS are fine for listening to music on the go, but sometimes people want to cast headsets aside and hear their playlists piped through the living room by a sound system.

Manufacturers offer dozens of devices that do this: the iPod pops into a docking station in an updated version of a boom box, and can be flicked on from the sofa by remote control. But the quality of the music will depend in part on the system that amplifies the signal from the iPod.

Now, to create the special rich sound that audiophiles love, manufacturers are selling docking stations for iPods and MP3 players with amplifiers based on an old but resilient technology: vacuum tubes.

Most people think of vacuum tubes as relics, long replaced by transistors. But a pocket of audio enthusiasts still values the tubes’ warm tones. Guitar heroes favor vacuum tube amplifiers in their instruments, many recording engineers tend to use vacuum-tube equipment in their studios, and some listeners pay thousands of dollars for high-end tube-based stereo systems and CD players.

Now Roth Audio, a company based in Reading, England, is appealing to the inner audiophile of iPod users with its Cocoon MC4, a compact docking station and amplifier topped by four vacuum tubes that glow when the power is on. Pop an iPod into the dock, and you have an odd couple: The iPod, apotheosis of the slim, portable and digital, and the flanking vacuum tubes that are fat, stationary and utterly analog.

Despite the retro look of the tubes, their audio characteristics may give iPod-stored music an additional, welcome dimension. That’s because most people store their music in compressed formats rather than in “lossless” formats, where data is not removed. Given these limitations, said Mark Schubin, an engineer and media technology consultant, “a vacuum tube can deal with the degradation in a potentially better and more pleasant way than a non-vacuum-tube amplifier.”

To enjoy a full range of sound, it’s still better to use lossless formats — vacuum tubes can’t restore data that’s been stripped away. But regardless of the storage format, “if you put an iPod into a docking station with good pre-amplification, it’s going to sound a lot better than putting it into a cheap one,” said David Chesky, a composer and co-owner of Chesky Records in Manhattan, which uses vacuum-tube-based recording equipment.

The Cocoon isn’t cheap: it will sell for $649, said James A. Roth, managing director of Roth Audio. But in the costly world of high-end vacuum-tube audio equipment, that’s a relatively modest price. After the tubes in the Cocoon do the pre-amplification, the audio signal goes to a solid state amplifier for additional power.

The Cocoon has audio inputs at the back for a CD player or a generic MP3 player. The docking station handles all types of iPods except the Shuffle. The units began shipping this month, Mr. Roth said.

He has already introduced another brand of vacuum-tube amplifier to the United States market: the Fatman iTube ($649), distributed by Bluebird Music in Toronto. The Fatman has a different look than the Cocoon.

“The Cocoon goes well on a desktop,” Mr. Roth said. “The Fatman is more for the living room.”

The Fatman comes in two parts: an amplifier and a separate docking station. The vacuum tubes are covered by a grill that can be removed for an elegant look, but popped back on if fingers need to be protected from the tubes’ considerable heat. The Fatman has a 27-key remote control that handles not only standard functions like play and pause, but also treble volume, bass volume and even backlighting.

The Fatman has two amber vacuum tubes, as well as a green tube. “I added that third, green tube for fun,” Mr. Roth said. “It shows you the music level. The higher you turn it up, the more it bounces up and down.”

BOTH the Cocoon and the Fatman come with a pair of white cotton gloves, to be worn to protect the high-gloss metal surfaces from fingerprints during handling. To assemble and try out both machines, I donned a set of the gloves, as did a friend who helped me.

The Cocoon hooks up easily to speakers, by using the red- and black-ringed connectors called banana plugs that come with it. We selected 110 volts as the setting for the transformer, rather than the 230 volts used abroad, and plugged the transformer into the AC wall jack.

Then we turned on the transformer and started the machine. Gradually, the tubes began to glow. Then we popped my iPod into the dock and tried out recordings in both compressed and lossless formats. A Brahms sextet poured out in an impressive stream, even in the compressed version.

Then we hooked up the Fatman. Unlike the Cocoon, it has a built-in transformer, and it was already set for 110 volts. After we connected the dock and the amp to the stereo speakers, plugged both components into the power outlet and flipped on the switch, the power light illuminated on the amp, but not on the docking station.

After 15 minutes of testing the connections and manual controls, we finally noticed the remote control and tried it, feeling foolish not to have done this sooner. The blue indicator light on the docking station immediately flashed on, and we were in business.

Jay Rein, president of Bluebird Music, said that ours was a common mistake. “If the blue power light does not automatically come up when you plug in the docking station, press the Power On button on the remote,” he advised in an e-mail message.

The Cocoon, the Fatman and other vacuum-tube amplifiers for iPods are relative newcomers to the United States consumer market. For instance, Lyric HiFi in Manhattan, a center for high-end audio equipment, does not handle any vacuum tube-based docking stations. But Leonard Bellezza, co-owner, said the accessories might soon be popular.

“Everybody has an iPod,” he said. “So anything you can attach to an iPod sells.”

 

Where’s the Other Half of Your Music File?
By Wilson Rothman
May 31, 2007

CHANCES are that even if you have taken the plunge and started building a digital music collection, you have never had to tangle with the word “bitrate.” That may be about to change.

The Apple iTunes store, the largest seller of music downloads, began selling tracks from EMI Music yesterday without any restrictions on copying, for a slightly higher price than usual, $1.29 instead of 99 cents. To sweeten the deal, those tracks have better sound, with a bitrate of 256 kilobits per second (kbps), up from the standard 128 kbps. Apple has gone so far as to say that this results “in audio quality indistinguishable from the original recording.”

So what exactly is a bitrate? Simply put, it is a measure of the amount of data used to represent each second of music. A higher number means that more sonic information can be used to recreate the sound. To careful listeners, or those with good audio equipment, more data can make a big difference.

Last fall, Dr. Naresh Patel, a physician in Fort Wayne, Ind., moved into a home he designed with his wife, Valerie. It has a home theater, complete with projector, surround-sound speakers and a high-end amplification system. The sonic centerpiece is two Bowers & Wilkins loudspeakers that cost Dr. Patel $12,000 “with a discount.”

It was all working beautifully until Dr. Patel connected his iPod to the system. Sitting down in the theater’s sweet spot to enjoy his music, he was instead appalled.

“I couldn’t believe what I heard,” he said. “You don’t need a trained ear to hear the complete lack of so many things: imaging, the width and the depth of the sound stage. It almost sounded monaural, like listening to music in mono. The clarity, silkiness, the musicality of the music, if you will, was not there.”

The problem was compression — the process of removing audio data to fit the music into a smaller file. Compressed audio making audiophiles crinkle their noses is not surprising, nor is it new. It has its roots in the debate of the 1980s, pitting the digital CD against the beloved analog vinyl record. The degradation of CD quality into something even more limited is simply proof to many fervent music listeners that Armageddon is indeed at hand.

But several factors are making the debate over sound quality and bitrates more relevant now. Digital storage is cheaper than ever, download speeds are increasingly fast and digital music files have taken the place of CDs in many home theaters and cars. Many people are specifically asking for higher-quality downloads, and Apple and other online retailers are eager to deliver them — for a higher price, of course. (The price of complete albums from iTunes in the higher-quality format will remain the same.)

Barney Wragg, who oversees EMI’s global digital music efforts, said there had been a shift in the music marketplace. “What was an entirely PC, MP3-player experience has changed; now people are wiring music via iPods into their stereos in their home and their car,” he said. “That’s what is driving the demand for increased fidelity. When I connect an iPod directly into the hi-fi in my car, I really notice the difference.”

Apart from bitrate, the sound quality of digital music is also affected by its format, which is determined by the software used to compress it, known as a codec. MP3 is one of the older techniques for compressing audio and is not widely used by online stores. Apple has chosen a newer format called Advanced Audio Coding (AAC), which plays on iPods and some other devices. Most other online stores use the similarly modern Windows Media Audio, or WMA, which does not play on iPods.

All three of these formats are “lossy,” meaning the encoding software surgically trims out audio information that is not easy to hear, because it is covered up by other sound or is situated at the highest and lowest ranges of human hearing. The Norah Jones track “Come Away With Me” is 33.4 megabytes when stored in an uncompressed format; the lossy compression methods bring that down to 6.1 megabytes at 256 kbps, or 3.1 megabytes at 128 kbps, regardless of the codec used. (When turning your CDs into song files on your PC, you can choose the bitrate you want in the settings of iTunes or Windows Media Player.)

Codecs do vary in quality. Mr. Wragg of EMI said that as a rule of thumb, an MP3 at 320 kbps is roughly the same as an AAC file at 256 kbps. “The difference between WMA and AAC is more difficult to say,” he added. “Each has a slightly different way of getting compression. But in double-blind tests they perform pretty similarly — bitrate for bitrate they sound similar, but some prefer one over the other.”

Until now, online retailers have dealt in 128 Kbps tracks — most retailers, that is. Two years ago, a group of audiophiles created MusicGiants, a digital download store that specializes in “lossless” files that are compressed in a way that does not discard any audio information, resulting in tracks that average 25 megabytes in size. MusicGiants now has more than 500,000 songs from most major labels.

Scott Bahneman, chief executive of MusicGiants, said that comparing lossless tracks and compressed tracks was like comparing photos taken with a high-end digital camera and those taken with a camera phone. “Every bit counts when you’re trying to get sound quality, resolution or anything else,” he said. The site’s core audience is the type of person who spends large sums of money on home theater equipment, and wants music stored as digital files rather than on CD.

Mr. Bahneman said his company planned to offer better-than-CD-quality music in files originally created for the DVD-Audio and Super Audio CD disc formats, which did not catch on with consumers. Each song will be 250 megabytes, about the same size as one episode of a sitcom on iTunes, but without the video. These “Super HD” files will have a bitrate of up to 11,000 kbps (that is, 11 megabits per second), and will be sold by the album rather than the track, at $20 each. Mr. Bahneman said that with the latest broadband services and huge hard drives, downloading and storing high-resolution audio files should not be a big hurdle.

MusicGiants’ giant files are unlikely to appeal to the masses. Most people agree that on run-of-the-mill headphones, car speakers and compact sound systems, it is not easy to tell a low bitrate from a high one, because what is lost in compression is also lost in the reproduction of sound through those kind of speakers.

To test the effect of different bitrates, I borrowed a sound system that was not an audiophile’s wildest dream, but was certainly higher quality than the gear owned by most music buyers: a Harman Kardon AVR 147 receiver ($449) and two JBL L880 speakers ($1,400 a pair), connected to an iPod via the Harman Kardon Bridge adapter ($70).

This unscientific study involved three people (including myself) who listen to music daily in a variety of formats, from FM radio to CD. I loaded an iPod with 11 versions of “Come Away With Me,” spanning various qualities of MP3 and AAC from 64 kbps to 320 kbps, as well as one in Apple’s lossless format. Sitting in the sweet spot, we each listened to the different versions, played in random sequence, trying to determine if each subsequent version was higher or lower in quality. It was a straightforward test, and the result was surprising.

The difference between 64 and 128 kbps was stark. All three of us picked up on it. As bitrates climbed above 128 kbps, however, our guesses became increasingly haphazard; none of us could determine the difference between 320 kbps and lossless. One unexpected result was that we all thought low-bitrate AAC files sounded better than low-bitrate MP3s.

Still, even if poorer-quality tracks do not sound so terrible to all listeners, the difference between 128 kbps and 256 kbps is real. Many people will spend extra money for better-quality merchandise, perhaps in anticipation of a future sound-system upgrade. You may not buy all of your downloaded tracks a second time at higher quality, but you may decide that from now on $1.29 is a fair price to pay for an improved track.

Dr. Patel said he had mixed feelings. He said he would always prefer CD quality to compressed audio, even at 320 kbps. Will the higher-quality downloads from iTunes matter? “I’ll take the best of what I can get,” he said, “but I’m not terribly excited because it’s not that much of an improvement.”