October 14, 2003
iPod for Audiophiles
By Wes Phillips, Stereophile Magazine, writes:
How does it feel to be One of the beautiful people
Apple's 30GB iPod is an extremely sexy gadget. As a piece of industrial design, it is remarkable in its beauty and operability. As an extension of Apple's lifestyle-friendly suite of music-photography-video applications, it is a screaming success. It's fun to use, and if just seeing one is enough to induce lust, actually holding one is enough to tempt a righteous man to larceny. But is it a serious piece of kit worthy of serious consideration by an audiophile
Surprisingly enough, I believe the answer is yes. The open nature of the iPod's playback format—or, more properly speaking, its lack of a single playback standard—means that the player can offer the sound quality its owner demands of it. Presumably, that could even include options not currently supported, including space-hogging, hi-rez digital files. However, that will happen only if audiophiles take hard-drive-based players seriously enough to participate in the ongoing dialog concerning their use and possibilities.
Fortunately, that's already happening, as a quick Google of the subject will reveal. Users are actively seeking better sound, even as they trade stories about how much fun they're having with the product as it currently exists.
And why shouldn't they be happy With the iPod, you can have your cake and eat it, too. On the outside, all that the rest of the world will see is that you're one of the iPod-totin' beautiful people; no one will ever know that under those headphones you're listening to monstrously good-sounding, hi-rez digital copies of your favorite demo discs. Baby, you're a rich man!
It was John Atkinson, that legendary ornithologist, who first pointed it out: "Have you noticed how frequently you see women using the iPod"
I hadn't. I'd been so darn happy striding about the streets of New York listening to Tom Russell and Carla Bley that I hadn't been paying attention. Gimlet-eyed, I now began examining my fellow pedestrians for the telltale flash of the distinctive white-and-chrome player and the giveaway white headphone cable that announced the iPod's earbuds.
What an astoundingly acute observer of the human condition Stereophile's editor proved to be! Of course, there were guys walking around with 'em (many wearing "Think Different!" T-shirts), but the streets were filled with fashionably dressed young women brandishing iPods as though they were this season's trendiest little Manolo Blahnik sling-back.
Holy cow! I'm running with the fashionistas! Can I still be an audiophile, too
What did you see when you were there
Apple's third-generation iPods are smaller, sleeker, more capacious than earlier models. The G3 is available with a 10GB, 15GB, or 30GB hard drive. [A 40GB drive is now available.—Ed.] The 30GB version is slightly larger and heavier than the other two, at 4.1" H by 2.4" W by 0.73" D and 6.2oz (compared to 0.62" D and 5.6oz). Our review sample was the 30GB model, which includes several accessories that buyers of the 10GB version have to buy separately: a docking cradle, a wired remote, and a carrying case of elastic and leather. A FireWire connecting cable is standard (it sports an extremely thin "dock connector" on the end that attaches to the iPod, since the iPod itself is too thin to accommodate a standard IEEE1394 plug.) The iPod can connect to a PC through a special 32-pin-to-USB-2.0+FireWire cable. The bifurcated cable has a 32-pin plug on one end, then splits into two cables: one with a USB plug for connection to the computer, the other terminating in a FireWire connector, which plugs into the iPod's power adapter so you can charge the battery.
The iPod is a product of Apple's industrial design department, headed by Jonathan Ives, which means it is very clean and contemporary. The back of the iPod is shiny stainless steel, while the front is bright white plastic. ("White's this year's black," a fashionista of my acquaintance assures me.) The face is dominated by three features: a 1 5/8" by 1¼" (2" diagonal, in TVspeak) backlit LCD display sits above a row of four touch-sensitive control "buttons" (Previous Track, Menu, Play/Pause, Skip Forward), which, in turn, lies above a large touch-sensitive "wheel" that is actually a multifunction control: the outer ring controls volume and navigates through menu choices, while the inner "button" serves as an Enter key.
What's surprising is how flexible and intuitive this seemingly rudimentary control array is in operation. Press Play and the iPod powers on, playing where it left off. Tap Menu and you're given several programming choices. The navigation wheel lets you highlight your choice, and a tap on the enter key takes you to that menu. Use the wheel to choose the option you want, tap enter, and you're there: a new playlist or a new song. All of this can be accomplished one-handed, while running.
The iPod's thin top edge has a 1/8" stereo headphone jack with an adjacent oval slot for anchoring the wired remote (added because users of Gen 1 and 2 iPods complained that the remote disconnected from the chassis too readily), and a sliding panel that activates the hold function for the controls. I found the touch-sensitive control extremely sensitive, so disabling it with the hold function proved a lifesaver.
The thin bottom edge contains the jack for the 32-pin dock connector (interestingly, FireWire uses only six pins—this may represent some sort of future-proofing on Apple's part). In addition to carrying data at 400Mbps, this cable also recharges the iPod's internal lithium-ion battery. Assuming you turn off all "frivolous" functions such as backlighting and EQ, don't skip forward and back much, and use the iPod only in moderate temperatures (50-95 degrees F), the battery will last eight hours. Otherwise, reckon on about six hours.
That cable dock in the iPod's base will fit either the cable or the docking cradle. The iPod slips into the docking cradle, fitting over the cradle's male 32-pin connector, leaning back at a 30 degrees angle (so you can read its display when it's sitting on your desktop). The FireWire-to-iPod cable connects to the back of the docking cradle, but that's not the cradle's only connection. Next to the 32-pin jack is a line-out stereo miniplug jack, an important option for audiophiles since it bypasses the iPod's volume control. The FireWire-to-32-pin cable can be plugged either directly into an Apple computer (for data transfer and recharging) or to the iPod's power adapter (recharge only).
All iPods ship with a pair of earbud-type headphones with 18mm neodymium-powered drivers. These have surprisingly good sound—at least compared to the phones included with most portable players. A pair of low-impedance Etymotic ER-4Ps ($330) offered much better sound and isolation from environmental noise, but that's a subject for another review.
The person who said "Beauty is only skin deep" certainly never popped the cover off an iPod. The design is just as jewel-like inside as out—packed, but definitely a gem of space conservation.
One item that's invisible but indispensable is the iPod's operating system, which, I've been informed, is not of Apple design. PortalPlayer, a company that specializes in developing OSes for cellular phones, PDAs, and other streaming and wireless applications, designed the iPod's human interface. The iPod is so easy to use that it's obvious Apple chose the right company for the job.
Parts choices are said to have been made with an emphasis on sound quality, availability, and "time to market" considerations. Parts vetted include PortalPlayer's own MP3 decoder and controller chip, a Wolfson Microelectronics D/A converter, a Sharp flash-memory chip, Texas Instruments' IEEE1394a interface controller, and a Linear Technologies power-management and battery-charging system. The essential innard is the hard disk drive (HDD), which is amazingly tiny—a 1.8" Toshiba design built to fit Toshiba's PCMCIA cards.
The iPod's PCB is a marvel of parts density—so much so that I was almost completely at sea when confronted with it. The largest item, by far, is the Sony-Fukashima lithium-ion battery, molded to fit over the HDD. The back of the circuit board is dominated by the LCD display and the controls, which are attached directly to the board. The board's landscape is dominated by three large chips, presumably the buffer, CPU, and FireWire controller (the only item I'm sure of, since it's next to the 32-pin input). The rest of the board is jammed with surface-mount components.
What are you going to play
The iPod can be used as an external hard drive for Apple computers—in fact, that's how it shows up on a Mac desktop—but its OS and Apple's iTunes4 software are what distinguish it as an MP3 player. PC users can't use iTunes4, so the CD that comes with the iPod includes MusicMatch software as well as iTunes. iTunes4 is available as a free download from Apple's website. In addition to supporting the iPods, iTunes4 includes several features not available in older versions of Apple's music-management software.
Some of these—such as music streaming, Shared Music, and cover artwork display—are interesting enough, but not germane to a discussion of the iPod's sound quality. The two biggest changes from older versions are linked. One is access to Apple's iTunes music-download website, not currently available to the 90% of computer users who use PCs. The other is the ability to "rip" music in MPEG-4 auto audio coding (AAC) format as well as MP3. (See Sidebar, "Bottom Liners," for details on how this relates to the iTunes website.)
MPEG-4 AAC (ISO/IEC 14496-3, Subpart 4) builds on MPEG-2 AAC's compression technology for data rates greater than 32kbps; at lower data rates, it employs additional tools that augment MPEG-2 AAC, adding scalability and error-resilience characteristics. AAC incorporates temporal noise-shaping, backward-adaptive linear prediction, and enhanced joint-stereo coding techniques. Apple included AAC in its QuickTime 6 software for a variety of reasons, but lists audio quality as the most important of them, citing the many advances in perceptual audio coding and compression that have been achieved in the decade since MP3's development. Apple says, "AAC takes full advantage of these advances, resulting in higher quality output at lower data rates, allowing even modem users to hear a difference."
Ah, modem users...Surely one of AAC's big selling points is its ability to improve compression, packing higher audio quality into smaller files. And, given the tiny size of the iPod and its battery, increased power-management efficiency didn't hurt, either—less processing power is required for decoding AAC files. Additional AAC hot buttons include support for multichannel audio of up to 48 full-frequency channels, and higher-rez sampling rates (up to 96kHz!).
The iPod supports several other audio formats in addition to AAC and MP3, including Audible (designed to download spoken-word files from audible.com, variable bit-rate (VBR) MP3, Audio Interchange File Format (AIFF), and WAV. (All of this choice is available only to Mac users—those syncing their iPods to PCs have to make do with MP3.)
The high-resolution ripping option is AIFF (so closely associated with Apple that some wags insist it stands for Apple's Interchange File Format). The format creates files that contain the raw audio data, channel information (monophonic or stereophonic), bit depth, and sample rate, as well as application-specific data areas, which allow different applications to add information to the file header that aren't removed when the files are processed by other applications—a feature of greater interest to folks who create music on their computers than to those of us transferring pre-recorded music to our storage media. In other words, AIFF is a memory hog, but it's an audiophile's kind of memory hog, since it throws away no data in an attempt to compress the file size.
But iTunes4 does more than rip recordings to stored-file status; it also organizes your music collection and allows you to arrange it into playlists. And it transfers all or any portion of your ripped files to the iPod—a process that's astonishingly fast, thanks to the IEEE1394a connection.
Using iTunes4 is stone simple. It's just as easy to use and intuitively simple as all those raving Apple enthusiasts claim. At least, I think so. As someone who has only recently purchased his first Apple computer, I have grown used to the MusicMatch music-management software, and my memories of learning to use that software have grown so dim that it seems second nature to me now. iTunes4 has a few foibles that differ from the way MusicMatch does things, but I won't swear they're less intuitive, just different from what I've grown used to. Except for one thing: Music Match automatically accesses the CD Data Base (CDDB) for CD and track information when you insert a CD in the disk drive; in iTunes4, you have to pull down the Advanced menu on the toolbar and click "Get track information" (footnote 1). If that strikes you as a trivial inconvenience, we're on the same wavelength.
Footnote 1: Our thanks to reader Gordon Neault, who reminded us that to access the CDDB database automatically on a Mac, you launch iTunes, go to iTunes: Preferences: General, and click the box at "connect to the Internet when needed." The iPod "is a music player an audiophile can love," summed up Mr. Neault.—John Atkinson
Apple iPod portable music player: Page 3
What a thing to do!
The iPod is different from CD players, SACD players, DVD-Audio players, and pretty much any other consumer audio player in that it is a data-storage device. At the moment, it offers a variety of data-storage formats; but while I'm aware of no plans to do so, in the future it could accommodate others—even higher-rez options.
The formats the iPod accommodates at the moment offer a wide range of options that balance disc storage space against sound quality. And this, not the iPod's size, is the revolutionary part: the consumer gets to choose which set of tradeoffs suits his or her needs.
This rather basic insight completely escaped me at first. I ripped the same piece of music (Carla Bley's "Looking for America," from the CD of the same title, WATT/31) in a panoply of formats to get to the bottom of the audiophilic question of which sounded best. While performing the comparisons, it gradually sank in that the iPod allowed its user to set the sound bar as high or as low as the situation required. But that wasn't the true brainstorm. No, that would be my realization that there might, in fact, be no single answer to the question, even for sonically picky listeners such as myself. It all depended on how I intended to use the iPod.
Even though the new iPod maxes out at 30GB, it's probably best not to think of it as the permanent repository of your entire music collection. That's what iTunes4 and your computer are for. With FireWire's high-speed data transfer, it's a matter of a few minutes and a few keystrokes to pack the iPod with situation-specific playlists. Going out for a long jog Download a few hours of music ripped at 192kbps on MP3 or AAC. It'll serve. Listening attentively through your big rig Download a program ripped in AIFF—it'll match the original for sound quality.
Of course, this means you may have to rip many songs, albums, or programs twice, which can gobble up masses of hard-drive space—but you can buy 120GB FireWire HDDs for a couple of hundred bucks these days. Jim Thiel likes to observe that "watts is cheap." These days, so is gigabytes.
What do you want to be
The iPod offers such an embarrassment of choices regarding file storage and playback that I had to begin by discarding quite a few of them as irrelevant to a discussion of its fidelity. That's not to say that 96kbps MP3 and AAC, for example, aren't useful space-saving options; simply that they represent sonic compromises most readers of this magazine wouldn't tolerate even while jogging. For the purposes of the following comparisons, I ran the line-out from the docking cradle (thus bypassing the iPod's volume control) to a Musical Fidelity Tri-Vista 300 integrated amplifier, which drove a pair of Amphion Xenon floorstanding loudspeakers. I used Shunyata Research Lyra speaker cables and a Kimber Kable stereo mini-to-RCA interconnect.
Things are somewhat better at 128kbps in both MP3 and AAC, but neither cuts the mustard for critical listening at home. MP3 robbed Steve Swallow's pulsing bass lines of dynamics and punch on the Carla Bley album, while blunting the shimmer of the brass overtones. AAC fared slightly better, offering better bass response (although it was still pretty lightweight compared to the original CD) and slightly more extended HF (again, shelved down in comparison to the CD).
Surprisingly, upping the bit rate to 160kbps did not result in major improvements for either format. Bass impact remained MIA in MP3, and the upper frequencies sounded strident, with that unmistakable "too much compression" punchiness. AAC again sounded marginally better, although Bley's big band still seemed flattened and lacking in dynamic variation.
The audiophile in me began to pay attention at 192kbps. Both MP3 and AAC began to exhibit a small degree of soundstaging, albeit not with great amounts of front-to-back dimensionality or layering. MP3's highs began to lose their stridence, and AAC sounded fairly detailed and revealing.
The compressed formats began to show some real promise at 320kbps. Definition, detail, and soundstaging were all impressive, and high-frequency response was almost liquid in its lack of edge effects. At this rate, differences between the two formats jumped into sharper focus: MP3 made transients "splashy," while AAC just sounded anemic compared to the original. With both formats, dynamic variation was considerably reduced compared to the CD.
Best of all—and, to my ears, completely indistinguishable from the original CD—was AIFF. Dynamics were impressive, imaging was nuanced and detailed, and the frequency extremes sounded extended and natural. On my reference rig, I could listen with immense pleasure for hours on end to files ripped in AIFF. In fact, I did.
Ah, some of you are saying, but what about VBR Variable bit-rate formats seem to offer extremely satisfying sound and show a great deal of potential, but those options deserve greater exploration in a dedicated comparison.