The AudioFile: Ultimate Pocket-Size Hi-Fi Rig

As part of HiFi week here at the ol’ Crunch, I’m detailing my favorite mobile high-end audio rig. I’ve spent a lot of time finding the right balance among portability, sound quality, and budget — which means don’t go freaking out about how your home setup is so awesome and can be taken with you as long as you have a portable generator and a power conditioner, not to mention a gazillion dollars.

If you’re like me, you’re not particularly interested in carrying a man purse, so my first goal was to make this entire rig pocketable. That said, you can scale this setup up or down slightly if you feel like lugging a small camera bag, or you can even slip this stuff in with your laptop. (The Dark Knight and Boy Wonder just use their utility belts, of course.)

The source
Needless to say, if you’re interested in audiophile-level sound quality, you’ll want to rip your CDs to the uber-pristine Apple Lossless format, though 320Kbps MP3 files will provide plenty of sound quality at smaller file sizes. Check out the following table for a rough guide to file formats and sizes. (Note that the numbers are averages, based on 4-minute song length, and 30GB iPods generally have about 27GB of free space.)

The player
Chances are you already have an iPod, given Apple’s 70-plus percent market share. People who’ve complained about the iPod’s sound quality are invariably talking about the headphone output, not the output through the digital dock connector on the bottom, so I’m going to recommend it based on that. (You’ll see why below.) And I went with the 30GB fifth-gen model because it’s the thinnest high-capacity player on the market.

The amp
HeadRoom’s Total BitHead is the obvious choice for a pocket-size headphone amp. There’s a lot to like about this versatile gadget, especially its USB audio input capability (meaning you can use it as an outboard sound card for your computer). The crossfeed switch is handy for evening out the stereo image on many recordings — particularly those that have instruments panned all the way to the left or right, since the circuit effectively bleeds a bit of one channel into the other and vice-versa. It’s not great for all music, but you can turn it off if you’re not feeling it.

The connections
The iPod’s headphone output is reasonably robust, but nothing beats the good solid digital line-output from the dock connector. You can take advantage of this with a tiny adapter–the SendStation PocketDock Line Out USB. Just plug it into the iPod dock connector and use a line-in cable to connect it to the BitHead’s analog input.

Use the BitHead’s included short line-in cable, or if you want to store the BitHead in a backpack and leave the iPod in your pocket, use a high-quality line-in cable from Monster.

The power
Lithium AAA batteries will keep your BitHead running for a loooong time (alkalines give you anywhere from 30 to 50 hours). Rechargeables are okay too, but just make sure they’re high output–1000ma/h if you can find them, but definitely no less than 850ma/h. (It will say on the packageā€¦ the higher the number, the higher the output).

The headphones
All you need now is a set of headphones that will block out as much noise as possible while giving you virtually transparent sound worthy of pro or pleasure listening. Etymotic Research’s ER4P fills that bill to the penny — and they’re easy for portable players to drive even without an amp.

But since you’re carrying around the BitHead, you’ll get even better sound if you pick up Etymotic’s optional ER4P-24 adapter cable, which effectively converts the ER4P into the even more audiophilacious ER4S. By doing it this way (instead of buying the one-piece ER4S), you can use these sweet canalphones with or without the amp, depending on the level of pocket bulge you can stand.

Make sure you attach the included clip to the headphone cable and your clothing to minimize the thumpy microphonic effects of the cable flopping around.

Cost analysis
In the audiophile world, even the cost of cables can be steep. So how much will this portable hi-fi dream gonna set you back? Here’s the price breakdown for my particular configuration, based on the cheapest prices I found online at the time of this writing. If the total seems outrageous to you, you should probably avoid audiophile equipment as the sticker shock may be lethalā€¦

iPod 30GB $250
Total BitHead $150
SendStation adapter $25
Etymotic ER4P: $170
Ety S adapter cable: $65
4 AAA Lithium batteries $10
Monster line-in cable $10

TOTAL: $680