Play the tape machine, make the toast and tea When I’m mobile

Well, I can lay in bed with only highway ahead When I’m mobile

Keep me moving

…or so sang Pete Townshend 35 years ago on The Who’s 1971 classic, Who’s Next. Today, the ubiquity of cell phones, laptop computers and portable audio devices hasn’t so much changed the world as given us what we’ve wanted all along: the ability to move around freely while taking the comforts of home along with us. What of these comforts do audiophiles dream about more than any other? I’ve got two: 1.) To carry my entire record collection in my shirt pocket; and 2.) to listen to it anywhere with the same high fidelity I enjoy in my listening chair at home. #1 is covered…my iPod has more than a solid week’s worth of music, all ripped at the highest bit rate possible, and it’s only half-full. But what about the “high fidelity” part?

This month I took a look at one of HeadRoom’s entry level offerings, the newlyre designed Total BitHead.

Haven’t I Seen You Somewhere Before?

The HeadRoom Total BitHead started out in 1998 as the AirHead…a portable headphone amp designed to replace the crummy headphone jacks on portable CD players. In 2000 the Total AirHead was introduced as an upgrade option, which included fancy, audiophilegrade capacitors and better op-amps (the chip inside that performs the amplifier function). In 2003 the AirHeads were redesigned, introducing the current style enclosure with dual headphone jacks and higher voltage (4 AAA batteries instead of 2 AAs). In 2004 the BitHead and Total BitHead were introduced (identical to the AirHead but with a built-in USB digital/analog converter) and the four amps were collectively dubbed the “Mobile Line”.

Just this year, the Mobile Line was redesigned to take advantage of some of the newer, better-sounding audio chips on the market.
The standard models have been discontinued, so now only the souped-up “Total” versions are available. These include upgraded chips & capacitors, a gain switch (to allow the use of low and high-impedance headphones), and (drum roll, please) a reduced price: $149 for the Total AirHead and $199 for the Total BitHead (down from $199/$269 for the previous versions).

HeadRoom Total BitHead review

Cool ‘Heads Prevail

From a technology perspective, the BitHead is an incredibly cool piece of gear. It doesn’t spin discs or store files, but it accomplishes every other aspect of the music reproduction process, and the thing isn’t much bigger than a deck of cards. The headphone system I normally use at work takes three separate boxes to do the same thing: a USB to S/PDIF converter, an outboard DAC, and a headphone amp I built myself1. None of the pieces (except for the USB converter) is anywhere near as svelte as the BitHead.

That said, the BitHead is not particularly cool looking…I mean it doesn’t look bad, but form definitely follows function. Form follows function on the iPod, too, but the iPod has a hip, Bauhaus austerity to it…the BitHead looks more like it was made for the Army. It feels like it was made for the Army too…not that it’s heavy: you could drop it on your foot from a height and you wouldn’t worry, about your foot or the BitHead. It has a solidity to it that practically invites mistreatment…throw it in your backpack, shake it around, drop it…it’s all good (do not try that with your iPod).

Plays Nicely with Others

Using the BitHead (or the AirHead, for that matter) with an iPod or portable CD player is easy: just run a mini-mini cable (included) from the headphone jack of your player to the analog input of the BitHead and you’re good to go. There is another option on the iPod: by using Apple’s Universal Dock or similar 3rd party product (I used the Sendstation Pocket-Dock) a line-out signal is available that is theoretically cleaner because it bypasses the iPod’s internal amplifier circuitry.

Connecting the BitHead to a computer is painless as well. Plug it in to any available USB port and Windows lets you know (in the lower, right corner of the screen) that it has found a new device, is locating drivers, and that it is ready for use. You might need to restart whatever music application you’re using (iTunes, Windows Media Player, Rhapsody, etc.). The procedure varied on the two Macs I tried (oddly, both are running the same system, OSX 10.4.4): on my wife’s iBook I had to open System Preferences and select “USB Audio CODEC” to get the BitHead to work. On my desktop, I simply plugged it in and it worked right away…no messages, no drivers to install, no firmware to download, etc.

Sound Good So Far?

For the first phase of my listening evaluation, I used the BitHead with my iPod (a 5thgeneration, 60GB model). It was obvious from the very beginning that the BitHead was capable of producing much higher volume levels than the iPod (I used the unit’s high gain setting for all listening tests). Much higher than you’d ever want, really, but that suggested good things about the unit’s potential dynamic HeadRoom. I’ve had many long-term listening sessions with the BitHead-iPod combination in a variety of contexts (at work, while moving around the house, late-night headphone listening after my kids have gone to bed, focused critical listening, etc.) and consistently found the BitHead to be a clean, musically engaging, low-noise performer. However, whenever I then switched back to the iPod’s built-in headphone jack, I found the iPod to be a clean, musically engaging, low-noise performer as well. The additional volume capabilty of the BitHead was nice when I wanted a little boost now and then (use with caution, it’s possible to permanently damage your hearing2 if you’re not careful), but for my money I want better sound, not just louder sound, and after extensive listening it didn’t seem like there was any area where the BitHead made an obvious improvement over the solo iPod. I needed to take a closer listen.

I built a headphone amp A-B switchbox a few years ago for situations just like this: it allows instant comparisons between any two active headphone jacks. Using the aforementioned SendStation PocketDock, I was able to directly compare the naked iPod headphone jack with the BitHead-amplified line out.

The most critical factor in performing A-B listening tests like this is level-matching the output. If not, the louder component will always seem to sound better3. This was particularly important in this test, where I’d already established the BitHead’s ability to play loud…the whole point was to find out what else it could bring to the table.

Note that this kind of listening test depends on being able to switch quickly, not on listening quickly. There are several sonic characteristics I listen for: frequency response, overall noise level, soundstaging, imaging, timing (the boogie factor), and dynamic range. Time and care must be taken with each of these. Very subtle sonic changes (like those brought about by changing amps, digital sources, cables, etc.), can often only be heard for a few seconds after a switch, before they “fade” back into the music and disappear. However, if the difference is real and not imagined, the test can be successfully repeated again and again, and the once subtle differences become easier to hear. Here are some of the recordings I use for reference:

• Miles Davis – Someday My Prince Will Come

Soundstage width (drums and piano are panned hard right/left respectively), imaging (Miles’ horn is just to the right of center), and timbral accuracy (Miles’ horn should sound bright & piercing but not strident).

• McCoy Tyner – New York Reunion

Good full-range recording with very lifelike instrument tones

• Also Sprach Zarathustra – Fritz Reiner/ Chicago Symphony (RCA Living Stereo SACD)

Great for dynamic range, this should sound enormous. Should be able hear the 32.7Hz tone of the organ’s 16′ pipe (and the tape hiss) in the intro before the fanfare.

• Beethoven Trio in C Minor – AnneSophie Mutter, Bruno Giuranna, Mstislav Rostropovich

Imaging, tonal accuracy: should be able to hear three instruments distinctly, yet with the harmonies coming together as one musical voice.

• Speech – Hoopla

Good, natural-sounding (relatively speaking) hip-hop recording. Should make you want to stand up and shout “Hey!”

• Crystal Method – Vegas

Has some earlobe-flapping bass tones, but overall if this doesn’t get your head bopping, the system is too clinical.

• AC/DC – Back in Back

One of the few really well-recorded rock ’n’ roll records. Should make you bang your head!

• Emmylou Harris – Spyboy

Well-resolving systems will reveal a few P.A. anomalies with this live recording (sibilance in Emmylou’s vocals, plus I think she’s standing too close to the mic on “Green Pastures”, etc.) but none of this should detract from the heartwrenching emotion of the performance.

Of course these tracks are all ripped lossless to my iPod.

With the A-B switch in play, I determined that the sonic output of the BitHead and the iPod were all but identical except for one area: bass. The BitHead offers up a faint hint more bass than the iPod, but it’s slightly smeared as well. It’s a very subtle difference, to be sure, but real enough once I knew what to listen for.

I can’t exactly call this an improvement, as equal numbers of listeners might prefer the sound either way.

Although the BitHead is easy to hook-up to the iPod, if you’re using it portably it is an extra box and cable to carry around, plus a set of batteries that requires regular replacement (one set of copper-tops gave me around 40 hours of music). Overall, I didn’t find the BitHead’s contribution to the sound of the iPod to be worth the extra hassle, let alone its $199 asking price.

On the other hand, with a computer, the BitHead actually adds convenience. Batteries are not required (it will run off USB power), and it’s much easier to plug headphones into the BitHead, which can be placed practically anywhere on my desk (given a long enough USB cord) and the volume control is easy to reach. Contrast this with my computer, which sits on the floor with the headphone jack in back, and the volume is controlled on screen through a series of click & drag sliders.

The BitHead performed marginally better using the USB output of my wife’s iBook G4 (I didn’t bother testing it with either of our desktop computers…the fan noise on each is loud enough to drown out any subtle improvements the BitHead could make). The increased bass was still there, but also a tiny improvement in treble extension…just enough to add a slight touch of additional air around high-frequency instruments like cymbals and triangles. Again, this was very subtle, enough that I could only detect it using the switchbox. With normal, casual listening I found the sound of the BitHead and the iBook’s built-in headphone jack to be indistinguishable.

Buying Advice

I was disappointed with the BitHead’s performance in my listening tests. This was difficult for me because I really like the unit, and in fact still use it with my computer at work. Keep in mind that it doesn’t sound bad, it just doesn’t add much that isn’t already there…at least with the sources I tested it with. In some respects, the BitHead is a cube-dwellers dream: lightweight, easy to carry to and from the office, easy to hook up, and easy to use. Also, my wife and I have taken to watching movies together in bed on her iBook, using the BitHead’s dual headphone jacks. Nonetheless, this is Affordable$$Audio, and at $199 I simply can’t recommend the unit for its convenience features alone.

For what it’s worth, I don’t believe the BitHead’s failings are indicative of any incompetence or snake-oil tactics on the part of HeadRoom, as some of their higher-end products are truly state-of-the-art. For example, I listened to the HeadRoom Desktop Portable ($848 including optional built-in DAC) in a shootout a few years ago, and found that it surpassed multi-box systems twice its price. I believe the culprit here (or rather the credit here) goes to audio chip manufacturers like Texas Instruments, Analog Devices, Cirrus Logic, etc. Some of the hardest working folks in audio, they are constantly releasing new products that are cheaper, smaller, and better sounding than the previous years’ offerings. This tends to level the playing field: as the price of better sounding ICs goes down, they start turning up in a wider variety of products, bringing sonic benefits even to what would previously have been considered low-fi electronics. The BitHead has continued to improve over the years, but so has everything else, so these days we don’t necessarily need to turn to dedicated audio components to get decent sound. However, as HeadRoom keeps working on the BitHead, improving performance (and lowering the price!) every few years, perhaps the next version will be the product that makes my portable hi-fi dreams come true. For now, I guess my iPod doesn’t sound so bad after all…

Headphones used in listening tests:

Sennheiser HD-580
Grado SR-225

• 1 You want to build a headphone amp? Check out the C-Moy…probably the easiest & cheapest project around to get you going in DIY audio.
• 2 Pete Townshend has said recently that his legendary hearing loss was not the result of his playing hundreds of 130db concerts, but rather the extensive use of headphones during studio recording sessions. May the iPod Generation beware.
• 3 Watch out for this trick when shopping for audio gear: the salesman gives the volume knob an almost imperceptible flick right when switching to the more expensive speakers you’re auditioning. Caveat emptor!

Manufacturer Responds

Dear Clarke and Readers,

I enjoyed reading your review of the BitHead and find myself in general agreement with many of your impressions:

Yup. It’s a tank of a little amp product, and pretty indestructible in our experience, but it does look a little like an iPod spent the night with a Hummer or something. And, yup, chip makers deserve a lot of credit for building some great parts that are now available to makers. And, yup, Apple deserves a lot of credit for actually putting some of these parts to good use in their products. We’ve consistently found Apple products (iPods and Laptops in particular) to be very good sounding. So I’m not surprised to hear that you didn’t hear dramatic differences in your listening tests. I can assure you, however, that there are plenty of portable players out there that are not built with the care and attention to detail (sonic detail, in particular) that Apple puts into their products, which benefit greatly from a solid performing amp like the Bithead.

Our effort with the HeadRoom Mobile Line is best viewed as a campaign. We see these products as a first step in providing audio fidelity improvements over what is available in stock consumer gear. There is a delicate balance that we have been working on for ten years in our AirHead/BitHead products to push the price of an entry level product down and still be able to deliver the value of an improved listening experience. The good news for consumers is that there are folks like Apple out there who do a better than average job of delivering a quality experience with their stock product; the bad news for us is that it makes us work hard to show worthwhile improvements with those products. The good news for us is that many…maybe most…consumer electronics companies develop products more often with a financial spread sheet that guides them to cut as many corners as possible by reducing parts cost (using cheap-not good sounding parts), which invariably produces negative effects on sound quality. In these cases we regularly offer significant gains in performance (too bad those same performance gains could be had for less if they were built into the product). That’s why we’re here, and why we continue to try to improve peoples listening experience with the gear that they have. I can assure you, we will continue to improve the sound quality and lower the price of future products in the line—with the aid, as you say, of the real heroes of the struggle for sound quality: the chip-makers.

Still, you did mention the BitHead was a more powerful amp, and that’s important. Not because you can play your music louder (which isn’t a good idea) but because a “stiffer” power amp allows us to power ALL types of headphones, including those that are difficult or inefficient to drive. I think you may have found some stronger improvements with the BitHead if you were using some of these cans. Also, the low gain setting allows you to more appropriately drive super efficient cans. These headphones require very little voltage to drive, and typical digital volume controls create deteriorating quality audio as they are turned down by truncating the digital signal. With the BitHead in this low-gain mode, the player can be turned up to full volume (resolution) and the amp acts as a way to lower the audio voltage but still provide the proper damping of a good audio power amp, which deliver a better quality signal in this case.

Also, I would have loved to hear your comments on our cross-feed circuit. This circuit is designed to mimic some of the psychoacoustic listening cues heard in speaker listening. Many find this circuit highly beneficial in reducing listening fatigue and improving the stereo image on headphones. Since you may not have time to respond to my comments, I’ll add (what you already know) that the headphone hobbyist community is roughly split down the middle on their desire for this feature. Some can’t live without it, some think there’s nothing wrong with normal headphone listening. The good news is that the cross-feed can be turned off if you don’t like it.

All-in-all, I’m unaware of an audio product any where near its price-point that does as much to ensure your ability to get a very good performance listening experience under a variety of mobile listening scenarios, and remain proud of our past work to develop the product. But I’m prouder yet of the design team at HeadRoom that continues to be committed to developing and delivering high-quality listening to a broader and broader audience through future lowcost HeadRoom Mobile Line products.

Additional info

HeadRoom Total Bithead Amp on Amazon.com

from affordableaudio, By Clarke Robinson