While the headphone has certainly become a ubiquitous part of everyday life, many people dismiss them as essentially low-fi devices to be used only if necessary. Sure, the bulk of the headphones available are made to satisfy the portable market. Loud is the main design criteria with fit and lightness coming in a close second. What many people do not know is that some of the best fidelity to be heard exists in headphones. And, while the price of some of these headphones may seem staggering ($200 to $700) they cost a mere fraction of what an equivalent pair of speakers would cost. How can they be so good?
The headphone designer has one clear advantage over the speaker designer: a reasonably controlled acoustic space. While each person has a slightly different ear cavity and external surround (both of which affect the sound, whether from speakers or headphones) the acoustic variables are miniscule when compared to the differences of room acoustics. There are other advantages as well. All headphones (with the exception of one, and that is simply a variation on the theme and not a wholesale departure from conventional design) have the advantage of dealing with only one driver per ear, no crossover. What this means is that with headphones you can actually hear a perfectly phase coherent wave launch, the coveted single point in space source. Headphones do not have multiple drivers to confuse the sound as it radiates toward your ear. Headphones do not have colorations from the varying signature of different drivers producing slightly different takes on sounds that cross over between them. And, finally, headphones do not have to deal with a crossover and its attendant loss of efficiency, phase distortions, and added stuff in the chain. With only a small area to fill with sound (your ear canal) headphones, even playing to very high levels, do not need massive amounts of amplification. Lower amplification power can mean better sound as there is no need to add more and more output stages to the amplifier. This in turn lowers the complexity of the amplifier which keeps it more pure sounding. Details are much clearer and bass is much cleaner and accurate. In order to fill a room with bass, a speaker must move lots of air; a headphone needs to move much, much less to produce the same amount.
Some downsides to headphones:
(1) The cord. While the promise of cordless headphones is always present, corded models, without a doubt, sound better. Some promising new designs using digital transmission are trying to change that, but the best of them are well over two to three times the price of a better performing corded model. There are ways to ameliorate the cord issue. Don’t use the coiled type extension. While they may stretch to twenty feet or so, they will be tugging at your head when you get over 6 feet away from the source. Instead, find a 25 foot extension made from uncoiled cable. With this type of cable it is a simple matter to route the end to the location that you would like to sit. No more line stretched out waiting to be walked through, no tugging at your ear, and, if it is a semi permanent set-up, the cable can be hidden so that all you have is a headphone receptacle at your preferred spot for listening. Even loosely coiling a straight cable after use is much easier than dealing with a pre-coiled cable that has been over-stretched and is forever knotting up with itself.
(2) External isolation and sound bleed from the headphones. I have found that the best sounding headphones tend to be of the open back design. This is the opposite of the kind of headphone that you see in recording studios. An open backed headphone does not have any acoustic block on the outside portion of the earpiece. On some models they are just as loud on either side of the earpiece and while that sound does not carry very far, very loudly, it can still be a nuisance to others around you. It also means that some external sound will get through to your ears and be mixed with the sound from the signal source. There is no solution to this. Do not turn up the volume in an attempt to mask those sounds as you can, and will, damage your ears. If you need to block external noise, get a pair of noise blocking ear cups. Headphone volume at a reasonable level can minimize it, but that is about all.
(4) The last problem with headphones is that, no matter what circuit design is developed to avoid that sound-in-the-head feeling, they just can not match the effect of having sound created in open space. Rather than dwell on what I would perceive as an inherent difference between headphones and speakers, I would prefer to simply deal with headphones on their level. The presentation of a soundstage is just different through headphones than it is from speakers.
If you ever get a chance to hear a really good pair of headphones, try to check it out. You might just find that they can really transport you to the music in startling ways.
© Cadence Magazine 1998