Thursday Nov 23

Mono matters for MP3

Here's an idea for headphone manufacturers. I'm offering it free of any obligation.  We need a music-quality single on-ear phone or in-ear bud that uses a stereo plug and blends the two channels into a mono signal for one-ear listening.

I know this because I see MP3 player-toting office workers putting one earpiece in place for listening and tucking the other one into the neckline of blouse or shirt.

They're solving a problem as best they can: listening with both ears blocks conversation and makes using stereo earphones extremely inconvenient in a work (or, for that matter, social or recreational) environment.

That ad-hoc one-ear solution has an obvious flaw. The listener must do without the music carried by one stereo channel. Mono earbuds and mono earphones exist, but they don't combine two stereo channels.  A few sport three-contact stereo plugs, but those may or may not have a connection between the ring (right channel in a stereo set) contact and the driver. One website, in fact, specifically states that for mono use the ring contact is left unconnected.

So I believe that there's a place in the market for a proper music-quality stereo-to-mono earphone or earbud.

In the meantime, you can accomplish pretty much the same thing by inserting a stereo-to-mono 1/8 inch headphone adapter between your stereo phones and the jack on your personal audio device. Radio Shack's item number 274-374 for $2.69 would do the job.

With such an adapter in place, you'll get a combined left- and right-channel signal from the left earpiece, and the right earpiece will be mute. It will, however, still be hanging around and will need the usual neckline tuck. Or, you could just snip it off.

CAVEAT: Since drafting this piece a year or so ago, I've found at least one MP3 player that craps out when the channels are combined at the jack.  It mutes or quits, probably an impedance mismatch issue of some sort.  No damage was done to the player or to the earbuds, but a manufacturer who decides to design a stereo-to-mono solution may need to do more than simply parallel the channels in the plug to guarantee full compatibility with all MP3 players.  (Portable CD players seem to be immune, but who uses those these days?)

tk