Cool Features

Noise cancellation headphones are the new craze, and personally I've only been impressed with a few designs. Some of the cheaper personal headphone designs I've seen offer marginal performance, but I've found that a good pair of form fitting in-ear headphones (like my Shure E3s) offer as much noise cancellation without any gimmicks. But results have been better with the larger over ear designs like this one.  

Rather than a simple switch to turn the function on, Sennheiser has gone to different lengths. On the side of the left earphone there is a small switch that is concealed under the stem of the headband. There is a Normal and Bypass setting. Bypass allows you to use the headphones just like standard ones with no noise reduction or talk-through features, regardless of whether they are turned on or not. The Normal setting engages the noise reduction function and talk-through functions.

Basically, noise cancellation is an active process, not simply good padding around the phones. A small microphone picks up the ambient noise where you are sitting, inverts it electrically, amplifies it a bit, and then introduces it to the earphones. So, the ambient noise is cancelled by the inverted version of the noise that the small amplifier is sending to your ears. The talk-through feature lets you hear someone speaking to you while you are wearing the phones. In this case, the sound from their voices is not inverted (because you want to hear them, not cancel them).

On the right headphone is an On/Off button, volume +/- buttons, and a Talk-Through button. You have to turn the headphones on before you can use the noise cancellation or talk-through functions, and a green LED will illuminate just above the controls. These features run on a single AAA battery that is included (along with a spare) in the package. The volume controls are only for the talk-through function and have no effect on sound coming in from your music player.   

The talk-through feature is nice, especially on airplanes where your listening enjoyment is disrupted almost constantly from announcements and flight attendants pawning off wretched snacks and sugar drinks. Simply press the button on the right earphone and the source feeding your headphones is muted, and the sounds outside of the headphones are amplified. You can now hear everything going on around you clearly without ever taking off your headphones. I know it's easy to take headphones on and off but personally I find it annoying, especially if I've had them on for a while. It seems the longer you have them on the more they've adapted to your head. Taking them off means you have to break them in again to get to the comfort you had before. The volume control simply allows you to change the volume of someone speaking to you (it does not affect music volume). The mic used to pick up the sounds around you is pretty sensitive so unless you want to hear the conversation a few seats away, I would recommend keeping the volume down a bit.

The biggest selling point of these rather expensive headphones is the noise cancelling function. I know this is a big selling point for frequent travelers like myself who find themselves in noisy airplanes quite a bit. The low rumble of the jet engines on a plane aren't the most soothing sound out there, and no matter how good the seal is on your headphones, they never seem to get rid of the rumble completely. Well, that problem is now solved.  

The noise-cancelling feature on the 450s eliminates the majority of the noise around you. I won't say all of it though. Instead of canceling the entire audio spectrum, it reduces the lower octaves (you know, the ones that include that soothing jet roar I was talking about). If you turn on the headphones simply to use the noise canceling function, you'll still hear the higher frequencies around you such as voices (though extremely faint) and wind noise. What you lose is the lower frequencies that put more pressure on your eardrum. In fact, as I write this, I am on a plane over the Caribbean and have the headphones on simply for the noise-canceling function, and the only thing I can hear right now is some faint wind noise from outside the plane and the lady in front of me talking to her travel companion. If I turn the feature off, I get the low bass rumble of the engines which drowns out just about everything else including the lady's voice in front of me. Pressing the talk-through function simply amplifies what I can already hear with the noise canceling function on. Wind noise is amplified slightly, and cabin noise is a bit more pronounced. If I try to carry on a conversation with my wife next to me, I can hear her very clearly, and the sound is nearly as natural as if I didn't have the headphones on at all.

The only real downside I've found with these headphones is the low bass response when I have the noise canceling function activated. If you use the 450s as standard headphones they have a very rich sound that is compelling and clean. Highs are delivered with detail and depth that create the illusion of space nicely. Mids are very clean and voices never sound boomy or thin. But bass response is probably the most impressive area. This is the advantage of a larger headphone that create a good seal around your ears. Bass response was consistently good regardless of the material I listened to; Rap, R&B, Rock, Jazz, Industrial, Country, you name it. Bass was clean, tight, and had nice extension.

But all of that goes away once you turn the noise reduction function on. There is still some slight extension, but it sounds more like what I would expect from an inexpensive pair of bud earphones. Highs are also slightly tinny when I activate the noise-canceling feature. So, ultimately you have to ask yourself if this is a compromise you can live with. Are you looking for a good noise-canceling feature that offers some compromise in the quality of the audio you're pumping into the headphones, or do you want zero impact on audio quality while enjoying the silence the feature offers? Personally I don't think it's possible.

The only way to eliminate a tone (or noise) is to create another tone that is its opposite in phase (but identical in frequency), thereby canceling it out. This headphone eliminates the lower frequencies that are surrounding you, so you also have to cancel that region in the source you're feeding into the headphones as well. And because digital signal processing (DSP) is taking place, sound quality invariably goes down just a bit. Thankfully, the quality doesn't take much of a hit here.

Comparisons and In Use

How do the 450s compare to the competition out there? Unfortunately I only have two examples to compare against: My Shure E3's, which don't have a noise- canceling feature and rely on their form fit to reduce the amount of noise around you, and the Bose Quiet Comfort noise-canceling headphone that you find on prominent display at just about every airport in the country.  

Compared to the Shure's, the 450s have a much richer, fuller sound. Bass response is far better with the 450s if you are not using the noise canceling feature, but slightly worse if it's on. The Shure's don't offer the same level of noise control though. They are very effective at eliminating higher frequency sound around you, such as wind noise and voices, but they aren't nearly as effective in the lower frequencies, so that low rumble of the airplane engines is still a bit of an annoyance.

Personally, I prefer the sound of the 450s. Even without the noise-canceling feature, they offer nearly the same amount of noise canceling due to the seal they create around your ear, but the sound quality is fuller and more dynamic. And if I were going to use one of the two for actual noise reduction in an airplane environment, the 450s are far more effective in the frequencies that actually annoy me.  

The Bose comparison is a far more even playing field and a better comparison. I see glowing reviews for the Bose all the time, and I will admit they offer great performance for the dollar. Their noise-canceling is about the same as the 450s and very similar in implementation. They don't offer a talk-through function though, which may or may not be a deal breaker for you. Voices are actually quite easy to hear with the Bose when you have the noise reduction on, but if you're listening to music, you don't have the advantage of muting the source from the headphones to hear things.  

The Bose headphones don't have quite the performance in audio quality that the 450s offer as standard headphones. Bass response isn't nearly as tight, and the soundstage isn't nearly as open and airy. You really don't get the sensation of having a headphone on with the 450s. The sound is imaged beautifully, and even panning effects are convincing. The Bose sounded closed-in by comparison and a bit weaker on the lower end. This isn't as much of an issue with a portable MP3 player as they tend to roll off the lower end on their own, but if you use these with a premium sound source or even an MP3 player that delivered good sound, the 450s would give you the more dynamic sound.

Conclusions

If you are in the market for a pair of higher-end noise-canceling headphones, this is definitely one to consider. They are nowhere near the cheapest set available, but their balance of performance and price make them a very attractive option for those who have the coin to spend.

- Kris Deering -

Associated Equipment:

Apple 30GB Ipod
Apple Ipod Shuffle