These ear buds have to be the worst in the industry. I have ordered 4 sets of the NC11, hoping that the others were just defective, but oh no, not the case at all. They simply do not do the job of filter out all outside noise. Not even close do they come. It is so disappointing because I have been a loyal Sony fan for many years, more years that I would like to remember. The NC11 is so bad ( how bad is it) :), that if I were Sony I would recall every set made and find another day job. HORRIBLE...HORRIBLE...
Sorry Sony, but that is the absolute truth of your noise canceling headphone. Wished there could have been a 0 star rating. And, it is a shame that there is no one to talk to at Sony that really give a big rats tail. They need to listen to the consumer. And then again, there are those who dont realize how bad this product is, simply because that havent tested other products. Ernest L. McCombs

I got these headphones in January, but they died just over the 90-day warranty. One thing before I get to the details is that Sony customer support is HORRIBLE. It really is like talking to a wall when you use the "live customer support". Don't even bother using the repair/exchange program for something out of warranty, for example, i got these headphines for about $80, and they wanted me to pay $76 plus shipping to give me a refurbished one or to repair it (the replacements have no warranty, so you might as well be asking for a broken one). Anyways, the problem i had with these was not the noise cancelling, which was wonderful, but the fit. I like the length of the right headphone, but the headphones themselves have a problem with tiwsting our of straightness so sometimes the point forward. The broken part of my headphones was the left earbud. It just died one day and would not work. The right headphone worked perfectly, noise cancelling and all.

I purchased these earphones because I wanted to hear less road and engine noise while riding my motorcycle. My stock MP3 player ear phones hurt my ears and did not stay put inside my full face helmet. I bought 2 different styles of earphones at Target, basing my decision on which earphone looked more comfortable inside my helmet.

After experimenting with the 3 different styles of earphones, I found the biggest problem was I consistently heard too much road, engine or wind noise. To overcome this problem, I decided to buy noise reducing earphones.

The Sony earphones were very, very comfortable, they fit well inside my helmet and would stay in place for hours. The noise cancelling feature was effective (see chart below).

The earphones also worked well when I did yard work (mowing, edging). I think the theory that you "save" your haring when you use them is probably true because you don't have to the volume turned up so loud because you don't have to overcome so much background noise.

The biggest disappointment is the earphone cords, they are way too long and get tangled easily. The other problem is remembering to turn off the sound reducing part of the ear phones. If you turn off the MP3, the earphones are still on. There is a red "idiot light" that glows when it is on, but it is very hard to see in the daylight. Below is a little chart to help you understand how I assessed various features (Scale is 1-10, 10 is the best)

Comfort 9
stability 9
(stays in ear)
convenience 7
effective 7
wind 7
engine 7
road 9
voices 8
yard equipment
mower 8
edger 7
battery useage 10
cords 4

I would reccommend these head phones.

As other reviewers have pointed out here (see E.K.Clark's detailed appraisal), these earphones hardly offer any more noise reduction than you would get with much cheaper soft 'earbuds'. Frankly the noise cancelling effect is so slight that it's difficult to tell whether the unit is switched on or off. I've tried them on planes and trains, and they fail to significantly reduce engine noise, voices or air conditioning noise.

This is the first time I've been disappointed by a Sony product, and I felt quite betrayed after believing the claims for noise reduction on the package. Claims of 'reducing noise by 70%', and 'peace and quiet wherever you go' are extremely misleading. Sony should be ashamed of themselves.

To make matters worse, the wires are stiff and far too long to make them comfortable to use even as ordinary earphones.

I can't understand the positive reviews posted here. I can only assume that the reviewers have never tried the 'ordinary' soft rubber earbud phones (Sony MDR-EX70LP), which do as good a job of sealing out noise, at a third of the price.

Sony, I want my money back.

I travel via air almost every week, and I've tried just about every headphone, earbud, you name it for my Mini iPod. I've returned them all. This is the first product that I have been satified with. I have my Mini set in Acoustic mode and it plays all genre of music cleanly across these earbuds. They pack very crisp bass for such small speakers. The noise canceling feature does buzz a little when no music is playing, but is not noticeable once it starts. I would not recommend them for just wearing as a noise filter. They are much better when both playing music and filtering noise is combined. I did try them while just listening to music on my computer, and was greatly disappointed. The sound quality just wasn't there. More likely the file playback on the computer than the quality of the earbud. Overall I believe that are an excellent value if you are an iPod junky like myself.