Pros: Good Quality Sound, Comfortable, Low Price
Cons: Feels a tad cheap, questionable styling
The bottom line: I believe these headphones are suitable for bass lovers with reasonable expectations that do not find themselves in busy environments often.
I find that earphones normally lack powerful bass desirable in many kinds of music. Unfortunately for me, (and those like me), they have a habit of coming with pretty much all Mp3 players in the present. I looked to these Sennheiser HD415s to solve my problem. I feel that I made an excellent decision.

Out of the box comes the pair of tin cans (well, plastic) and a handy cable winder. There is also a 1/4" converter included with the package.

Build:

First impressions are important, and these headphones only foul the fingers slightly. The smooth plastic feels a tad hard and cheap, but the adjustment clicks smoothly and substantially. The words “Sennheiser” are printed in large font on the headband. The foam cushion feels good to wear and looks upscale. Save for the plastic, the rest of the headphones feels well put together and the fit and finish is quite good. The only issue would be some creaking when the headphone is on, whether the pads are chaffing the headband or some of the plastic faces are pushed.

Sound:

The Sennheiser HD415 is an open, dynamic headphone. The sound quality is decent, considering the inexpensive price. The bass is pushed forward and can get a little thick at times, but certainly can also be quite warming and fun. The treble is slightly recessed but one can still hear most of the high notes. The sound quality is better than Sennheiser's own earphones which alone are quite good for earphones. I lack true, flagship class audio equipment to reference but these headphones sounds decent to me, again, if a little bass heavy and muddled at times. These headphones seem more suited to rock/pop music as opposed to classical music placing less emphasis on bass. When contrasted to a pair of AKG studio monitors, these much less expensive headphones compare well, though I find the AKG's provide more clear notes and accuracy, if a more recessed bass.

The frequency response is 18 to 19 000Hz, which strikes me as a little bit small going to the top end but I'm not an audio engineer. The impedance is good, at 32 ohms, meaning that one will not have to turn the volume up on their sound systems in order to hear music, like one might on the Sennheiser MX50 with an impedance of 64 ohms.

Comfort:

A good pair of headphones should be comfortable. The Sennheiser HD415's can certainly be considered a 'good pair'. The headband is padded with a very comfortable foam, it works so well you won't know that it's there. Speaking of comfortable, the ear pads are similarly very pleasant to wear. Some types of closed headphones with the 'cup' ear pads can be uncomfortable depending on the user's size. This pair of headphones is comfortable for all users, as they set on the ear, not enclose it. They do not 'clamp' down on your ears, they rest comfortably without slipping off, and without trying to redesign your ear. Like many headphones of the type, they tend to get a little warm after an hour or so, but this problem is easily corrected by resting them on your neck for a while. The one sided cable is less fussy than one that connects to both sides and the headband adjusts to fit all sizes of head.

Style:

For those of us who are style conscious, these headphones are not terribly chic nor especially unattractive. Styling is subjective, so before you buy, look at the pictures, but I've personally found the style to be relatively acceptable, with no 'loud' bits. Silver is a good neutral colour, but it stands out against most colours of hair. People will notice when you wear these headphones. The gunmetal gray grille on the headphone adds a 'hi-tech' look. I'm not a big fan of the “HD 415” written on each side, but it is not unbearable. Overall, not an ugly piece of hardware, but people won't be asking “Say, did that cost you hundreds of dollars?”

Ergonomics:

I can see why this pair of headphones comes with a cable winder. The cord is rather long, especially if you intend to use these with a portable audio device. The winder keeps things short and organized, but can get frustrating if the two wires become tangled or interlocked. A small 'catch' secures the length of the cord for both the wire coming out of the audio device and out of the headphones. Frustratingly, there are only two spots where there is a 'catch'. This can cause a bit of fuss depending on whether your Mp3 player is above or below the winder and how long you like to have both cords.

People who like to rest their headphones on their necks will be pleased to learn that these medium sized headphones should not graze one's chin when not in use. Although you can feel their presence, especially under multiple layers of clothing, you don't get a 'choking' sensation like some of the larger 'tin cans'. Decent size for people on the go.

Usage:

If you use these headphones in a crowded environment, you may want to be cautious. These are open headphones, and they let sound inside and out. Music can be drowned out by background noise in very bustling environments, such as a crowded hallway or cafeteria. This may cause you to have to turn up the volume to a high level. The good thing is that the background noise easily cancels out any noise leaking from the headphones. If you are in a tight environment, such as a car, one can hear music leaking from the headphones quite easily, even if travelling at a high speed where there is wind, road and tire noise. Even medium volumes can cause others to hear what 'tunes' you are listening to while in a small space. Perfect for listening alone in a quiet area, even with PC fans humming, but less desirable for the streets or a busy classroom setting.

Overall:

If you like your bass and have reasonable expectations, you will enjoy these headphones provided you listen in quiet environments. The build quality is durable enough for everyday use and it expands well to fit all sizes, The long cable will make it a little more fussy but will be appreciated when using them as TV headphones. You will be noticed on the street, though not always for the right reasons. Provided you require these specifications, I feel comfortable recommending these headphones.