The Sennheiser HD 418 has a funky design moulded into its plastic body, and this flashy artwork will attract people looking for a distinctive look. Its build quality is good for constant daily usage, though the hinges which hold both the earphones may need a little care, as they feel weak.
The Sennheiser HD 418 is a circum-aural full size headphone with a closed back design which blocks out much of the outside noise and leaks less sound than headphones with an open-back design. The single-sided cable (attached to the left earphone) is less prone to tangle, and clears away the clutter.
The headphones are lightweight at 380g, and the ear cups cover the ears well and feel comfortable. The headband can be adjusted to fit different head sizes and it is padded well, which made wearing these cans really comfortable. In terms of fitting and wearing the headphones, we had no complaints even after 8 hours of usage.
However, due to the cushioned earpad and closed back design, our ears used to get a bit warm at normal room temperature after long use, which can become an issue during summer.
The single cable measures 1.4m which is good enough to use with your MP3 player or iPod, but quite limited for PC use unless you have a front audio port. The non–detachable cable is an oxygen free copper type, which is supposedly good for enhancing low frequency, and the cable uses a gold plated 3.5mm straight connector.
The Sennheiser HD 418 is a standard dynamic headphone and employs two neodymium magnets on both the drivers. The rated frequency response is 20Hz–20kHz which is in line with most headphones in this price range and its impedance is rated at 24 Ohms. It has <0.1% THD (Total Harmonic Distortion) and SPL is rated at 108dB. The overall feature set is quite decent for headphones in this price range.
The Sennheiser HD 418 sounded loud enough with iPod, Apple iPhone, PCs and laptops, so they won't require a separate amp. However, with players like Cowon D2 or J3, including most multimedia phones, they sounded a bit underpowered and we usually had to plug in our portable FiiO E5 headphones amplifier, not necessarily for louder sound, but rather to hear more details.
In the first listening, the most noticeable fact was the headphones' overall warm sound signature. We burned them in for more than 100 hours to get brighter and more open sound, but it did not really help much. The Sennheiser HD 418 definitely offered warm and punchy bass which would impress casual listeners but we still felt it could have done better in terms of depth and details considering the bass-driven sound tag it carried.
Amidst the mids, lower mids were also more prevalent and were more pronounced than the rest of the frequencies. However, the overall mids including the higher mids sounded slightly muffled which made us crave for more resolution and details. Guitars and male vocals sounded good, but the unrefined upper mids and the highs with poor extension made the overall sound lack transparency.
Soundstage and stereo separation were on par, but the overall sound reproduction needs better refinement. The headphones also tend to get distorted at louder volumes when we connected it to the Cowon D2+ and iPod touch 64GB (both amped). Overall, the HD 418 failed to deliver well refined and analytical sound. However, if you're looking for a pair of full sized headphones that is comfortable to wear and offers a warm sound signature with average details, they would fit the bill.
The HD 418 from Sennheiser has comfortable design and are designed for iPod and portable media players. In terms of sound quality, the headphones offered warm sound but lacks refinement when it comes to details and resolution. They would be just fine for casual listeners but audiophiles would be disappointed by the muffled sound.