Pros: Flat, Natural SQ. Lightwieght, Multi-purpose, Super Comfy
Cons: Accurate, yet weak lows. Amping helped more than intuition suggested.
As a young audio enthusiast with most of my knowledge base centering around car audio, I found my appreciation for sound begin translate across into the home. Audio nuts run in the family, so between knowledge obtained from relatives and my own satisfaction of curiosity, I have come to learn much about the extremely complex niche of home loudspeakers. Being a college student makes living situations far from ideal to venture (as a consumer) into the large, lovely loudspeaker market. Naturally, the right avenue to achieve beautiful sound seemed to be headphone Ave. While not related to the product I am reviewing, I feel as though to really deliver accurate information to the reader - and essentially give you, the reader, what you're looking for - I should give you a background to better understand my role in the sound community. With this understanding, it will be easier for you to judge the accuracy of my writing and the validity pertaining to your needs or wants. I hope to deliver useful, indicative information to you - not to necessarily persuade a purchase.
With all the background aside, let's focus on these phones. These Sennheiser HD 448s are a closed circumaural headphone, with an impedance hanging around 32 Ohms , SPL ~114dB and a frequency response from 16 -24000Hz.
Comfort: Technicals aside, these are a super comfortable phone. The earcup is large enough to indeed be circumaural, although those with over-sized ears may find this a tight fit. These aren't the smallest cups I've seen on a circumaural headphone, but they're smaller than the pictures show initially. The photo below (even though a bit is cut off) shows the cups to be around 3.5 inches on the outside but only about 2.5 for the ear itself. My ears are of average size, and I have no problem fitting into them for a seal. Pads are mildly stiff to create a seal, but the pressure on the head is barely noticeable. The headband rests nicely with an additional pad included to reduce pressure. It is easy to forget these cans are on your head. This is barely worth mentioning, but hours of listening does lead to a pair of warm ears. With headphones that have any isolation at all, this is to be expected. The comfort and weight give a distinct advantage for traveling. The included bag is pretty standard (black, cloth, subtle Senn logo with drawstrings) but is nice for packing around a portable device in addition to the phones. All in all, these give a comfortable, semi-loose fit on head - isolating quite well despite the low clamping force. I will say if you prefer a secure, tighter fit as opposed to a more loose pillow like fit you may find these to not be as secure.
Durability: This is where the 448s are probably the weakest. To be honest though, anything that isn't fragile can be taken care of with just a little conscious effort. For a 100 dollar headphone, they're about what you would expect - adjustable plastic headband and exterior with above average padding, and a small cable (diameter) w/permanent one sided connectivity. I do like the jointing system included here for limited swiveling and rotation, but improper care might render these plastic joints a weak point. Bottom line: I think with some care these should be durable enough. I've had them for over a year now with no issues and have taken them on numerous trips.. planes, trains, automobiles.
Sound Quality: I'm quite picky when it comes to sound, so I may tend to err of the harsher side (although not always). I will do my best to offer a perspective here with my experienced ears outside of headphones. When I started my consumer research with the goal of obtaining my first set of solid headphones without destroying my wallet, I ran through some options hovering in the $150 range. While I found some nice options, I absolutely made the right choice by backing off price-wise to obtain these HD448 (ehm, ATH-M50 - greatly prefer the 448).
I'll start with the highs: I'd say for ~$100 you're getting more than what you paid for. Symbols are present, yet not harsh. Higher frequency female vocals sound controlled and accurate with no distortion. The presence of the highs is significant enough in that you won't need to seek them out, but do lack the excitement to raise the hair on the back of your neck. I would describe the highs as natural, and very relaxing. Some may accuse the highs to be a bit boring, and if they did I wouldn't be able to tell them they're wrong. I do thoroughly enjoy the emphasis on how organic the highs are in these cans however, almost like a sense of refreshment. While the highs lack the excitement you might find in a Grado, I promise these headphones won't generate the listener's fatigue you'll find in brighter setups. In fact, even against much nicer headphones, I could argue that these are one of the least fatiguing in sound signature. The overall dark presentation could be considered favorable for long plane rides. The highs are well controlled here, without hiding too much.
The Mids: I tend to enjoy this part of the spectrum more than the high or lows, and I feel a good mid-frequency is what separates the nice from the poor. Mids are absolutely underrated in the untrained ear. That being said, mids add an unrealized dimension to those who have been listening to less than ideal sonics. The mid-range frequencies produced in these are absolutely unmatched for headphones I've heard in this price range. The mids alone in the 448s make a Bose price tag look like even more of a joke than it already is. The vocals are wonderful, and way beyond what I expected for this tier of can. Guitar string recoil is refined and separation from the vocals is definitive. Piano mid-notes are true. The foundation of the sound can tangibly be associated in this range of the spectrum. The quality mids add a body to the music that compliments the neutral highs quite nicely, avoiding an airy, empty sound which strands the highs as sound lacking mid-range does. These cans avoid the mudding together of mid-notes, which is more common than it should be for a lot of audio equipment. The aforementioned makes these headphones ideal for vocal and acoustic based sound. Sennheiser outdid themselves with the mids here in this price range - I was impressed.
The Lows: Overall, I would have to say quite disappointing at first, and still lacking a bit. Running these 3.5mm and no amplification really causes the 448s to draw a blank here. They lack the enjoyable thump in fast paced rock and certainly don't have the balls for any hip-hop oriented music. These seem to have trouble with a specific mid-bass note, it almost comes out "fuzzy" at times. This could be my picky ear speaking, but after logging hours on another (more expensive) headphone I really notice it. However, this isn't to say they can't hit the lows. These Senns reproduce them quite accurately in fact, just in a muted fashion. Mid-bass percussion and bass guitar strumming sound articulate, just muted. This is where a better sound source or amp can drastically improve these cans. I ended up amping them (FiiO e7), and while I did notice a mild positive difference in the highs and mids, the assistance in the lows introduced a substantial improvement. I was able to get some thump out of them with some bass-boost assist on the amplifier (low setting on FiiO e7). Generally, I try and steer clear of bass boost, given that I am far from a basshead and it usually just skews the spectrum - but here it really was necessary. To be honest, I found these headphones a surprisingly difficult 32 ohms to drive. I know impedance isn't tell-all when talking about ease of drive, and the HD 448 are an example of that. They sound just fine unamped, but amping them helped quite a bit - even more so than amping a set of 32 ohm Beyerdynamic DT 770 in my opinion.... surprising, right? I guess the take home message here is this: don't expect much of anything from the lows (below mid-bass) unless you're listening for it, but know you can improve these later on with amplification if you're tight on money at the moment.
Additional Notes: Just like any headphone worth owning, it will require some burn in time. Out of the box these sound quite harsh with noticeable crackling. I recommend at least 30 hours of burn-in, and wouldn't be surprised if more was needed. Don't be fooled by their sound out of the box!
Also, these isolate quite well as a closed can - making these even more ideal for traveling. They have no problem reducing background chatter, but do not completely block outside noise (not active noise canceling). They leak very subtly despite sounding quite loud off the head.
As with most closed cans, imaging is inferior. The sound quality is great, but the soundstage is limited by the closed back design of the headphone. That being said, it isn't all that narrow... just not as favorable as some of the open models I've experienced.
I would also consider these cans aesthetically pleasing, if this is of significance of you.
In a Nutshell: these cans are a steal for the money. I had no hesitation giving these 5 stars in the value department. I am happy I went with these over some more expensive models I was initially eying. Highs are fine, mids are glorious and lows are disappointing (unamped). A ton of sound for 100 bucks, and operate fairly well right off a portable device. These still represent one of the best "values" I know of. I find myself recommending them to many people who are on a tight budget and appreciate a natural response that isn't necessarily bass dominant. If you don't plan on amping these right away, I suggest you do so in the future. Most headphones of higher quality than these will require amplification anyways - these flirt with the line of amplifier necessity.
If you have any questions about the Sennheiser HD448s, reply with a post and I would be glad to answer!