The HD448 were my first headphones that I could call my own, and my first foray into high quality sound. I bought these in late 2010 for use with my iPod Classic. Like most people entering the headphone game, I was after "more bass, please" (keep in mind that I was coming from the PX100, which little did I know at the time, was actually somewhat bassy). I was also after headphones that were portable, seeing as I wanted to use them primarily with my iPod.
When they arrived, I opened them up, plonked them on my head, and gave them a whirl. To my immediate disappointment, I discovered that they were less bassy than the PX100! (and as we all know, bass quantity = sound quality) However, during my research into these headphones, I had been introduced to the idea of burn in. I told myself that the headphones would sound better with time, and so I kept listening.
Once again to my disappointment, the bass didn't magically grow, but with comparison with the PX100, I realised that the overall clarity, and forwardness of the mids was noticeably higher on the HD448s. So, really, the 448s taught me (in good time) that bass quantity isn't everything. The mids are indeed the standout of the HD448. They're rich, a little forward (but not too much, it's subtle compared to a Grado) and well defined. Vocals are placed right, instruments like guitars strike a pretty good balance between being "liquid" and "detailed". It's very satisfying. I didn't find the treble to be particularly noteable in any way, either positively or negatively. It's simply competent treble that won't wow you, but it certainly shouldn't offend you. It's definitely a bit on the darker side, which I really don't mind for easy listening, fatigue just isn't an issue for these cans.
The letdown in the sound is the bass. As my taste in sound matured I realised that the bass quantity was indeed, as my inexperienced self noted the first time I heard them, lacking. But the bass quality tells the exact same story! It was somewhat loose, not particularly well defined, lacked punch, and lacked speed. The only real compliment I can give to the bass is that it's not going to bleed into the other frequencies. Not only is the bass not good quality, but I think the vast majority of people (audio enthusiasts and audiophiles included) will be dissatisfied with the very low quantity. The bass really won't please anybody other than those who simply don't know what good bass sounds like. I honestly think the bass of the PX100 sounds superior. To give you an illustration at how pathetic the bass is, look at this graph:
I owned the 225i for 12 months, and those had a pretty unsatisfying level of bass (moreso in the sub regions than anything. As you can see, the HD448 has even less bass than the Grado, right across the board. As you can see the PX100ii in green, it's no wonder I noticed significantly less bass the first time I tried them. There's a near 20db difference in the sub regions. All I have to say is that the HD448s bass is an enormous let down and will really only please people who hate bass.
Sound-staging is what you would expect from a sealed headphone of this price, nothing poor, but not outstanding in any way. Mildly narrow, and "boxed-in" sounding.
Being sealed, these headphones seal half decently, however they have almost no clamp force, so you won't be completely isolated. Once you have them going at a moderate volume level, you'll be fine (unless you're listening in a construction site or airport runway). The plus side of this lack of clamping is the comfort factor. I've owned 4 full sized headphones and 2 supra aural, and the HD448 are the most comfortable of all. Admittedly, Comfort is probably 3rd or 4th on my priority list of what makes a good headphone (within reason, it can't be completely painful to wear), but regardless, these headphones were super comfy. Due to the lack of clamp, they put practically no pressure on the side of my head or ears, and since they didn't seal 100%, my ears could breathe enough that heat wasn't a problem. The headband padding was generous, and the headphone's light weight left me without experiencing any hot spots. Very comfy!
The HD448s are not only inconsistent in sound, but also design. Keep in mind, these were marketed as portable headphones. This is really only 50% accurate. They do some things right regarding this. Firstly, they're fashionable. From the black grille with the aluminium Sennheiser Badge, to the headphone jack, these headphones look very nice. They're really downright mature looking in comparison to the waves of gaudy trash out there. Secondly, they're efficient. You'll be able to get enough volume from any capable PMP, no worries. Thirdly, the cable isn't bulky, and it's just the right length for reaching from your ear to your pocket with some slack. However, for portability, these headphones don't really fit the bill. Why?
They're full sized headphones! This is debateable, but as far as I'm concerned, if they're big enough to be circumaural, they're too big to really be taking out with you. For portable use, I favour supra-aural due to their ability to easily and comfortable sit around your neck when not in use, and to more easily pack into bags etc. The HD448 also have no ability to fold, or become compact in any way, they're just annoying to carry around. It's disappointing, because the cable was clearly intended for portable use, yet they're non-foldable full sized headphones. What's the deal with Sennheiser not understanding that that's such a contradiction? They've done the same thing with the momentum, too. If your headphones can't fold, then they should be compact to begin with to ensure they're actually portable (eg. V-Moda M80).
The build quality is a bit mixed. The main cups of the headphone are quite solid and don't feel cheap in any way to me. The Aluminium badge gives it an extra bit of quality. The cable is what you would want for portable use and feels solidly attached to the left cup. That's all well and good, but moving northward, the headband feels quite hollow. It just does not retain the solidness of the cups, and it will creak if bent. It feels less solid and trustworthy than the PX100 headband, which was just solid aluminium with a plastic rim. Not to mention, it's less flexible. My other problem with the headphone is that the padding isn't removable, and I never saw any replacements available anywhere online or in store. The 50% cheaper PX100 has removable padding available for both the headband and earpads. The pleather of the HD448 is the part that is most likely to wear out, so why not make it replaceable? Stupid.
So, what is the HD448? It's a very comfortable, very fashionable full sized headphone for $100 (When it was available, it's now been replaced by the HD449). It sounds respectable, but nothing noteworthy (all things considered). The mids are great, the treble is competent but the bass is very underwhelming. However, it's biggest problems are in it's design. The build quality is lacking in some areas, user replaceable parts simply don't exist for it, and it's flat out false advertising to say that it's a portable headphone, if you ask me. It's certainly not a bad headphone, for someone new to the headphone game with a budget of $100 in the year 2010, I could have done infinitely worse. Not bad, but not great. Just OK.