We recently got a pair of the classic Sennheiser HD 25's in their most recent iteration, the HD 25-1 II professional monitoring headphones. These are what you might call classics having been around since the late 80s and used by many a pro DJ/Producer over the years. So after two days of testing from standard listing to an actual DJ gig, here are our findings.
Design / Quality: These headphones are very, well, German. The first thing you will notice about them is the no frills and very functional design, much like the early Porsche 911s. The HD 25's are about performance, not fashion and that has made them a favorite among audio professionals for over a decade. Another thing you will notice immediately is how incredibly light they are which is great for traveling DJs/producers. One disadvantage is that the HD 25's do not fold flat or collapse, so they need a little extra room in your bag. The plastic construction might feel cheap to some, but it's quite strong, scratch resistant and take a couple drops without damaging the unit. Also, every part of the headphone is replaceable and pretty easy to replace (which makes it kind of like an old Volkswagon Beetle - still German). You are getting the basics out of the box: the headphones, replacement ear cushions, removable 1/4 adapter and carrying pouch. You can order upgrades like a longer cable or one with a mic/controller should you want them. These are true professional headphones built for one key purpose, monitoring.
Comfort Factor: Lightweight is always a good thing. When you are DJing or working on a track for long periods of time, little details like weight make a big difference. The headband on the HD 25s can be split to help you displace the pressure on the top of your head which does indeed help quite a bit. The one thing that will cause some fatigue is the clamping force of the headphone, but it's very manageable for the most part. If you are using them to DJ, the sound isolation is superb and you never really have to deal with much fatigue unless you wear them the entire gig. I don't mind the Vinyl pads that come on the model, but some people like the feel of the velour pads come along with them, which is an excellent option.
Sound Quality: The sound quality is what you would expect for a $250 headphone from Sennheiser. These are excellent all around portable headphones for the price and work great for DJ monitoring and production on the go. The bass is tight and precise which is helpful when you are standing in front of loud monitors but, what's more, important are the mids and highs. Those are where the details are hiding and if you don't hear those clearly you can blow a mix when you are mixing more complex tracks. I honestly wasn't expecting these to be as good as they were especially from an on-ear headphone. I've always DJ'd with over-ear headphones primarily for the sound isolation, but those types of headphones are heavy and clunky.
I also used the HD 25's with my laptop both with a DAC and without and they performed great. They sound incredible with my Cambridge Audio DAC but also performed quite well without it and on my iOS devices (iPhone/iPad). I listened to just about every genre of music I could, and they navigated them all quite well. The only style that you might want a little more punch from the bass would be hip hop.
Conclusion: The Sennheiser HD 25-1 II's are a great pair of headphones for the money and perform notably well for a portable on-ear model. They are rather comfortable and work well in many functions from DJ monitoring to mobile production work to just every day listening. Some of the things that could be helpful would be to include a slightly longer cable that also had a remote control/mic for DJs on the go that only want to use one headphone for everything.
Frequency Response:16-22,000 Hz
Impedance: 70 Ω
Cord:5ft (1.5m), single-sided; Angled Plug
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