Sennheiser HD 25 ALUMINUM On-Ear DJ Headphones


New Head-Fier
Pros: SIGNIFICANT bass boost (extension and volume) over the regular HD25, fast, excellent isolation (better than HD25), less harsh highs than HD25
Cons: Slightly less airy than the regular HD25, bloated mid bass and overemphasized kicks in some tracks
The HD25 ALUs have the exact same drivers as the HD25-1 II (differences in build are the earcups and the earpads), thus it retains most of the good points of the HD25 in terms of build, isolation and sound quality. As an avid HD25 fan, I will focus on the differences between these HD25 ALUs and the regular ones.
The Good 
Sound signature is quite similar to the HD25. The attack, PRaT, decay and details are spot on. These headphones are fast. If you like the standard HD25, then you're gonna love the ALUs. The thing that really stood out to me when comparing it to the standard HD25 is the bass difference. You don't need to test them side by side to notice the difference. That's how much it has 'improved'. The ALU comes with a different set of earpads - somewhat of a leatherette one which increased isolation. The HD25's isolation is already topnotch, but the ALUs are over the top.
The Bad
As much as I would like to praise the bass boost of the ALUs over the standard HD25s, the boost is sometimes too much for my liking - it is distracting, and on some tracks I find it to be bloated. Too much mid bass for me. The kicks are overemphasized in some tracks. And the ALUs, for some reason, sound less airy than the regular HD25.
Played around with the ALUs, HD25 and the Amperior for quite a while and I discovered that it's the earpads that play a huge factor for all these differences. I seriously can't believe it at first, but after trying out different combinations, it is indeed the earpads and not the earcups, as opposed to the consensus, that caused the massive difference in the sound, especially the bass. The earpads also caused the treble to be less harsh and increased isolation. Replace the earpads of the ALUs by the standard earpads then it will sound exactly like a regular HD25 with the tiniest of the differences.
If you're a basshead then ALU > Amperior > HD25.
If you want balance and the fastest/best PRaT then HD25 > ALU > Amperior. 
Take note that the PRaT of these three are almost the same, except that the HD25 just came out on top for a little bit. I am just nitpicking the tiniest of the differences here.
Overall, for me, HD25 > Amperior > ALU (the bloated mid bass is just too much for me) But don't get me wrong, the ALUs still has the HD25's great sound quality and signature and is definitely still a great buy .
The Third
The Third
I am quite sure the cups play a larger role than the earpads. Right now I got the adidas HD25-1-II pads on the Alu's, and the Alu's still sound a lot bassier and have a better timbre despite having a larger bass body, sub-bass extension/control and extended highs. It's true the bass can get overwhelming on some tracks but on others the Alu's are more detailed and controlled. You are right on the money with the HD25-1-II feeling a bit more spacious though, that mostly is due to the bass being less bodied and so everything feels more distant.

The Third

100+ Head-Fier
Pros: Excellent sound: Rich and slightly warm non-fatiguing sound, punchy bass, excellent extension & detail, speed, seperation and musical. ALUMINIUM!
Cons: Lower treble not as upfront, Dominant 100-300hz bass region not for all genres, not as spacious or airy as over-ear
I bought the HD25 Aluminium 3 months ago and so far this headphone has done nothing but impress me.
For the qualities it delivers I find it's still a highly overlooked headphone due to the predecessor still being sold.
I can easily say that these are far better than the HD25-1-II's and are probably the best portable on ear headphones in the market today.
This can has a dominant bass presence that definitely will attract bassheads but the mids and highs are perfectly balanced alongside that bass.
This headphone is of audiophile quality back to back.

It hits all the check-boxes of what a headphone should do good and is as good as a tool as it's entertaining.

These are a hyperdetailed set of cans.
The control and speed is amazing and came very unexpected to me, as I heard the HD25-1-II's before, and they did not give me those qualities. When tones
switch quickly, or when there are many sounds running through each other, this headphone is faster than my DT770 32 ohm which tends to sound slow in comparison.

The soundstage is good. Excellent depth but limited XY width and height due to their on ear nature, so don't expect the spaciousness that over-ear headphones bring.
I did notice a significant increase in soundstage when switching from my Ipod 5.5 to my LG V40. The LG V40 opened up this can to such a degree that most of the time I forget I am wearing an on-ear headphone. It got rid of the congestion that was happening with the Ipod 5.5 pairing.
There is a very nice and precise center image.
Though while the HD-25 are precise, they still don't excell at orchestra or classical because of the limited XY width and height.
They are thus extremely engaging with superior imaging, positioning and seperation.
And the best part of all, they sound like they got an "out of head" soundstage which I would wager is best in class for an on ear.
However looking for an expensive soundstage should definitely opt for the Soundmagic HP1000 instead, but that is a full sized over ear headphone.
These sound great out of portable DAC's, but scale well with better equipment.

The HUGE bass presence never bleeds into the mids or the highs, and after burn in the bass becomes more controlled. Sub-bass is very present, bass lines can easily be tracked due to the speedy nature of this can. From 25hz and up the Sub-bass is perfectly present. I own the HE-400 so am used to quality bass, these don't disappoint. It's the respectful kind of bass, with that huge present body and a nice hint of physical vibration. Next to the detail the Sub-bass is the biggest improvement over the HD25-1-II's.
The kicks are the star of the show though. These kick really hard, and are so perfect for DJ-ing and Hip Hop/Rap. On poorly mastered recordings or bad pairings(some Ipods/Iphones) they can get out of hand but that is not entirely the fault of the headphone. At higher volumes ofcourse the bass gets a bit muddy but it's never out of hand.
Again, the bass to me never distracts from the rest of the spectrum but it's definitely the main characteristic and most present part of the spectrum. It's ideal for outside playback or while being in busy crowds.
The 100-300hz range add a lot of weight and body to the sound, but can get a tad bit overblown(too present) with certain recordings.
On some recordings it really shows of the bass body. Bass-Head would love this can for sure.

The mids have an immense control, not missing a hint of detail. There are a lot of subtle nuances to be heard. Vocals are always positioned perfect within the track.
Nothing and no one get's left behind. The mids are very organic, smooth, textured and weighty though. The slightly recessed higher mids in the 4khz region create this warmness though not too much detail is lost.
My only compliant is that female vocals could use just a tad bit more energy to them. The mids have excellent dynamics and Timbre so I would not call these headphones a V-shaped headphone. It's a balanced headphone with emphasized bass. This headphone with good pairing (with the LG V40 for example)
is a really balanced headphone.

The highs are excellent, well controlled and never fatiguing. The highs don't roll off too quickly and so the extension is perfect to my ears. They have a nice bite to them and are very energetic.
They are also very articulate so they decay quick with a lot of transient response.
They have a slightly dark signature due to the toned down 4-6khz region.
This toned down recession is mostly positive to my ears as I dislike harsh sound.
But there is the classic HD25 spike around the 8-10khz area that adds load of excitement and a tad of brightness to the sound. Perfect for EDM and electronic music.
On higher volumes this spike can create some slight sibilance with emphasis on slight and might give the impression this can is bright. Though i noticed the sibilance is more source dependant than it being the fault of the headphone.
It's really not bright, to my ears this is headphone leans to the warm and laidback side of the spectrum with a treble spike on top.
I'd actually call this headphone really balanced next to the massively present 100-300hz region.
While neutral recordings sound slightly warm, very bright recordings still sound slightly bright.
The highs while not recessed might not be upfront enough for some. If you're a hardcore treble head then I would look elsewhere, like at the DT770 or preferably the HP150.
I thought these sounded warmer at first, due to my IPod 5.5 having slightly rolled off highs but they sound pretty neutral to me now that I pair them with the Toppings D30 and LG V40

The isolation is just dangerously good. You won't hear anything except for the sound being beamed in your ear canals. They isolate better than the DT770.
Ladies will be ignored and meteorites will fall down from the skies without a notice. While riding my bike or being in windy areas, I did not notice the wind affecting
the sound enough to be bothered by it. In a loud train while you can still hear the music clearly, the train rumble isn't entirely cast outside by the isolation. So on
flights noise cancelling headphones are still the better option, even though these will do more than just fine.

The comfort is good but not excellent; At the first the clamping was a bit too much, but give it a few days and it becomes perfect. It remains an on ear headphone however, so it won't massage your ears like full-sized over-ear velour headphones do. You'll have to experiment where the headphones sit best on your ears, but they seal really easily and the sound does not change much when changing position. The good news here is that you don't have to play around too much with the headphones positioning on the ears. They always seal easily.
Fatigue sets in after an hour and a half for me. Quick breaks easily remedy this fatigue. The present bass will tire your ears on higher volumes. Thankfully these produce excellent detail on low volumes and the superior isolation allows no disturbance to listening experience.

Build quality is nothing short of excellent. This is a tank. Aluminium cups and aluminium buttons on the pivot points. I believe the headband is reinforced with a metal wire running through it, but I can not confirm this. I absolutely love the look of the silver aluminium. The cable, while remove-able, is a bit on the long side for a portable, but are easily braided to fit your portable needs. The build quality feels sturdier than it's predecessor, which was a tank to begin with.

Man I can keep going on how good these headphones are. They have officially become my favorite portable headphones. They are a warm headphone with as much excitement added as possible before fatigue sets in.
I am walking around the city with these headphones tied to a rockboxed Ipod 5.5 Wolfson WM8758 / LG V40(Recommend the Note above all) and FIIO E11, playing my favorite albums in FLAC format.
I don't have the most experienced ears in comparison to other Head-fi'ers , but I am a young grasshopper, no pun intended, that can confirm these are an excellent step up from the HD25-1-II's and are a serious contender for the best headphones around 250$. I also own the Soundmagic HP150 and these are easily tied to those when it comes to detail retrieval. They have excellent dynamics and speed that the older HD25 models simply did not have. It is a shame people skip on these because the older HD25 is cheaper. They are worth the extra price you pay. These are easily one of the best portable headphones out there today.

Recommended for: Portable walk around, DJ, Electronic music production, exercising and vacation headphone.
Recommend Genres: Acoustic, Electronic music (EDM, techno, etc), Pop, Trip-Hop, RnB, Hip-Hop, Rap
I wouldn't recommend these for: Solely for Gaming or watching Movies.

This EQ setting turns these into an Energetic treble can, but makes it lose it's organic and detailed nature slightly.
I use this EQ while running or making Gains in the gym, good for energetic motivation.

*Ask away in the comment section!
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The Third
The Third
Stock the HD 25 Alu's are bass headphones with great detail in the mids and highs, overal presentation being warm but never muddy. You will have to EQ the bass down for the mids and highs to become more upfront and thick. Stock EQ does fine on a lot of tracks but on some tracks it can sound way too bassy, but then again, this can responds well to EQ and does not lose any of it's separation/detail when eq'ed.
Pedro Oliveira
Pedro Oliveira
To me even with eq the amperior were always too bassy\boomy and recessed on the mids and highs. My former hd25 was exactly the opposite. Flat without any eq ad maybe a tiny bit boring and lacking on bass quantity for my taste but with a slightly v shaped eq.... Oh boy.... Near perfection for my taste. The original momentum over ear (still havent tried the 2.0) and the hd25 remain my favourites so far.
The Third
The Third
The original momentum were lacking highs but are a nice relaxing pair of cans for my tasted. The original HD25 lacks resolution to me, where as this one does not. As far as I know, the Amperior used differently designed drivers with a resulting impedance of 18 ohms. I did not compare these to the Amperiors, but these cans have a huge controlled bass presence( though in my opinion never boomy). This is probably because when DJ-ing in a loud club, you need to still be able to track that bass. Eq'ed HD 25 Alu's can sound very close to the originals, even brighter if one desires to do so. I switch back and forth; When I want to relax I use the original EQ (warm and bassy), or when I go jogging I use the energetic EQ setting ( I posted the picture of this EQ in my review just now! :wink:  )


500+ Head-Fier
Pros: Extremely tight bass response, clear, sturdy, good seperation, excellent isolation
Cons: too long cable for portable use, staging somewhat limited due to the size
The HD25 series need no introduction, I think the Aluminiums are the best in the lineup, they sound very balanced with tight punchy bass that extends lower than the original HD25, it is a warm, clean sounding headphone. The Amperior in comparison packs even more punch, but always sounded a little hard to my ears when it comes to bright female vocals, this is much improved on the Alus while still retaining its sparkle. These are a real winner :)
Compared to some closed over-ear rivals they lack some soundstage height, width is decent though, it will still sound expansive on binaural recordings but it is not an over ear or open headphone obviously. Just something to keep in mind.