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.
Conclusion
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 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.
Conclusion
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 .
