Review: Sennheiser HD25-2 with the SAA E-Series cable
Sep 15, 2012 at 2:30 AM Thread Starter Post #1 of 3


Dec 14, 2009
This is a review of the Sennheiser HD25-2 along with the Stefan Audio Art E-Series cable. 
Well, my quest for the holy grail of audio started years ago when I first bought myself a pair of ALR-Jordan floor standers. At that time I was a novice and did not really understand audio but since the last 14 years my systems have changed and so have my tastes. I moved into headphone listening 5-6 years ago and have owned equipment ranging fro the HD800, T1, GS1000i to the more modest Sennheiser HD25. Today I will be covering this very headphone the Sennheiser HD25-2. 
I bought this headphone as I was looking for a sealed portable can that I could power from my phone. I tried out the AKG 450, the vmoda 80's, B&W P5's, P3's and of course the Sennheiser HD25-2. Needless to say it has outperformed all the previous headphones which is why I still own it.
The Sennheiser HD25-2 looks like it came out from World War 2. It is built like a tank and has an industrial look to it. It needs to be run in for a few hours before it opens out in sound. I review equipment on many different parameters and we will cover all of them today. Please note that I rarely write reviews because very rarely have I found a product worthy of a review. However the HD25-2 along with the SAA cable qualifies for one!
I used this headphone with a Ray Samuels Hornet and Mustang portable amp and an iPad with a fiio line dock for listening tests. Cables used were a 6 inch cards mini to mini and the stock HD25 cable and of course the SAA E-Series cable.
First the review with the original cable:
Resolution - this is the ability of the headphone to convert detail within detail. This is why people report hearing things they never heard on a cd when they listen to high end equipment for the first time. With the original cable the HD25-2 has mid level resolution. You will be able to hear different instruments on the recording but it does not have the ability to deliver the detail within detail. This means that you will not be able to hear the creaks or croak within a voice and hear the difference in tonality as a singer changes pitch. However none of the other closed portable headphones delivered here either.
Transparency - Imagine listening to a narrator talking form behind a curtain. Now imagine what it would sound like if that curtain was removed. This is what transparency means. Most headphones are like listening to a singer veiled behind a ton of curtains. As one tries higher end equipment, uses better isolation, uses better sources, uses better cables these curtains get removed one by one thus bringing you closer to the singer. Once again the HD25 is average here. I think the B&W P5 was the most transparent of the lot here though it too lacked resolution.
Frequency extremes - there is a concept known as mistakes of omission or commission. Speaker manufacturers have two choices, Either make the speaker omit a particular frequency range so that it performs well within its design limits or to push the speaker into a frequency range it isn't designed to do. The earlier one is very often experienced with bookshelf's where designers concentrate on the mid range and highs and roll of the lows. On the other hand there are tons of cheaper bookshelf's where the bass is boomy and that is because the designer has pushed the woofer to deliver lows though the design does not allow it. 
The Sennheiser HD25 is slightly rolled of at the top though certain notes can be strident. The bass doesnt extend super low but is adequately present. The HD25 probably has the most bass from the other portable sealed headphones. It is reasonably well controlled and times well. It doesnt bleed much into the mid range either. The WORST performer of the lot was the B&W P3. It had horrid one notish bass that totally destroyed the mids. The Vmoda was a little restrained in the bass but it was probably the most neutral of the lot.
Now coming to the frequency balance:
Highs - the HD25 has decent presence. It extends reasonably well enough but if a singer pushes her voice higher the hd25 can sound slightly one notish and even get strident a bit (very slightly). It doesn't have much air to the sound where the instruments float above.
Mids - it has the standard Sennheiser mid range. Its full, lush and present. Voices sound full. Never over done nor thin. It is not as good a the HD650 for those looking at these two headphones. The HD650 is miles ahead in this department though it does sound slightly slower compared to the HD25.
Lows - The HD25 can be slightly one notish but it does have decent impact. It is not a lean headphone by any means. The sound is full and present. Just that it doesnt extend very low as some of the better open ears that I have heard (HD800 Im looking at you). 
Soundstage - no soundstage at all. Instruments are thrown in and muddled together. Then again only the vmoda had some kind of soundstage to it.
If I had to rate the portable headphones in order of preference they would have been:
HD25-2 = V Moda (slightly leaner but more neutral) = AT ES9W (VERY VERY beautiful headphone, very comfortable, very musical but coloured and not as much fun to listen to as the HD25. HD25 has more resolution too) > B&W P5 (decent mid range but very coloured and can be shout) > AKG 451 (rubbish headphone) > B&W P3 (even more rubbish)
In comes the Stefan Audio Art E-Series cable. 
Let me tell you a but about SAA. I first became a customer of SAA when I bought their Endorphin cable for my HD600. At that time I had a Meier concerto with a Simaudio CD-player. With that cable there were times when the mid range turned so revealing that I could hear reverberations that I never knew existed. I slept at 2am everyday because I had to relisten to every cd in my collection. As time went on I wanted a portable headphone and so in came the HD25 and once again I turned to James at SAA. 
HD25-2 + SAA E-series.
This is not their top of the line cable. Yet it is good enough to transform the HD25 into a beast.
Wow - wow - wow - the first thing that you will notice is how balanced everything sounds. The soundstage comes to life. Instruments are held in place. Everything seems more controlled. The frequencies blend together and are close to seamless. Josh Groban's voice nearly jumped out of the headphone at me.
Resolution - Improved the resolution 2x. It is still not as good as the HD650 but now is very very close to it. For a portable headphone though this is good, very good I must say. It still lacks the ability to show the detail within the detail. This is the only place where the HD25 is finally found lacking compared to the high end open cans. However it leaves every other sealed portable in the dust! Larger sealed headphones like the AT W1000X will easily outperform it here but in the portable category this combination is a killer.
Transparency - this is where this combination excels. You will feel like you are listening to a live feed from the singer. The veil gets removed and you just get closer to the voices. I wish it was more transparent in the bass but once again this is a portable closed can.
Frequency extremes - highs highs highs! The stridency is gone. It extends cleanly. Not as high as the HD800 but the highs are open. They dont sound rollled off. You can hear cymbals, you can hear high pitched notes extend cleanly without any sibilance or stridency. Control and openness is what this delivers. The bass is better defined with more control though it doesnt really extend lower.
Highs - Open with more control. 
Mids - this is its strength. The mids are clean, controlled, lush, transparent, just like dew drops on a leaf. Remember that Im listening to music of an ipad not my dedicated setup. The ipad's dac has limitations im sure but wow what mids. You can hear the dynamics in voices, you can hear breaths and pauses that singers take before they begin a note and move to another. Duets are beautiful.
Lows - control control. It doesnt extend lower here but the lows are better defined and this brings control to the soundstage. 
Soundstage - it is present, small but present. Like I said duets are beautiful. Each singer gets a place on the stage and it integrates and times superbly.
Well this is it. The cable is pricey but it transforms the HD25 into a high end headphone. Music connects with you with this cable. For those who don't believe in cable upgrade try out SAA's cables and you will be surprised. 
Sep 15, 2012 at 12:52 PM Post #3 of 3
The stock cable is made from steel. That severely degrades the sound and hence changing the cable makes a huge difference. For a cheap upgrade just use the HD650 cables on this headphone and it will improve as well. And for those who find the HD25 uncomfy due to their tight grip wash the ear pads, soak them in water for ten min and let them dry. It reduces the stiffness of the foam.

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