OK, after a solid month of research, it was between the HD 598, K7XX, DT990, and the HD 6XX. I decided to go with the HD 598 because they are easy to drive, and according to many, have a solid soundstage and are great for gaming/movies as well as film soundtracks.
I just got them in today from BLINQ. I must say that they are in exquisite condition, and this won't be my last purchase from BLINQ. Having said that, before I get into what I think about the HD 598, I'll give you a breakdown of what I actually own:
1) Koss PortaPro (my most used headphones simply because they work with everything, I don't notice them on my head, and I love their sound even though I can hear their limitations
2) HifiMan RE0: I really like these IEMs. They have quite a bit of headroom and can be tailored easily to what I like with a very slight 3dB bump to the bass
3) Rock-It R-50: Great BA IEMs. The fit is a bit finnicky, but the sound is warm, yet resolving
(NOTE: All songs I am listening to are either 320kbps MP3 or FLAC. I am driving the headphones with a Fiio E17K)
Ultimately, I was looking for a full sized headphone that would give me a bigger and overall better sound/presentation/soundstage than the PortaPros. I really thought the HD 598 would be it. But I am completely underwhelmed by these. The soundstage is larger than the PortaPros, but sound separation, indeed sound resolution at the upper mid frequencies is worse on most tracks. This has to be what people dub as the infamous Sennheiser veil. Its not that the sound isn't there, its just REAAALLLY laid back. And I'm coming from PortaPros which aren't known for being particularly resolving, bright or accurate. In some music, instrument placement is more engaging on the Sennheiser, in other songs its distracting because the upper mid frequencies are so far back there, it sounds like someone is singing from down a round hallway.
What the Senns definitely have over the PortaPros is much better bass accuracy and resolution. Here, there is a clear delineation of sound quality. The highs are resolving as well, though I can't perceive enough of a difference here that make them stand out whereas I feel my RE0's are likely ever so slightly more resolving than the Senns, with the PortaPros just behind the Senns but barely. Mids are solid, though when the sound starts to drift to the upper mids, they sound a bit muffled. A great example track I use is Peyroux's This is Heaven to Me:
Her voice should sound like velvet just caressing your ears. The Senns absolutely fail on this. Muffled, veiled, Chloroformed vocals. The PortaPros don't do much better here, but I am comparing a $200 pair of full sized headphones with some $40 1984 on ear technology. The PortaPros get a bit closer, but the RE0's nail this when I bump up the bass to warm their more upper-midrange prominent sound. The background instrument placement is definitely more interesting with the Senns, and this is a good track that demonstrates their soundstage capabilities. Its not as large as I had thought it would be, but it is noticeable compared to the headphones I own.
I am obsessed with big, ethereal orchestral tracks from games and movies. This type of music typically has a simple melody, and no words which mates perfectly for work where I often find myself needing to concentrate. Anything with words just messes with my concentration, as do complex Classical or Jazz music. I love the potential for this type of music to be huge in its space, as if the strings and brass instruments' sound waves traversed over huge mountain peaks, converge into the valley and into your ears. Three songs I use to test openness, expansiveness and imaging are:
1) From Past to Present (Jeremy Soule)
2) Welcome to Jurassic Park (John Williams)
3) Ginnung (Jeremy Soule. Timestamp: 9:54)
Here, the Senns do win in soundstage but they are a mixed bag overall in terms of instrument placement and that ever nagging upper-mid ultra-laid back nature. In the first song, the strings are missing the air on the Senns that can be heard barely on the PortaPros, better still on the RE0. Imaging is best on the Senns and that likely has to do with some of the lower mid strings and their overall soundstage presentation. Overall I like the Senns best here, but its not a resounding win for me.
On the second song, The Senns are noticeably better everywhere but the upper mid timbre in the cello strings. This is one of the only songs where I feel the Senns are the clear leader.
On the 3rd, the build up to the crescendo has good space on the senns, but once it finally hits, the upper mid veil takes away quite a bit of the impact. Instrument placement is best on the PortaPros here, with the RE0 winning the upper mid resolution of the trumpets. There is no decisive winner here, which to me is a problem since I'm comparing a $50 IEM, $40 on-ear to a $200 full-sized headphone.
So the verdict: I have already boxed up the Senns to be returned and have decided to up my budget a bit and spring for the AKG K7XX from Massdrop. I believe they will give me the overall resolution I'm looking for with the large soundstage of the 598 (possibly larger). At the end of the day, if I'm spending $150+ on a pair of headphones, they should be noticeably better at just about everything than my $40, 40-year old tech PortaPros. For me, the HD 598 was just not that.
I just got them in today from BLINQ. I must say that they are in exquisite condition, and this won't be my last purchase from BLINQ. Having said that, before I get into what I think about the HD 598, I'll give you a breakdown of what I actually own:
1) Koss PortaPro (my most used headphones simply because they work with everything, I don't notice them on my head, and I love their sound even though I can hear their limitations
2) HifiMan RE0: I really like these IEMs. They have quite a bit of headroom and can be tailored easily to what I like with a very slight 3dB bump to the bass
3) Rock-It R-50: Great BA IEMs. The fit is a bit finnicky, but the sound is warm, yet resolving
(NOTE: All songs I am listening to are either 320kbps MP3 or FLAC. I am driving the headphones with a Fiio E17K)
Ultimately, I was looking for a full sized headphone that would give me a bigger and overall better sound/presentation/soundstage than the PortaPros. I really thought the HD 598 would be it. But I am completely underwhelmed by these. The soundstage is larger than the PortaPros, but sound separation, indeed sound resolution at the upper mid frequencies is worse on most tracks. This has to be what people dub as the infamous Sennheiser veil. Its not that the sound isn't there, its just REAAALLLY laid back. And I'm coming from PortaPros which aren't known for being particularly resolving, bright or accurate. In some music, instrument placement is more engaging on the Sennheiser, in other songs its distracting because the upper mid frequencies are so far back there, it sounds like someone is singing from down a round hallway.
What the Senns definitely have over the PortaPros is much better bass accuracy and resolution. Here, there is a clear delineation of sound quality. The highs are resolving as well, though I can't perceive enough of a difference here that make them stand out whereas I feel my RE0's are likely ever so slightly more resolving than the Senns, with the PortaPros just behind the Senns but barely. Mids are solid, though when the sound starts to drift to the upper mids, they sound a bit muffled. A great example track I use is Peyroux's This is Heaven to Me:
Her voice should sound like velvet just caressing your ears. The Senns absolutely fail on this. Muffled, veiled, Chloroformed vocals. The PortaPros don't do much better here, but I am comparing a $200 pair of full sized headphones with some $40 1984 on ear technology. The PortaPros get a bit closer, but the RE0's nail this when I bump up the bass to warm their more upper-midrange prominent sound. The background instrument placement is definitely more interesting with the Senns, and this is a good track that demonstrates their soundstage capabilities. Its not as large as I had thought it would be, but it is noticeable compared to the headphones I own.
I am obsessed with big, ethereal orchestral tracks from games and movies. This type of music typically has a simple melody, and no words which mates perfectly for work where I often find myself needing to concentrate. Anything with words just messes with my concentration, as do complex Classical or Jazz music. I love the potential for this type of music to be huge in its space, as if the strings and brass instruments' sound waves traversed over huge mountain peaks, converge into the valley and into your ears. Three songs I use to test openness, expansiveness and imaging are:
1) From Past to Present (Jeremy Soule)
2) Welcome to Jurassic Park (John Williams)
3) Ginnung (Jeremy Soule. Timestamp: 9:54)
Here, the Senns do win in soundstage but they are a mixed bag overall in terms of instrument placement and that ever nagging upper-mid ultra-laid back nature. In the first song, the strings are missing the air on the Senns that can be heard barely on the PortaPros, better still on the RE0. Imaging is best on the Senns and that likely has to do with some of the lower mid strings and their overall soundstage presentation. Overall I like the Senns best here, but its not a resounding win for me.
On the second song, The Senns are noticeably better everywhere but the upper mid timbre in the cello strings. This is one of the only songs where I feel the Senns are the clear leader.
On the 3rd, the build up to the crescendo has good space on the senns, but once it finally hits, the upper mid veil takes away quite a bit of the impact. Instrument placement is best on the PortaPros here, with the RE0 winning the upper mid resolution of the trumpets. There is no decisive winner here, which to me is a problem since I'm comparing a $50 IEM, $40 on-ear to a $200 full-sized headphone.
So the verdict: I have already boxed up the Senns to be returned and have decided to up my budget a bit and spring for the AKG K7XX from Massdrop. I believe they will give me the overall resolution I'm looking for with the large soundstage of the 598 (possibly larger). At the end of the day, if I'm spending $150+ on a pair of headphones, they should be noticeably better at just about everything than my $40, 40-year old tech PortaPros. For me, the HD 598 was just not that.
I didn't like my HD380 at first and was about to return them, but then decided to give them some time and was pleasantly surprised.
Maybe you would be too.