Sennheiser HD650 & Massdrop HD6XX Impressions Thread

Apr 30, 2025 at 7:42 PM Post #46,951 of 46,976
Does anyone prefer these or even the JAR600 to the Atrium?
I think this is probably a very unpopular opinion, but for as much as I loved it, I did not find the Atrium to be a definitive upgrade to the 6XX (bass, imaging and sound stage were unambiguously all better, but I do prefer the mids of the 6XX). I still own my 6XX, but no longer own the Atrium or JAR600. The collector in me wanted to keep both (especially as I waited a year for the JAR600, and the Atrium was the first ZMF I bought new), but the minimalist in me hated to see them collect dust.

It wasn't so much that I prefer the 6XX to either outright (although in some respects, I do) but more that it remains a reference against which I tend to measure everything else (especially from a value perspective). And on a high output impedance tube amp, they are still quite special.
 
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Apr 30, 2025 at 9:02 PM Post #46,952 of 46,976
Even though its feels like we will forever own a Senn 600 series, the curiosity bug still niggles away.

q9t69k7rmoxe1.jpeg
 
Apr 30, 2025 at 9:26 PM Post #46,953 of 46,976
My problem with the Atrium is that it's $2500 and weighs a ton. I'm sure it sounds great, but at that price I start looking at just going nuts with an electrostat setup of some sort.

My problem with the JAR600 is that no one has taken one apart and actually taken a look at what was done. There's also no good measurements on a modern GRAS or B&K rig. I have no reason to believe it's any more effective than a couple EQ filters at this point.

Anyways, I got the Capra strap today. It's quite nice
 
Apr 30, 2025 at 9:37 PM Post #46,954 of 46,976
My problem with the Atrium is that it's $2500 and weighs a ton. I'm sure it sounds great, but at that price I start looking at just going nuts with an electrostat setup of some sort.

My problem with the JAR600 is that no one has taken one apart and actually taken a look at what was done. There's also no good measurements on a modern GRAS or B&K rig. I have no reason to believe it's any more effective than a couple EQ filters at this point.

Anyways, I got the Capra strap today. It's quite nice
.... I'm glad that your third paragraph does not begin: "my problem with" .... 🤷🏻‍♂️
 
May 8, 2025 at 3:50 PM Post #46,956 of 46,976
Just got the ZMF suede pads for the HD6XX series. Here my initial thoughts of using them on the HD650. I had stock pads that were basically new when I swapped to the ZMF.
  • Definitely more room in the cups vs stock pads
  • Clamp force feels higher
  • Suede is very comfortable, as expected
  • As the measurements show, they do indeed have a bit of a "HiFiman Dip" before the ear gain. I cleaned this up with a +1.5dB filter at 1800hz with a Q of 2.5. May still tweak it from there though.
  • The shoutiness that I would typically have to EQ out of the HD650 has mostly disappeared. The extra bits of energy around 3300 and 5100 hz are smoothed over.
  • The mid-bass bump feels less boomy/muddy.
  • I'm getting a sense of a bit less treble overall above maybe 5khz. DMS's measurements seemed to show this as well. Or maybe I'm just being extra critical and it's placebo. Who knows.
  • Bass overall feels more defined.
  • Soundstage is less three blob, even after the aforementioned EQ to remove the midrange dip. If I were to commit to a description of it, it's like the soundstage has moved slightly forward and I'm no longer experiencing the "sound helmet" feel from the stock pads. It's not like an HD800 or something, but it's a surprisingly noticeable difference.
 
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May 8, 2025 at 9:44 PM Post #46,957 of 46,976
.... 6XX has been having a great time with Nitsch DSHA-3FN ....
IMG_1055.jpeg
IMG_1056.jpeg
.... or so my ears tell me ☑️
 
May 9, 2025 at 6:32 AM Post #46,958 of 46,976
Actually, most measurements of the frequency response of the HD 650 don't show any treble roll off at all. The "veil" must have been just a result of comparisons with those really bright headphones that dominated the scene of reference headphones of the time. To stretch this even more one could think that it was a marketing weapon of competitors' supporters and dealers to save sales of their more aggressive and fatiguing models.
The veil IMO is the excess midbass which lowers the center of gravity of the sound to the lower mids. Low male voices are too deep IMO vs the 600 which has very accurate timbre.
 
May 9, 2025 at 7:15 AM Post #46,959 of 46,976
The veil IMO is the excess midbass which lowers the center of gravity of the sound to the lower mids. Low male voices are too deep IMO vs the 600 which has very accurate timbre.
Yep, that's part of it for sure. Lowering the midbass is a bit of EQ significantly improves the sense of detail for sure.
 
May 9, 2025 at 7:33 AM Post #46,960 of 46,976
Just got the ZMF suede pads for the HD6XX series. Here my initial thoughts of using them on the HD650. I had stock pads that were basically new when I swapped to the ZMF.
  • Definitely more room in the cups vs stock pads
  • Clamp force feels higher
  • Suede is very comfortable, as expected
  • As the measurements show, they do indeed have a bit of a "HiFiman Dip" before the ear gain. I cleaned this up with a +1.5dB filter at 1800hz with a Q of 2.5. May still tweak it from there though.
  • The shoutiness that I would typically have to EQ out of the HD650 has mostly disappeared. The extra bits of energy around 3300 and 5100 hz are smoothed over.
  • The mid-bass bump feels less boomy/muddy.
  • I'm getting a sense of a bit less treble overall above maybe 5khz. DMS's measurements seemed to show this as well. Or maybe I'm just being extra critical and it's placebo. Who knows.
  • Bass overall feels more defined.
  • Soundstage is less three blob, even after the aforementioned EQ to remove the midrange dip. If I were to commit to a description of it, it's like the soundstage has moved slightly forward and I'm no longer experiencing the "sound helmet" feel from the stock pads. It's not like an HD800 or something, but it's a surprisingly noticeable difference.
Thanks for the impressions, I've been considering these. I guess I'm wondering if you feel they are a keeper and if they are worth the price...
 
May 9, 2025 at 7:35 AM Post #46,961 of 46,976
I will continue and finish it off...

The HD650/HD600 doesn’t do anything flashy, but it does everything well enough and without obvious flaws. That’s what gives it lasting value. It's not chasing the flavor of the month — it just works.
Quite so. I put it: what they do, they do very well, what they don't do, they don't do. So, there is very little fatigue factor. To me the best of them is the 600.
High-end “TOTL” headphones often exist more for prestige and marketing (halo effect) than for actual sonic improvement. They use exotic materials and flashy designs, but tuning can suffer as a result. Sometimes it’s intentional (to wow at first listen with exaggerated bass or treble), and sometimes it's the result of chasing a “house sound” that doesn’t age well.
It's been like this for over 50 years in the 'high end'. But there are gems to be found.
While there are headphones with greater technical refinement and resolution, few can match the unique charm, natural tonality, price and timeless musicality these offer. For this reason, everyone should own a pair — whether for daily listening or simply to stash away as a reminder of greatness through simplicity.

And this is why summit-fi cult is close to a joke class and must be mock and ridicule...
I have held for some years that on a tight budget a used HD-600 and a modest/used OTL amp is the cheapest way to get close to the recording.

However, price no object I have heard about 25 headphones (>2k average) that get closer then the 6** series, and at least 75 that don't.
 
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May 10, 2025 at 12:25 AM Post #46,963 of 46,976
.... on a whim .... a fun, amazingly great pairing !! Senn HD-6XX driven by Grado RA-1 (twin 9V battery powered) headphone amp !!
IMG_1065.jpeg
🎼 🤪 🎶 This tango can go on a while !!
 
May 10, 2025 at 2:37 PM Post #46,965 of 46,976
Just got the ZMF suede pads for the HD6XX series. Here my initial thoughts of using them on the HD650. I had stock pads that were basically new when I swapped to the ZMF.
  • Definitely more room in the cups vs stock pads
  • Clamp force feels higher
  • Suede is very comfortable, as expected
  • As the measurements show, they do indeed have a bit of a "HiFiman Dip" before the ear gain. I cleaned this up with a +1.5dB filter at 1800hz with a Q of 2.5. May still tweak it from there though.
  • The shoutiness that I would typically have to EQ out of the HD650 has mostly disappeared. The extra bits of energy around 3300 and 5100 hz are smoothed over.
  • The mid-bass bump feels less boomy/muddy.
  • I'm getting a sense of a bit less treble overall above maybe 5khz. DMS's measurements seemed to show this as well. Or maybe I'm just being extra critical and it's placebo. Who knows.
  • Bass overall feels more defined.
  • Soundstage is less three blob, even after the aforementioned EQ to remove the midrange dip. If I were to commit to a description of it, it's like the soundstage has moved slightly forward and I'm no longer experiencing the "sound helmet" feel from the stock pads. It's not like an HD800 or something, but it's a surprisingly noticeable difference.
To expand on this just a bit, I think the difference between stock and ZMF is like the difference between listening to speakers before vs. after a bit of room treatments. Fundamental tonality may not shift much, but things like extra resonances/reflections are smoothed over, changing some aspects of the presentation. What could be happening is that the new pads are simply smoothing over the peaks, which makes the perceived overall treble seem lower. When I do tone sweeps, they do seem to be less sharp than the stock pads, though that's completely subjective.

I've been working on my EQ settings for these, and I have some confidence in what I've got below. Obviously, these will need to be tweaked based on your ears/tastes, but I generally hear the headphones how DMS and Zach measured them, so I think the overall treble presentation is darker with the new pads vs. stock.

Preamp: -1.9 dB
Filter 1: ON PK Fc 140 Hz Gain -1.0 dB Q 0.800
Filter 2: ON PK Fc 500 Hz Gain -1.0 dB Q 1.000
Filter 3: ON PK Fc 1800 Hz Gain 2.0 dB Q 2.500
Filter 4: ON HSC Fc 5000 Hz Gain 1.5 dB Q 0.710
I'll try to explain where I'm coming from with each filter
  • Filter 1: This reduces the mid-bass hump on the HD650, bringing out detail and increasing overall clarity. I go a bit back-and-forth on the value. On stock pads, I have it set to like -1.8, but the ZMF pads seem to help a bit here so I make a smaller adjustment.
  • Filter 2: Voices can sound a bit boxy/honky with the new pads, so a wideband cut in the 500-700hz area helps here.
  • Filter 3: The ZMF pads introduce an obvious "HiFiman Dip" that helps with the soundstage, but hurts the timbre and vocal presentation. This filter corrects it
  • Filter 4: A treble shelf somewhat high up brings up some extra detail and airiness.
I'm always tweaking this. I could see the bass cut changing, along with the treble boost.
 
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