Sennheiser HD250 Linear II

Discussion in 'Audio Science' started by stratocaster, Oct 5, 2015.

  1. stratocaster

    stratocaster Friend

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    I measured asome Sennheiser HD 250 Linear II with stock pads. Subjectively, they are quite nice and balanced sounding. The bass is strong and has some nice punch, male and female voices sound surprisingly natural and clear too. That comes as a surprise, since people have been describing a recessed midrange. The peak at 8k is audible but not too much of a killjoy, the narrow dip at 6.5k indicating ringing in disguise. I am quite digging these and I am certainly going to mess with them.

    stock_fr.jpg

    stock_csd.jpg
     
  2. kapanak

    kapanak Canucklehead - Friend

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    One of my favourite blasts from the past headphones. I look forward to your exploits with these :D
     
  3. JoelT

    JoelT Friend

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    I need to pull my pair out and give them another try. I had been loaning them to a family member, but I recently got them back. I did mod mine with extra damping on closed interior of the cup, some TP over the driver to reduce the treble peak and a different set of pads. Time to revisit them with my OTL driving them. I didn't particularly like them out of my Ragnarok, and definitely felt they were a bit tonally "V" shaped. I suspect they'll be better with some tubes.
     
  4. Deep Funk

    Deep Funk Deep thoughts - Friend

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    Thank you for this measurement.

    This headphone deserves more appreciation. Is almost has that AKG midrange with ample of bass and highs without ever sounding harsh or bassy. For me this headphone sounded right and fun at the same time, slightly more than the AKG K240 DF.

    I must buy one and keep it for good. f**k Sennheiser for discontinuing this great headphone.

    P.S. If you really like its sound, keep it because few headphones come close.
     
    Last edited: Oct 6, 2015
  5. stratocaster

    stratocaster Friend

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    So, after some modifications ...
    I applied some more damping and replaced the stock pads with some modified HM5 pleather pads,allowing some very slight leakage.
    They still isolate very well and have become my go to closed cans, being very light and comfortable. I have been targeting the sound to my reference, the HD600. And I must say, they do come close. They exhibit more bass slam but lack a little bit of the mid and high frequency finesse of the open 600s. But, as far as I am concerned, these are quite impressive, also if one looks at the distorti on and CSD plots.

    fr_mod.jpg

    csd_mod.jpg
     

    Attached Files:

  6. JoelT

    JoelT Friend

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    What did you end up using for damping material? I found space to be fairly limited with shallow cup backs.
     
  7. stratocaster

    stratocaster Friend

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    Space is indeed limited. What I did was to approach the back of the driver, which has no HD600 like foam disk, but this kind of dual-vent lid. I eliminated the lid and put some dense foam disk over the driver vent (HD600-like). Anyway, this did not really change the signature drastically, it is the pads that - as in most other mods I have been trying - make the biggest difference. In most cases it is not enough to find an alternative pad, you will almost always have to work on the pads too in order to be really satisfied. IMHO, pad replacement/pad modding + appropriate damping = 90% of modding success.
     
  8. Darsus

    Darsus Insatiable bowels - Member

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    Let's write the review finally. Stock, they don't sound that good. That 200hz deep is a killer, taking away punch from the snare and creates somehow shallow sound, making lows and highs even more pronounced, and that's probably why many of them call them V shaped, even tho they aren't exactly.

    BUT, when EQ-ed properly, these sound amazing. I love them because they extend sooo well. After some experimentation with noise generator and EQ, I am very satisfied.

    Bass - very detailed, especially sub bass, you can actually differentiate kick tail from a sub bass. When EQ-ed properly, call me crazy, but it reminds me of LCD-3 sub. Now, recalling sound signature from your memory is not a good option, but I might compare them in the future.

    Mids - very good, voice sound really natural on them.

    Highs - Extremly detailed, Royal Blood - Loose Change, at the end, I think you can hear every coin falling on the ground.

    Btw, I like them stock for watching movies, i think their FR is really good for it.

    P.S. Pads are a bit worn out, but I doubt it affects sound so much, because it matches with measurements pretty well. Some small differences, 200hz deep I percieve as -8.5db etc.

    Current EQ - it is heavy, but it does wonders.

    [​IMG]
     
  9. Azteca

    Azteca Friend

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    I would find that chart much more useful if we could see the frequencies on the X axis. And +9 and -6? Yowza. But hey, if it works in your setup, right on.
     
  10. Darsus

    Darsus Insatiable bowels - Member

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    Unfortunatelly, ProQ2 is made that you only see frequencies when you run over the dots. Here are some rough numbers, from left to right:

    45, 200, 450, 2200, 4800 (that small blue one), 5800, 9100, 13100

    Yes, I was worried too, especially when I saw the measurements. But it worked great, wish you could hear them. I still haven't EQ-ed them in detail, but this does the work more than properly.

    My K400 are also unrecognizably better after EQ-ing, would recommend it to everyone for their headphones before deciding to upgrade.

    P.S. If you have HD250 II too I could export some A/Bs.
     
  11. millan

    millan New

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    Darsus, I have the Sennheiser HD250 II. Could you please send me the exported EQ settings for FabFilter ProQ2 to [email protected]? Many thanks in advance.
     
  12. stratocaster

    stratocaster Friend

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    Got hold of another HD250 Linear II and decided to tweak it a bit.

    Stock:
    stock.jpg

    Modded:
    tweaked.jpg

    Overlay:
    comparo.jpg

    I used some baffle damping and some modified HD800 pads, which I had 'leatherized' and glued on two felt rings (about 8mm thick), allowing for some controlled leakage. I also finally used a layer of felt (1mm) in front of the driver to align the response around 8kHz with the rest of the spectrum.
    mod.jpg

    These sound surprisingly good now. Plus, they are ultra lightweight and isolate really well, too.
     
  13. Deep Funk

    Deep Funk Deep thoughts - Friend

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    Really well done.

    I wish Sennheiser would make these headphones again instead of things like the HD700.
     
  14. stratocaster

    stratocaster Friend

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    Distortion and CSD below ...

    distortion.jpg

    csd.jpg
     
  15. stratocaster

    stratocaster Friend

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    Well, I guess I am done with these now. Below you will find my final version. I guess extension is really good now, the pads rest further away from the baffle, allowing a cavity deep enough to provide plenty of space for the ear - not quite HD800 wide/deep, but almost. Very comfortable at least.

    final.jpg
     
  16. stratocaster

    stratocaster Friend

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    Worked on a second set. This time I used stock HD800 pads and allowed more venting in order to bring up the upper bass and lower mids a bit.
    Stock, there is this black cap with its two vents behind the driver, which also 'closes' the cup under the hinges of the headband. I replaced this cap with some kind of foam stopper. I had to find just the right amount of foam/density to get the bass under control. Using a measurement rig definitely helps here.

    set2_changes.jpg

    HD800 pads (with felt foundation to allow controlled leakage) on the new set, really comfortable:
    set2_.jpg

    Measurements (Overlay left/right):
    set2.jpg

    This sounds more dynamic, has more body.
     
  17. Serious

    Serious Inquisitive Frequency Response Plot

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    Stratocaster sent these to me for testing.


    Generally I was very impressed by both of these headphones, although overall I preferred the first with the leather earpads to the one with the HD800 earpads. Looking at strato's measurements I would've sworn that the 2nd pair should sound better, but the midrange tonality was too warm for me.

    Impressions (first pair):
    • Not as efficient as HD800 or even HD600. Yes, efficient (not sensitive) here because all three are essentially 300 Ohm headphones with similar impedance curves.
    • Lean and mean tonality. Even without my glasses it's lacking some warmth, but bass actually has decent extension. Not as good as my speakers, but much better than the HD800.
    • The tonality is just at the edge for me, but it manages to pull back before it gets painful 85% of the time. I actually like it like this and think it's well done, but I have to listen without my glasses. I'm sure Hands wouldn't touch this headphone with a 10ft pole. The treble is somewhat rough and sibilance can be a problem, but it's pretty good for a closed headphone. Still, my HD800 is overall the meatier, warmer and more natural sounding headphone. Vocals also sound more complete on the HD800, but the vocal tone is still pretty good in the overall scheme of things.
    • The treble sounds tonally compressed. There's a peak at transition region between upper mids and lower treble (say 5kHz) and then it dips before rising again in the midtreble and upper treble. The peak and the 9kHz+ region is too high in level, but the dip balances it out a bit. The dip in the lower treble can make it sound less bright than the HD800, but with most content it sounds brighter
    • The stage is surprisingly big for a closed headphone and imaging is pretty precise. Some channel imbalance and I have a harder time getting a good seal on the right ear, but these are DIY.
      Staging is pretty comparable to HD600. I actually think it sounds natural than the Eikon staging. The Eikon felt much more closed so despite an overall smaller stage the boundaries are more open here, so to speak.
    • Not nearly as resolving as the HD600. Lots of ambient information seems missing from Hotel California. I also think the felt in front of the driver reduces the microdynamics, but given how bright these are already I wouldn't want to know what it's like without the felt.
    • Despite the worse resolution clarity actually seems pretty good. I'm sure a big part of this is a function of frequency response enhancing perceived clarity, but it seems to get going more easily than the HD600. Or to put it another way, it doesn't scale nearly as much as the HD600 from the Vali to the Rag.
    • The lack of real resolution and articulation also seems to somehow enhance clarity and perceived speed. Has that fake clean sound that makes it unable to disappear, but can also make it fun sounding.
    • Bass quality doesn't seem any better than the HD600 sadly. There's also always this thing with closed headphones in that the bass never sounds as effortless and natural as with open headphones. Same thing here.
    • Apart from the bass it seems to keep composure at high volume levels unlike the Eikon
    Second pair:
    • More comfy. HD800 pads rule.
    • While the first was lean and bright this one is warm or even slightly u-shaped. Vocals sound disappointing.
    • Because of the recessed upper midrange the treble sticks out more.
    • I expected the staging to be more expansive with the deeper pads, but it's only slight at best.
    • Treble also doesn't seem to be much smoother, but both are quite good already in the overall scheme of things for closed headphones.
    • Lower midrange sounds more coherent, but bass extension is worse. Also sounds too warm so I wear my glasses when listening to break the seal a bit. Still a bit warm as it's now less seal dependent.
    • The recessed upper midrange is too much for me. I prefer the first one

    Misc:
    Leakage is pretty bad for a closed headphone and so is isolation. I'm not sure I'd feel comfortable blasting Tool at 100db in the subway like I do with my IEMs. Still, it's obviously a closed headphone.
    The cable:
    The cable seemed more flimsy than the HD600 cable and feels more like the HD540II cable (the coating looks the same). It's slightly thicker than the 540 cable, but not as thick as the 600 cable. Because of this I was worried that the cable would sound like the 540 cable, which is one of the brightest and in general just worst sounding cables ever, just after the HD800 cable. Fortunately that's not the case. The cable sounds closer to the HD600 cable, but not as refined (not that the 600 cable is particularly smooth and refined sounding).

    Considering the price and that they're closed headphones I enjoyed them a lot. No, they're not as good as the HD600, but they do enough right to sound interesting. I also really liked the suspension headband construction for comfort, even though I prefer the looks of the HD600.

    Measurements in the next post
     
  18. Serious

    Serious Inquisitive Frequency Response Plot

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    Measurements after I sleep for a few hours. The measurements here are actually sort of interesting because they show how measurements can be deceiving sometimes
     
    Last edited: Dec 21, 2017
  19. Serious

    Serious Inquisitive Frequency Response Plot

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    So @Lyer25 just reminded me of this post that I completely forgot about. I vaguely remember trying to make a post about how measurements can lie because the coupler measurements were opposite to how I heard these two headphones and even the in-ear measurements don't even correlate perfectly to what I heard (or something), but after one and a half years I'm really not sure what I was going on about. Well, here are the in-ear FRs of both headphones:

    First pair (the one I preferred) without glasses:
    [​IMG]
    (grey lines are without glasses)

    Second pair (white line above is a L/R avg of my HD800):
    [​IMG]
    (grey is the right channel without glasses)
     
    Last edited: May 11, 2019
  20. Lyander

    Lyander Official SBAF Equitable Empathizer

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    I was hoping that'd happen, yes :))

    And +1 measurements not always panning out, that philosophy's one reason I've come to like this forum a lot.

    Thanks @Serious! Saw a NIB one pop up for $400 on HF and was curious about them.

    EDIT: Wait there's yellow there?
     
    Last edited: May 11, 2019

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