Sennheiser HD 650 over-ear open-back Headphones - Official Thread

Oh, you are not alone with this assessment.

As much as I appreciate the naturalness of the instruments and voice reproduction, the overall tonal balance of the 650 is comparatively too “dark” for me, while the 600 seems almost “refreshing”.

Since I got new Dekoni pads in the mail today – and a spare 6XX in the drawer – why not doing some quick ‘n’ dirty pad rolling and see if my preferences or perceptions have changed over time w.r.t these pads?


  • I already have Dekoni fenestrated sheepskin pads installed in both HD600 and HD660S. The new kid on the block for me was the Elite Sheepskin (regular for short);
  • I did not listen to their whole portfolio. Until today, only tried two of their leather lineup;
  • the HD650 had part-worn stock pads;
  • information given below is purely subjective so take it with a grain of :salt:

Some pictures, shall we?

HD650 with fenestrated sheepskin and HD6XX with regular sheepskin

HD650 with choice leather pads and HD6XX with regular sheepskin

HD650 with stock pads and HD6XX with fenestrated sheepskin


  • for the nth time, can’t beat stock pads tuning; :man_shrugging:
  • however, the fact that these pads can last a long run (3 or more years) and they do break-in with time, makes it a competitive option down the road. Not to mention the aesthetic.

Choice Leather

  • makes the HD650 even darker, bloated and muffled;
  • not tolerable for my taste.
  • good comfort;
  • for a 2 years old faux leather I’m impressed it is still in one piece, i.e., no signs of cracking. Time will tell though.

Elite Sheepskin

  • a little bit too warm for my taste but tolerable after brain burn-in (~20 minutes);
  • it may work well on tracks from the 70s but will likely to sound bloated in more modern recordings. On the edge of my tolerance;
  • the most comfortable set of this exercise.

Elite Fenestrated Sheepskin

  • mildly warmer than stock but elevated upper bass is “ignored/normalized” after brain burn-in (~20 minutes);
  • it is still my favorite of their line-up as it is the closest I perceive against stock;
  • very comfortable as well.

So what’s next?

The obvious:

  1. the HD650 will continue with the stock pads;
  2. the spare HD6XX has now the fenestrated sheepskin and is going back to the drawer;
  3. the brand new regular sheepskin pads are going to the drawer to be revisited sometime in the near future. Need to try this one with the HD600. Maybe it’s a good fit;
  4. Choice leather was installed in the HD58X for 2 years and it will finally go back to the drawer.

Cheers. :beers:


Didn’t DMS do a 6XX pads video within the last few months in which he used ZMF pads? If I recall, he really liked the end result.

Just in case you’re still on the hunt. :grinning:


I just bought a pair of fenestrated sheepskin ZMF pads for my 6XX. Eager for them to arrive this week.


That’s awesome! I’ll be curious to see what you think. I believe the ZMF replacement pads are the only ones I’ve ever seen said to be as good or better than the original HD 6XX/650 pads.

Looking forward to your impressions!


Here are the Sennheiser HD 650 measurements done on the B&K 5128.



I will eventually replace these with channel matching as well, but currently waiting on an additional adapter to make that an easier part of the process.


First 5128 measurement? Nice!

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I’d love to see a measurement of the AKG K361.

Can you post your new target as a *.txt file?

It’s not finalized yet. We still have a bunch of testing to do.

Ah I see, sure thing!

Hi I(Totally agree, Cables can increase the sound quality. Some people are sceptical but I have experienced a 10% gain in Sound Quality Stronger Bass, and a more spacious soundstage. I am using it on balanced port of my K9 Pro Ess, which is a awesome Dac/Amp and makes everything sound better.Here is link for anyone interested in swapping out cheap stock cable.

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My personal take on headphone cable theory:
An amplified audio signal is often altered purposefully in order to selectively filter certain frequencies. The most simple implementation is that of a first order crossover. By simply inserting x value of resistance or capacitance in series of the circuit, one can filter selective frequencies from the audio transducer. This is how your tweeter, and woofer may have divided high frequencies to a tweeter, and low frequencies to a woofer.
Taken to minimal measurements of conductors within our headphone cables, measurable impedance exist. Certainly only a fraction in comparison to an actual electrical component capacitor or resistor. Nevertheless, a measurable quantity of resistance. This would absolutely have an audible and measurable filtration of certain frequencies that would react with varying impedance of the connected transducer.
Also, within the construction of our headphone cables, a compounding factor are the resistance effects of the connectors utilized as plugs at both ends. When all three of these are combined, it is possible to have minute existence of higher order filtering taking place beyond first order, which in theory would also affect phase. I am not too concerned about any minute effect on phase. Although there is the possibility that it exists in some headphone cables that are designed with poor quality connectors.
Another element of concern when combining multiple components of the headphone cable and transducers is the reaction of the amplifier reaction to these various occurrences of resistance and capacitance. However, quality amplification designs are usually engineered to be robust enough to meet variations of impedance with adequate sustained voltage. So, this should not really present too much concern in real world scenarios unless one is using a really crappy amplifier. Yet it remains on my mind because I am fascinated (obsessed) by these minute audible characteristic differences that different amplifiers present with different combinations of headphones.
Solder used in headphone cables:
I also chose to use silver solder when I construct cables and interconnects in order to minimize resistance compared to lead solder. But I really don’t think that it makes any audible difference. I only do this because the slight increase of conductance of silver helps put my mind and conscience at ease so that I can sleep at night.
But then what if we think in extremes? What if someone were to give me a headphone cable made from pure silver conductor, soldered with pure gold, and terminated with pure gold? Would it improve my headphones? I hypothesize that such a headphone cable would be too conductive and would reproduce the audio signal in a manner that amplifiers were not designed under. Designers of amplifiers likely test their designs using the most common and abundant headphone cable designs that end users use. That would be oxygen free conductors, combined with lead solder, and cheap mass produced Chinese connectors. So that is likely what the acceptable baseline is that one should begin with. From that point we may each deviate to our subjective cozy cable.


Try my quantum mechanical cable in which the signal arrives before it is produced.


You mean like the one Marty McFly was wearing?
If his parents don’t get back together, doesn’t the audio signal disappear from existence?


HD6XX on massdrop! Great price. I own them upgraded cable with 16 core occ balanced output, sounds awesome.

I upgraded my HD6XX with 16 core occ copper with balanced 4.4 m jack, and they sound amazing!

Hi everyone - I’m writing to share my quick impressions of the HD6XX. I purchased them a little over a month ago and, out of the box, wasn’t really fan (they sounded fuzzy to my ears). I burned-in the headphones using Tara Labs Cascade Free Burn In Disc (on repeat, at night only, for a week, with the headphones covered in a blanket to muffle the sound). There was a very big improvement - they sounded more detailed relative to when they were out of the box. They just “cleared up”. While I don’t think the HD6XX is the last word in detail, they are a lot of fun to listen to.

However, I still found the HD6XX to be bright (I think this is the 5-6k bump I saw in the measurements) and lacking in bass extension. I read on another forum about Accurate Sounds’ EQ filters for headphones by Mitch Barnett. While the articles focused on the impact his filters had on the Raal CA1A, Audeze TOTLs, and Abyss headphones, I saw that Mitch sells a filter for the HD6XX. I really found the HD6XX improved greatly after applying his convolution filter. I’m running his filter through HQPlayer. Bass extension has improved dramatically and the “brightness” I noticed recessed greatly. Music sounds far more balanced, while retaining the big and fun sound these cans deliver. With the EQ, I find the presentation far more balanced and cohesive. For the price of the HD6XX and the EQ filter, I think you get one hell of a headphone.

Have others here used Mitch’s filters? Or other EQ curves?

My chain, if anyone cares:

HQPlayer (PCM, Sinc L / Sinc M, TPDF, 768khz) / PGGB-RT > Netgear GS108E Switch > ultraRendu (LPS 1.2) > Gustard X26 Pro > Topping A90 > HD6xx (Accurate Sounds Convolution Filter) / Drop + DCA Open X / Thieaudio Oracle Mk 1 / Tin Hifi P1 (USound EQ)


I have a hard time paying $40 for convolution filters when Jaakko’s have worked wonderfully for me and are free. But I’m glad you like Mitch’s filter.

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Have you guys tried the Resolve 5128 EQ for the HD 650? It’s free. I no longer own the 650, but his 5128 EQ for the 600 sounds darn good.

Not sure how it’ll compare to the convolution filter EQ, but it’s worth a shot.

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