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The Difference between the HD 600, HD 650, and HD 660S according to Sennheiser

Chris Kelly

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According to this official Sennheiser video, the HD 650 is intended to accommodate more modern music by way of a "warmer" sound. The HD 660S is intended to accommodate modern music by way of a warmer sound like the HD 650, and also accommodate today's devices by way of a lower impedance. The HD 600 is intended to reproduce the input signal as faithfully as possible, which is what I'm looking for.]this official Sennheiser video[/url], the HD 650 is intended to accommodate more modern music by way of a "warmer" sound. The HD 660S is intended to accommodate modern music by way of a warmer sound like the HD 650, and also accommodate today's devices by way of a lower impedance. The HD 600 is intended to reproduce the input signal as faithfully as possible, which is what I'm looking for.
 

staticV3

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Accommodating certain types of music by changing the frequency response is as stupid as those Pop/Rock/Jazz etc presets that you can find in some players and sound systems.

The intended sound is already encoded into the music itself.
Doing that a second time on top makes things worse.

That being said, measurements back up Sennheiser's claims about "warmth". In order of descending treble quantity: 600->650>660S
Screenshot_20221104-172738_Chrome.png
 
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Chris Kelly

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Accommodating certain types of music by changing the frequency response is as stupid as those Pop/Rock/Jazz etc presets that you can find in some players and sound systems.

The intended sound is already encoded into the music itself.
Doing that a second time on top makes things worse.

That being said, measurements back up Sennheiser's claims about "warmth". In order of descending treble quantity: 600->650>660S
View attachment 241135
I never posted that I depend on screen magnification, text-to-speech, and Braille. So I'm afraid PNG files won't help me. But at least audio is a good common ground in this case, which is why I didn't think it would be necessary to let anyone at this site know. I think the thing which interested me in the Sennheiser 6## series is that a few people at AVS Forum who use Pioneer universal Blu-ray/DVD/DVD-AUDIO/SACD players use Sennheiser HD 6## headphones when they aren't using their speakers. I understand these headphones have become a standard for the UHD cinema/high-resolution music combo enthusiast. Also, could I have misunderstood what was said in Sennheiser's video?
 
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isostasy

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I never posted that I depend on screen magnification, text-to-speech, and Braille. So I'm afraid PNG files won't help me. But at least audio is a good common ground in this case, which is why I didn't think it would be necessary to let anyone at this site know. I think the thing which interested me in the Sennheiser 6## series is that a few people at AVS Forum who use Pioneer universal Blu-ray/DVD/DVD-AUDIO/SACD players use Sennheiser HD 6## headphones when they aren't using their speakers. I understand these headphones have become a standard for the UHD cinema/high-resolution music combo enthusiast. Also, could I have misunderstood what was said in Sennheiser's video?
The png posted by staticV3 shows the frequency response measurements by oratory1990 on a GRAS coupler of the HD600, HD650, and HD660S. It shows the HD600 and HD650 are actually almost identical, with the HD650 being only 1-2dB lower in the treble, whilst the HD660s is around 4-5dB lower in the upper mid-range and closer to a whole 8dB lower in some parts of the treble. The HD660S also loses a few dB under 200Hz which is not desirable considering both the HD600 and HD650 are also deficient in this area.

I interpreted one part of the video differently to you. He says "the hd650 is an evolution of the hd600, and reflects an ongoing shift in listening habits. The hd650 upon its release was the perfect complement to this change in listening habits, as audiophiles had started listening longer, louder, and to more modern music that had a more aggressive sounding profile". I think the emphasis is more on the listening habits, i.e. listening for louder and longer, so needing a little lower treble so they are not fatiguing over long periods of time. He's suggesting this could be particularly pertinent when listening to modern music which is 'more aggressive' i.e. has more upper midrange and treble, though this is a broad statement and not necessarily true of the music you listen to.

As for the HD660S I think it is all just marketing speak. He goes on about the vented magnet, reducing turbulence, steel mesh, etc. it just seems like rubbish to me, the proof is in the frequency response and the HD660S is clearly not as neutral as the other two.
 

Paolo

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The HD 600 is intended to reproduce the input signal as faithfully as possible, which is what I'm looking for.
If your looking for a faithful reproduction you may be better served with the AKG K371 It is a relatively cheap, around 150$, closed back headphone, with a frequency response that matches the Harman target pretty well. I am simplifying the concept, but the adherence to the target indicate what is defined as faithful.
Depending on your budget you may find other options, if you want an open back headphone look at the Sennheiser HD 560S, another model with good adherence to the target. The HD 500 series is cheaper than the HD 600 series, for some is even more comfortable to wear, me included, but usually less technically accomplished. The HD 560S is an exception, same shape of the other 500s, but really good drivers, matching the ones in the 600 series.
 
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Chris Kelly

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As a sight impared individual, I prefer playing my music, movies, and shows at comfortable listening volume levels through open-back headphones in order to be aware of my surroundings. However, I still prefer reference quality. Also, after using closed-backs and open-backs throughout my audio/video journey, I prefer the spaciousness of open-backs. I tried and returned the HD 560S and the HD 400 PRO because I thought voices sounded more like they were being heard through a telephone's earpiece than in person, resulting from a boost I'd say around 1KHz-2KHz. I don't have a meter, but after playing with equalizers every now and then, I think I have an idea of what the various frequencies sound like when boosted and cut too much. Although I didn't try the 400 PRO and 560S within minutes of each other, but I understand they're designed the same way. So if I don't like one, I wouldn't like the other one in the case of the 400 PRO and 560S. I have the HD 559 and hd 599. With the 559, when watching movies and shows, I notice there are times when footsteps and other subtle background noise such as running refridurators, fans, air conditioning, etc. have more bass to them than in person. The 599 has the same bass response as the 559, and also adds some treble boost I'd say within the 5KHz-10KHz part of the spectrum which makes singers such as Andrea Bocelli, Celine Dion, and Enya less mello. The 599 is what I understand to be the Harman U-curve or V-curve. Based on the frequency response charts, the HD 600 seems to be the most neutral. Although perfection would be a design with the bass response of the 560S and the response of the 600 throughout the rest of the spectrum. And with the way technology is evolving, I think THIS should be Sennheiser's NEXT open-back headphones. Regarding Sennheiser's video, I get what you're saying. The 650 and 660S were designed for those listeners who don't like as much treble as originally recorded. That makes sense.
 
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oleg87

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I would caution against inferring too much about a headphone's neutrality from how naturalistic some sound effect in a film is, unless those frequencies are chronically over or underemphasized in everything you listen to. A film's sound mix is a fairly artificial creation geared towards some filmmaking effect, and the sound effect may be enhanced or entirely created with foley work.
 

jae

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I would say the differences between the 600-series are not even worth considering, because the Massdrop x Sennheiser HD 6XX, which is equivalent to the HD650, costs $199. Getting a new 600, 660s, or original 650 costs way too much these days, sometimes costing as much as $300-400+ USD depending on where you live and the differences are not worth paying that price premium if you are willing to EQ them, in my opinion they all need some sort of EQ anyway.

The main difference between the 560S and the 600-series is that the 600 series is a bit hot in the 3-4k region, while the 560S is instead more hot from 4-6k which is much more noticeable and unnatural to most people. Other than that, they are quite similar with 600-series maybe having a bit more upper treble/air roll-off and slightly more energy in midbass/vocal regions of 100-300 hz. If you could see the FR plot, they are all a lot more similar than different.

In my opinion your best bet for an open headphone in that price range would just to buy something like a Drop 6XX or 58X and then EQ to your liking. I would say the next best upgrade beyond that would be the DCA Aeon X/RT Open at $450-500, which arguably sounds worse than a 6XX without EQ, but will perform better with EQ.
 
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Chris Kelly

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I would caution against inferring too much about a headphone's neutrality from how naturalistic some sound effect in a film is, unless those frequencies are chronically over or underemphasized in everything you listen to. A film's sound mix is a fairly artificial creation geared towards some filmmaking effect, and the sound effect may be enhanced or entirely created with foley work.
While my ultimate goal is to have one headset which will accommodate everything, if worse comes to worst, I can use my HD 559 for mellow music like Andrea Bocelli, Celine Dion, Enya, etc., my HD 599 for music which would benefit from a U-curve or V-curve, and whatever new headphones I wind up getting for movies and TV. For Classical music, I'm not sure if the warm, mellow quality of the 559 would be better, or the more neutral headphones I'm looking for would be better suited for that.
 
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Chris Kelly

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I would say the differences between the 600-series are not even worth considering, because the Massdrop x Sennheiser HD 6XX, which is equivalent to the HD650, costs $199. Getting a new 600, 660s, or original 650 costs way too much these days, sometimes costing as much as $300-400+ USD depending on where you live and the differences are not worth paying that price premium if you are willing to EQ them, in my opinion they all need some sort of EQ anyway.

The main difference between the 560S and the 600-series is that the 600 series is a bit hot in the 3-4k region, while the 560S is instead more hot from 4-6k which is much more noticeable and unnatural to most people. Other than that, they are quite similar with 600-series maybe having a bit more upper treble/air roll-off and slightly more energy in midbass/vocal regions of 100-300 hz. If you could see the FR plot, they are all a lot more similar than different.

In my opinion your best bet for an open headphone in that price range would just to buy something like a Drop 6XX or 58X and then EQ to your liking. I would say the next best upgrade beyond that would be the DCA Aeon X/RT Open at $450-500, which arguably sounds worse than a 6XX without EQ, but will perform better with EQ.
I've been assuming the HD 560S and the HD 400 PRO are the same. But if the HD 400 PRO is hot between 1KHZ and 2KHZ, then maybe I should consider the HD 560S again. Not all my gear has EQ. I prefer a similar sound from each device I use.
 
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Chris Kelly

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They are. Same internals, same dampening. But different color and one additional cable. Confirmed by Sennheiser here.
This is good to know. While I had a week with the 400 PRO, I only had an hour with the 560S and didn't get to play the same material I played with the 400 PRO. So I guess I can assume I'd have gotten the same results in this case. Thank you.
 
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