Sennheiser HD660s - divisive headphones

[Limopard]

Have a fresh HD 660s here and while it initially sounded slightly off to me, I like it very much. Compared with my old 650, the 660s is significantly less smooth, which can leave the impression of a slight harshness. On the other hand, the 650 is inferior in speed and accuracy.

I ordered a 600 for a shoot out, then either this one or the 660s has to go. My 650 is too old and has severely chipped paint on the headband, so selling this one isn't an option.

 

[Tup3x]

At least my HD 660S sound very dark and lacks clarity and detail. It sound like the sound comes under the ground or there's billows between the driver and ears. Somehow the 6K area is too pronounced relative to surrounding. It makes the treble sound opposite of smooth but not more detailed. In short it just sound wrong. Also it really doesn't need that 1k boost.

Out of the HD 600, HD 650 and HD 58X, HD 650 sound widest and has nicest sound stage to my ear. Overall sound of HD 58X is quite close to HD 650 and at least my unit doesn't sound anywhere near how my HD 660S sounds. HD 600 is too hot around 3K to me and has somewhat odd soundstage.

If they'd truly want to improve HD 650 they should just make it faster, improve sub bass and maybe add dB or two around 8-10 kHz area. HD 650 already fixed what was wrong in HD 600 (except it sound slower, to my ear at least).

 

[bo_knows]

I have the 5 ,6 and 700 from all of them i prefer 6 line the most , 600 are the most in your head vocals and so tight and pushed to me , HD 650 are smooth but without losing detail they have a warm tone to them that 600 doesnt have , And 660s are like something from both of them , they are for sure more detailed than 650 way better imaging and instruments separation but they lose this smooth veil that make bad recording sound so good on HD 650 . All of them are amazing headphones and sound signature is the same . It just those little things that someone will like or not , but in the end in my opinion the most capable is the 660s.

I never use EQ because i want to know exactly how a headphone sounds , when i chat with others and say my opinion .

The clamping force is rough and I have a smaller size head. LMAO. In the beginning, I got a headache from wearing them.
In direct comparison with my KEF R500, highs are less extended and midrange is a little forward. Details and dynamics are excellent.
They replaced my 15 years old HD650 and in comparison, they sound less warm and I "think" they have a tighter bass. Also, I like their look very much which was one of the most deciding factors why I bought them.

 

[solderdude]

its all about these small difference that u said ? for example paper ,membrane are what makes the tune of the driver

Yes, but in this case it's more about slightly different plastics, slightly different flexibility or changing thickness on strategic places in the membrane and or dome.
Driver designers can also change voice-coil height, impedance and play with damping paper over rear holes.

Totally agreed on swapping headphones around and your experience mirrors mine.

From HD660 to Sundara brings more 'impressiveness' going back makes the sound boring but after getting used to it is more 'relaxing' to listen to.
Fortunately most people don't have to choose and own more than one HP (to your liking) when one can afford it.

Somehow the 6K area is too pronounced relative to surrounding

have a filter for that (same as for HD58X) it lowers the 6kHz 'peak' to normal levels. It just sounds fine and 'smoother'. Slightly different from HD650 though.

The clamping force is rough

Clamping force can easily be adjusted (same way as for HD650)

they sound less warm and I "think" they have a tighter bass

My experience too... slightly 'tighter' as in less 'woolly' in the bass.

 

[solderdude]

Somehow the 6K area is too pronounced relative to surrounding

have a filter for that (same as for HD58X) it lowers the 6kHz 'peak' to normal levels. It just sounds fine and 'smoother'. Slightly different from HD650 though.

 

[AdamG]

Have a fresh HD 660s here and while it initially sounded slightly off to me, I like it very much. Compared with my old 650, the 660s is significantly less smooth, which can leave the impression of a slight harshness. On the other hand, the 650 is inferior in speed and accuracy.

I ordered a 600 for a shoot out, then either this one or the 660s has to go. My 650 is too old and has severely chipped paint on the headband, so selling this one isn't an option.

Welcome Aboard @Limopard.

 

[usersky]

Ok just called Sennheiser official seller and asked via phone if my HD 660s and HD 700 use the same driver , and told me its based on HD700 driver with different tuning . I also open a ticket to be sure on Sennheiser Germany so i can have that written and copy paste it .

They do use the same magnet/frame and ( coil ??? i see it its exactly the shame and its a blue line that only 700 and 660s driver has that) , all the others from 5 and 6 line have red only coil and some other differences .

The order codes are different that make sense because they do have different tuning ... i guess this is what i understand different because clearly the 660s drivers if we put them on HD700 they will sound different even if they have different frame i get that i see your point .

What i understand is that for u a driver that has the same magnet, same membrane, same frame, same looks ,same coil , same pcb , same holes behind the driver ,but sounds different ( in the same frame and pads) is a different driver ....
But For me its the same driver with different tuning and i am not saying different tuning because of the frame , i speak for the driver and pcb only.

So lets agree u are right because they do sound different in the end of the day so technically u are correct .

Other than that it would be nice to see something from Sennheiser or someone else to prove that HD 660s driver and HD700 driver are not Physically exactly the shame for example the thickness of membrane or the power of the magnet ... until then...... .

Really, they cannot be the same and sound different the slightest difference makes them pysically different. The sound is a function of physical properties.

 

[Agony]

Have a fresh HD 660s here and while it initially sounded slightly off to me, I like it very much. Compared with my old 650, the 660s is significantly less smooth, which can leave the impression of a slight harshness. On the other hand, the 650 is inferior in speed and accuracy.

I ordered a 600 for a shoot out, then either this one or the 660s has to go. My 650 is too old and has severely chipped paint on the headband, so selling this one isn't an option.

This is what i get exactly from those , also my 6xx it doesnt sound exactly to my 650 the one is ireland the other romania.

 

[Agony]

At least my HD 660S sound very dark and lacks clarity and detail. It sound like the sound comes under the ground or there's billows between the driver and ears. Somehow the 6K area is too pronounced relative to surrounding. It makes the treble sound opposite of smooth but not more detailed. In short it just sound wrong. Also it really doesn't need that 1k boost.

Out of the HD 600, HD 650 and HD 58X, HD 650 sound widest and has nicest sound stage to my ear. Overall sound of HD 58X is quite close to HD 650 and at least my unit doesn't sound anywhere near how my HD 660S sounds. HD 600 is too hot around 3K to me and has somewhat odd soundstage.

If they'd truly want to improve HD 650 they should just make it faster, improve sub bass and maybe add dB or two around 8-10 kHz area. HD 650 already fixed what was wrong in HD 600 (except it sound slower, to my ear at least).

Something must be wrong with your HD 660s ( to be fair u are the second that i saw post with the shame opinion )

I have HD6XX,58X,600,650,660s ( 58X i give them to a friend) and sound signature wise for me 58X was close to 660s with more low bass.
My HD 650 was the darkest and smoother of them all by far .
Soundstage on 650, 58x, 660s for me was the shame , only on 600 was smaller and i can notice it .

For me its not about improving something on the line , but make something for different taste thats why i guess they keep all the line HD600,650,660s all of them share the shame characteristics but they win and lose on something.
HD660s is the fastest of them all and its easy to notice the biggest difference when i A-B 650 with 660s imaging also is better , but on some songs like u said there is some harshness , 650 are smoother .

About sub bass i dont like eq like i said because i want to remember exactly the character of a headphone when i chat , but when i use one it was ok there was no clipping to my ears on logical volumes , so for people that want that i guess its easy to do .

I think Focal Elex has this sub bass that u need , but is heavier , with a lot of quality problems from what i read , and some clipping on louder volumes when bass hits .
Ps. I think u gone like HD560s it must be on your character more , its more spacious not in your head and brighter ( personally i like darker headphones )

 

[Agony]

The clamping force is rough and I have a smaller size head. LMAO. In the beginning, I got a headache from wearing them.
In direct comparison with my KEF R500, highs are less extended and midrange is a little forward. Details and dynamics are excellent.
They replaced my 15 years old HD650 and in comparison, they sound less warm and I "think" they have a tighter bass. Also, I like their look very much which was one of the most deciding factors why I bought them.

They all clamp a lot i dont know why is that ? Maybe Senneheiser wants them to fit in smaller heads , But u have to know that this Clampling and those hard velur pads get softer in about 150 hours of use . Or u can just put them on pillows for 2-3 days and they will open up.

Exactly thats how they sound compared to HD650 less veiled , less warm , faster with tighter bass , in my opinion is more capable driver , but HD650 have something magical the smoothness and this veil is so good on bad recordings i never feel any harshness or brightness .

 

[Limopard]

In terms of perceived darkness 650 and 660s are almost identical to me. A 560s is brighter than both, but still far from Beyer-bright. The 600 ... I will find out next monday.

 

[Agony]

Yes, but in this case it's more about slightly different plastics, slightly different flexibility or changing thickness on strategic places in the membrane and or dome.
Driver designers can also change voice-coil height, impedance and play with damping paper over rear holes.

Totally agreed on swapping headphones around and your experience mirrors mine.

From HD660 to Sundara brings more 'impressiveness' going back makes the sound boring but after getting used to it is more 'relaxing' to listen to.
Fortunately most people don't have to choose and own more than one HP (to your liking) when one can afford it.



have a filter for that (same as for HD58X) it lowers the 6kHz 'peak' to normal levels. It just sounds fine and 'smoother'. Slightly different from HD650 though.



Clamping force can easily be adjusted (same way as for HD650)



My experience too... slightly 'tighter' as in less 'woolly' in the bass.

So even a small change on voice coil height can change the sound ... That makes sense and its logical what u said because even if the drivers look exactly the same they can be changes that we cant see that change the sound . Ok you are correct , thats what i like in these forums, when someone change my mind with logical explanation .

 

[solderdude]

In terms of perceived darkness 650 and 660s are almost identical to me. A 560s is brighter than both, but still far from Beyer-bright. The 600 ... I will find out next monday.

HD650 vs HD660S vs HD600 (plots heavily smoothed so tonal balance difference are more obvious (2dB/div scale)

HD560S is more pronounced around 4kHz to 6kHz but can (should) be EQ'ed. Better 'imaging' and bass extension, less midbass hump at the expense of less 'quality' feel.

 

[Agony]

Really, they cannot be the same and sound different the slightest difference makes them pysically different. The sound is a function of physical properties.

I was wrong , he explain it to me and i get it they look the shame but they sound different , like he said there must be some small tweaks that a naked eye cant see.

Now that is solved about the driver , there is a way the shame driver to sound different if it use different frame or different damping material in front or back of the driver . I disassembly my HD599 so i can add my HD58X driver there ... but i stopped in the middle of the road I was so curious to see the angled frame of HD5 series react .
I make a lot of tests on the dampening materials , Mostly on HD 5 and HD 58X that are fully open of the back , and easy to be back to stock.
I use Silk , coffee paper , different types of foams with different mass ,

Now i am working on a Beyer 770 frame with HD6 series driver inside .

 

[Limopard]

HD650 vs HD660S vs HD600 (plots heavily smoothed so tonal balance difference are more obvious (2dB/div scale)

HD560S is more pronounced around 4kHz to 6kHz but can (should) be EQ'ed. Better 'imaging' and bass extension, less midbass hump at the expense of less 'quality' feel.

I already stumbled upon your site (thanks for the great work, btw., greatly appreciated). In this case it looks more different to me than it sounds.

When I read about the very different reviews for the 660s I sometimes wonder whether there are variations in the production. Considering the price there shouldn't be.

 

[solderdude]

The HD599 has an under damped driver (different rear damping) and on top of that the HD599 has different pads and above all different angle.
Even if the drivers were the same (which they aren't) then they will sound different due to the pads and angling.

Materials used in the rear affect mid bass and low bass when damped too far. Materials added in front of the driver affect highs. Materials covering the acoustical impedance between rear and front of the driver can affect mids. Pad thickness and material affects tonal balance (thicker/newer) pads are further removed from the ear and have less low/lower mids.
Foam type influences pad bounce (between 60 and 120Hz range).

 

[Agony]

HD650 vs HD660S vs HD600 (plots heavily smoothed so tonal balance difference are more obvious (2dB/div scale)

HD560S is more pronounced around 4kHz to 6kHz but can (should) be EQ'ed. Better 'imaging' and bass extension, less midbass hump at the expense of less 'quality' feel.

Can u please explain something to us ... How is it possible for people having HD650 and HD 660s get different impressions about the darkness ? I read some posts saying that they have the shame darkness and others like me saying that HD660s sound clearly more fresh and not that dark ?
I even try to test them on people that have no idea about sound and they said to me that 660s have more clarity on highs .
How is that possible ? Is it the dac / amp ? is it the songs ? or its just different batch of headphones or pads that we dont know ?

 

[Agony]

I already stumbled upon your site (thanks for the great work, btw., greatly appreciated). In this case it looks more different to me than it sounds.

When I read about the very different reviews for the 660s I sometimes wonder whether there are variations in the production. Considering the price there shouldn't be.

I read his site many years and honestly its the only measures that i trust , But again something strange is happening with the HD660s maybe there are variations because clearly to me HD660s sounds more bright than HD650 ( shame pads new pads) I have listen 3 HD 660s until now the old one Ireland with the 3 dots on L frame ouside , and 2 of the Romanian with the Dots inside the frame and all of them sound brighter compare to HD 650.
I really dont get that .

 

[solderdude]

I already stumbled upon your site (thanks for the great work, btw., greatly appreciated). In this case it looks more different to me than it sounds.

When I read about the very different reviews for the 660s I sometimes wonder whether there are variations in the production. Considering the price there shouldn't be.

clarity/stridency/forward sound is in the 1-6kHz range opposite average levels between 150Hz and 500Hz. The HD660S is just 3dB less 'clear'.
This range is where a lot of complaints towards HD600 (and HD650) were about. This is 'solved' with the HD660S driver but those changes also created the 6kHz peak which makes the treble a bit less refined. From 7 kHz upwards the treble (cymbals) are about equal in amplitude so those aren't changed.

Harder to explain is the perceived tightness of the lows. FR is about the same and distortion is about the same.
Of course, there is a thing like tolerances and for sure not all HD650 are created equal. There will also be variance in the other models.

 

[Agony]

The HD599 has an under damped driver (different rear damping) and on top of that the HD599 has different pads and above all different angle.
Even if the drivers were the same (which they aren't) then they will sound different due to the pads and angling.

Materials used in the rear affect mid bass and low bass when damped too far. Materials added in front of the driver affect highs. Materials covering the acoustical impedance between rear and front of the driver can affect mids. Pad thickness and material affects tonal balance (thicker/newer) pads are further removed from the ear and have less low/lower mids.
Foam type influences pad bounce (between 60 and 120Hz range).

Thanks a lot for the info ... There are so many things that effect sound wow.