[rafaelo]

This i can say... Sundara are the most demanding of all HD 5 6 7 series of Sennheiser .
Sundara can sound loud but they need powerful dac amp to sound great .

The same is true for me with the 4XX. Is more difficult to drive properly even than my 6XX. I probably never extracted everything from this headphone.

 

[KingFiercer]

Happy user since 2018. Many years ago I started my hobby with the HD600. After trying a lot of headphones, I ended up going back to Sennheiser

 

[smashey]

A question about running in a pair of 660s...
I’ve a pair of HD660s on the way and wonder if they take long to bed in from new. I’m re-focussing on headphone listening after a long gap and my existing home headphones are DT990 pro’s. I know the beyer’s are flawed in terms of frequency response and fully expect my initial impressions of the Sennhiesers to be skewed due to that. I’ve a limited window to return if I don’t get on with them, but would they be showing their true colours after say 30 hours use? I got a Chord Mojo recently and that would be the source I’d use. Listening to a wide range of music from popular classics through folk rock to EDM.

 

[MarkJohny3]

A question about running in a pair of 660s...
I’ve a pair of HD660s on the way and wonder if they take long to bed in from new. I’m re-focussing on headphone listening after a long gap and my existing home headphones are DT990 pro’s. I know the beyer’s are flawed in terms of frequency response and fully expect my initial impressions of the Sennhiesers to be skewed due to that. I’ve a limited window to return if I don’t get on with them, but would they be showing their true colours after say 30 hours use? I got a Chord Mojo recently and that would be the source I’d use. Listening to a wide range of music from popular classics through folk rock to EDM.

Chord Mojo should be more than enough for 660s. It can power decent even the 650 or 600 but will struggle a bit with lower frequencies there. 660s sounds okay in terms of loudness and SQ even with a regular laptop jack. Currently I'm listening on 660s only with LG V40 and with a bit of EQ it sounds really good to me, just a little less loud compared to Mojo. So the Mojo will have enough power for 660s even for sub-bass, don't worry. I don't feel the need to listen to 660s on an expensive desktop DAC/amp. Regarding burn in, I have the pair for almost 2 years, but i remember when they were new there were very lackluster in low frequency, sub-bass and mid bass aspects. After around 50-100 hours (approximate because I didn't count the time exactly) of use I can say there is plenty bass and sub-bass, the drums kick pretty hard. Also I just got a pair of 6xx and I find the sound signature of 660s a bit warmer, so currently at least until 6xx are burned in I like 660s more.

 

[MarkJohny3]

This is a really good pair of headphones imo but I find the instrumental separation not extremely good on some heavy/fast metal songs with lots of instruments playing on the same frequency, also there is some harshness on 2-4 Khz on some songs same with 6xx (but I change this with eq so it is fine for me as long as i have eq). For other music genres especially opera and rock ballads and less heavy and slower metal songs they sounds really good.

 

[smashey]

Chord Mojo should be more than enough for 660s.... Regarding burn in, I have the pair for almost 2 years, but i remember when they were new there were very lackluster in low frequency, sub-bass and mid bass aspects. After around 50-100 hours (approximate because I didn't count the time exactly)

Thanks - I'll allow a good amount of burn in time before judging them.

 

[cel4145]

A question about running in a pair of 660s...
I’ve a pair of HD660s on the way and wonder if they take long to bed in from new. I’m re-focussing on headphone listening after a long gap and my existing home headphones are DT990 pro’s. I know the beyer’s are flawed in terms of frequency response and fully expect my initial impressions of the Sennhiesers to be skewed due to that. I’ve a limited window to return if I don’t get on with them, but would they be showing their true colours after say 30 hours use? I got a Chord Mojo recently and that would be the source I’d use. Listening to a wide range of music from popular classics through folk rock to EDM.

Yes. You should have a good sense of what HD 660S sounds like in 30 hours

ASR measurements indicate the Mojo can put out 71 mw into 300 ohms. HD660S is 104db/V 150 ohms.

Headphone amp calculations indicate the HD660S need 2V and 27mw to reach 110db. So most people are going to be fine with the Mojo unless they're using a lot of bass boost and listening loud.

 

[Tripokaridos]

I just got a pair of 6xx and I find the sound signature of 660s a bit warmer,

To me was the opposite 6xx sound warmer than 660s. Both with new stock pads.
But i am sure that older pads give more warm tone on every 6 series so i guess if your 660s are over 1-2 years and like u said your new 6xx has new pads then that makes sense.

 

[Tripokaridos]

I know the beyer’s are flawed in terms of frequency response

Personally i.dont think that there is flawed frequency response , To me its all about taste some people like that beyer sound others like LCD 2c signature or B&W for example i love HD6 signature but some people find it boring , i understand them .
On this hobby u should discover what U like and not what others say or Graphs say.
Harman target is not the holy grail to me , i heard headphones that are closer to it that didnt like and others that wasnt so close and like them way more .
I sold my 990pro ( wasnt my style) very easy the reason was that many people like them.

 

[Lolito]

I finish Listening the new 2020 Sundara with , HD 660s and for 5-6 hours i listen them side by side with HD 6xx ... So i can have all around opinion.
The comfort is better on HD 6 series for me because of the lower weight the oval pads that fit all my ear inside and last one the foam on the headband fills better for me.
Whenever i put Sundara they sound more spacious more clear some details are like more forward to me like they pushed ... Compared to HD 660s ,again and again the imagining on 660 is more presice like there are a lot of steps between left and right ... Sundara have more space between the instruments i can feel it but it doesnt fill realistic to me it feels unnatural like the instruments dont blend together like they should when u listen in real life and imaging its good but not 660 good. Soundstage feels closer more realistic to me on HD 660 , both are fast no problems with that ... If i had to describe the sound better HD 660s are warmer more analog and Sundara sound Digital so clear that feels fake to me ... bass on Sundara its tight like 660 but i can feel it goes deeper but HD 660s feels again like it has more progression i dont know how this happen but its there .
About HD 6XX that i listen right now writing that... Sundara feel like u are going from CD to HD 650 vinyl ... again Sundara are clearer ( not harsh like some beyer) pushing detail bass is tight like HD 660 but HD 6xx are smoother warmer with mid bass that u can feel on most songs .

Ofcorse i will keep Sundara i like this different type of sound its nice and excitement is there . But i prefer Hd 660s again ( i was hoping that Sundara 2020 would change that) , honestly i also prefer HD650 more than Sundara .
This is my opinion and only , i like warm sound signature with normal soundstage singer in front of me and intsuments around her also i like resolution and detail that is there but not pushed to me .

Very good review. Have tried any other planar that you liked and recommend? other reviewers say sndara is so much better than 600 series, but it smells like that is not true really. everyone praises 600 series, and then anything over 1000€ from audeze or others, but under 1000$ 600 series is the only decent thing really, I guess, no?

 

[equalspeace]

I have saw this list they write for HD660s.

An even darker HD6X0. A comparatively muffled mess just barely propped up by its decent resolving ability.

This list cant been taken seriously. For obvious reasons. A) there are way worst headphones over the 660s and B) what they write has not truth at all.

I have never listen Stax but Focal Clear are amazing if they worth the 3 times the price its something that audiophiles expect for that 10% more u have to pay sometimes.

I agreed with that review by Crinnacle in it’s entirety. The 660s is a really dark headphone that is not very resolving of fine details. it’s only redeeming qualities for me were it’s imaging and that i could drive it off my DAPs. Other than that it’s behind both the 600 and 650 to my ears.

 

[smashey]

Personally i.dont think that there is flawed frequency response , To me its all about taste some people like that beyer sound others like LCD 2c signature or B&W for example i love HD6 signature but some people find it boring , i understand them .
On this hobby u should discover what U like and not what others say or Graphs say.
Harman target is not the holy grail to me , i heard headphones that are closer to it that didnt like and others that wasnt so close and like them way more .
I sold my 990pro ( wasnt my style) very easy the reason was that many people like them.

Sorry - you're right and I apologise to Beyerdynamic and their happy customers, "flawed" is the wrong word to use. The 990's are just a different presentation - one which I found initially very alluring. They'd also be my benchmark for comfort.
Also you're point on discovering what works for me - precisely why I'm trying the HD660S

 

[kman1211]

Sorry - you're right and I apologise to Beyerdynamic and their happy customers, "flawed" is the wrong word to use. The 990's are just a different presentation - one which I found initially very alluring. They'd also be my benchmark for comfort.
Also you're point on discovering what works for me - precisely why I'm trying the HD660S

Honestly Beyers are all over the place in terms of tuning, don’t expect others to sound like the DT 990; many are a bit trebly though, but the DT 990 is one of the worst offenders in terms of treble among Beyers. The DT 990 is a bit v-shaped with strong treble. The DT 880 neutral bright. The DT 150 neutral warm. DT 1990 is neutral bright with powerful dynamics. Amiron Home and T1 Gen 2 are warm and relaxed with some treble brightness. DT 1770 is subbassy and dynamic with treble brightness. The T1 Gen 3 is dark, dynamically powerful, and probably the warmest sounding open-back on the market. Senns are generally more midfocused and less bright in the treble with a characteristic treble smoothness except on the HD 800/S which I found a bit sharp sounding in the treble.

 

[Tripokaridos]

Very good review. Have tried any other planar that you liked and recommend? other reviewers say sndara is so much better than 600 series, but it smells like that is not true really. everyone praises 600 series, and then anything over 1000€ from audeze or others, but under 1000$ 600 series is the only decent thing really, I guess, no?

I like the Sundara also but 660s more thats my taste.
I understand why people love Sundara they sound more clear with more soundstage and thats something that pops when u have them.
Reviewers domt use 1 headphone for months years they just review them for some hours and thats it, when u really listen at your home calm for many hours and many music styles its better .
I like the lcd2c also they are dark also, personaly i like warm sound. I didnt like 4xx.

 

[Tripokaridos]

I agreed with that review by Crinnacle in it’s entirety. The 660s is a really dark headphone that is not very resolving of fine details. it’s only redeeming qualities for me were it’s imaging and that i could drive it off my DAPs. Other than that it’s behind both the 600 and 650 to my ears.

I have listen 3 different pairs of 660s 2 of them new Romanian, none of them sound dark or hiding any details , i even change the pads with old ones that muffled the sound and again didnt sound like u say.
I respect different opinions but there is no logical explain to understand this opinion.