[Currawong]

I was, funnily enough, linked to this on IRC by a friend.  Nice work!

 

[kohan69]

Hit front page on reddit:
 
http://www.reddit.com/r/todayilearned/comments/fk6s6/til_sennheiser_adds_a_bit_of_muffling_foam_to/
 
 
 

 

[Steve999]

Quote:

Originally Posted by Kevin Brown /img/forum/go_quote.gif
....
 
 I do see the 580's get a lot of good press though.
 
So then I'm back to a good 1st step being to get the 555's and try the foam in or out, and then decide what to do from there.  I am aware that the 600 seems to have a fundamentally different sound than the 555/595's, so I'm keeping that in mind too.

 
This was a great thread.  Thanks everyone for the humor and information and entertainment.
 
I've got an old pair of HD580s and since I was dying of curiosity I just got a new pair of HD555s.  They are pretty different.  
 
My initial impression is that the HD555 bass is punchier and flatter and goes lower and growls when it needs to better than the HD580, and that the HD555 mid-to-treble is smoother without that big notch.  Score two points for the newcomer.
 
I believe the HD580's midrange sounds a little more natural, less resonant, and the higher frequencies sparkle a little better compared to the HD555s.  Score two points for the old guy.
 
I'd put these (I'm wearing the HD555s now) in the same general ballpark as the HD580, SR80i, and DT880, which is meant as a compliment.
 
I'm not sure I would want to do the HD555 mod.  I'm not sure I'd want to accentuate resonances in the earcup area.  I get a sort of cupped-sound feeling, but I'm not sure if it's my imagination.  Less damping could make it, or my imagination of it, worse.
 
The HD555s remind me of a nice pair of restrained hi-fi speakers.
 
I'm not too impressed with Sennheiser with what appears to be some funky product differentiation and continuing to use materials inthe headband that crack over time, even with the 558 and 598.  I don't think I'd buy anything high-end from them after finding out this information.  The HD580s I got for about $110 several years ago and these HD555s I got for $85, those are excellent prices for the sound quality in my opinion.
 
I don't think the HD555 sound is something you just come across by accident.  It's a nice accomplishment, a good product.  It keeps the Senn personality.  Definitely on the smooth dark side!!!

 

[Kevin Brown]

 Steve- Nice post !! 

 
I fear that your info makes me want to hear both of them though ...
 

 

[pp312]

"I'm not too impressed with Sennheiser with what appears to be some funky product differentiation and continuing to use materials inthe headband that crack over time, even with the 558 and 598.  I don't think I'd buy anything high-end from them after finding out this information."
 
Except that the higher end Senns are a completely different design and don't suffer this problem. The only time I've heard of a 600/650 cracking is when someone has bent it too far trying to relieve clamping pressure.  

 

[Steve999]

Quote:

Except that the higher end Senns are a completely different design and don't suffer this problem. The only time I've heard of a 600/650 cracking is when someone has bent it too far trying to relieve clamping pressure.  

Good point. I've had my HD580's (pretty similar to the HD600s) for several years and could probably pick the lint off of the earpads and pass them off as new, even though I have used them a great deal.
 
I am finding the HD555's very interesting.  Normally I would not like that bass-oriented of a sound signature but there is something appealing about them.
 
I notice the HD555s are pretty similar to the HD650s, and the HD558s are pretty similar to the HD600s (and by implication the HD580s), if Headroom's graphs are to be believed:
 
http://graphs.headphone.com/graphCompare.php?graphType=0&graphID[]=853&graphID[]=563&graphID[]=573&graphID[]=2861
 
My ears take this with a grain of salt, though, because the HD555s seem to me to do much better in the low bass than the HD580s.

 

[xnor]

Steve999, what are you powering the HD555's with? On a solid state amp with low output impedance those graphs are pretty accurate on the low end.
 
On the other hand, if you use, e.g., a stereo receiver you'll get quite a boost there.

 

[Steve999]

Quote:

Steve999, what are you powering the HD555's with? On a solid state amp with low output impedance those graphs are pretty accurate on the low end.
 
On the other hand, if you use, e.g., a stereo receiver you'll get quite a boost there.

 
I would be very interested to know about how much the bass was attenuated (by about how many decibels at what range of frequencies) by the remove-the-foam mod.
 
I see from headroom that the impedence curve for the HD555s is very elevated centered at around 100 hertz, which if I remember correctly would explain the elevation in the bass you are talking about from a headphone jack with a high impedence?
 
I have plugged them into many things, I generally have stopped paying attention to such things, but I do have an original Corda HeadAmp-1 (from back when such things were cheaper!) from many years ago, which has both a near-zero ohm jack and a 120 ohm jack.  As I see the impedence curve of the HD555s is significant, I'll compare the headphones from both jacks.

 

[pp312]

The 555s are bass oriented? That's actually something of a new take on them. Others have complained of the opposite problem.  

 
Quote:

 
I am finding the HD555's very interesting.  Normally I would not like that bass-oriented of a sound signature but there is something appealing about them.
 

 

[xnor]

Since it's very source dependent that's actually possible, but normally I'd classify it as lower-mids oriented. ^_^

 

[Steve999]

 
Quote:

Since it's very source dependent that's actually possible, but normally I'd classify it as lower-mids oriented. ^_^

 

I think Xnor is right, which of course he knows.  This is not smoke and mirrors but normal electronics, which I only understand marginally.
 
Here is the impedence curve for the HD555s.  I've added the Grado SR60 impedence curve, which is very flat, for comparison:
 
http://graphs.headphone.com/graphCompare.php?graphType=7&graphID[]=563&graphID[]=393
 
As you can see there is a very pronounced hump in the impedence curve centered at around 70 hertz for the HD555s.
 
As I understand it, from a near-zero impedence headphone jack, this will have no effect on the frequency response.
 
As the impedence of the headphone jack of the source goes up, the impedence curve of the HD555s will result in a peak I would guess at most of a few decibels in the low-to-mid bass area.
 
By comparison because the Grado impedence curve is flat the impedence of the headphone jack will have very little impact on the frequency response.

 

[xnor]

Precisely, see http://www.head-fi.org/forum/thread/493436/dampening-in-amplifiers#post_6660782 for a sample calculation.

 

[Melvins]

kmm

 

[Steve999]

Quote:

The foam removal mod resulted in a slight increase in frequencies around 1.2 kHz followed by a valley at 3 to 4 kHz - reverted that one too.
 
^ In german I like to say something like "to think [believe] means to be clueless", see Nietzsche.

 
Thank you for you data and impressions; they seem reliable and are very interesting and helpful.  I think I probably will not be using the foam mod.  It seems from your measurements that the midrange would be both less bright and less smooth after the mod.   I also do not want to lose a marginal amount of low bass, as I believe you indicated also occurred with the foam mod in another post.  It sounds like the overall impact might be to make the phones marginally more dull but with some "air" (resonance?) added at about 1 khz.

After a few days of getting used to them I am really happy with the Senn HD555s.  It did take a little while for me to get used to them, as the type of balance is new to me, but now I am very taken by the sound of them.
 
The HD555s do sound better balanced (less bass-heavy) to me from a near-0 ohm jack as compared to a 120-ohm jack, which is a little odd since Senn provided the phones with the larger sized jack you would ordinarily use for equipment with a higher-impedance jack such as a stereo receiver.  
 
Thanks to everyone providing so much information about these headphones, it helps me to understand and enjoy them.
 
I notice by the way that from the headroom frequency response graphs the HD558's and HD600s look very highly similar, aside from the HD558's precipitous drop in the upper treble:  
 
http://graphs.headphone.com/graphCompare.php?graphType=0&graphID[]=573&graphID[]=2861
 
My feeling is I already have a pair of HD580s (already so similar to the HD600s) so I don't need to go down the HD558 path.  The HD555s do sound quite different from my HD580s.
 
It looks and sounds to me like it's the HD555s that have carved out the interesting new territory in the best way--in the style of the HD650s but not to the extremes of the HD650s, which are ultimately a little too bass-heavy for me personally:
 
http://graphs.headphone.com/graphCompare.php?graphType=0&graphID[]=853&graphID[]=563

 

[peskypesky]

ok, after seeing the youtube video showing the easy mod that makes HD 555s into 595s, and seeing that the HD 555s were only $84, I ordered a set. i have to say, the easy foam mod is just too intriguing. i have to try it myself.
 
also, i've never had Sennheisers, so i'm interested in their sound compared to my Grados and Shures. after this, no more headphones in 2011!