[paulguru]

Senn 558 is a warm HP ? 
 
By this measurements i see the perfectly same bass and mid bass compared to 598 and more enphasis on the upper mids and treble, then ..... 558 should be more brighter with little bass, and instead i read it is a warm HP with punch bass, how is possible ?
 

 

[karljs]

For starters, don't read just one review and assume everything in it is objective and exactly what you will experience.  A lot of people's headphone impressions are biased by what they are comparing against or the sound they are most used to.  Furthermore, a lot of people use vague words like "warm" to mean different things.
 
Also, make sure you are reading the graph correctly.  It's incorrect to say that either headphone has "little bass" since both are above neutral from 40Hz and up.  The only thing potentially lacking based on the charts might be the lowest audible sub-bass around 20Hz, which probably isn't a very big deal.  I think if "warm" is used to mean a very full bass, then that seems entirely plausible from the chart you posted.
 
Also, the higher response from the 558 around 3000Hz does not make a headphone bright.  This is solidly in the "mids" category and, to me, the chart suggests some part of the mids might be a bit more forward on the 558 than the 598.  The actual "highs" are more like 6000Hz and higher, where it looks like the 598 actually has a marginally (maybe not audibly) higher response.

 

[paulguru]

both use the same drives ?