[PDVJAM]

  Sounds like dynamically compressed music.  Looking at waveforms on Audacity, I noticed music of compressed waveforms are prone to sibilance. Some headphones are not good at taming it.  Sounds like LCD could be something that you maybe looking for. LCDs dip in the sibilant region.  With this, I noticed vocals sounded distant with the LCD2. After headphones, I find it's more to do with the amp's ability to tame the treble depending on if the amp has a bright characteristic.  It's apparent tube amps would suppress the harshness.
 

 
No, most of songs were in flac. You can check them yourself for any sibilance: Arena - The Great Escape, Arena - What if?, Twilight Of The Gods - Destiny Forged in Blood, Madonna - Love Profusion songs.
 
BTW, what is LCD?

 

[Music Alchemist]

  No, most of songs were in flac. You can check them yourself for any sibilance: Arena - The Great Escape, Arena - What if?, Twilight Of The Gods - Destiny Forged in Blood, Madonna - Love Profusion songs.
 
BTW, what is LCD?

 
Dynamic range compression refers to the recording and mastering process, not lossless file compression.
 
Audeze's line of LCD headphones.

 

[SilverEars]

Yes, what MA said. 

 

[PDVJAM]

   
Dynamic range compression refers to the recording and mastering process, not lossless file compression.
 
Audeze's line of LCD headphones.

 
Ah, understood. Looks like you're right, coz all previously mentioned songs sound with sibilance of almost all headphones I've ever tried. Except Koss Porta Pro, which is definitely has lack of high frequencies.

 

[Music Alchemist]

  Ah, understood. Looks like you're right, coz all previously mentioned songs sound with sibilance of almost all headphones I've ever tried. Except Koss Porta Pro, which is definitely has lack of high frequencies.

 
You can always use equalization settings to help tame that, whether from the DAPs themselves or external software programs.

 

[SilverEars]

Bright phones like the HD800 peaks at the 5-10k region where the sibilance is.  This is also the area that provides details to sounds hence people love the resolution with limited music types out there since boost in this region will produce unpleasant result with dynamically compressed music like the ones you listed. Thus, audiophile recordings, classical, and jazz are more enjoyed with them.  I personally think Audeze purposely tuned their headphones to dip at the harsh region.  Reason why I think it's purposely dipped is that Audeze phones are planar like the HiFiMans, and the HE-6 has the treble boost also like the 800.

 

[SilverEars]

Also, it would be enlightening to look at the frequency spectrum of the uncompressed music to see the output response and how well they interact with the headphone type. My guess is that certain headphone type can work well with certain genres because of the spectrum they may output.  There are also other gear related factors that goes into it.  Like how the headphones responds to amp's output from the DAC.  There are lots of claims of some gears causing changes to the sound.

 

[PDVJAM]

Tomorrow I will try to catch difference between DAC's one more time. Final. If I fail, I buy DX50, because I need replacement for my very old D2+ and DX50 has rockbox with parametric EQ and replacement battery, which is cool.

 

[Music Alchemist]

  Tomorrow I will try to catch difference between DAC's one more time. Final. If I fail, I buy DX50, because I need replacement for my very old D2+ and DX50 has rockbox with parametric EQ and replacement battery, which is cool.

 
Yeah, there's no point spending an extra thousand dollars on a DAP if you don't hear any difference when listening to it...however, you would probably notice more of the differences by using better headphones. I have my eye on the DX90 myself, but also want to try out/buy the TOTL DAPs, headphones, etc. I recently installed Rockbox on my iPod Classic and was surprised how different it sounds. Before, everything sounded so bland and boring on the default setting, so I had to switch to the Electronic EQ setting to make music listenable; now, even without altering the EQ, it sounds better than I thought the device was capable of! I still need to learn how to effectively work the graphical EQ. The basic bass/treble settings distort the audio too much.

 

[castleofargh]

in the last years I can't remember having only one DAP (usually it was mostly because I'm curious and too lazy to resell, not that I even wish or need to have several). I can only talk for myself, but the fact is that I never spent the most time using the better sounding one. I always ended up spending more times with the ones with great battery life, or just the most convenient ones( small, good EQ, clever UI, podcast features...).
and clearly my favored DAPs were the one that didn't break when I dropped them, several times! all the TOTL scared me away because of that. they never look like they're built to fall and that doesn't feel right to me. because even if you give me a baby, at some point in time, I will drop it or fall with it while doing something stupid. so my portable stuff should be prepared for that.
 
 
 
also PDVJAM, DAP ≠ DAC

 

[PDVJAM]

Two days ago I did listening tests once more. Checked AP100, DX50, DX90 and Fiio X5. Used more uncompressed songs with big dynamic diapason (checked by http://dr.loudness-war.info/) . Listened them for about 3 hours and decided to buy DX90 (AP100 and X5 have no rockbox): in my opinion, it does not have much difference with the younger brother, but he sounds a bit more gently. I didn't do ABX, but tried to compare them on same volume (DX90 with a but louder, so volume 200 on DX50 same as ~190 on DX90) as fast as I could (by switching SD card). Well, I'm happy with it Maybe I'm wrong and this "gentlyness" because of price difference.

 

[SilverEars]

Below shows that output impedance(was spec to be <.3ohms, never trust specs!!!) is not linear with DX50 and there will most likely be bass roll-off with iems.  Anybody know what the audible affects of subbass roll-off?
 

 

 

[SilverEars]

Also these graphs shows that line-out isn't always beneficial.  Notice the THD of the line-out of X3.  Not sure how accurate the data is since for the X3, the THD for left channel is magnitudes greater that the right.
 

 
 

 

[PDVJAM]

For my ears and CIEM's bass on DX50/DX90 same.

 

[SilverEars]

  Below shows that output impedance(was spec to be <.3ohms, never trust specs!!!) is not linear with DX50 and there will most likely be bass roll-off with iems.  Anybody know what the audible affects of subbass roll-off?
 

 

Another comment regarding output impedance.  Tyll calculated the output impedance of AK240 being 3.24ohm, but this was done using a tone.  AK240 is spec'd to be 2ohms, and likely the AK240 also has non-linear output impedance response.  I would think all sources have non-linear output impedance response to a degree.  Possibly Calyx off has bass roll-off with different loads because of the same reason.  We all know specs don't tell you the whole picture.