You sound a bit harsh and offensive, like your headphones. Maybe you should calm down first, take a deep breath, relax. Now let's take your statements one by one.
I have had many laptops in my miserable life. Talking about Vaio's, I will mention the three most recent: a FW31 made in China, a P21 and the top of the line business Z twenty something, carbon fibre, both made in Japan. The Z was a lovely machine, one of the best screens at the time, but a crap, tiny, distorted sound and a crap sound card. And I wouldn't say the other two were any better. Usable at best but nothing to write about. I got rid of them in the end not because of the sound but because I couldn't stand the amount of bloatware needed to keep a Sony machine running, the incredibly poor support, with driver upgrades once every few years if you were lucky to see any upgrades at all. The same thing with their media players, book readers etc. Very accomplished hardware, rubbish software.
iBasso - I have yet to hear something decent manufactured by this company. I have had a few of their amplifiers / DAC's (don't ask me numbers, I really can't tell but I do remember maybe one of the worst of the lot - T10, highly acclaimed here), never been impressed. If anything they made my IEM sounding slightly better / weightier but with any proper, full size headphones they invariably degraded the sound. Mr Meier's creations, the iQube to give just a few examples are in my humble opinion in a different league.
I think the sound signature of a headphone is more or less indistinguishable from its sound quality. You are free to dissect notions if it makes you feel better but harshness has as much to do with the sound signature as with the sound quality of a product. And having owned plenty of good headphones - including 900 Pro, two Edition 8's, T1, D7000, HD580, 600, 650, 800, K701, Grado - most of them up to and including GS1000, even toys like Aiaiai, B&W, plenty of IEM's including my current JH13 Pro etc, I think I have a pretty good idea about headphones generally and Ultrasone particularly. Which is not to say that my opinion is any better and more valid than yours. But...
Ed.8 sounded pretty bright and shrill from my Vaio sound card output, been there, done it. I don't have a Vaio anymore but since Sig Pro has a similar sound signature, I would expect similar results. Most Ultrasone headphones have a specific voicing, dividing opinions. Signature Pro however is probably the least Ultrasone-like and the most balanced, neutral, smooth headphone manufactured by the German company. You find Sig Pro bright or harsh or whatever, then
maybe Ultrasone is not the brand for you.
All Ultrasone headphones have a recessed midrange and an overall "V" shaped frequency plot and Signature Pro is no exception, therefore I strongly disagree with the "upper midrange" emphasis. However Signature Pro is less so than other Ultrasone headphones so it's not as striking (although still obvious). But purely for vocals, voices, Ultrasone would certainly
not be my first choice.
As to how certain things improve what, I have said it a million times. Garbage in, garbage out. Get the best source you can afford,
then make statements. There is a reason why audiophiles don't use laptop outputs as sources in their systems and it's not snobbery. If you don't already know the reason, hopefully you will find out in time. The iPhone is also a pretty decent DAP but, sorry to report, my HDTracks FLAC's (I have the FLAC player installed in case you're wondering) sound no better than decent bitrate mp3's so the proof is in the pudding. And compared to, say, my Hifiman or bug (read Dragonfly) it sounds slightly metallic, digital, lean, harsh. So yes, I have all these toys, I can compare them, I can tell you first hand what is what. Can
you try the Sig Pro on a DAC202 to see what you are missing?
As for amplifiers, most "audiophile" amplifiers I've heard are not purely linear, transparent, "wire with gain" as they like to put it. Most of them implement various trickery to heighten and widen the soundstage, boost the bass, smooth the highs. With Sig Pro / Ed.8 you don't need quantity, they're both very efficient headphones and they hardly need any power at all (although more power always means better control) but the sound signature of certain amplifiers can compliment well their own sound signature.
Having said all this, I find Sig Pro one of the least harsh headphones I have heard to date and I'm not saying it because I like it, preferring in fact my Ed. 8 as I have stated before in another thread. Now I would like to hear opinions about Signature DJ please
.