They might be a bit narrow sounding at times if that's what you mean, though being myself an owner of the HD598 which have a HUGE soundstage, I can tell you that when it comes to music the more important aspect is accuracy and how convencing the soundstage and imaging at any given time can be and sure nothing in particular chaotic or unrealistically wide. My HD598 are great for movies and gaming but I honestly don't like them for music for two reasons: i) their grittinness in the highs which ruins the timbre (makes them sound metallic) and ii) the rediculously ''overdone'' wide soundstage which is vastly exagerrated and that is evident with recordings and albums I am familiar with for decades. When I want to test the speed of an iem or headphone I usually throw in some early Avantasia songs from the first 2 albums when the production was more organic and a lot less computer processed, compared to their later recordings or some late 80's Helloween or Running Wild. These recordings are difficult to handle due to the analogue old school recording techniques they used back then and are usually prone to sibilance and harshness.However, those recordings -if rightly (re)presented- can sound magical with their organic lifelike nature. The RE-400 remain amazingly cohesive and fast with those. I seriously can't fault these iems. To my ears, they don't have any particular flaw in their sound signature. There might be better iems when it comes to transparency or others with a more prominent low end but at the same time those would lose somewhere else, eg in timbre, neutrality, naturaleness. Having said that, no iem is perfect and I'm sure this is something widely accepted even by the owners of the most expensive ones out there. The RE-400 just do everything right and effortlessly with a great balance, and the less possible compromise in every single sound parameter.