He 1000v1 more warm sounding? Maybe (or most likely) but it has been a while since I parted with mine via the upgrade to the He1000SE. However, I think the He1000SE crushes the v1 in detail-retrieval at both ends of the spectrum, refinement, airiness, and texture in both high and low frequencies, and imaging, without sacrificing anything important, and most importantly, without becoming fatiguing. Soundstage sounds like a wash between the two, and although I did love my He 1000v1 a lot, the He-1000SE made it (the HeK) sound relatively rolled off at the top, and maybe a tad too smooth (which is why I cannot directly answer the question about whether it was more "warm sounding," which I am finding difficult to distinguish from the "smooth-sounding"-slightly rolled-off part). At any rate, to these ears, the SQ upgrade to the He-1000SE had no downsides that I can remember...although, as usual, mileages may vary. For one thing, the v1 is already very good in its own right, and has to be played side by side with the He-1000SE for one to reliably compare the differences. Those differences are not necessarily subtle, although the two headphones retain the same hifiman high-end HP house sound, if there is such a thing. As usual, aftermarket cables are a must for best results, in my opinion, whether one is sticking with the v1 or upgrading to the HeKse.