However I wouldn’t mind some headphones I could also port across to my hifi.
Thoughts on the AKG 702’s? Appreciate they don’t come with a mic, but there is the ModMic option...
Would my sound card be enough to drive them, or would a dedicated amp be required like the Asus U7?
No reason to not use same headphones for gaming and music.
Headphones good for binaural sound do well in music, because binaural sound needs good overall sound quality.
(unless music means only bass and nothing more)
AKG K701/702 are among absolute top headphones for binaural gaming.
With neutral bass taking back seat to details they're pretty much at aural "god mode/wall hack" level in locating sound sources.
ATH-AD700x has equal sound stage, but its bass is below neutral lacking lower bass lowering overall immersion.
That highest possible "competitiveness" always means compromising in "fun factor", because stronger bass makes foot steps and such details not so obvious.
DT990 does well in that fun factor, but also with sound stage notch below AKGs isn't as high in competitiveness.
Though lot better than average headphone and especially closed gaming stuff. (also famous for music HD650 Sennheiser would lose clearly)
K712 has AKG sound stage with above neutral bass, losing little to DT990 in fun but being more competitive.
Myself have five years old DT990 and couple months ago bought K712 and second hand K702 for bass neutral reference.
(+tape keeping parts from falling HD595 Sennheiser, which lacks above neutral bass of DT990/K712 while having DT990 level sound stage)
Also V-Moda BoomPro mic could be used with detachable cable AKGs when using this kind adapter:
BGS 3 Pin Mini XLR Female to 3.5mm Female Stereo Headphone Jack Adapter with AKG Wiring
That would avoid separate cables of ModMic.
While Asus certainly brought competition to sound cards in some areas mostly they just managed marketing hype lot better than Creative.
That Xonar U7 looks to be of those hype products.
Its headphone output seems to be even weaker than that of integrated Realtek codecs which do 1 Vrms to 32 ohms:
http://reference-audio-analyzer.pro/en/report/amp/asus-u7-hp.php#rw11
And SB Z does better than Realteks.
Also Dolby Headphone of those Xonars is overall mediocre with bass bloat and echo.
Though those AKGs are certainly more demanding than average headphones with their current requirement.
(with lower current draw 250 ohm Beyers are actually easier load)
In high dynamic range content like classical music SB Z could struggle to drive them fully.
In such content average signal level is low and you ramp up volume basing to that, while there are shorter transients and moments with lot louder sound requiring much more power.
Though again in games signal level is kept lot more even.
Because it would be annoying to have ears ringing when shooting match starts, if having enough volume for hearing foot steps.