Hi, I have both cards in my system. Wrote a very brief review some time ago (see below). I now use EMU0404 exclusively for foobar2k playback. And the AV710 for regular things like movies, PC sounds, games etc. Both card outputs hooked up the AUX1/AUX2 line-in on my Exposure amplifier, so that I can easily switch between the cards.
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After spending some time comparing the 2 cards, my comments are:
AV710 sounds slightly thinner across the frequency spectrum, while instruments (esp. acoustics) on the 0404 sounds fuller.
AV710's very-high frequencies sounds exaggerated. Which is great for expanding sound stage and make ambient-electronica compositions positively ethereal. Which is very cool, if you are into those sort of music. Also, my equpiment is excellent at smoothening harshness; so I would hazard a guess that better resolving and more accurate equipment would reveal the exaggerated highs to be quite harsh sounding.
As for mid-range and lows (can't comment on very lows as I have bookshelf speakers), AV-710 lacks the control of the 0404. Songs with lots of mid-range content sounds like "a lump of music" coming at you. But with the 0404, there is noticeable separation in instrumentation as well as vocals. The 0404 is also a tad more refine and less fatiguing. But not so much that makes it sound boring.
Equipment:
Exposure XX int amp
Mission 780 mk1 modded with solid-copper wire(TaraLabs)
TaraLabs solid-copper speaker cables
Homebrew Cat5e litz interconnects to soundcard
Virtually inaudible PC setup
Music tested:
Telepopmusic - Dance Me/Incertitude D'Heisenberg
Air - Universal Traveller/Alone in Kyoto
Kosheen - Wish/Recovery
New Radicals - You get what you give
Barber's Adagio op. 11 (unknown performers)
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