The AD-900X has adequate bass--it goes deep and it has a nice sense of impact, but it does not rumble or boom. Rap and electronic are meh on it. The DT-990 has much more body in the bass. For everything else, it's either a tie or the AD-900X wins. It has a more natural tone, larger sense of space, and it's less harsh.
The 990s are excellent for normal studio use when you want to hear everything clearly, since the 770s have low output on mids and highs. I own all three and they all have their uses, but the v modas work the best for djing. Pay close attention to ohms. The v modas are efficient enough to be driven by dj controllers, but the 770 and 990 are not.
Perhaps the AKG K501 (old but really good), K612 Pro et al. The Beyers have a voluptuous bass that muffles the mids especially in fast music. The DT 990 Pro also has a very peaky treble below 10KHz which is very noticeable and annoying while the DT 770 has a boomy bass and a bright treble too.
What is the differnce between DT 880 PRO and DT 990 PRO? Why does my DT 770 / 880 / 990 PRO have mismatching Logos on Product and Packaging? Why does my DT 770/990 PRO have another connection cable with a smaller thread? Which amplifier or interface should I consider to buy to get the best sound out of my DT 770/880/990 PRO with 32/80/250 ohms?
I since then decided to buy a Magni 3+/Modi 3 Schiit stack and want to take advantage of the power output capable of these two devices. I was wondering if upgrading to a DT 1770 250Ohm would be worth the hike in price from the DT 770 250Ohm. The DT 770 250Ohm i can get for $160 compared to the DT 1770’s being $430 currently.