Free on the app store today, Audio-3D Player 7.1 is a home cinema emulator for your iDevices that simulates not only a 7.1 surround hi-fi system, but also sports a 2.1 HiFi emulator with 360 degree directional audio functionality. I'm always impressed by audio math, and having written some of these algorithms myself I'm always excited to see what engineers come up with especially in the HRTF realm. [caption id="attachment_3148" align="alignleft" width="150"] Headphone Selection[/caption] When the app first boots, you're presented with the option to select your headphones. "Great!" I thought, "I've got my Momentum's right here." My first impressions were mixed. The interface on the app is good, and it lets you run these tests with any of the music from your iPod library. Switching between the simulators and messing with the positioning was easy to do, but that's where things took a turn for the south. The EQ curve they placed on my trusty cans made them sound brittle and sterile, with just a touch of headache. In either mode, 7.1 or 2.1, they took all the life out of the headset that I've begun to love so dearly. Good thing this app was free. [caption id="attachment_3149" align="alignright" width="150"] The apps main screen[/caption] That being said, they did make it sound like I was listening to speakers... they were just over in the next room. The reverberation effect that's applied was just subpar and lifeless. Either that, or its an incredibly realistic reproduction of one of the worst sounding rooms I've heard to date. Couple that with the built in EQ curve for the Momentum, and even the subwoofer test sounded distant and terrible. I was literally wincing from pain after just 2 minutes of listening with the 7.1 system engaged. Full disclosure, I am not a listener who uses crossfeed or advanced processing. I usually listen with no EQ applied and a very clean signal path. I am, however, a big fan of the technical aspect and the math behind transfer functions and its ilk. I do want to bring the best sound processing possible to those who want it, and I think there is a lot of room in this space for expansion. What Dolby Headphone is doing is quite amazing, but this app here my friends, this isn't it. But hey, download it for free today. We all hear things differently, so give it a shot. Maybe I'm wrong... Let me know! You can also read more at Audio 3D's website.