I purchased the Apollo Duo to up my game a bit in the stereo concert recording work that I do. I had been "getting by" with the mic pres and converters on the Avid MBox 2, and as a back up was recording the stereo feed into a Zoom H4 recorder. The mics were a spaced stereo pair of AKG 414's. The H4 came to my rescue a couple times over the years as I sometimes experienced Pro Tools crashing in the middle of a recording. (Reminder: always have a backup!) Overall, the sound was certainly acceptable and people complimented me on the fidelity of the recordings.
Well, the time and opportunity came for an upgrade to my mic pres and converters and I jumped on it. I researched on the internet, read reviews, consulted with my Sweetwater guru, and also another very experienced engineer friend who really knows about high end recording gear. I ended up selecting the UAD Apollo Duo based on its price point and feature set. Many reviews were overwhelmingly positive.
I recorded the concert (Asheville Community Band) on the new Apollo rig via an external FW800 drive as well as the H4 for backup. .wav files were recorded at 24/96. I got back to my studio and, on a whim, compared the two stereo recorded tracks: one the H4, the other the Apollo Duo. I soloed back and forth with both continuous and looping time aligned tracks. My studio rig is a Pro Tools HD Accel 3 with the Avid 192 I/O interface.
I was astonished to discover there was virtually NO DIFFERENCE in the recording quality. Nothing. I scrutinized every comparison I could think of... stereo imaging, dimensionality and depth, hi end graininess, low end sonics, noise floor, transient response (audience applause) very loud passages, solo passages, etc. There was no discernible difference between the two. This got me more than a little irritated... What is this? Is it me? Why doesn't the Apollo blow the N4 away? What am I NOT hearing? (I've been an engineer a long time and am supposed to hear stuff like this)
I returned the Apollo Duo and am going to stay with the gear I already have for the time being. For all those out there seeking the next level of audio quality, it is absolutely true that *a lot* more money has to be spent to get really hi end sonics. The Apollo is a fine unit, don't get me wrong. If you are blown away by the sound of it compared to your old rig that's great, but that was not the case for me and might be the same for others who read this.
My sales engineer at Sweetwater correctly said that discerning audio quality is a very subjective thing, to which notion I was already familiar with. Even so, I was shocked the lowly Zoom N4 matched the Apollo Duo sonically. He also admitted the H4 (and its successor the H4n) is an amazing value for the money. To my ears, the converters (not the microphones) of that device do just as fine a job recording digital audio (24/96) than gear costing almost 10x as much! It's also hardware and never crashes! (At least not yet)
The Apollo Duo has many more features of course. The front end console software runs great. It comes with a bounty of excellent plug ins. It sounds good. It's beautifully packaged, almost like opening up an Apple product. But think twice before you spring for the hype. No need to "upgrade" into this huge upper middle class of preamps and converters unless you really need to... you will only be trading sideways. The truly high end stuff costs a lot more than the Apollo class does, and is in a different realm of sonics entirely. Is it worth spending hundreds (or thousands) of dollars more for a slight incremental improvement in sound quality? You decide. I'm sticking to what I've got for now. I give three stars because it is still a quality product.