I've been a fan of the SRS iWow audio adapter for my iPod Classic for a number of years. What this dongle did is make iTunes audio sound dramatically better. It tightened the bass, improved the treble and added a good deal of presence to my music with the largest difference being heard in acoustic or orchestral tracks. It also punched up the audio of videos to an extent.
This wasn't done by just increasing the volume, which would be the easy way. Instead, it added proprietary post processing to improve the sound. The downsides were that there were no settings outside of on or off, it was rather big and clunky, and it reduced iPod battery life by 26 percent.
At Macworld 2011, I met with Shawn Kamal, an engineer turned product marketing manager, who introduced me to the next generation -- now made smaller, totally redone and retitled the SRS iWow 3D (US $59.95). The product is now shipping in black, and there is also a bundle for $79.95 that adds four snap on color face plates -- the colors used are those of the majority of iPhone cases -- and a pair of ear buds that are nothing special.
Comparing the old and the new
I was very interested to compare the older iWow with the iWow 3D and hear if it was worth buying again, since there will be no special upgrade price for the new unit. The answer is an unqualified yes. The bass is tighter, the treble clearer, and the soundfield is much wider -- usually sounding like it's a few feet to the left and right of your head. The 3D effect is less than precise, but it is there and does make a big difference, particularly when listening to sound coming from a video -- especially an action movie. I couldn't hear specific sounds behind me, but the holographic effect was dramatic. In fact, I'd go so far as saying that it will make your headphones or speakers plugged into the iWow 3D sound twice as good as they do now.