Taken from : //www.macnn.com/reviews/kanex-xd-for-27-inch-imac.html

Kanex XD for 27-inch iMac

May 8th, 2010
Kanex lets iMac owners turn their screen into a TV.

The Kanex XD is in theory the dream device for apartment dwellers, or just those who don't want to buy a separate TV: it turns the 27-inch iMac into a full-fledged TV for anything that works with an HDMI input, such as a PlayStation 3 or even your cable set-top box. At $150, however, is the feature set good enough to have you abandoning conventional TV sets? We hope to find out in a full review. What's included and setting up

There's not much to bundle in the box with the XD, but thankfully Kanex has included what arguably matters the most. Besides the essential power adapter, the box hides both a 3-foot Mini DisplayPort (miniDP) cable and a 3-foot HDMI cable. As such, it's not hard to get started even if your source equipment doesn't have a bundled HDMI cable; the modern PS3 and Xbox 360 are the notable examples where this becomes distinctly useful. That said, the short cable length means you'll still be shopping for a longer HDMI cable if the source can't sit close by; any set-top boxes you use will probably have to sit on the desk itself.

Connecting it all up is, not surprisingly, quite simple. About the toughest part was plugging the miniDP cable into the iMac itself, which required more force you'd suspect. Kanex rather thoughtfully has lights on both ends of the adapter, so you'll know if the miniDP cable or iMac isn't receiving the signal even if the XD can tell its HDMI source is working.

By far the most appreciated touch is simply the nature of the format: because you're converting from HDMI to miniDP, both of which support audio on the same signal, there's no separate audio cables to plug in. It would be nice if there was the option to route audio separately -- some may want to bypass the iMac entirely for this -- but the simplicity is hard to argue.

There aren't any manuals, but Kanex is quick to point out that a quick Command-F2 shortcut will switch back to the iMac's main display. That's really all that's needed and a definite time saver given that few will unplug the XD every time.

The one obstacle is simply the plugin order. To get the "best results," Kanex recommends that you first power the device, then connect to the XD and finally link the miniDP cable. It's logical, but if you have to reconnect often it could get to be a nuisance.


When everything is set up properly, the Kanex XD largely works as advertised. The all-digital signal shows no noticeable degradation or scaling artifacts, and audio comes out at a good volume and quality. We didn't detect any tangible audio or video lag with a PS3 or a Zune HD AV dock. That's especially important for PS3 and Xbox 360 gamers who might lose in a fighting game due to any significant delay between their input and what's on screen.

It's here, though, that we encounter the XD's primary limitation: its maximum 720p resolution for many HDMI sources. Despite the iMac supporting up to 2560x1440 on its own, you're reduced to just a quarter of that resolution (1280x720) for the actual signal. We can somewhat understand why this is, since 720p scales neatly on the iMac's display, Kanex doesn't have to do elaborate scaling for the output to look correct. For the PS3, Xbox 360 and Zune HD, this won't be much of an issue since they rarely if ever output above that resolution. For Blu-ray players and other 1080p-capable devices, it's a major inconvenience; you're only sitting 2-3 feet away in normal situations, so you'll notice the imperfections of 720p much more than you would with a TV.

The limitation is hard-coded, too. We tried plugging in our PS3 while it was configured for 1080p, and it simply generated a blank screen. This admittedly isn't likely to happen if you're setting up the PS3 for the Kanex adapter first or if you were already using 720p, but it can be a definite hassle. Combine that with the spec's current limitation to stereo audio and you won't quite have a real home theater experience.

Before we criticize Kanex too harshly, we should note that some of the fault here is Apple's current implementation of the 27-inch display's resolution modes. As of this writing, the EDID (Extended Display Identification Data) for the screen will only accept 16:9 aspect ratio input in either the iMac's native resolution or 720p. The Kanex XD therefore can accept 1080p -- but not from an iMac. It doesn't change the reality for the end user but does mean the add-on could get more advanced resolutions with future iMac firmware updates, if any.

Wrapping up

Kanex is very forthright with what the XD does and makes it as easy as possible to get started. If you're in a studio apartment and your choice is either a 27-inch iMac or a 27-inch TV, you can get the adapter knowing it should accept most current HD properly and will save you both some cash and some space.

The operative term is, of course, "most." For $150, it's somewhat disappointing the adapter won't change resolution to accommodate 1080p. What the adapter does now is good for many purposes, but we can see a point a few years into ownership where the Kanex XD is made obsolete by newer consoles or 1080p-plus TV sources.

It's still a definite success as an adapter, but don't expect to never need another adapter again.

Until 7/20/10 click here to enter our Kanex XD giveaway.

- Good image and audio quality.

- No visible lag.

- Simple setup.

- No 1080p or surround audio.

- Expensive.