Verified answer

I hate to point this out, but the first answer is indeed wrong.

Both receivers are in fact 3D ready receivers.

It is true that the 1611 is 7.1, while the 1612 is 5.1. The reason the 1612 is slightly more expensive is because it has built-in upscaling.

Will you lose quality or features with the 1611? That depends. If you go with the 1611, you will actually gain an extra 2 channels. But then again, most people don't even have rooms large enough to need a 7.1 system. If this is your case, then you would be adding a feature that you really don't use.

If you buy the 1612, you will get upscaling. Again, this may be a feature that you do not use. The most useful aspect of an upscaling receiver is if you have a standard DVD player. It can actually upscale the DVD's 480 image to 720. If you have a large TV and no Blu Ray player, this could be a nice feature.

The 1611 is 7.1 and 3d the 1612 is 5.1 and no 3d are the two main things. The 1611 is also cheaper. Read Items 2 and 3 in the link under source.