Originally Posted by rsar
What kind of additional amplifier do I need to utilize all of the 929 speaker outputs?
To get 11.1 audio you have to add a stereo amplifier. Without it the receiver only does 9.1. (the sub outputs are like a y connector and mono so the 929 should really have been called 9.1 not 9.2)
Just about any amplifier will do so if you have an existing vintage receiver with an adapter patch bay on the back for graphic EQ you can use the input half of that patch bay (you can also use the aux input if you leave the volume set to about 50% and disable tone and loudness and boost/cut filters), but if you want quality sound from the wides equal to what the rest of the channels are capable of you should plan on a receiver or integrated stereo amp that will output ~130WPC into 8 ohms.
Note that the center speaker will be doing most of the work so you can probably get by with less wattage on the wides but if you have to buy new you should probably match the capability of the receiver anyway.
Only 3 titles were released in Neo:x encoding so the only advantage of the wide or height speakers in Neo:x decoding with this receiver is in 'upmixing' for ambiance extraction. DSX does something similar but seems not to work very well IMO, probably because it tries to simulate reflections of a large room rather than just working with the program ambiance.
Speaker placement is critical. Your wides need to be right between your front mains and side surrounds, along the side walls and at the same height as the front mains or only slightly higher.
Your heights should be in/on the ceiling directly above the center of the room and spaced left to right about the same l/r separation as your left/right mains. If not in/on the ceiling then maybe try separating them more to the l/r and placing in the edge between side wall and ceiling.
Typical instructions place the heights as high up as possible on the front wall or in other words in the edge between front wall and ceiling. IMO this does not give them enough separation from the front l/r mains and reduces their imaging. They need to be closer to the front-to-back center of the room and preferably in/on the ceiling so that they sound like they are coming from directly overhead. If they are in the center of the room front-to-back they also occupy the space between the wides and side surrounds and that helps add separation by maximizing their distance to all other channels.
Note that deviating from the typical instructions (front wall as high as possible) as I suggested will make the 'screeen centered dialog' function add center channel to the mains and also to the heights that are directly overhead. That might sound odd with center channel dialog directly overhead, but IME 'screen centered dialog' sounds oddly monoaural anyway. I only use it for dialog intelligibility at very low volumes.
If you position any of the speakers in odd places you may find the imaging is not good due to speakers being too close to each other and not hearing any separation between them. The more speakers there are in a room, the more critical it is to ensure they all have maximally distant angular separation from each other as measured from the main listening position. My recommendation to put the heights overhead in line with the l/r mains maximizes the separation and that gives the most pleasing result with Neo:x upmix IMO.
Remember, if you are using Dynamic EQ for listening substantially below reference (-15dB or lower) you might want to adjust the side/rear surround levels down about 2dB, or if you have run out of downward adjustment range like me you can increase all the other non-subwoofer levels up about 2dB instead. Dynamic EQ applies more level boost to the surrounds the lower the volume control is set and IMO it makes the image sound unnaturally 'inside the head' like listening through headphones, with almost no front-to-back depth at all, particularly with surround music. Reducing the relative output of the surrounds restores the natural front-to-back balance. THX Loudness Plus (configurable in the setup menu) also increases surround level at lower volumes but the change is so subtle it is hardly noticeable.