Originally Posted by ComponentActual
I actually ended up purchasing the Onkyo TX-NR818
My impressions of Audyssey DSX, DTS Neo:x and PLIIz align with yours.
Glad you got what you wanted. My observations are noted after the details of my system (noted for perspective):
I purchased the TX-NR929 from accessories4less, refurbished, at just barely over your price range. It has 9 amplifiers and 11.1 preamp out. It allows speaker connections for 2 of 3 height/wide/rear. In 11 channel mode it requires an external amp for wide.
I also purchased Sapphire/TSC towers/bookshelves/center and dual SVS PB10 subs and a Crown 210 external amp.
I purchased everything used at ridiculously low prices and/or built/repaired it myself in order to stretch the budget. This explains the odd choice of speakers that I find to be incredibly good for what I paid (~$2500 total for the whole 11.1 system).
The front L/R are the mid-height MTM ST2 tower.
The wides are the SB bookshelf hanging in basketball nets at 5 feet high.
The heights are SBL mounted to the wall at ceiling height.
The center is 2-way 'MTM' TC2 (actually the same MTM drivers as the towers but 2-way crossover instead of 3-way) in a huge rear-projector-style glass/metal shelving unit.
The surrounds are the taller MTM ST3 towers.
One issue I have is a smallish room with too much in it but little wall treatment (so far).
During calibration sweeps I noticed a marked ring from the left height channel as the sound ping-pongs between front and rear walls. This might be affecting my ability to distinguish height from the rest of the sound. There is a tapestry opposite the right height channel and it has no such issue.
Another issue is the small and light but not so great SBL model connected as heights that I rarely hear much from.
More troublesome is my impression that the height signals are actually mono? even though they are amp'ed and eq'ed separately. Anyone know anything about this?
One aspect of my front sound stage is that dialog can be difficult to hear from the center. The Sapphire/TSC TC2 center channel is slightly boomy in my shelving unit, so I stuffed a folded/balled pair of gym socks into the port and that seemed to tame it some.
'Screen-centered dialog' improves dialogue intelligibility by blending center channel content into the l/r/lh/rh channels.
Of my entire system, I found that the channels that are causing me the most grief are those that are also subject to the worst placement constraints -- the tiny height channels and the cramped center channel, both 2-way designs to save space in cramped/boomy/ringy mounting location and both also having the inherently worst sound of all the speaker models. Maybe this sort of issue is affecting your setup also?
Have you tried connecting better speakers to your height channels? Wall mounting is tough in the top corner. Have you tried putting yours on/in the ceiling? Room treatments?
I find the DTS Neo:x algorithm seems to add almost nothing to most of my 5.1 media (especially music). The sound is nearly identical to native channel mapping and when I put my ear against the height/wide/rear speakers almost nothing is there. Same for PLIIz, it seems to add almost nothing to PLIIx although PLIIx definitely sounds markedly different from 5.1. The effect on movies may be better but I rarely use these modes after having experienced little 9.1/11.1 enhancement before.
Audyssey DSX on the other hand is a little bass-heavy but improves imaging and intelligibility when Audyssey Movie/Music eq is also selected. I keep the reference level of the dynamic EQ at about 10dB but sometimes I lower it to 5dB or 0dB depending on the material.
Occasionally rain and wind do seem to come from the heights but they rarely seem to contribute.
In contrast to the heights, the surround improvement from the wides is very noticeable with Audyssey DSX. Perhaps this is due to the difference in algorithmic approach from Neo:x.
Audyssey in general works extensively with time-domain functions and the wides/heights are used to add an 'early reflection' from the side wall and ceiling of the 'venue' rather than using FFT ambiance steering. I find this effect much more compelling than Neo:x or PLIIz. Audyssey also works with PLIIx on my receiver and I really like that algorithm for generating 7.1 since the rear sound stage is very convincing. Finally, Audyssey not only drops the entire 7.1 soundstage by 3dB but also allows +/-3dB adjustment of the height/wide channels so the balance can be corrected and I did notice this helps on material with less 'ambiance' effect but I usually leave it at 0dB.
Whenever I do change to Neo:x or PLIIz, I have to re-adjust other parameters, particularly I have to turn off Audyssey movie/music EQ mode and reset the reference level for Dynamic EQ back to 0 (I usually keep it between 5 and 10) so this is an inconvenience that discourages me from experimenting with the less satisfactory algorithms.
I am not a gamer so I have no insight except that game modes seem to have less processing and better directionality while having possibly poorer imaging overall.
I hope my observations help you tune your system. Enjoy!