I thought I would post my experiences with Pioneers MCACC and Audessy XT32 for those who are looking at getting an AVR with one of these room correction softwares. Ill try and keep it simple enough that a newbie can understand but not so simple that it will bore most of you.
I purchased an Onkyo 818 specifically because it has XT32 and wanted to see how it was. I also purchased a Pioneer SC-1522k because it has a newer version of MCACC than my old Pioneer has. If you ask me, room correction software is pretty much a must. You can have the best speakers in the world hooked up to the best AVR/Amp, but have you thought about your room? As most people know rooms play huge into how speakers sound. Rooms can make speakers sound bright or muddy depending on its shape/layout and where the speakers are placed. Speaker placement can often be challenging....most of us don't have rooms built from the ground up around our speakers and there's always the wife/girlfriend that insists a piece of furniture has to stay put or we can't put our massive towers in the perfect location. Basically, it's rare to have speakers placed in their optimal locations in an optimal room. That's where room correction softwares come in. For those that don't know, the software works by playing various test tones over the speakers and using a calibrated mic to take measurements and compensate the sound accordingly to get a more optimal response since rooms will often color(I.e. change) the sound of our speakers. MCACC, Audessy, and YPAO these are some of the most popular room correction softwares. I only have experience with the former two so I will only comment on those.
MCACC vs Audessy XT32(Onkyo flavor)
Lets jump right in.
Speakers used: SVS Ultra Towers. A neutral sounding speaker with great detail and bass.
Room: 12ft x 12ft, untreated.
The newer MCACC setup, looks better than the old style version found on my 7 year old Pioneer Elite but it doesn't look quite as polished as Audessy does.
To my surprise Audessy's correction procedure was very fast.... I always hear about how Audessy's software is better than MCACC so I expected to hear a bunch of test tones and for it to take quite a while. Instead all I heard was 2 test tones played through each speaker. The first round of tones were a sort of speaker detection sound and the next presumably for EQ and other magic. That was it. In contrast MCACC seemed to be far more busy. MCACC played many different types of test tones, ones for speaker distance, channel level, frequency response, reverb, group delay etc. Maybe Audessy somehow managed to fit all these tests into one tone. I'm not sure. Without knowing what's really going on(I'm not an expert on these systems) MCACC sounded more through and sophisticated, which means nothing really, just thought I would mention it since I found it interesting.
On to the sound :
Fresh after each AVR was done with its calibration I changed some settings(set the x-over to 80hz etc) but I left the EQ parameters alone to hear what they sounded like "naked". In my room with my speakers I wasn't blown away with either XT32 or MCACC. They both sounded flat and a bit bright(again, this is in my small room. I've ran MCACC on my old receiver in my large home theater room and it sounded great without any fooling around, I'm sure XT32 would sound better as well I wish I could have tested them out in a few different rooms but I only had time to try my main listening room.) I invited a few friends over for some listening tests to get additional pairs of ears in the mix. To my surprise, without saying anything my girlfriend commented that the 818 with XT32 sounded flat and bright, my friend who is a DJ said the exact same thing the next day when he walked into my room as i was playing some music(I didn't even ask, he just said it). I made sure not to say anything that could influence their opinions. The onkyo flavor of XT32 has 2 options for target curves. Movie and music. In my room with my speakers the music/flat curve was way too bright, I couldn't use it so I stuck with the movie curve which has a high frequency roll-off. Unfortunately it was still a bit too bright with the movie curve. I tried running Audessy again using a better mic stand and experimenting with different mic placements; however, the end result was the same. In comes MCACC. As I mentioned before it also sounded flat and bright. Here is where MCACC's true advantage comes into play, in my opinion. You can manually edit the EQ curve without losing the other room correction benefits such as reverb correction, phase control, group delay etc. This is XT32's biggest downfall in my opinion. It spits out a curve and gives you only 2 options to choose from, if those options don't suit your ears then you are kind of screwed(you may be able to use the tone controls to help out as I did but it didn't give me enough control). I went ahead and experimented gently cutting some of the higher frequencies(mainly 4k and 8k) after modding the curve I enjoyed the sound MUCH more. Everyone's ears are different, some people are more sensitive to certain frequencies, it's really nice to be able to be able to make your speakers sound right to your ears. Ill also add that MCACC let's you modify up to 6 curves and have them available to switch on the fly. If a certain source is particularly bright or dull you can compensate using your own pre-saved EQ curves. I have 3 curves for now, one for music, one for movies and one for games. If your not EQ savvy and messing with a 9 band EQ seems like a daunting task then Pioneer has included a super easy to use EQ feature. You can select how steep a high frequency roll off curve is applied(-dB/Octave) It's not as precise as getting in there and messing with the EQ but its as simple to use as the tone control on your cars head-unit.
Now, at this point you may be thinking that I hate Audessy and that I think MCACC is the cats meow. Not quite....
If I remember correctly XT32 has a significantly higher filter/EQ resolution than MCACC. What this means is that it will do a much better job of catching peaks and dips in the frequency response. If MCACC is 480i, then XT32 is 1080p in terms of EQ resolution( I'm just using this as an example, I pulled those numbers out of my a**). If I'm incorrect on this please let me know. Additionally MCACC doesn't really touch the subwoofer. XT32 on the other hand does EQ the subwoofer(or if you don't have one, it will EQ as low as your towers can go). This would be a major problem for me if it wasn't for THX BGC. BGC is boundary gain compensation and its basically a patch fix for those who have seating positions close to the back wall or if your sub sounds too boomy. In my small room I am seated directly against the back wall(a big no-no, but I don't have another option). To keep it simple BGC uses a fancy algorithm(or maybe it's not that fancy...I don't really know
) to cut certain frequencies which are commonly a problem. Note however, that it is not a real EQ that takes a measurement and applies a change, it's just sort of a guess filter and for me it works really well! Without it my SVS sub sounds very boomy due to its location and my seating position. With BGC on the boominess is greatly reduced, but it doesn't sound as good as when XT32 EQed my sub.
Basically it's a compromise. If you aren't very picky and want something really simple that works very well for most rooms then get XT32. If your like me and you like messing around with your EQ and having multiple settings to play with then get MCACC.