I'd like to share my experience with Audyssey MultEQ XT32. I started using MultEQ XT32 back in 2013 when I pudchased a Marantz AV8801 processor. My small listening room, in effect my living room, measures 13 x 13 x 8 feet (4 x 4 x 2,4 m). Despite the 13 channels available on the AV8801, because of the limited space I have and the right side of the room flanked by a pair of windows and a door leading to the balcony, I only really have space for a 5.1 multi-channel setup although I'd like to run a dual subwoofer configuration sometime in the future.
The goal for the acquisition of the AV8801 at the time was to have an up to date AV processor that sounded great with my growing collection of multi-channel DVD-Audio, SACD, and later on Blu-ray audio along with support for the new Blu-ray losless audio codecs (Dolby True-HD & DTS Master-Audio) and the addition of Audyssey's MultEQ XT32 digital room correction to help reduce room modes.
Before the use of Audyssey, I had horrible room modes where the bass resonated way too much for my taste. You could really tell that it muffled much of the sound from the midrange. Audyssey really did a great job of taming the room modes and opening up the sound letting through more midrange detail. I mostly favored the Audyssey flat curve.
However, through the years and with repeated critical listening tests with Audyssey active and off on the same tracks, it became clear to me that there was a side effect that I was hearing and that I had indeed heard before but that I had pushed to the back of my subconscious mind since the results in terms of reducing the room modes were so successful. This side effect that had resurfaced from the inner depths of my mind and that I could no longer ignore is a compression of the soundstage. It's a clear reduction in the width of the stereo image and also of the depth of the soundstage. Many musical instruments also seem to be somewhat slightly elevated vertically. Later on after some searching online, I found a couple of Audyssey users on other forums that reported observing a similar compression of the soundstage.
When a good audiophile friend of mine would come over to listen to music, he was never too convinced with my demos of Audyssey althoughh he couldn't quite put is finger on what didn't sit well with him in spite of the clear reduction of room modes. He would always ask me to turn off XT32. A few years later on one occasion of critical listening to some new recordings, I pointed out to him what I had come to realize or rather accept. We listened to a few tracks with Audyssey both on and off and he agreed with my observations.
I haven't given up on finding a DRC solution that will again tame those foom modes without affecting the soundstage. I want to try Dirac Live on a future HTPC build project as it appears to have become a much preferred solution in the last few years. Some audio companies have like NAD and Wisdom Audio have actually ditched Audyssey in favor of Dirac over the last few years. One characteristic that seems to be superior with Dirac versus Audyssey is the improved impulse response allegedly made possible by their particular use of mixed FIR and IIR filters or so they claim. Measurements by a few users on some forums seem to lend some credence to such claims like the one
posted by AustinJerry's measurements posted on AVS Forum. According to the Dirac white paper that has been pointed out by a couple of previous posters on this thread,
"ON ROOM CORRECTION AND EQUALIZATION OF SOUND SYSTEMS" , Mathias Johansson of Dirac Research makes the following assertion:
I can't say for sure that the phenomenon related in the excerpt above is the exact explanation of what I'm observing with respect to the soundstage compression but it may be a possible cause.
In the last few years I use Audyssey on movies but when I sit down to listen to music, I turn it off and live with the room modes. I actually prefer the sound coming out of my Oppo UDP-205 straight into my Parasound A21 amp and their little brothers. The Oppo's DACs and analog outputs walk all over the AV8801's TI PCM1795 DACs and much overhyped Marantz HDAM analog section. Furthermore, in light of Amir's review of Marantz's latest but lackluster AV8805 measurements sporting the much newer and arguably better AKM DACs with improved HDAM modules versus my now aging AV8801, it follows naturally from the Oppo UDP-205's excellent measurements that it sounds better.
Damn! this little hobby becomes expensive over the years.