Has anyone else ever reached an audio impasse?

You say SACDs do not sound better than regular CDs. Do they at least sound different?

The reason, I suggested trying an ELS speaker was in fact for you to see, if the "coating" still persists, because those kinds of transducers never come close to "coating" the music even ever so slightly. A "positive" result would rule out, that the cause lies in your Dynaudios. Perhaps, as was suggested above, it is indeed your listening room.
I've been in a similar quandary before, which I was also quite unable to resolve, but later learnt to put down to overwork and mental fatigue, which simply closed my ears down for a while.....

Detlof - this might be something we should try. At least it will help us to determine the bottle neck - if any. And you may be correct. We could have been listening too much lately - and become burnt out.

Drubin - CORRECT! SACD's sound almost exactly like the regular CD. In fact in most cases, the regular CD (un-remastered) sounded slightly better than the SACD version.

For instance, the degree that the 15K cd player is better than the $900 SACD player is virtually the same if the SACD is playing a SACD or a redbook CD. AND - if the SACD player is playing a SACD compared to the redbook player with a normal CD.

Likewise, the 100 DVD player sounds only marginally different (better or worse is difficult to determine) than the 15K CD player or the SACD player (with both formats).

This simple test is what has me stumped. It seems that regardless of source component or software, the system has reached a level of resolution with its preamp/amp/cables that cannot be outdone or even altered by the source component. I hesitate to think there is a "bottle neck" but what else could it be?

The easiest and most noticable difference between the various CD (DVD/SACD) players in the past has been the size of the sound stage. Playing the Sony caused the soundstage to collapse dramatically when compared to the 15K cd player.
It took less than a second to hear the difference as it was not subtle.

For whatever reason - now there seems to be no difference. My gut tells me that something we did to improve other areas of the system - somehow adds dimension to the less expensive CD players but doesn't seem to benefit the more expensive CD player as much.

Dont get me wrong - the system sounds fantastic. I am simply in a quandry as I try to figure out why there isn't a more dramatic change in character between the various source units and software.

Detlof may have the answer. Maybe it's those darn Dynaudio's but they are simply one of the finest speakers in existance. 5 way design which ranges from a super tweeter - tweeter - dome midrange - midrange/midbase - dual 10' bass drivers. This speaker should play anything which is thrown at it and if it is the bottle neck, I would be very, very, very, surprised.

Argh!!! This is making my head hurt!

B, I sincerely hope that I'm NOT right. The Dynaudios will play louder, higher, deeper and dynamically punchier than most of the ESL would. However those are unbeaten in the midrange, where most of our finer listening takes place, so I'd try the experiment all the same, if you can. Also, If you cannot get stators, perhaps you could try some of the BBC type monitors, like the Spendor, which have also excellent midrange rendering. Also Maggies would do, I think. Good luck and hopefully it won't spoil your holiday!

If neither you nor your friend can hear an improvement between CD and SACD on his 100K system, then you have both lost your hearing, or you should immediately sell the 100K system and purchase a 20K system, or this is an early April fool's joke. The improvement from CD to SACD is so pronounced that even a mid-fi system should reveal it. Maybe you should introduce another CD player (at the 2k or so level) to the test and listen for differences. It seems that you have a very wide gap among your current candidates. You wouldn't be the first serious listener to discover that an outrageously expensive component just isn't worth it.