Frustrated with the sound of my system

Original Poster,
I wasn't planning on another post because I still stand by what I originally said in my first post. After reading through some of the above recommendations, well meaning as they may be, I want to make just a couple of quick points that may help you out. Of all the posts on this thread, not one person, myself included, knows what is wrong with your system. That should be apparent. From what I can see, the only fix that wasn't mentioned yet, is to just bulldoze your house down and start over using audiophile building materials and room dimensions. Don't worry though; if you decide to go this route, I'm sure that we can all give you some construction advice. Aside from that, you should also realize that this is a problem that you are going to have to fix yourself. I don't deny that it may take some time and patience but if you use you head and make some careful decisions, you will get it right. (You'll also gain a lot of knowledge and experience that you can share with others just like we are all doing on this post. Another opinion is always needed.)

Over the years, I have posted several questions about possible things I might be able to do to improve my sound quality. Some questions were about speakers, some about amps, and so on. On almost every thread, advice was strongly given to treat the room. Well, the other day, I put about a 4' by 4' section of insulation on the right wall in my bedroom system, at the first reflection point. This fairly well sucked the life out of the sound. This is not to advocate against room treatments, and I think a smaller panel might be the ticket. But, apparently, it is very easy to do too much treatment.

Now, I would also recommend trying different speaker cables. The biggest recent improvement I have made in the aforementioned bedroom system(Monitor Audio Silver 9i speakers) was going to a set of Goertz MI-2 speaker cables(I had tried them years before in a different system and were in storage). Before that, I had been using some Morrow SP2 cables which I thought were pretty good on the highs, but I wasn't getting much bass out of the speakers. With the MI-2, however, I now have much more and better bass, great attack on transients, and really clear dialog on movies and vocals. YRMV, of course.

Oh, and be sure to install the Zobel networks if you try the Goertz cables.

I think there is a fatal flaw in trying to get good sound from this system, apart from the sonic's of the equipment which I agree may not approach optimum.

The OP sez that the speakers are 5ft apart and he listens to them from 12 feet back. The speakers are only 2ft off the back wall and are not symmetrical to any of the walls in his 18x18x9ft room, not good room dimensions as we all know, and the excessive nulls and nodes which will defy correction, will all be too apparent. The room will have more reflections than just the important 1st reflections to deal with. But with a lot of work via experimentation with set up he should be able to get something reasonable.

The OP complains of harshness which could be from excessive 1st and 2nd reflections off the walls, as well as reflections off the ceiling. He wants more 'air' but in my humble opinion he hasn't even approached the height/width sound stage available let alone the sense of depth and 'air'. In fact even if he is listening in a triangulated seat/speaker placement, he still isn't getting much more than expanded mono and the attendant congestion caused by having speakers too close together.

IMHO the OP need to think out side the box by discarding for the moment what won't practically or esthetically work for him and play with setting the speakers up in a classic manner (starting with the Cardas methodology) and also set his system up in a very near-field set up well away from the boundries to see what his system really sounds like without room boundary reinforcement and reflections. He should also be mindful of the benefits of proper toe in used to minimize 1st reflections as well as optimize speaker focus without getting a hot treble (which depends on the speakers driver's designs on and off axis.

He should also realize that, as he has already been told, there is no cure for his problem without a lot of experimentation. You can't buy what he needs other than some good books on all things audio, especially rooms, set up, and managing reflections appropriately.

FWIW.

Newbee, The OP states the speakers are almost placed across a corner. I take that to mean diagonal placement. If that is the case the majority of your post regarding speaker placement does not apply. The same is true of the Cardas program which does not work for the majority of people.

The OP knows the speaker placement is not ideal, but has constraints based on room layout and aesthetics.