Listening Fatigue & Speakers in Small Room

Not to rain on your parade, but usually when small tubes grow old they loose some highs and become dullish. Usually.

On the other hand some new tubes are often dullish and take some hours to open up in the highs. So what you hear initially is not necessarily where you will end up after 24 hours.

I think Bombaywalla's comments are quite good and could be very helpful, especially those in the first and last recommendations. It is possible that if you are listening in the near field these speakers may not be appropriate, at least for the best results. Re toe in, don't omit trying some severe toe in where the speakers axis crosses well in front of your listening position. This can solve all kinds of issues including 1st reflection issues off the side walls and ceilings as well.

Lastly, tonally speaking, tube brands can make a very big difference.

I have experimented with toe in, and currently have them
firing straight ahead. However, I never tried extreme toe
in, so perhaps that's next. Also, there's no more room
behind me to sit, so I am maxed out in that regard.

10x10x8? Monitors and a sub. That will be the ticket. The cubic feet of the room is very small and should be perfect for some monitors on stands and a small sub. You should get phenomenal sound with that. Agree with the above comments on B&W and time coherency. I ultimately think you will head down the new speaker direction.

Bombaywalla ... I tried your suggestion about toeing in the
speakers so they are pointing directly at me. WHAT a
difference! I have a Monster Bass Trap on the rear wall
directly behind my listening chair, so it appears that certain
sounds are being absorbed by it. Also, I notice a decided
reduction in room energy, which is likely the elimination of
certain reflections; although the room is treated, not every
portion of it can be. So that huge change, coupled with the
new tubes, seems to have made the situation a whole lot
better. Thanks so much to you and everyone else for the
suggestions. BTW, if it turns out that I do need new speakers,
do you folks have recommendations for really good monitors?
Thanks, again.

BTW, if it turns out that I do need new speakers,
do you folks have recommendations for really good monitors?
Thanks, again.
Rlb61

you know, I'm a time-coherent speaker kind-of-guy. So, I'm going to recommend Green Mountain Audio speakers (they are based in Colorado Springs, CO) such as the entry-level Rio & the next level up Eos. Visit their website & pick up the phone & talk to the owner/designer. He's a very nice person to talk to - give him the details of your room, distance of your chair from the speakers & any other limitations you have to see if Green Mtn Audio speakers will fit your application.
http://greenmountainaudio.com/rio/
No affiliation to this company, just a satisfied ex-customer & a time-coherent speaker enthusiast.
FWIW. YMMV.