Why are these speakers so bright but others not?

I'm in the process of upgrading my 10 year old system. It currently consists of:

Arcam FMJ CD23
VPI HW 19jr./Audioquest PT6/Sumiko BPS
Audible Illusions Mod 3 pre
OCM 500
Monster Sigma Retro Gold interconnects and speaker cable
Monster AVS 2000/HTPS 7000 power conditioners
Martin Logan Odyssey speakers

I previously had PSB Stratus Gold's and had finally tuned and tweaked my system so that it was reasonably balanced in my room (approx 20 X 13.5 X 7.5, glass on one side with only partial treatment). I had the opportunity to borrow and purchase equipment from work with mixed results.

ML Odyssey - these worked great so I bought these and am sticking with them. Bass is still uneven and not as extended as the PSB's though.

Revel Ultima Studio - very bass lean and tinny

Magnepan 3.6R - edgy and bright. way too big for my room anyway so I'm selling these.

What gives? Why are two speakers so well suited to the room and too very highly regarded speakers not?

I'm going to borrow an amp from work to see if that changes the situation since I know some of these speaks are tough to drive. Any more ideas?
the psb's are by far the best match with your system. the ocm is avery neutral ss amp and the arcam is likewise. the psb's easily are the best overall performers in this group.
I did play with speaker and seating placement somewhat, but I was just surprised how not good I found the Revel and 3.6R's in my room. Not that they aren't excellent speakers - the clarity and lack of distortian in Revel's midrange came through unhampered as did the sense of space with the Maggies (although obviously constrained in my room and placement).

The PSBs and the Martin Logan's ended up being located very close to the same location which was interesting because they are so different a design. My PSBs (original golds) are front ported and the MLs have the panel and on of it's woofs rear firing. I think the MLs also did well in my room because of the narrow dispersion (i.e. mitigating brightness of untreated room). I thought I could place the Revel's in a fairly similar location to the PSBs, but I could't get enough bass without putting them pretty close to the front wall. I do have lumpy response in my room below 60Hz.

I originally built my system around the PSBs way back when, hence the amp, but I fell in love with vocals and instruments on the MLs despite some of the other tradeoffs (bass in my room, some dynamics). Midrange is so much cleaner and so much more detailed.
It could be a number of things, but since I have had a similiar situation recently, I wanted to let you know that uncovered windows (at least in my room) were a disaster.

My system was sounding bright, and I recently bought auralex room treatment. I put it on all of the critical spots; my system was still harsh sounding. Then I saw a picture of someone's room on this forum who had a similiar room setup and size (smaller than your) and bingo! I had blinds over my windows and assumed that they would defuse the sound WRONG! Just like this gentleman, I put a folded blanket over the blinds and added some other treatment to just the window. I got the soft warm fuzzy sound back instead of the "I paid all this money for this kind of sound what the?"

Can't promise you it will work and I feel your pain, but it just takes a minute to listen to it before and after you throw a comforter over the window to see if it helps.

It looks like your system is a bit bottom heavy....in this I mean that you have focused much attention on the speakers and yet a major upgrade to your phono or CD setups and perhaps even more so, the preamp, would bring far more refinements than trying $4k+ speakers in your system.

I heard the AI Mod 3 years ago and it was not bright at all. In fact, it was a bit too laid back for me compared to the ARC LS5, CJ Premier10, Sonic Frontier SFL2 and CAT preamps I auditioned at the time. I would think the AI is a good fit if your system is typically on the bright side. But the AI is also a subtractive product when it comes to resolution.

Another link in your system that is key is the preamp to amp cable. Something like a Cardas Golden Cross could do wonders for you to bring on more warmth and remove some of the edgy brightness and fatigue.

I understand how Magnepans would be considered bright in many systems. I have always needed to use at least a 1 ohm resistor in the tweeter attentuator for the 3.3s and/or 3.5s and my system was not bright at all. My guess is that Magnepan designed this to have their speakers work in a wide variety of systems. If you still have the 3.6s, you should try 1, 2 and 3 ohm resistors at the attenuator terminals. I use BAT 31SE, AesthetixIo, Manley DAC and Wolcott electronics....none of which are bright at all and yet I use 3 ohm attenuators.

My room is nearly identical to yours so I have the same placement limitations. The 3.5s work incredibly well now that I have focused much attention to upstream components.

From what you have written here, you should check out a great deal on a pair of Vendersteen 2 sigs or the 3A. Each of these are much less than the other speakers you have tried and the extra money spent in other areas would be of far greater benefit. But I think speakers like the Maggies will reveal much of the other "problems" upstream.

Hope I have given you some ideas to consider.

Rob: Which Auralex product did you buy for treatment in which areas? What was the price? I know I need to do something. I only have these blackout blinds on one window (fortunately, the one where first reflection point would be) and I can tell a difference with that shade down and only listen with that shade down, but it's no doubt pretty wimpy compared to real acoustic treatment. This is a new room/house for me and I know I have a long way to go down this path for sure.

John: the CD player and the speakers are the updates so far to my 10yr old system. Amp, preamp, and phono would be next. I figured speaker upgrade followed by amp to make sure I have a synergistic match there (OCM was originally bought to go with the PSBs) (I guess this is a bit of a what-order-do-I-upgrade-my-components thread). I definitely wouldn't expect the AI to be causing the brightness (resolution loss is a concern too), but more immediately have been wondering about the amp (have heard in some cases OCM is good bass amp but rough on top end, but I have nothing to compare with at the moment), hence my plans to at least swap to try it out.

Where do I pick up 1-3 ohm attenuators? I'm new to Maggies. I also forgot to mention that to audition the Maggies, I had to borrow some Monster M2.2 speaker cable with bananas since my sigma retro gold has spades and I didn't have spade/banana adapters on hand to audition that way. maybe that was part of the problem there, but I should be able to do a little bit more of an apples to apples comparison with bananas on sigma soon.

I actually had recently toyed with the idea of Vandy 3s (10 years ago, I wish I had gone that route rather than the PSBs). To be frank, I had very good deals on the MLs and Maggies - too good to pass up so it's definitely been worth my trouble to go this route.