Ohm Walsh vs. Mirage OMD 28

yes, the OHMs are not hard to place compared to most designs, but careful placement is still needed to yield the best results possible. You can put them most anywhere and they will sound fine for background listening perhaps but imaging accuracy and detail and bass levels may not be optimal.

Is it recommended to use damping materials at the first reflection point?

I have seen Ohm setups with a lot of absorptive materials not only at the first reflection points, but almost all around the front and side of the room at ear level. Remember: the "first reflection" point for an omni is not the same as for a conventional dynamic cabinet loudspeaker. I have the traditional first reflection point more or less covered, as well as the front ceiling corners, but plan on adding more foam panels along the side and rear walls at ear level in the future.

I think need for use of damping materials will depend on the room and user preference. I have never used any nor been strongly tempted to.

Historically I've found wood or other lively floor materials to be the main issue in that the OHMs are bottom ported and a lot of energy is directed towards the floor.

"Remember: the "first reflection" point for an omni is not the same as for a conventional dynamic cabinet loudspeaker."

The first reflection point for an omni is variable depending on listening location I believe since you can listen from a wide range of lcoations and not just the "sweet spot". For the "sweet spot" the first reflection point on the rear wall would be the same as for other speakers in teh same location essentially I think. It would change depending on where you listen from. So it might become a difficult task to treat the room optimally in this way in a manner that works best for a wide range of listening locations.

I always view omnis like OHMs as best applied in scenarios where you want to use the room as it is as your concert venue as opposed to typical audiophile scenarios where you become obsessed with modifying the room to avoid interactions with the speakers.

Of course, some rooms can just make flat out lousy concert venues, so in these cases, you might want to think twice about using more omni designs like the OHMs.

I haven't listened to Ohms since I worked at an audio store in the mid-'70s, but I have owned the OMD-28's little brother, the OMD-15, for 1-1/2 years, and the concerns leveled about the OMD-28s have no substance. These things are seamless, both in dispersion pattern and crossover points.

As for placement, the Mirages are very forgiving particularly in one way--you will always get a room-filling sound with realistic timbres regardless of where you place them. They are not naturally bright, though you can control brightness by opening or closing window shades and deciding on your wall hangings.

There are two placement issues with the OMDs, however. If you want that deep, holographic soundstage, you want to pull them further into the room and place them wider if you can. If you put them where you put a typical forward-firing speaker you'll get some center clustering, though the timbres will be spot-on. If you want a sonic hologram, bring'em out into the room.

Secondly, the OMD-28s have very strong bass down into the 20s, so that's another reason to have them out from the front wall. I have my OMD-15s a little more than 3 ft into the room. If you have the room to bring OMD-28s 4-6ft into the room they'll probably blow your mind.

The other thing to consider is that these are fairly easy to drive, reasonably sensitive, but can absorb huge amounts of power and translate that into dynamic range. Even my little OMD-15s are bi-ampable and rated for 250 watts power handling.

I have had live music in my living room, and no speaker I've had energizes the room and reproduces the correct timbres as precisely as the OMDs.