When I tested the flat panel speaker designs, I did not include my impressions of each speaker design in the video. I did this on purpose so that I would not sway the opinions of any viewers. I really wanted to hear what people thought.

Now that some time has passed and I've heard from a lot of viewers about their impressions of each speaker setup, here is what I thought about each design after listening to them in person:

• Klipsch R-41M Bookshelf Speakers:
These speakers provide a very good image and sound stage, but are quite directional and tend to work best in a "near field" setup. The fidelity in the highs is better than any of the panels, but the mid range is substantially muted in comparison. They lack punch in the lows.
• Common to all the panel designs:
All the panel designs "fill the room" with sound. It is far less directional than the Klipsch book shelf speakers... when walking around in the room with the Klipsch playing it is always obvious where the speakers are. When any of the panels were playing, I just felt enveloped by the sound. It's important to make the distinction that this is not meant to imply a "surround sound" feel, but rather that if I closed my eyes and had someone spin me around I could easily point to where the Klipsch were, but would have a harder time pointing right at the panels. It's a really cool effect. None of the panels offer excellent performance in the highs. Some are good, but none are as good as the Klipsch. If I was going to put a system together that incorporated any of the panels, I'd use them as a mid-range driver with an equalizer on their channel to de-emphasize the highs, then add a separate tweeter.

Here are my impressions of all the flat panel designs, ranked loosely from what I considered to be the worst to the best.

• Triangular
These had less volume, as well as a "thinner" tone to them. Much more of a nasal sound, with pinging highs and considerably less low end. I found the midrange to be pretty muddy/sloppy on them as well. These were easily my least favorite.
• Painted
Similar to the triangles, these lacked quite a bit of depth in comparison to the rest of the flat panel designs. These managed to somehow dull the highs and muddy up the mid tones at the same time. If you need a color change, go with a fabric.
• Square No Sanding
These produced a very bright tone, with pretty sharp high end - essentially turned the treble up too much. Their mid tone production was good, but the highs were so strong as to cause listener fatigue pretty quickly.

The prior three I would not recommend for anyone. They are pretty hard to listen to, even for something like like setting up in a shop or garage. Go with one of the next ones.

• Fixed Exciter
These suffered a bit from having the exciter held firm, at least at the volume level where I did my testing. They had a pronounced "tinniness" to the sound. Also, there was some distinct abrasive interference with the exciter frame slamming into the back of the panel... especially noticeable on the classical guitar piece. Much of the depth and "room filling" feel was lost with these, sort of like how you hear old-time records through a phonograph.... this effect was not very pronounced, but moving in that direction. However, if they are driven at a lower volume level, they move back towards the sound of the original design suspended from the corners. If you don't need them to be loud, and prefer to have a hidden mount, this may be an alternative. I would always opt for a suspended mounting system, though, it's just got a fuller sound.
• Medium Weight Fabric
These were very close to the original design, with somewhat muted highs. I suspect the heavier-weight fabric being stretched around to the back of the panel did "stiffen" the panel a bit, preventing it from vibrating quite as freely. If you go with a fabric cover, use a lighter weight.
• Square Sanded
Much better control of the highs than the non-sanded panel. Nice full mid tones. These are *very* similar to the original design... I would describe them as slightly sharper in the mid tones. If you prefer squared off corners as a design aesthetic, you won't likely notice much of any difference between these and the original panels.
• Original flat panel design AND Light Weight Fabric
These 2 are grouped together, because they were more or less indistinguishable. Great mid tone reproduction... acoustic instruments (cello, guitar, piano) sound unbelievable on these. They do a good job with pop and rock, but do sort of fall apart with extremely busy music such as heavy metal. The highs are a little ... less distinct than I would prefer. As mentioned above, add a separate tweeter to make up that difference if it bothers you.
• Originals with Subwoofer
All the great stuff from the originals, with as much earth-shaking bass as you prefer. I like a thicker low end than typical, I think, so make sure if you add a sub you do it such that you can independently control both the volume and frequency cut-off of the sub so you can tune the overall balance to your liking. The originals with a sub would make an excellent system for a garage or workshop, or any casual listening environment.
• Originals with 2 Exciters
These were surprisingly excellent. Adding a second exciter did increase the volume a bit, but it also brought even more depth to the already pretty excellent performance of the single exciter. This was definitely the best "level up" I found among all these designs. As bad as the triangles were, dual exciters where that much better than one alone.
• Originals with 2 Exciters and Sub
Outstanding. With some equalization and the addition of a separate tweeter, these would make a good system for TV, if you don't need surround sound. Any acoustic or classical music on these sounds VERY close to being at a live performance. If you want them to be a different color, wrap them in the lighter fabric.

Dayton Audio (the manufacturer of these exciters) has some excellent reference information about the best materials to use for them, as well as great tips about how and where to mount the exciters to suit your environment.

If you have more thoughts to share about these speaker designs and my testing, feel free to continue the discussion back in the comments section of the video at the link above.

Thanks!
-- Amplify DIY