Originally Posted by Soulburner
This is mostly a curiosity at this point, but I want to know the sound differences between two classes of speakers.
A) 3-way high fidelity designs such as the BMR Philharmonitor, Ascend Acoustics Sierra Tower w/RAAL, Selah Tempesta
B) High efficiency designs such as those from PSA and JTR
I'm looking for someone who has heard both types. Say you got one of the speakers in Group B, so you're running a compression driver, and you're listening to music at not crazy levels, maybe 75-85dB. You have subs crossed at 80Hz. Do you miss the RAAL ribbons? Do you miss the wide dispersion and smooth on and off-axis response of the speakers in Group A? How would you describe the differences in sound?
I've heard and have both types. The basis for choosing either type typically boils down to your listening tastes and preferences.
Loudspeakers with Ribbon Tweeters
Do you desire clarity and detailed resolution in the higher frequencies? Ribbon tweeters, particularly the RAAL, are known for their rapid transient response. If you listen to DVD audio, SACDs or concert blurays, especially at the non-reference range, it's hard to beat a great ribbon tweeter.
It's important to note that good ribbons not only resolve high quality recordings, they can also reveal the lack of audio engineering craftsmanship in the poorer made recordings. The wide lateral dispersion coupled with the narrow vertical dispersion of, for example, the RAAL, expands placement options and yields a broader sweet spot. The limited vertical dispersion also obviates the need for absorbing or diffusing ceiling reflections. My Philharmonic Audio speakers sound great in multiple arrangements irrespective of the room.
As all of the ribbon based speakers you mentioned above are quality 3-way designs, there is less of a worry about the midrange driver dispersion being problematic the closer you get to the limits on the driver's higher frequency range. Otherwise, you run the risk of the midrange suffering from being directional (compared to the ribbon) and struggling in the frequency range that overlaps with the ribbon’s lower frequency output.
Loudspeakers with Waveguide and Compression Driver
JTR makes great loudspeakers and they use high quality parts in their construction. PSA offers great value with their offerings. Another option is DIYSG, which uses quality parts but farms out the labor to you, the end user. When designed properly, a waveguide allows for more natural integration with larger drivers/woofers, as the tweeters' low end output can be increased. This can facilitate successful two-way designs. Additionally, a compression driver can be used to achieve higher sensitivity and, as a consequence, higher output.
As I'm sure you're aware, no matter how great a set of speakers measures in an anechoic chamber, our rooms, and their various idiosyncrasies (i.e., reflections, shape, liveliness, etc.) ultimately determine the actual nature of the speaker's sound signature. If you're using speakers with a wide sound dispersion pattern (e.g., ribbons), then absorption or diffusion may be necessary. However, waveguides offer controlled directivity. Movies particularly take advantage of a strong direct sound field. I believe it was Toole who established that you can (especially for movies) minimize wall reflections and maximize clarity and intimacy by achieving narrow dispersion.
I love my waveguide speakers in my HT because they are effortlessly dynamic. They have no problems with the rapid dynamic changes in a movie's audio track. Additionally, the controlled directivity helps with resolution. I wouldn't use anything else for my HT.
In sum, if you are primarily using these speakers for movies or a dedicated HT, you can't go wrong with a waveguide speaker (JTR, JBL, DIYSG, etc.). If you're primarily a music listener or you desire a broad sweet spot, real resolving power and clarity in the upper frequencies, I'd recommend a set of speakers from your first group. Lastly, to throw a wrench in your plans, you can always choose the option that includes both: a ribbon with a waveguide (e.g., SEOS-RAAL).