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Speaker of the Century Award Goes To ....

The 2.5 way speaker.


You guys probably thought I was going to fanboy over a brand, and I'm not. I'm going to fanboy over a speaker design. IMHO the 2.5 way speaker is THE ideal high end speaker for the majority of enthusiasts.


First, what is a 2.5 way? It is a speaker with 3 drivers, but the mid range lacks a high pass filter, so  it shares output with the woofer.  It has a number of advantages over smaller and larger speakers:
  • Similar footprint to stand mounted 2-way speakers
  • Ideal bass output for apartments and modest homes
  • Easier to integrate than big speakers
  • No subwoofer
  • High sensitivity compared to a 2-way using similar drivers
  • Reasonably priced


A number of brands have taken this approach including:
  • Focal
  • Joseph
  • Monitor Audio
  • DIY kits like the Klang Ton Ophelia, and Zaph Audio

So for the average enthusiast who is not a San Francisco billionaire I argue here (for the sake of an argument) that the 2.5 way speaker should be considered one of the great technical innovations in terms of users and results.
erik_squires

Showing 3 responses by bdp24

bdp24's avatar
bdp24
10,096 posts
 

@atmasphere’s post reminds us of why electronically separating a woofer from the midrange/tweeter drivers can provide better sound; bi-amping, with an outboard x/o over dividing the signal before the two power amps, one amp for the woofer, the other for the m/t. Done so, nothing the woofer does (amplifier power supply demands, back-emf, etc.) effects the m/t drivers, the same with the woofers’ amp.

A side benefit of this arrangement is that the component values used in outboard x/o’s are generally of much lower value than those in speaker-level x/o’s. Line-level components are much cheaper and smaller than speaker-level ones, and can have less of a sonic signature.

Then there is the matter of the physical vibrations created by woofers. With the woofer removed from the structure housing the midrange and tweeter drivers, the m/t are free of the structurally-transmitted woofer vibrations, a good thing. And, with the woofer in its’ own enclosure, if the x/o frequency is low enough that enclosure can be located so as to optimize the woofers' performance, the m/t drivers to optimize theirs’.

bdp24's avatar
bdp24
10,096 posts
 
The Sound Labs and Acoustats may play @110 dB, but my old Quads sure won't ;-) . Not sure about the Sanders, Music Reference, Martin Logan, Kingsound, and others.
bdp24's avatar
bdp24
10,096 posts
 

It’s a shame so few have heard the Eminent Technology LFT-8b. It has about the same size footprint as Erik’s 2.5-way, but stands 5’ tall. The LFT-8b can actually be considered a 2.5 design; it has a pair of planar-magnetic midrange drivers (180Hz-10kHz!), a ribbon tweeter (10kHz-up), and an 8" woofer in an enclosure (180Hz-down). Though it is on the low side of sensitivity (though not to the degree Maggies are), it is an easy 8 ohm amplifier load (the panels are 11 ohm, for those who choose to bi-amp). Feed it with a 100w/ch tube power amp, and enjoy!

Robert E. Green’s review of the LFT-8b in TAS begins with: "The Eminent Technology LFT-8b is an extraordinary speaker." Following adjectives include "distortion as low as electrostatics---but with lots of dynamic oomph", and "The low distortion in particular is striking; these speakers are capable of really beautiful sound", and "speakers that in some respects are among the best there are."

It is Green’s description of the LFT-8b producing "sound floating in the air at ear level---where it belongs---with no sense of vertical compression the way point sources do", that makes planars my choice of loudspeaker. $2499 will buy you a pair of LFT-8b, or a pair of Magnepan LRS and a coupla (or four ;-) subs. ’Tis a great time to be a poor audiophile!

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