Addendum $7000 Tower Speaker

I wasn’t interested in including my Infinity IRS Epsilon that I use as a center channel in the results, because it:

• Doesn’t have any driver redundancy
• Isn’t horizontal without killing someone
• Lacks any similar model to compare it to, and
• Is not a design that is in current production (originally $14,000 per pair)

But while I had the test equipment setup, I was curious about how well it measured. Were my guests actually enjoying a coherent center channel sound, or were they just saying what they needed to get me to go away?

As you can see in the below 1/6 octave horizontal frequency response chart, the vertical array of drivers do not exhibit wave interference. There is a fall off in the top frequencies of the tweeter, which is common.

Infinity’s Cary Christie explained in his white paper on this speaker, “As the wavelengths approach the dimensions of the diaphragm, the waveshape begins to become planar rather than spherical. In a typical [one inch] dome tweeter, for example, this narrowing, or “beaming” becomes serious at about 10 kHz. If the dome had flat power response, the on-axis response would actually rise, and some do, however most show a roll-off in power response due to the reactive mass of the dome. The on-axis frequency response of such a tweeter may show a ‘flat’ characteristic out to beyond 20 kHz, but this is only because the energy is concentrated in an increasingly narrower angle. The actual power response of the dome is falling off rapidly, beginning its drop-off as low as 6 kHz.” The somewhat improved the off-axis response of this planar tweeter by adding a second one in the back. Even though this could in theory cause wave interference across the horizontal plane, the back tweeter’s response is randomized by reflecting off the back wall. My speakers are 6.7 feet from the back wall, which reduces the rear tweeter’s ability to help out. Regardless, I still have much more top frequency roll-off away from center than the W(T/M)W speaker that was used in configurations 8 and 9. My credit card just moaned.

From the test results, wave interference from redundant horizontal drivers or crossover overlap is not an issue. However well the Epsilon can possibly sound in The Captain’s Chair, it responds consistently across all seats in the room. My guests are surely experiencing as good a sound as my budget allowed for, but I’d guess they’re still appeasing me somewhat with acclaim. The last thing they’ll do is encourage me to spend more money.