I feel the need to try to set the record straight regarding our designs.
The Infinite Slope design we employ is absent of any ringing.
None. Nada. Don't believe me?
Go look at the review of the RM33si in Stereophile, see the waterfall plot of the RM33si. (it's online now)
Yet, the impedance curve is also well-behaved - not a "hard load" for an amplifier at all. Richard Modafferi is a stickler for excellent impedance curves, but then again he has the knowledge of filter theory necessary to properly implement this crossover.
The irony of all this is that initially, both Richard and I believed that phase linearity was an important factor in loudspeaker sound. Richard had concocted many experiments to examine loudspeaker phase. Richard's problem was that he had a stubborn professor who effectively debunked Richard's attempts to prove that it was significant. Richard finally had to come around to the viewpoint that it was not a serious problem. If phase is not such a big deal, then what is? Frequency response, and radiation patterns.
The off axis comb filtering of low order crossovers is a serious problem, which is why companies that employ that method often require the listener to tilt or "focus" the main lobe towards the firmly dictated listening position.
The broad overlap between the non-coincident drivers will create large peaks and dips in response if one moves from the optimium spot. This flaw in the radiation pattern of
slow slope crossover designs may be what certain listeners are accustomed to hearing from a stereo system.
That energy does not disappear into the sunset, but rather is bounced around the room, scrambling the magic "phase coherence" that the designer so carefully
struggled for.
Once I had lived with speakers that are free from this artifact, I found it impossible to go back. Whenever I listen to slow slope crossover designs, I find that I'm easily distracted by the large changes in tonality observed with small shifts in listening position. Which listening axis is correct? And if you can contort yourself into that position, can you stay there and refocus your energies on the music? And if you should stand up, the stark balance shift reminds you that what you're hearing is fake and unnatural.
While the idea of filtering bad recordings through such a speaker may have merit, it's more likely to be dynamic compression and radiation pattern that is taking the edge off the ol' Janis Joplin records, not superior phase response. Remember you're talking about a multi track phase scrambled recording played into a phase scrambled listening room. It's too bad that filter is not defeatable. Anyone who's visited us at shows knows that our speakers are equally at home with Louis Armstrong, Frankie Laine, Bill Evans, Nirvana, Norah Jones, Cassandra Wilson, Elvis Costello & the Soggy Bottom Boys.
Happy Tunes to you!
Jeff
