Loudspeaker Designs and Articles for the DIY Enthusiast
A Design utilizing both
Quasi-Transient Perfect
Conventional Crossovers
Listening Impressions:

Surprisingly enough, (or not) the QTP an NTP versions sound audibly different,
and those that have heard them seem to have a very marked preference for one
topology or the other. Wayne and I spent many hours to voice them as close as
possible, so any differences attributable to timbre should have been minimal.
Apparently, which design sounds best seems to be a very personal decision. The preference of listeners at Iowa DIY 2009 seemed to be right down the
middle, but for a number of differing reasons. –Wayne and I are split on our preferences as well, so it was not all that surprising. Consequently, the only way
to determine which will suit your tastes better is to build them as I did: with both topologies incorporated and a A/B switch. (Or would that be a Q/N switch?)
Since you all know how a conventional speaker sounds, I can describe some of the attributes attributed to the QTP version, however.

I found the QTP design was most evident when toed in slightly in front of the listening area. Less toe in equated to less QTP ‘effect’, so it is easily adjusted
to a person’s preference. When ‘properly’ toed in the Soundstage exhibit a ‘bloom’ or more expansive soundstage, which seems to expand the soundstage
width outside of the speakers themselves. The stereo image, while being slightly more diffuse, held together better when listened to off axis. That is, the
relative positions of performers did not change significantly as the listener moved off axis. Another interesting aspect: The size of the soundstage appears
to be related to the spacing between the speakers. When auditioned at the auditorium in Iowa, I noted the soundstage also grew significantly in height,
compared to my impressions in my listening room at home.  

Copyright 2009 Curt Campbell and Wayne Wendel
Free for non commercial use only
Links to:
Design Goals and Driver Selection
Cabinet Construction and Drawings
Crossover Design 1
Crossover Design 2
Bill of Materials
Listening Impressions