The Triune '07
Revised crossover design
Response plots
Off-axis response curves
Click for a larger image
Driver selection
A temporary shortage of PE's DC130BS-4 4-ohm drivers used in the TriTrix designs
has prompted me to update the Triune project. This is the 4-ohm variant of the TriTrix,
utilizing the DC130BS-8 5-1/4" Classic Shielded Woofer and the DC28FS-8 1-1/8"
Shielded Silk Dome Tweeter. Originally designed a couple of years ago using the 3rd
generation Dayton silk dome tweeter. This tweeter has since been replaced with an
updated version, which necessitated the changes to the original Triune crossover
design.

Design Goals
My initial thoughts were to simply amend the tweeter crossover, but I wasn't satisfied
with the results. Consequently this is a 'clean sheet' design, and no crossover
components are shared between the original and the '07 version. Thinking that some
may want to mix and match the various Triune and TriTrix designs, I voiced the
TriuneTL using the TriTrixTL as a reference. They sound very similar with the Triune
being a bit more sensitive and having a few Hz of additional bass extension.
Click for a larger image
Click for a larger image
Crossover Networks
Enclosure Design
There are enclosure designs for a Transmission Line as well as an L/C/R speaker, in both sealed and vented iterations.
See the previous versions of the Triune for enclosure drawing and details.

Crossover design
While I voiced this crossover in a TL enclosure, particular attention was paid in the crossover design to maximize its
capabilities as a horizontal center channel. As can be seen by the modeled plot of the vertical off-axis response curve
group, the response only drops a maximum of about 6 dB from nominal at 30 degrees off axis. This would be the horizontal
off-axis when turned on its side and used as a center channel.

The crossover networks both use 2nd order electrical topologies to emulate 3rd order acoustic transfer functions with a
crossover frequency of just under 1500 Hz. The crossover is about as simple as you can get, with only 4 elements in the
design. The impedance minima is jut above 3 ohms, but the impedance phase is quite benign and should pose no
problems for 4 ohm capable amplifiers. Looking at the phase plot, the woofer and tweeter phase track each other fairly well
through the crossover region.
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TriuneMTM
L/C/R        
TriuneTL
Click adjacent links for original
designs and additional
information: