Design Goals

In the tradition of the earlier Triune design, this is intended to be a
high-value design with multiple enclosure possibilities, and will allow it
to perform well in a home theater or music applications. The
crossover design is optimized to provide good horizontal off-axis
response when used as a center channel, as well as in a vertical
alignment for mains or surrounds. For maximum versatility, it can be
built as a sealed, vented, or transmission line design. The TriTrix
utilizes all Dayton drivers, but unlike its Triune predecessor, boasts a
very easy 8 ohm load in an MTM format.

Driver selection

The 8 ohm system capability became possible when the DA130BS-4
was released. This 4 ohm version of the well respected 5.25" Dayton
Classic, boasts a sensitivity 3 dB higher than its 8 ohm sibling. Using
two of these in series resulted in a system sensitivity nearly as good
as the Triune.

The DC28FS represents the latest version of this popular tweeter,
and is arguably the best sounding version to date, demonstrating a
bit of a BBC dip around 4 kHz, and exhibiting a smoother top end
than its predecessors.

Enclosure Design

A significant advantage of the TriTrix is its relatively small enclosure
requirements. For the sealed design, only 10 liters for a Q of .707, is
required or 33% smaller than the Triune enclosure of the same Q.
Consequently the sealed TriTrix enclosure external dimensions are a
diminutive 20" x 6.5" x 8.25" deep.  The sealed TriTrix is very
forgiving of enclosure size with anything from 7 liters to 15 liters is
certainly acceptable, with the best power handling in the smaller
enclosures. The f3 remains relatively constant at just under 100 Hz,
and an f10 around 60 Hz. Yes, the f3/f10 frequencies are a few Hz
higher than the Triune, but IMO, this is a very fair trade for the
smaller enclosure. -In the 7 liter enclosure the max SPL models at in
excess of 104 dB.

The TriTrix in a vented enclosure also lends itself to smaller volume. -
Only 19 to 22 liters, vs. 29 for the Triune, with an f3 in the low to mid
50’s and an f10 right at 40 Hz.  Tunings around 40 Hz modeled
the best. A 2" vent around 6.5" long for the 19 liter, and 5" long for
the 22 liter, the larger enclosure buys you a couple more Hz of low
end extension.   

In the TriTrix transmission line, I used the same enclosure as the
Triune. I suspect the low end extension to be very close to the
Triune, but some variations in stuffing may be necessary. At this
juncture, I have the back section of the line unstuffed, leaving the
front section fully stuffed, but this may change as the drivers break
in. While I did not measure the low end extension, it appears to be
similar to the Triune TL, in that it provides acceptable bass down into
the low 40's.

This design was intended from the beginning to be functional in
multiple enclosure types and applications. The test articles I used
were the transmission line variation, but I suspect very similar results
with the sealed and vented versions as long as the baffle size and
driver position is not severely compromised.
The
TriTrix
An All
Dayton
8-ohm
MTM
design...
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