SONIC REALISM
CENTER CHANNEL SPEAKER PARTS LIST
Qty. Description
■ 1 8” speaker three-way Pyle PLG8.3 (no Thiele/Small parameters
available) from MCM (#51-1157) about $46/pair, 200 watts RMS
Allpanels are3/4” maple plywood, measurementsare outside dimensions, Top,
bottom, and side panels have 45 degree miter cuts on two sides (see Photo 4).
■ 2 Front/back panels: 10” x 14. 5” (front panel has speaker cutout as required)
■ 2 Side panels: 16” x 8”
■ 2 Top/bottom panels: 8” x 11. 5”
Internal corner members
■ 4 6. 5” long 2” x 2” (nominal) pine (1.5” actual)
■ 4 1.5” x 11. 5” x 3/4” plywood
■ 4 1.5” x 7” x 3/4” plywood
■ 50 1.25” drywall screws (approx.)
■ 25 2” drywall screws (approx.)
■ 4 Speaker mounting screws
■ 1 Wood glue
■ 4 Rubber feet
■ 1 Speaker terminal
fact, the clearest example that, under
certain circumstances, sonic reality
can be achieved. It should be pointed
out that the entire room was visible
as she entered, so it was impossible
for someone not to be seen.
Additionally, the room was on the
second floor and she turned to look
towards the outside wall. There was
no speaker there.
Recording Hints
Not all recordings provide the
same realism. It seems that the simpler
recording techniques, the better.
Voices generally sound best if they are
natural and free from electronic
enhancement. Keeping the microphone about two feet away from the
singer helps to create a more natural
mix of high and low frequencies (less
obvious pops and hisses). If possible,
record individual instruments and
voices with a single microphone or
channel. For multiple people and
instruments, use two closely spaced
but directional microphones; one for
the left and the other for the right
channel. Multiple microphone mixing
doesn’t seem to work too well.
There are several current
commercial recording concepts that
generally produce good results. These
are “Binaural” recordings that use
a facsimile of a human head with
microphones buried in the ears. The
other is the “QsoundTM” from Archer
Communications. There may be additional techniques, as well. However, it
is difficult to find recordings grouped
by the engineering technique.
BURIED TWEETER SPEAKER PARTS LIST ■ 2
Qty. Description
■ 2 Woofer speakers: Sony Xplod XS-L121P5, 4 ohm
impedance, Rdc= 3, 2, Fs= 26. 4, Qts=0.42, Qes=0.44,
Qms= 5. 86, Vas=1.96 cu. ft. Rated power=350 watts
RMS, 1,200=watts peak, weight= 20 pounds.
■ 1 Tweeter driver: Motorola/CTS KSN1142A, 1.8 kHz-
30 kHz. Rated power=400 watts RMS.
■ 1 Diffraction horn: 10-5/8” x 3-7/8” x 7-1/4” with
1-3/8” diameter threads @ 18/inch # 54-290 from
MCM ( www.mcminone.com)
■ 1 Crossover network (see Figure 1)
■ 4 Main vertical struts: 3/4” x 1.5” x 50. 5” (actual) maple
Side mounting arms: 9” x 4. 5”
All internal corner members are made from 2” x 2”
(nominal) pine (1.5” actual).
■ 8 Front/back members: 14. 25”
■ 8 Side members: 10. 5”
■ 1 Speaker terminal
■ 100 2” drywall screws (approx.)
■ 30 1.25” drywall screws (approx.)
■ 20 Speaker mounting screws (approx.)
■ 1 Wood glue 8 oz. (approx.)
■ 10 ft. “Frost King” vinyl foam weather-seal self-stick
tape 3/8” wide, 3/16” thick (approx.) (see text)
■ 1 Grill cloth: 9. 25” x 60” (approx.) (optional)
■ 4 Mounting feet
All panels are made from 3/4” thick maple plywood.
Measurements are outside dimensions. All panel edges
(exceptthoseatspeakeropening and the woofermounting
panels) are cut to 45 degrees.
■ 4 Front/back panels: 17. 25” x 21”
■ 4 Side panels: 15” x 21”
■ 2 Top/bottom panels: 15” x 17. 25”
■ 2 Woofer panel: 13. 5” x 15. 75” (with proper cutout
for woofer)
Tweeter mounting pieces are made from 3/4” thick
plywood, square cut edges.
■ 1 Back panel: 9” x 17. 25”
Materials/Parts Center Channel Speaker
The center channel speaker is a more conventional box
design ( 11. 5” x 16” x 8”). It is much easier to build and costs
much less. The speaker selection was more arbitrary than
for the buried tweeter design. Photos 3 and 4 show the
basic design and construction method. A table saw is not
required but it is helpful. Actual dimensions can be varied
to some degree. Because the speaker has a four ohm
impedance, a four-ohm resistor was added in series to
increase the impedance to eight ohms. If your center
channel amplifier can drive four ohms, then this resistor is
not needed.
64
June 2007