Advertisement
DLS SOUND HANDBOOK - SPEAKER BOXES
7:th order bandpass box
Speaker mounted in a vented box playing into an-
other vented box. All ports going out.
What is valid for 6:th order boxes is also valid for 7:th order
boxes. The difference is that this box gives a 6 - 10 dB peak at
the tuned frequencies.
8:th order bandpass box
Speaker mounted in a vented box playing into
another vented box with all ports playing into a
third vented box.
This type of box becomes rather large but the port openings
can be covered with cloth. It has like the 6:th and 7:th order
boxes high efficiency and power handling capacity. It also gives
a 6 - 10 dB peak at the tuned frequencies.
3-chamber bandpass boxes
Both 5:th order boxes and 7:th order boxes can
be built as 3-chamber boxes with two speakers
playing into a ported chamber. The picture shows
a 5:th order 3-chamber box. In a 7:th order 3-
chamber box all chambers have ports.
ISOBARIC BOXES
Two speakers mounted on the same axis and
operating in the same phase and direction (push
and pull).
All box types can be built isobaric giving the following
advantages and disadvantages.
Advantages:
Reduced box volume with the same F-3 dB
Higher efficiency
Lower distortion
Disadvantages: Difficult to build and calculate
The speaker specifications changes (Qts
and Vas)
Isobaric-connection:
Isobaric speakers are connected with the inner sub
in phase with the outer, but phase reversed as in the
drawing below.
If both are in boxes the one in the smallest box should
be phase reversed.
+
+
+
-
-
+
-
+
-
-
-
Speakers
in parallel
+
+
Speakers
in series
-
16
4:th order isobaric box
7:th order isobaric bandpass box
Use DLS BP-75 and BP-110 conical
ports to avoid port noise.
Advertisement
