To simplify matters somewhat, I used equations found at:
Please be aware that you really need to add a First or
Second Order Passive Crossover (which would make this into
a 5th or 6th Order Bandpass box); or, you will have to have a separate
power amplifier that has an active crossover for this cabinet that restricts
the frequency response accordingly (4th Order Bandpass cabinets have very
uneven frequency response at frequencies above the Sub-Bass range (200 Hz or
more) - you will need to manage this with either a Passive or Active
First Order Crossover Networks and
Second Order Crossover Networks
for information about adding one to this box.
Also see Additional
information about this application and its use.
Please fill in the following Information.
Diameter: Speaker Diameter in Inches
of cabinet material
Speaker (Driver) Data
Hz - Low Freq Roll-off
If you have a specific Port material that you want to use, and you know the
inside diameter in inches (ie. 1 3/4 inches = 1.75), or in mm, you may
enter this value manually. Select the right scale to use.
This value must be entered as a decimal value (the program does not
This software generates results for a single speaker. You may consider adding
a second speaker to your system, if you do, all parameters stay the same,
except Vas. Assuming identical drivers:
You can define the Diameter parameter as the the size of both the drivers
put together - ie. 2 6 inch speakers = 12 inch Diameter. Make this
correction to the Diameter parameter you enter before calculating
Also be aware that the published specifications of your Speaker is based on
a sampling of the production run. Large variations may exist in any 2
speakers produced by the same manufacturer with the same model number. This
is not as big an issue as it could be. The relationships of the major
parameters tend to be quite consistent and while it could impact your design,
it may not be significant. If in doubt, there are systems that can be used
to individually measure speaker parameters available from Parts Express
and LinearX (and others) using a Windows based PC.
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