Design of a multiple driver loudspeaker requires quite a few tools. Without
these tools the design / trial and error process is lengthy and often doesn't
show the required results.
Absolutely mandatory for designing are multiple driver loudspeaker is a tool
to measure the sound pressure level depending on frequency, and - if possible
- best in such a way that room resonance doesn't come into account.
Each driver requires its own compartment, if the rear is not encapsulated
(two of the same drivers may be placed in the same compartment).
One of the first steps should be the calculation of required compartment
size for each driver.
The Alcone Dirac XT uses an encapsulated XT300 tweeter and two Alcone AC
5.25, one in a closed compartment and one in bass reflex cabinet.
Using the following calculators:
- simple calculator for a closed
- simple calculator for a
bass reflex cabinet
- LspCAD Lite(also for band pass)
the required volume for a 7 litre closed cabinet and a 22 litre
bass reflex cabinet may be calculated, where also the DC resistance of the
1mH coil with 0.28 Ohm was taken into consideration. Since there are two drivers
the coil acts like two parallel 2 mH coils with 0.56 Ohm, where one affects
just one driver.
For all calculators you will need the Thiele and Small parameters which we
list for all our drivers. If we design a loudspeaker for you the Thiele and
Small parameters are measured and confirmed
by us to be sure.
- LspCAD Professional
- Netcalc (on Waldo CD) a DOS
based programme that runs by using a clock
- for mathematicians: Microsoft Excel + plug-in for complex numbers and Solver
The easiest to use is surely LspCad, Netcalc has got the best price / performance
Finally the total frequency response and the phase response should be measured
again for confirmation; afterwards it's time for a listening test.
There is no guarantee that a loudspeaker with perfect frequency response
also sounds perfectly. Nevertheless, it's still a high quality loudspeaker,
that would not have been possible without the use of measuring tools.
If the speaker's sound shows too much presence, try to reduce the midrange
...we hope you enjoy your new loudspeakers....
PS by Peter Strassacker:
If you work according to our suggestions you will good results. A common problem
when building speakers yourself: the designer wants to be creative, and therefore
tries to design everything himself. Without the required tools the results
are often not as good as expected.
If you do not own measuring tools we recommend to buy loudspeaker kits. You
may still modify the finished speaker and the result will be excellent. For us
it's important that you own loudspeaker that provide many years of listening