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(Regi) wrote in message . com...
There is no pressing reason for this misadventure other than to
experiment. Theory talks so much about the disadvantages of passive
network... you see . I think best strategy would be to assemble a
low powered system myself. Otherwise, it will not be practical to buy
6 mono amps from market within my budget.

Thanks, Regi

Going to an electronic crossover is a good idea if one can't afford a
high-end ($2000-$10,000) power amplifier. An electronic crossover can
greatly reduce the distortion of medium priced power amplifiers. With
an electronic crossover, medium priced amplifiers can come very close
to (or sometimes equal to) the sound quality of high-end amplifiers.

You can build your own electronic crososver for about $7.00. Below is
a schemetic of a 2 kHz electronic crossover:

From preamp--------------------10K Ohm--------- To low frequency amp
| |
| 0.01uF
| |
| Gnd
|
-----------0.01 uF-----
|
10 K Ohm pot
--- To high frequency amp

|
Gnd

The above crossover is 6 dB per octave and is designed to work into an
amplifier input impedance of 50K Ohms.

Since the crossover has only four components, (two capacitors, one
resistor, and one pot) it is easy to build. You can build it on a
Radio Shack eight phono jack board. Part# 274-370, (cost $2.19).

This crossover has the advantage over active crossovers, in that it
has less distortion. The disadvantage is it has only a 6 dB per octave
rolloff rate. Only the highest quality (read expensive) drivers can
handle 6 dB per octave crossovers. Medium priced tweeters, for
example, will distort at higher sound levels.

Most drivers require at least a 12 dB per octave rolloff rate. This
can be achieved by adding a passive componet in series with the woofer
and the tweeter.

From low side power amplifier------------640 mH----------
|
8 Ohm woofer
|
Gnd

From high side power amplifier ----------10 uF----------
|
8 Ohm tweeter
|
Gnd

The electronic crossover (top) and the passiver crossover (above) will
combine to give a 12 dB/ octave rolloff to the system.

Use the 10K pot to balance the levels of the system. (Pick a tweeter
that is 3 dB more efficient than the woofer. For example, a tweeter
with 91 dB sensitivtiy, and a woofer with 88 dB sensitivity.)

With the money you save by building your own electronic crossover, you
could buy high quality drivers from Madisound.
Vifa, Audax and Morell all make good drivers, that are not too
expensive.

If you don't like woodworking, you could, go to the Salvation Army
Store or a garage sale, and buy some old bookself speakers. Rip out
the old drivers and put in high quality ones.

You will need to do some homework to be sure you get the correct
drivers/enclosure combination. Other than that, this is a no-fail
recipe :-)

If you want to have a lower crossover frequency you can increase the
size of capacitors and inductor. For example, doubling the size of the
capacitors and the inductor (to: 0.02 uF, 0.02 uF, 20 uF and 1280 mH)
will drop the crossover frequency down to 1000 Hz.

Bob Stanton