"Arny Krueger" wrote in message


As if high price makes an amplifier necessarily more distortion free, or low
price means it has to have audible distortion. Just isn't true!


Which of the low priced amplifiers is totally transparent? Do you have
this information on your website?

For example, the near-universal choice to use electronic crossovers with
subwoofers has a lot to do with the costs and inconveniences related to
making a passive crossover at say 50 Hz for a 8 ohm speaker that is designed
to work with a low source impedance.

That's right. For a *very* low frequency crossover (60 hz), the
component cost is high. However, the cost of components, for a 2kHz
crossover, is low.


Potentially problematical given that so many power amps have input
impedances of less than 50 K.


One should check for conventional input impedance (50k to 100K) before
buying.


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).


IMO if you are going to do something, do it *right*.

What is wrong with building a crossover on a Radio Shack phono-jack
board?


This crossover has the advantage over active crossovers, in that it
has less distortion.

It has less noise, too but in fact noise and distortion from reasonably
good, modern electronic crossovers just isn't a problem.

Yes, active electonic crossovers have very very low distortion. All I
said was, passive electronic crossovers have lower distortion. OK, it
doesn't matter, but they do have lower noise and distortion.


Here's an example of a good, modern, relatively inexpensive but
comprehensive electronic crossover of the digital persuasion:


*Very nice*, but not for an $800 budget.

Again price really doesn't have that gosh awfully much to do with it. Once
you get past the crappy drivers (which sell for a wide range of prices
ranging from low to high) you can find a lot of reasonably-priced drivers
with good performance including ability to work with low-slope crossovers.


Again, price doesn't matter if you *know* which cheap drivers are the
good ones. Do you have this information on your website?

Rolling your own loudspeakers and getting good results is far from simple
unless you stick to subwoofers. Doing a two-way woofer/tweeter speaker
system *right* is actually one of the tougher technical chores around.


Going to an electronic crossover *greatly simplifies* the design
problem.


Here is how to design a speaker system using an electronic crosover:

1) Stick to a two-way system. (If you want three-way system, buy a
subwoofer with an integrated amplifier, and make your satellite
speakers two-way.)

2) Buy a woofer that is of good quality from Vifa, or Audax or
Scan-Speak. Pick drivers that don't require a compensating network to
be flat.

3) Pick a woofer that is designed to work into a closed box. (Avoid
buying woofers that need to work into ported enclosures.)

4) Note what volume enclosure the manufacture recommends, and buy or
build, a *sturdy* enclosure of *that* volume. Fill it lightly with
(acoustic) fiberglass.

5) If the tweeter isn't sealed on the back, mount it in a seporate
enclosure.

6) Solder a series resistor-capacitor across the driver terminals.

------------------------------
| |
R = 8 Ohms |
| 8 Ohms driver. (Woofer or Tweeter)
C |
| |
------------------------------


The value for C depends on the inductance of the driver.
For the typical (8 Ohm) woofer, the value of C = 15 uF.
For the typical (8 Ohm) tweeter, the value of C = 1 uF

Here's your chance to invest in measurement and analytical tools! The good
news is that they are far less costly today than they were years ago.


I agree. Cooledit for $69 has an excellent little spectrum analyzer.

If you want two good small two-way speakers, you will probably save money
(not to mention time!) in the end by looking at speakers from manufacturers
like Paradigm, NHT, PSB. Boston Acoustics, etc.

Are prebuilt speaker system as low cost as similar ones you build
yourself? I doubt it.

Bob Stanton