Well, finally got the preamp working (with a lot of help from my friends).

The next project is to build the Pi Seven Theater Series cornerhorns. Since I do my sanding outside, it's time to get started.

Before ordering Eminence drivers, I'd like to determine if any of the woofers I have would sound better. I have a pair of 15" paper cone woofers from a pair of old Magnavox consoles and a pair of 1961 Jantzen hybrid electrostatics that use a very nice pair of red 11" woofers that sound really nice.

I've tried to figure out the Pi software and methods used to measure speaker attributes, but I cry uncle.

Anyone in the area who'd like to help out?

1. What tools or equipment I need

2. How to use them

3. What to input into which program

In other words, the whole thing.

Prices of each of the computer-based systems are varied. Some are pretty expensive but one of the popular freeware programs is Audia's Speaker Workshop. This system is popular because it measures system response. Another program that is popular for finding driver parameters is Claus Futtrup's Driver Parameter Calculator. This program is made specifically for obtaining the parameters you need. If you already own a computer and sound card, then use of these PC-based systems might be the most attractive option for you.

In any case, after you've obtained Frd, Vas and Qts, you'll enter these values into PiAlign. Actually, you'll want to enter the reciprocal (1/Qts) of Qts as Qd, Vas as Vad and Fts as Frd. The program will then recommend cabinet and port dimensions for you. For more information, please read the "readme.txt" file in the PiAlign distribution archive.

I have a scope, but my signal generator took a dive this weekend. I was going to order an inexpensive Temna (sine only) or Allied Electronics (sine and square wave) to replace it.

For these tests, what do I need? Can I get away with just 1 Khz or do I need a range?

Also, what size and value resistor?

I'm accustomed to chasing a circuit with a scope, just by checking if the sine is oscillating or clipping. Do I need to do anything more sophisticated?

At this point, I know nothing of speaker testing.

Thanks.

if u know R and reactive part? u can find angle?
this will depend on frequency? eg at resonance.below,above.

that speaker measureing site is quite comprehensive i likethe manual!

mmmmmm trig! :-)

:^)

• http://homepages.slingshot.co.nz/~mike.e/Z.bmp

I'll order the generator tomorrow.

One last question: Once I measure the parameters of the woofers, I will be able to determine enclosure volume. But then how would I determine which woofer would work best in the seven cornerhorn, and if the choice would be better than the Eminence woofer?

θ = ArcTan |XL-XC| / R

Please keep us posted with your progress!