Some progress pics from my Dayton RS125S and Seas 27TBFC/G project

[owdi]

I've been slowly working on this project for half a year now, and am finally getting close to finalizing the crossover. Things are getting easier now that I have a decent measurement setup.

I used Arta with the following hardware to take measurements:
- Behringer ECM8000 microphone
- Behringer UB602A for phantom power and preamp
- Niles Audio SI-275 amplifier
- M-Audio Delta Audiophile 2496 sound card (in 96khz/16bit mode)

The baffles are 17 inches tall and 5 inches wide. I don't think this is that messy, but the wife is not happy.





A close up. The left and right edges were rounded over with a 1/2" bit. I can remove the baffle by removing those 4 ugly screws.





The back looks worse in this picture than it really is. A flash sure brings out the flaws in my amateur paint job. To save money I used brass screws from Home Depot instead of binding posts.





I put the crossover in a wooden box I bought at Michaels for $3. Once I dial everything in I'll move the crossover into the enclosures.





Here is the nearfield FR and CSD of my Dayton RS125-S. The crossover is a simple coil and cap. No impedance compensation or notch filter. There is an energy problem around 900hz.







The result of my first attempt at a crossover. These are on axis gated measurements (1m, 3.5ms). I matched the levels of the tweeter and woofer pretty well, but the phase could be better. The bottom line is the ambient background noise.





I had initially measured without any compensation for the microphone, and incorrectly thought the tweeter was too bright. I modified the lpad and ended up with this (re-measured with my new setup). The tweeter is padded too low, but the reverse null looks great.





The gated CSD of the speaker as it currently stands. It's pretty easy to see where the Seas 27TBFC/G takes over, because it really does stop on a dime.





My next goal is to adjust the lpad to get the correct level and deep null, since I've read that a deep null is a good indicator of a well designed crossover.

Dan

[sreten]

Hi, why do you have a wide driver spacing ? , /sreten.

[owdi]

Originally posted by sreten
Hi, why do you have a wide driver spacing ? , /sreten.

Good question. I initially made these baffles for a single HiVi B3S, then chose to try a two way. In order to reuse the baffles, either the tweeter or the woofer would have to be placed in the original cutout. I modeled both, and chose to put the woofer where the original cutout was, because the tweeter was far more senisitve to baffle placement.

Below is the diffraction simulation. The first image is on axis, and the second image is 15 degrees off axis.





Dan