Hi Everyone,
So I'm posting this as part of my learning process, helpful comments appreciated. I'm done playing around with my much maligned Focal's. I wanted to share the results and lessons learned. Here is the current measurements, with grill on (red) and off (blue).
This started off as a "I want to play with expensive parts" project. Originally I wasn't going to tweak anything but upgrade the crossover parts, like the padding resistor, serial caps, midrange inductor and got completely out of hand. 🙂
So, first lesson, any test tool is better than none. The Dayton Audio Omnimic V2 has been fabulous, and the $50 add on DATS great for inductor measurements. It's spot on.
Second, trust no vendor.
Third, I really should have measured thoroughly before proceeding. I made the mistake of assuming things about the tweeter crossover that were just not true just from looking at it. I assumed it was 4th order and therefore the phase reversal made sense. It wasn't. It's effectively 2nd order and the phase reversal was unnecessary.
So, major changes:
Mechanical - Added felt to the tweeter housing and grill wings.
Tweeter: Added a little EQ boosting around 2db at 3kHz, also caused crossover point to be lowered.... part of my beginners luck.
Midrange: Added Zobel impedance network because I think "Zobel" sounds cool. Second part of beginners luck, advanced phase by about 15 degrees at new crossover frequency, bringing total phase mis-alignment from 165 to 180 degrees....
Back to tweeter: Reversed polarity and added L pad. My EQ (0.1mH + 0.5 R) used the series resistor in the original design, so I was left with a tweeter that was about 2.5 Db too hot.
So I'm posting this as part of my learning process, helpful comments appreciated. I'm done playing around with my much maligned Focal's. I wanted to share the results and lessons learned. Here is the current measurements, with grill on (red) and off (blue).
This started off as a "I want to play with expensive parts" project. Originally I wasn't going to tweak anything but upgrade the crossover parts, like the padding resistor, serial caps, midrange inductor and got completely out of hand. 🙂
So, first lesson, any test tool is better than none. The Dayton Audio Omnimic V2 has been fabulous, and the $50 add on DATS great for inductor measurements. It's spot on.
Second, trust no vendor.
Third, I really should have measured thoroughly before proceeding. I made the mistake of assuming things about the tweeter crossover that were just not true just from looking at it. I assumed it was 4th order and therefore the phase reversal made sense. It wasn't. It's effectively 2nd order and the phase reversal was unnecessary.
So, major changes:
Mechanical - Added felt to the tweeter housing and grill wings.
Tweeter: Added a little EQ boosting around 2db at 3kHz, also caused crossover point to be lowered.... part of my beginners luck.
Midrange: Added Zobel impedance network because I think "Zobel" sounds cool. Second part of beginners luck, advanced phase by about 15 degrees at new crossover frequency, bringing total phase mis-alignment from 165 to 180 degrees....
Back to tweeter: Reversed polarity and added L pad. My EQ (0.1mH + 0.5 R) used the series resistor in the original design, so I was left with a tweeter that was about 2.5 Db too hot.
I have collected the relevant charts here. I'm afraid that I don't have true measurements from when I started this project.
I think someone on this forum mentioned that with the right crossovers the Profiles would be closer to the Utopias. I just found this on Stereophile, I guess he was right, I ended up with a tweeter balance that's pretty close.
Doh, forgot to add the proper link. The Stereophile chart refers to the Focal Nova Utopia reviewed in 2004
Here is the chart from the S&V Review, grill on. Notice how much smother the response is now from 1K on up. Also, from around 3K to 10K there is an upward slope, whereas the modified crossover has a gentle, downward slope without the ragedness:
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