Zaph: Thanks for the idea about using 2nd order filters on the ZDT3.5

[fjhuerta]

Since John regularly reads this place...

I used the ZDT's for a while (with the Vifa DQ25 tweeter) and liked their sound. But, as you may remember, living in a place with hardwood floors and walls didn't help the sound at all.

I did RTA measurements in room and found that I needed to drop the midrange and tweeter levels a bit, and decided that one of the easiest ways to do so would be to change the midrange / tweeter crossover points to a 2nd order L-R.

An extra resistor in the midrange circuit (on the inductor shunt) and a 2nd order electrical in the tweeter did the trick at 4 KHz. A bit of tweaking on the woofer circuit flattened the response a bit more.

All I can say is WOW. Now I know why people like so much L-R 2nd order. I'd suppose what I'm hearing has a lot to do with a flatter power response. The crossover points are completely undetectable, and the speaker sounds great everywhere in the room!

Thank you for the idea... it did work! :T

[jkrutke]

I'm sure I did give you some advice, I just don't remember it. How does your vertical polar response look? While the power response might be smoother, you're probably still getting some vertical directivity around the tweeter-mid crossover that helps in your room.

[fjhuerta]

I'm sure I did give you some advice, I just don't remember it. How does your vertical polar response look? While the power response might be smoother, you're probably still getting some vertical directivity around the tweeter-mid crossover that helps in your room.

Yep, when I mentioned I was using the Vifa DQ25 instead of the Dayton neo, you mentioned trying to use 2nd order slopes all around. I need to check out the vertical directivity - quite honestly, I didn't really consider it.

One thing I did notice was that sensitivity dropped from around 88 to 86 dB. There was really a lot of excess midrange and top end energy around the room.

[fjhuerta]

Here is the vertical polar response. Design axis is on tweeter axis.

[ch83575]

Very interesting. I must say Javier, I am not an expert, but I cant see why this would help with a lively floor. The suckout below the listening axis looks very similar to the original design in location and severity, but now there is a suckout above the listening axis as well that isn't there in the original. Do you think that is what accounts for your perceived difference? Or did you change the on axis FR a little as well? Perhaps you have answered this elsewhere, but did you take measurements and modify the original 4th order crossover for the bigger tweeter in the first place? If you did modify the 4th order crossover for the new tweeter which components did you change?

-Chad

[fjhuerta]

No, I changed the on-axis FR a bit. The new tweeter has a simple 2nd order electrical now.

I believe it wasn't as much the vertical polar plot helping, but the new FR and the added horizontal dispersion what makes me prefer this version.