SpeakerTalk

speakerguru · Posted: Sun Jul 24, 2016 11:34 am Post subject:

Going back to basics, I don't believe you have actually stated what you are trying to do; just that you have the wrong replacement B300s.

re your last post

brucegseidner · Junior Contributor 10+ Joined: 05 Jul 2009 Posts: 12

I have taken to heart your encouragement to go active in my substitution of B300's in this 105.2 Franken KEF project. I will build 70liter enclosures and mount the B300's and use the original 105.2 heads on top. I will be using the original XO's for the HF/MF drives. I need to specify the parameters for the active XO.

So, after I get the enclosure built, I will measure all of the parameters you have asked for. I see that the way I have been doing this takes a lot for granted using tables with some trial and error. I can already measure my actual drivers and find they are always significantly different from published specs and from each other. Now I just need to step it up and measure actual sound in my projects going forward. The cost of this equipment is reasonable these days. I have to chuckle and shake my head at the systems I built 35 years ago. But it's been fun.

Thank you for your support. I estimate a few months to get this all together.

speakerguru · Posted: Mon Jul 25, 2016 1:44 pm Post subject:

If the original B300s work well enough to act as xo loads, then, using the original bass section xos and the units in boxes, all you have to do is measure the terminal volts across the the B300s wrt to frequency and then design the active part to regenerate the same terminal voltage curve. It's a relatively simple copying process as long as you know what is and what is not possible using biquads.

Good luck with your work.