Quick ? on a Troels design ...

[TurboFC3S]

What does the 47ohm in series with the 1mh on the woofer (R2011) do in this design?

http://www.troelsgravesen.dk/AT-R.htm

[augerpro]

It's helping the inductor to shape the woofer response properly. Somewhat similar to how a "proper" BSC circuit would function, although here Troels is using it how any designer would, to help shape the response. The basic idea is that he can use a bigger inductor to get the "knee" of the transfer function low while not rolling off the upper response too much.

EDIT: BTW it's in parallel, not series. Taking some inspiration for your commercial design for the upcoming RMAF?

[TurboFC3S]

Originally posted by augerpro
It's helping the inductor to shape the woofer response properly. Somewhat similar to how a "proper" BSC circuit would function, although here Troels is using it how any designer would, to help shape the response. The basic idea is that he can use a bigger inductor to get the "knee" low while not rolling off the upper response too much.

EDIT: BTW it's in parallel, not series. Taking some inspiration for your commercial design for the upcoming RMAF?

Thanks, I was just wondering ... first look at modeling it with/without and I didn't see any difference in the transfer function. But on second look I do see how it changes the shape of the knee.

I have my network pretty much finalized, maybe a tiny tweak or two now that it's soldered instead of clip-leaded together. But yea, I saw that this evening and was curious. My AT driver is a bit different than his, and he gets a bit more rising response than I do so ... but we do have very similar networks, 2nd order with a notch for the rising response. That 47ohm works since he's crossing over a hair higher than I am.

Thanks again for the reply.

[TurboFC3S]

Oh, and here's new pics of my design