autoformer general question

[boom3]

"Hooking the tweeter filter cap to the junction of the autoformer input (pin5?) and the 13uf cap causes the tweeter roll-off to react as a second order network electrically rather than first order. Dr. Eugene Patronis calls this an "improved 3 way network" in the 3rd edition of Sound System Design by Davis and Patronis. Hooking a tweeter filter cap directly to the xover input will allow more tweeter output below cutoff."

I pointed out once in the past the notion that I thought the original tweeter connection on tap 5 was possibly of a higher order than its frequently referred-to first-order status. As would be shown in a schematic diagram, the "input - 13uf - #5 tap - 2uf - voice coil" arrangement closely resembles a third order design (not saying that's what it is); however,my point at the time was simply to state that I found a greater sense of presence and HF energy, as well as clarity overall, with the autoformer completely out of the equation. For me, that was a more significant improvement overall than what was derived by simply connecting the tweeter filter to the input IN FRONT of the 13uf cap. With the tapped choke gone, the tweeter, as you pointed out, would be connected directly to the input, and a true bandpass would be connected in series with the squawker. That is another benefit, IMO.

In any event, a response plot of the original setting in the type 'A' was posted, indicating an essentially first order slope (if I recall correctly). It was posted in response to my suggestion that the autoformer might be having some influence on the behavior of the tweeter. I also pointed out the value of capacitance normally used for a 6dB tweeter network @ 6kHz would generally be different from what is used in the type 'A' example -- which has certain implications...........

What matters is that we are satisfied with what we have, and that is the case for me until I am able to sort of 'liberate' the system of passive chokes, caps, and resistors.

Erik

Thanks for the insights, yall.

Yeah, I meant to specify what network I was asking about. It makes sense that a single cap will result in more tweeter output since it offers less insertion loss than multiple components. Considering the autoformer (just for this notion) to be a mere piece of wire with only DCR, the two caps in series will divide down to a value less than the value of the smallest cap. In this case of 13 uF and 2 uF, the resulting cap is 1.73 uF, giving an"later" (higher) roll-on than a 2 uF cap alone.