Quote Originally Posted by Old Guy View Post
Because they are not used as L-pads. I've been trying to say they are part of the complex filter (since it is two combined).

http://home.earthlink.net/~jmarkwart...1201-8aRev.pdf

Just look at the schematic- do you see one AFTER the filter? An L-pad goes between the filter and the load. As has been said, you can use just one section, and it is a variable resistor.

See Rontec's post...the crossover normally would be BEFORE the L-pad. In the model 19 the VARIABLE RESISTOR- not being used as an L-Pad- is IN the filter, or complex filer as it is two combined...hope it makes more sense now? An L-Pad only varies VOLUME (theoretically), where as in the Altec they are used to vary bands not the entire out put. I think your mistake is you think there is a separate HF section- there is not. there is only one driver. So you have to vary the response in the crossover, you don't have a mid and high driver you can turn up and down independently. THEN you would use L-pads. I apologize if not clear, but a LOT of engineering by better men than I went into the 19 crossover.
Yes, that makes more sense to me now. Sorry, I can be slow!

The reason I am asking this is because I have been mucking about with a L-pad wired onto (but after) my crossover as both a variable resistor and an L-pad in order to tune the GPA-IIIs horn to the cab/room better. I found that by using it as series-R instead of an L-pad, the sound was slightly better - a bit more "clear" is I guess is how I would characterize it, and I am trying to better understand why.