Im not very good at this sort of thread but I thought I'd have a go. What the hell? :) Also I have a digital camera now (all thanks to a kind gent on the forum) so can take pictures as I go.... any excuse! I'll put up posts as I go. Im 'subcontracting' the work to friends and people I know in the right trade, because I want a good job, not for it to look/sound crap. ok, here's a few points I should make which should explain the rationale.. 1) Altec and Vitavox horns cut off at about 16k. Hearing (I have read) goes to about 18k. The graphs of the Altec horns I have begin to drop from about 14k, and are pretty low when they get above 16k. The idea of adding a tweeter is to get just a little 'spark' or 'tiz' or 'fiz' or 'add your own silly hifi word here' - basically just that top air and space thing. At the moment (on only some recordings) things sound a little restrained at the top. 2) I am cheating, the drive units I am using are not supertweeters - they go up to about 25k - so thats just a particularly good tweeter.. maybe I should change the title of the thread.. no bollocks to it... 3) I AM however going to get the crossover set with an L-pad, so that the resistance (attenuation/volume/whatever) can be altered according to amplifier & room variables over time. Just like on a supertweeter. 4) I am told I am getting a first order crossover with an L-pad, for those of you to whom that means something. 5) I selected the JBL 2405.. for a few reasons... i. Because Living Voice use them for the same purpose above the Vitavox horns they use, so thats a similar situation and a good model! ii. because they are 99db efficient and 16 ohm which matches well with the horn iii, because they are used in pro studio monitors and the like, and are supposed to sound very good and be very robust iv, because they are supposed to have the right kind of 'sound difusion' to go with a horn or something. Anyway, step one and two have already happened.. more to come..