Hi all. I made some supertweeters using fostex horn tweeters FT17H and use them with my CSS FR125SR fullrange bass reflex speakers and very impressive they are too. Make vocals much clearer, cymbals etc. Now when I connected them to my fostex horns and on another occasion my mates proac studio 140's they were much quieter and laid back, could still hear them but very faintly. I don't have crossovers on the full rangers ( obviously) or the fostex horns that are full range too. Also when connected to the proac's they were connected to the binding posts BEFORE the crossovers. Why would that be so ?
If I've read that right you don't have any cross over on the FT17H? If not you'll need a capacitor atleast to prevent damage to the tweeter. This would also explain why you had problems with the proacs.paulfk said:
I use my FT17H's as a super tweeter and use a .22uF with an L-Pad. If using them as a helper tweeter on a full ranger you might need a larger cap.
thanks for the reply, yes I have a 1.5uf cap and l pad attenuator fitted. I have no problems with the CSS speakers, but when used with the fostex horns and proacs they were almost inaudible. If I use a meter what should I expect to find when testing across the terminals and adjusting the L pad. Just a thought, could it be that the CSS are 85.5db and so less loud than the Fostex 93db and the proacs 91db.
Good new on the cap 
. Given you've connected the tweeter up the same as the datasheet. Measuring across my l-pad the resistance stays pretty constant at around 8.5 Ohm.
When using mine as super tweeters I can hardly tell their on, even with my ear at the tweeter only very liitle sound is evident. At the listening position though it is easy to tell that the top end is crisper and cleaner.
. Given you've connected the tweeter up the same as the datasheet. Measuring across my l-pad the resistance stays pretty constant at around 8.5 Ohm.When using mine as super tweeters I can hardly tell their on, even with my ear at the tweeter only very liitle sound is evident. At the listening position though it is easy to tell that the top end is crisper and cleaner.
ok, have measured resistance at the binding posts and there is nil. So have dismantled tweeter, removed driver checked resistance 7.2 Ohms, tested L pad between terminals 2 and 3 and got a maximum of 8 Ohms down to zero when adjusting on spindle. Between 1 and 3 I get 7.8 Ohms up to 42 Ohms. Between 1 and 2 I get 7.8 Ohms - 42 Ohms. Can someone advise me on the correct wiring.
after checking the resistance between 1 and 2, 2 and 3, 1 and 3, it made sense to follow the daves wiring, which is the same as fostex. wired up one cap and attenuator outside the cabinet and tried it out, can now adjust the volume. Wired both supertweeters in the cabs and now waiting for glue to set. Had to glue the attenuator as the spindle will not protrude through the ball shaped cabinet.
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