How to wire my supertweeters with full rangers

veroman

veroman

Member
I am putting together a fostex supertweeter project and have only 1 set of speaker outs on my integrated amp. Can I just run 2 sets of wires from each speaker post on my amp? The diagram indicates I should not run them from the main speaker connections. Both sets are 8 ohm fwiw. Any help appreciated.
 
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You'll need the appropriate high pass crossover between your amp and the supertweeter, but there shouldn't be a problem running it off the same set of terminals - as long as the crossover is present in the line to the tweeter.
 
Can you post the schematic/diagram/instructions?

Either way you described is a parallel connection to the amp. So, it's not real clear what the point is of not connecting to the speaker terminals right at the speakers.
 
The diagram does indeed show the supertweeter (via its crossover) parallelled with the (full range) speaker wiring.
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Look at it this way. Whether it's at the speaker terminals of the integrated amp itself, or at the full range speaker connection, same difference.
 
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veroman said:
are you 100% positive i caould wire from the full range posts?
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Yes, you need to connect it to the full range posts. That is the full range signal. Of course you will need a crossover connected to the tweeter so it doesn't get the full range signal or you will blow it up. The crossover eleviates the bass portion of the full range signal so the tweeter can only get the upper mids and highs. That's what they are designed for.

The illustration in post #5 is what you want whether it is at the amps outputs or the speaker wires at the speaker itself.
 
I'm kind of a dolt, so bear with my stupidity. Is the 1.5 uF capacitor used to roll off the low frequencies for the tweeter? Is that all a first order crossover is?
 
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Yup! But I will go a step further. What is shown in post #5 is a 2 way speaker connection. A 3 way speaker connection with crossover uses 3 speakers. A woofer, a midrange, and a tweeter. The midrange and tweeter will use different crossover capacitors to get the proper signal to each speaker but the connections are the same.
 
thanks, that saves me much trouble on cable runs. i hope the 1.5 is the magic number. both drivers are rated @ the same sensitivity so fingers crossed. now to figuer how the connect without solder.
 
1.5uf should be about 13kHz 6dB/oct high pass, if the tweeter is ~8 ohms.

Oh, but then the attenuator, so it may be different...
 
thats what i got too. no attenuator i hope.... i may have to raise the x over but..... its all new to me. good to have this site!!!
 
The 1.5uf series capacitor does not "roll off" any signal for the main speaker. It only allows high frequencies to go to the super tweeter. Since it is just a capacitor, it is a 6db per octave slope. So for every octave the signal level increases (or decreases, depending on which way you go from the cross-over point). The attenuator controls the tweeter's output to allow you to match it up with the efficiency of the main speaker. The attenuator is an "L" pad that puts resistance in series and in parallel with the tweeter's voice coil. This keeps the resistance level constant while at the same time, allows for a variable output of the tweeter. Since the capacitor (and its cross-over point) is based on the resistive value of the coil, it is necessary to circuit.

'ner
 
yep. hoping i wont need an l pad as they match up in db ratings. never know tho as the full range are in open baffles and i am not sure if that diminishes loudness
 
having used a super tweeter on my dynaco a25s long ago, i have some experience. if the speaker uses banana jacks for input, you can save a long run from the amp. plug the tweeter in parallel using the cap and pot. after listening for about a couple of days and then reverse the phase of te tweeter at the speaker terminals which puts the tweeter electrically out of phase with the main driver. this may or may not sound better. use the phase that sounds the best.

the dynas were flat to about 12-14k and i first tried a 1u cap but the switched to 0.5 and it sounded much better. then when i changed the phase, if was glorious. ymmv.
 
veroman said:
yep. hoping i wont need an l pad as they match up in db ratings. never know tho as the full range are in open baffles and i am not sure if that diminishes loudness
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Well, remember that now you will have 2 drivers reproducing some of the same information. Without a level control, you are going to get a "hump" in your frequency response. The "super tweeter" is suppose to take on where your main tweeter leaves off.
 
hifitommy said:
having used a super tweeter on my dynaco a25s long ago, i have some experience. if the speaker uses banana jacks for input, you can save a long run from the amp. plug the tweeter in parallel using the cap and pot. after listening for about a couple of days and then reverse the phase of te tweeter at the speaker terminals which puts the tweeter electrically out of phase with the main driver. this may or may not sound better. use the phase that sounds the best.

the dynas were flat to about 12-14k and i first tried a 1u cap but the switched to 0.5 and it sounded much better. then when i changed the phase, if was glorious. ymmv.
Click to expand...

i am a bit perplxed. i have ordered a 1.5 AND A 1.0 cap. the xover at 1.5 is 13k and 19khz for the 1.0. it must be a bit of a mystery as to how a cap of .5 is effective in this application. my drivers fall off at 15 and do so fairly quickly fwiw. the tannoy seem to be in the same league. i will spend more finding the right cap than i did on the tweeters....god i love stereo.
 
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