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Buddy,I was trying to write "tongue in cheek", but the purist in me still resists adding a sub (not needed with my Bob Brines FTA-2000s) or supertweeter (as Bob says, the need is probably more a question of your age than anything else). IMO the meat/heart of the music is between 40 - 8,000 Hz (8 octaves). 50 years ago or so designers were happy for the most part to call 80 - 8,000 Hz (7 octaves) full range. If you look into vintage speakers, few went below 40 Hz and most mid/tweeters were front loaded horns. (Both done to keep efficiency up with the small amps that were about the only thing available in their day.)Putting in another plug for Brines: he offers plans, pre-cut cabinet panels, assembled cabinets, or fully assembled speakers all at very reasonable prices. So for as little as $300 for the parts you could glue up and veneer a very nice 37 - 20,000 Hz, 94 dB/w/m, 8 ohm pair of floorstanding speakers (less than what many pay for just speaker stands).The supertweeter question also reminds me of designs that use a simple tweeter/cap design, like the smaller Reference 3A models, but don't promote themselves as single driver designs. So there is a potentially "slippery slope" here. It's ironic to me that some would spend more on the supertweeter (to fill in one octave) than the original driver (that's covering the heart of the music).Your supertweeter application doesn't seem to fall into any of these "practical" pitfalls.
i must respectfully disagree that subs are not needed w/single-driver speakers. even bob brines fta-2000's. i used to own a pair of thiel 3.5's, which were -2db at 20hz. even those speakers benefited from being actively crossed over to subs. not only was the bass quality & quantity better, but the thiel's upper bass & lower midrange was better, as its 10" driver didn't see any frequencies below its 80hz crossover point. w/a full-range driver, the improvements to be gained from it not having to deal w/any low-frequency info, are even greater, imo...ymmv,doug s.
doug,You knov I am a bass hound, but I think this depends on the music you are listening to. I am all for a full range coverage on a main system, but if you are specifically using the single driver speakers to focus on voices and small ensemble music, coherence and simplicity of a single driver may vin over having the first octave. Of course, I say this even as I contemplate using a supertveeter, but it vill just be a first order highpass on the tveet....
I have the following.Capacitors (2)Super Tweeters (2)Attenuators (2)Small boxes (7 3/4” W x 6” D x 3” H) to house the cap and attenuator (2) SpeakersSince I have never done this before, can some body give me the right schematic? I plan to drill a hole on the front side of the humitor for the attenuator. Cap will be glued inside. Do I need to put binding posts on the box and biwire or run the wire to the speaker's binding posts?
if you bi-wire or run the tweets from the omega's jacks, you will be cutting the impedance load of the speakers in half. ie: if both speakers are 8 ohm rated, then the load is 4 ohms to the amp. depending on the actual impedance of your speakers
The series cap on the tweeter causes the impedance of the tweeter circuit to rise dramatically below the XO point, meaning we can effecticely ignore its impedance at low frequencies. The inherent inductance of the full-range causes its impedance to increase at high frequencies such that where the impedance of the tweeter gets down to 8 ohms the FR has a high enuff impedance that it does not contribute significantly. Bottom Line. No problem. (if there was multiway loudspeakers would not work at all)dave
Very nice. I was thinking this. If I glue the super tweet on top of the box and put a trunk hinge on it, I can vary the vertical angle of the super tweeter. Would that be more beneficial or would the additional 3" from the box be bad?Doug, I do have an XM9 somewhere out on loan. I want to try the passive and compare to active later.
You may also just want to try without the attenuator and a really small cap (you need a whole bunch of caps to be able to dial these sTs in).dave
Oh, don't forget you'll need to reverse the phase on the tweeter when you connect it. Just place the cap on the positive terminal and then flip positive and negative when you connect it to the binding posts. It's pretty simple.
Quote from: woodsyi on 26 Sep 2007, 08:35 pmVery nice. I was thinking this. If I glue the super tweet on top of the box and put a trunk hinge on it, I can vary the vertical angle of the super tweeter. Would that be more beneficial or would the additional 3" from the box be bad?Doug, I do have an XM9 somewhere out on loan. I want to try the passive and compare to active later. At the large (given the frequencies involved) distance even if you mounted it on the box as close as possible more distance may or may not be better. I'd just set it on top with the cute little round legged holder/stand. Back & forward will have more affect, but even that will depend on where you hold your head.You may also just want to try without the attenuator and a really small cap (you need a whole bunch of caps to be able to dial these sTs in).If my XM9 iexperience is any indication, it will be far too veiling to be used in this application. You best bet if you want to biamp is to use a 1st order PLLXO (which can be as simple as shrinking a coupling cap in your amp)dave
