Are they relevant? Might make for an interesting diversion.
Inaudible High-Frequency Sounds Affect Brain Activity: Hypersonic Effect -- Oohashi et al. 83 (6): 3548 -- Journal of Neurophysiology
Dan
A knocked up crossover got me ruler flat with this from 1200-12k tonight. 1200 being below the horn's loading it's not ideal as and XO point, but it's nice that it doesn't go haywire below the passband. 1400Hz 11 ohm parallel notch and 4.7uF 4.7ohm (parallel with each other, in series with the load) EQ network, with an out-of-band protection cap (52uF).
Naturally they'll want a 2k or greater HP tacked on top. Oh. Driver was 2426h.
Naturally they'll want a 2k or greater HP tacked on top. Oh. Driver was 2426h.
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Testing with dome
In my urge to get a supertweeter together (I have some, but I wanted to DIY this one), I have hacked the Selenium and a dome together. In optimizing this, I removed the ferrofluid and got a loaded Fs of about 1050 at Qts .95, when loaded on the horn. Should be pretty good. Removing the ferrofluid exposed a little bit of resonance in the construction, but none too bad.
The dome was the Apex Jr. high sensitivity dome. The opening in the flange was over 1", so the selenium does act to constrict the input. A little smoothing of this transition was done, hopefully we don't have too much effect from this, as it's specifically top octave response I'm hoping to pull out (supertweeter usage). I'll try to measure (RTA, nothing truly useful, but enough to determine if there are big problems) tonight and post.
Also shown are my near-ready OS waveguides.
In my urge to get a supertweeter together (I have some, but I wanted to DIY this one), I have hacked the Selenium and a dome together. In optimizing this, I removed the ferrofluid and got a loaded Fs of about 1050 at Qts .95, when loaded on the horn. Should be pretty good. Removing the ferrofluid exposed a little bit of resonance in the construction, but none too bad.
The dome was the Apex Jr. high sensitivity dome. The opening in the flange was over 1", so the selenium does act to constrict the input. A little smoothing of this transition was done, hopefully we don't have too much effect from this, as it's specifically top octave response I'm hoping to pull out (supertweeter usage). I'll try to measure (RTA, nothing truly useful, but enough to determine if there are big problems) tonight and post.
Also shown are my near-ready OS waveguides.
An externally hosted image should be here but it was not working when we last tested it.
Rough test results are very positive. Big shocker: It's not CD in the top octave. Below that, though, it's fairly clean and does well maintaining CD (so far as basic RTA testing can show). And, the big plus- in addition to keeping fairly CD, it's essentially flat from 1200-20k with just a 3.3uF cap. Naturally the tweeter isn't happy at and below Fs (1100), but it's well-loaded down to about 2k it would seem. And since the compensation cap is so small, one could easily create a first order rolloff with just a small parallel inductor.
All in all a success.
All in all a success.
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