I have a pair of Dayton DC50FA-8, which are 2” dome midrange drivers. I look through their data sheet and wonder whether I can use them without low-pass filters. I mean to treat them as the tweeters, no low-pass for limiting high frequency production but only high-pass for preventing damage from low frequency, is it possible? Because I see no break up occurs at high frequency on their frequency response curves. I also have a pair of 19mm. Scanspeak HF drivers and plan to use them as the super tweeters. If it’s possible, which frequency is recommended for crossing over the super tweeters to the 2” Dayton tweeters?
The usual way to blend a super tweeter is to use a very small value of capacitor. Cross it high and let it slope down first order to blend. Change the capacitor to change the tweeter level, and if that doesn't work you would introduce resistance.
Frankly, I’m not familiar with first order crossover because I used to read somewhere, maybe in Dickason’s textbook or some papers, that the first order crossover would suffer from the comb filtering. So I started with second order in all of my designs. Since I have never experienced with super tweeters anymore, I don’t know if the first order with it is not bad. But every section in my crossover schemes including this project involves second order crossovers, would it be good to use the second order with super tweeters instead? Or it’s not necessary?
You can try 2nd order. If you don't blend it well, it may seem to cut in more distinctly.
The method I've described above is a power cross rather than a response cross. It is also used as a starting place for tweeters not on the front baffle.
If you want to do a normal cross, you can. You have said you want to leave the mid without a crossover so I figure you're up against the natural narrowing at the top end.
The method I've described above is a power cross rather than a response cross. It is also used as a starting place for tweeters not on the front baffle.
If you want to do a normal cross, you can. You have said you want to leave the mid without a crossover so I figure you're up against the natural narrowing at the top end.
Do you mean the “break-up” or “beaming”, at high frequency, phenomena?
If so, according to the response curve provided by the manufacturer in the data sheet, these 2” Dayton’s don’t have them in the graph but I’m not sure why you mentioned them.
think you should try 2nd order on (super)tweeter.
That Dayton has smooth response and natural HF rolloff like 12-14 dB/octave, so it looks like good match is possible.
For start, set crossing frequency 8-9 kHz, and revert the polarity of (super)tweeter.
Higher order filter gives less overlap and reduces vertical comb filtering, but it would still be an issue in crossing zone, due C-C spacing much larger than crossing vavelenght.
That Dayton has smooth response and natural HF rolloff like 12-14 dB/octave, so it looks like good match is possible.
For start, set crossing frequency 8-9 kHz, and revert the polarity of (super)tweeter.
Higher order filter gives less overlap and reduces vertical comb filtering, but it would still be an issue in crossing zone, due C-C spacing much larger than crossing vavelenght.
The only caveat to this, is that above about 5KHz- while the on-axis response of the 2" dome is good- the OFF-axis response starts to fall off, due to wavelength effects.
In that range- the 19mm Scan-Speak drivers should have superior dispersion.
I'd be inclined to use a normal crossover, say at about 5000-6000 Hz or so, for that reason. Less comb-filtering/off-axis response issues.
Regards,
Gordon.
In that range- the 19mm Scan-Speak drivers should have superior dispersion.
I'd be inclined to use a normal crossover, say at about 5000-6000 Hz or so, for that reason. Less comb-filtering/off-axis response issues.
Regards,
Gordon.