Howdy folks, am working on my first passive crossover design. Using a Celestion CDX1 1446, JBL clone 12" waveguide (Dayton), and a Visation 300w 12" woofer, 78L ported cabinet tuned to 35hz.
Pictures are the current schematic with response and impedance, then the response blown up, and then the polarity inverted on 1 driver to show reverse null.
I've been told the inductor on the tweeter should be under 1mH, however if i go lower than 2.7mH as shown, i get an increasing spike in response at the crossover, and it throws the phase out a bit. the impedance spike is quite high, however on the low side impedance looks good bottoming out at around 5ohms. The amp i'll be using is rated to 2 ohms.
Would be good to bring the level's down a bit on the woofer from 400-700, and also the peak at 1600-2000hz if possible - appreciate comments.
Thanks 🙂 fun fun.
Pictures are the current schematic with response and impedance, then the response blown up, and then the polarity inverted on 1 driver to show reverse null.
I've been told the inductor on the tweeter should be under 1mH, however if i go lower than 2.7mH as shown, i get an increasing spike in response at the crossover, and it throws the phase out a bit. the impedance spike is quite high, however on the low side impedance looks good bottoming out at around 5ohms. The amp i'll be using is rated to 2 ohms.
Would be good to bring the level's down a bit on the woofer from 400-700, and also the peak at 1600-2000hz if possible - appreciate comments.
Thanks 🙂 fun fun.
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Wow, thanks Nelson!
Haha, it's Hugh. (very low brow given my usernam) - the speakers are for my sister - Alice, and her husband 🙂
Haha, it's Hugh. (very low brow given my usernam) - the speakers are for my sister - Alice, and her husband 🙂
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Other question is the inductors have different impedance ratings.
2.7mH - 21awg = 1.56 ohms, 18 awg = 0.9ohms.
3.6mH - 21awg = 1.76 ohms, 18 awg = 1.1ohms.
If i can i'd rather use the 21 as they're cheaper, does the minimum system impedance determine the impedance rating required for the inductors, or is it something else i'm not looking at?
Any reason i wont be ok with 21 awg?
Thanks!
2.7mH - 21awg = 1.56 ohms, 18 awg = 0.9ohms.
3.6mH - 21awg = 1.76 ohms, 18 awg = 1.1ohms.
If i can i'd rather use the 21 as they're cheaper, does the minimum system impedance determine the impedance rating required for the inductors, or is it something else i'm not looking at?
Any reason i wont be ok with 21 awg?
Thanks!
Sorry Nelson, my knowledge is so poor on electronics, i'm not even sure if you're being serious 🙂 given the impedance of both 18 and 21 awg wire inductors is well below my minimum system impedance, am i ok to use either?
Or will the thicker wired inductor actually perform better?
Or will the thicker wired inductor actually perform better?
Ok, on good advice i've included baffle step compensation on the woofer, definitely flatter and has tamed the woofer peak from 400-700hz a bit. Phase over crossover point is better matched too.
Moved to Multi-way 
You could probably tame the 1.8k peak of woofer resonance by using a small resonance trap across the first woofer inductor. About 0.2-0.5uF should be good.
Lower DCR inductors will have better damping, but you do need to retune the crossover a bit when changing tweeter inductor DCR.
Response as is might sound a bit bright, I usually aim for -2dB between 1k and 4k response.
Lower DCR inductors will have better damping, but you do need to retune the crossover a bit when changing tweeter inductor DCR.
Response as is might sound a bit bright, I usually aim for -2dB between 1k and 4k response.