Building Passive Crossovers

BoneZ

OK, so I bought this pair of CDT HD-2BL Hybrid Mid-tweeters. Their frequency response is rated from 250Hz - 20kHz. I contacted CDT about the proper high pass frequency and they recommend 1500Hz at 24dB/Oct.

Now, building a 4th order passive crossover is easy enough, but my question for the audio gurus here is which style?

• Bessel
• Butterworth
• Gaussian
• Legendre
• Linkwitz-Riley
• Linear Phase

I never really knew the differences between these and I'm hoping someone here does.

tommyguns

Here's another source for that kind of help. diyAudio

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RonRizz

Or why not look into Harrison Labs FMods, and do your crossover in the pre-amplified stage, where amplifier energy is not wasted.....

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P99rs Head Unit--- Amps- 2 Pioneer Prs800d --- Zapco ST1000MX---Zapco ST-4XSQ---- SI BM mk5 Subs---SI TM65v2 Midbass--- SI M3 mids--- SI M25 xbl2 tweeters ----- 2016 MECA street class 3rd place at world finals

BoneZ

Interesting. I wonder if the 3000/12 hp would be similar to the recommended 1500 / 24. I'll have to look into these. Thanks.

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RonRizz

you can google it... They are inline crossovers that plug into your rcas, and the x over point chosen stays a constant, unlike in a passive setup, which fluctuates with the impedance of the driver while playing. Because it is done pre-amplified signal, there is no wasted power. Passive xovers burn energy filtering an already amplified signal, so you lose a slight amount of power when using them.
Also..... I am running a set of CDT ES-02's which also show a freq range of 250 - 20hz...
They recommend crossing at a higher freq for power handling purposes. I have crossed mine as low as 500hz at 100 watts, and had no issues with them.

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P99rs Head Unit--- Amps- 2 Pioneer Prs800d --- Zapco ST1000MX---Zapco ST-4XSQ---- SI BM mk5 Subs---SI TM65v2 Midbass--- SI M3 mids--- SI M25 xbl2 tweeters ----- 2016 MECA street class 3rd place at world finals

RonRizz

I think they are like $25 a pair. Hell, I may have a set in the garage.... If they are the right freq Ill send em to you. Been YEARS since I had them in one of my cars.

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P99rs Head Unit--- Amps- 2 Pioneer Prs800d --- Zapco ST1000MX---Zapco ST-4XSQ---- SI BM mk5 Subs---SI TM65v2 Midbass--- SI M3 mids--- SI M25 xbl2 tweeters ----- 2016 MECA street class 3rd place at world finals

BoneZ

Good to know. Thanks. I will probably go this route.

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BoneZ

Hot damn in the city. Thank you.

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RonRizz

found 2 sets..... just have to check the Harrison website to see what freq they are... I'll let you know. Leaving for tonight, gotta go set off some 4th of july fun!

Attached Images

fmods.jpg (184.4 KB, 13 views)

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P99rs Head Unit--- Amps- 2 Pioneer Prs800d --- Zapco ST1000MX---Zapco ST-4XSQ---- SI BM mk5 Subs---SI TM65v2 Midbass--- SI M3 mids--- SI M25 xbl2 tweeters ----- 2016 MECA street class 3rd place at world finals

RonRizz

just checked... the black lettered one is 1000hz LOW pass,
the red lettered is 100hz HIGH pass. The black set you could use for your midbass/subs, but you will need a 1000hz high pass for your cdts.

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P99rs Head Unit--- Amps- 2 Pioneer Prs800d --- Zapco ST1000MX---Zapco ST-4XSQ---- SI BM mk5 Subs---SI TM65v2 Midbass--- SI M3 mids--- SI M25 xbl2 tweeters ----- 2016 MECA street class 3rd place at world finals

BoneZ

Many thanks friend.

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BoneZ

I planned on just letting the woofers roll off naturally. I am going to order a set of these though. Hope they ship quick.

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BoneZ

Is 1000Hz hp going to be high enough with only a 12dB/oct slope? CDT told me 1500 @ 24. I was almost inclined to get the 2500Hz.

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RonRizz

Depends on the power you put in them...they are listed to go as low as 150hz, but not at rated power. I personally think 1000 is still too high, because your missing out on the lower midrange freq. That these speakers love.
I currently run mine at 630 with 100 watts, and they perform quite well.

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P99rs Head Unit--- Amps- 2 Pioneer Prs800d --- Zapco ST1000MX---Zapco ST-4XSQ---- SI BM mk5 Subs---SI TM65v2 Midbass--- SI M3 mids--- SI M25 xbl2 tweeters ----- 2016 MECA street class 3rd place at world finals

BoneZ

I'm only going to be hitting mine with 60 watts each.