Passive Crossover... without an amp?

[RustyHo88]

i was just wondering if anyone knows of a manufacturer that makes a truely passive crossover. not one that conditions the signal from a head unit to an amplifier, or from an amplifier to your speakers, but one that conditions the signal from your head unit to your speakers. my head unit puts out more juice than i need, so i dont want to have to buy an amp just to condition my signal. and, as well all know, bass blockers and inline crossovers are worthless. i need something that just cuts out signals above and below certain frequencies without amplifying my signal. any suggestions?

[RustyHo88]

gosh, either nobody understands what im asking, or i am just an idiot. should i just buy a cheap 40x4 amp and forget my stupid idea of a passive crossover... or what?

[87DXHatch]

I don't really know what you're after...

If I were you, I'd get a 40 X 4 amp, or something similar, and just do a high-pass crossover on it, cutting the frequencies 100 hz and lower to your speakers... if that's what you're looking for. You'll enjoy a bump in the SQ of your system with the increase in power as well.

[RustyHo88]

more than anything, i just want to extend the life of my speakers. my head unit has a built in crossover, but i only have the option of cutting out frequencies of 125 hz, 80 hz, or 60hz. and that is for all 4 speakers. so, what i really want to be able to do, is control the frequencies going to my rear, as well as my front speakers. im not worried about my high frequencies, just the low ones. all i really would need i guess is a passive crossover like the ones that work with an external amp, that has direct wire connections rather than RCA jack inputs and outputs. so basically, i need a glorified component system crossover. one that hooks up in-line to my speakers, but allows me to mess with the frequencies. maybe i should get a degree in electronics engineering and invent something like that. that along with that crazy idea for a switch that turns on when no remote power is going to it.

[87DXHatch]

Sorry man, but the first thing doesn't exist. Those passive crossovers are a network of capacitors and inductors that shape the sound and have slopes of the crossed frequencies. I'm pretty sure what you describe would be damn near impossible to build to... if you did build it, it would be pretty big to house all the electrical components you'd need. It'd be WAY more practical and cost-effective to just use active crossovers, and then passives before the speakers.

As for your second thought, those do exist, they're called SPDT relays I have one in my car... one circuit switches on when you apply power (aka, my remote wire) to it, while the other switches on when the power is taken away... you can use it to wire up like a blinking LED when your system is off to ward off thieves.

[RustyHo88]

hahaha.... we had a whole other thread dedicated to finding out what that 2nd switch was. now we know, thanks 87dxhatch. however, i was wondering.... active crossover? wouldnt that be like an equilizer? i have no problem hooking up a crossover to my battery, as long as its cheaper than buying an amp. unless by active crossover, you mean the built in crossover on any amp. if there is such a thing as a crossover that conditions my signal, withouth neccessary amplifying it, even if i have to have a remote, power, and ground wire hooked up to it... then that is what i want. where can i get one?

[87DXHatch]

Well I don't understand why you care so much that the signal remain un-amplified...

If you're only using a HU, then you have two options:
1) use the crossover features that came with the head unit.
2) use external processing and external amps.

I highly recommend #2, it's what I use, and it's the easiest way to get the best sound from your speakers.

What it sounds like, is that you want to cut some of the lower frequencies from your speakers, correct? "To prolong their life" right? So if you got a 4-channel amp, and ran RCA's from the HU to it, and your speakers off of it, then you could do that from the amp. As long as the 4-channel amp wasn't something dirt cheap (aka Roadgear, Rockwood, Kenford, etc) it will have a crossover system built into it. This means that you can actively (aka by using electronics, not static electrical components) cut the lower frequencies from your speakers by engaging the high-pass filter. Most often they are variable too, so you can play with it to see what you like the best.

If you wanted to go a step beyond that, even, you could use an EQ inbetween the HU and the Amp... this is what I do, and I can adjust the knobs on the fly for how much bass my front speakers reproduce...

If you're looking for a cheap 4-channel amp, email [email protected] and ask him for a catalog... they have cheaper amps than you can get on eBay, and they're quality all the way... look for a US acoustics amp. I've bought 2 amps from him so far, and I wouldn't hesitate to buy again.

[87DXHatch]

Or you could use bass blockers inline with the speakers, but I've heard those make your speakers sound really crappy.

[RustyHo88]

yea. bass blockers just mute the entire signal it seems, and they dont do a very good job of blocking low frequencies. i probably will just get a 4 channel amp, i just hate to see the 40x4 watts generated by my HU go to waste. im not fussy enough about my speakers to buy a crossover on top of an amp, having the crossover feature inside the amp will be enough. ive been using the crossover feature in my HU, and it does an ok job, i just need something more exact. i hate having to choose between having speakers that sound like they came out of an elevator, and speakers that sound like their about to blow up. i suppose to get what i want, ill have to shell out more cash ::sigh:: oh well, it was worth a shot, thanks.

-will

[87DXHatch]

BTW, the "40X4" coming out of your HU is more like 18 watts per channel RMS. Your speakers will sound MUCH MUCH MUCH better and get MUCH cleaner signal with the external amp.

[POS carb]

don't say something doesn't exist without knowing, passive crossovers are a lot more common than active ones, the only problem is that most are not adjustable and the frequecy of cutoff depends on the speaker's impedance. The most simple way to cut bass from a speaker is to wire a capacitor in line. For 5 1/4 speakers you can go with something around 220uf and get it over 50v if possible. The larger the uf of the cap, the lower the cutoff frequency and it would be 6dB/octave

[RustyHo88]

ive tried using a capacitor (bass blocker) and they just dont work. if there is such a thing as an adjustable passive crossover, then that is what i want. i have seen them before, but they came with component systems, and i dont want to pay $150 for new speakers with a crossover, when i could just buy a new amp. i was thinking... what if i bought an active crossover, and then used rca adaptors to wire my direct speaker lines from the HU through the rca inputs in the amp, and then use more rca adaptors to wire the speakers to the crossover? would i lose a lot of the signal doing that? hmmmmm, any ideas?

[87DXHatch]

POS, he's looking for a passive crossover that has adjustable frequencies... I am almost positive that such a device would be VERY impractical to make, and thus I have never came across one, or even heard of one.

[POS carb]

yeah plus it would probably not handle too much power. If bassblock isn't enough you can also wire an inductor in parallel along with the cap in series and you'll get a 12dB per octave rolloff

[Zigman168]

i make passive crossovers 6db & 12db
lowpass highpass 2way 3way

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