Newb question on Crossover and impedance

[Chris Hammer]

Ok so I keep thinking about crossovers and how two 4ohm drivers on a crossover can be a 4ohm load, but if you run without xover you get 4ohm for your mid and 4ohm for your tweet.

So does that mean they are wired parallel and the crossover network brings the impedance back up to the standard 4ohms? I don't know I am asking a ?...just trying to wrap my head around stuff i know little about.

If the above is true, then do your tweeters/mids get equal power when on a passive xover..or does one receive more then the other?

Also if you power a set with lets say 50w...will the tweet get 25 mid get 25, or are they both getting 50? Both getting 50 seems impossible to me, but I don't really understand anything about xovers really, just about different crossover points and slopes...If you asked me to tell you what the components in a xover network do I would be lost.

The reason I am thinking about this is I have a set of soundqubed comps coming, I already have some AQ tweets but they wouldn't sell me just mids and xover. I really like the tweets so I am giving the mids a shot.

ANYWAY I am trying to decide if I should run active and give tweets 55w with 4k 12db xover as a starting point... and mids passed at 60-4k 12db on 55w too.... OR should I just run the passive xover and power them both with 55w.

TO sum it up...should I run active at 55w on each driver..or passive with 55w a side and maybe do a second set later if I like them.

[bcbrassard]

The crossover takes the freq and separate's the signal to what the tweeters need and what the midrange speaker needs but keeps the wattage the same to each speaker. But a crossover takes power to work away from what the speakers truly see, anywhere from 11-20% from what I have read. Basically crossovers are the simplest way to run components but not the best. I thank active in the right set up delivers more power and control to your components. Can be a totally different sound and experience, I went from passive to active on the same speaker & power and it made a huge difference in my set up. Went from SPL more to SQ which after upgrading speaker will be closer to. Hope this helps, good luck.

[Chris Hammer]

Thanks for lending some more insight. I was hoping I would get a more technical answers form some others on here...but no one showed any interest really. I think I am still going to stay active so I can go with 2mids each side and one tweet...I'm not of fan of loud highs,,,I always have to tone them down through eq or gain.

[Sutliff]

Thanks for lending some more insight. I was hoping I would get a more technical answers form some others on here...but no one showed any interest really. I think I am still going to stay active so I can go with 2mids each side and one tweet...I'm not of fan of loud highs,,,I always have to tone them down through eq or gain.

See I like the loud highs, per se, but am always tuning them down when the little Lady is in the car. "Turn the bass down, too?"

#Ugh

[bbeljefe]

From an amplifier impedance standpoint, the inductors and capacitors on a crossover act as a barrier between the amplifier and speakers... for lack of a better term. The amplifier only sees the impedance of the crossover, while the crossover sees the impedance of the drivers connected to it. As for components... inductors (coils) filter high frequencies and capacitors filter low frequencies. And then, depending on how they are connected to one another, they can be used to filter a narrow bandwidth of both high and low frequencies, which is the most common network you'll see in car audio. They only have a high pass filter (for the tweet) and a bandpass filter (for the mid) while, say, a 3-way crossover will also have a low pass filter such as those you see in home stereo loudspeakers. Those guys have a lot larger inductors on them for the low pass filtering.

In more complex crossovers resistors are also used to limit the amount of power going to the tweeters and it's those resistors that chew up a lot of amplifier power, because it is dissipated as heat energy rather than being sent to the tweeter. Obviously, this is one of the main reasons why active filtering is better but, it comes at the cost of added final amplification since the filtering is done in the preamp stage.

That make sense?

[bbeljefe]

The 12volt has a pretty good explanation of passive crossovers here.

I thought about that last night but I was zombified tired and didn't want to look it up. It's more articulate than my coma rant.