Component set

[Bwap]

Anyone know of a component set that has a 4 ohm woofer, and an 8 ohm tweeter but the final impedance is 4ohm after the xover that can handle 200 rms?

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[trumpet 5,000+ posts]

What does it matter what the impedance of the woofer and tweeter are if you will run them through the crossover? Are you looking to run mids and tweeters active? You can buy mids and tweeters separately from some manufacturers.

If that isn't what you're looking for then I don't understand the question. Car audio tweeters are usually 4 ohm.

 

[Silverado SS 10+ year member]

Please explain why you want 2 different ohms?

 

[Bwap]

Well I plan to wire a supertweeter into the input of the crossover, dropping the ohm load to 2.66 ohms. My amp pushes about 250 watts at 2.66 ohms.

When below the crossover point of the tweeters, the woofer must be able to handle 150rms.

When playing above the xover point of the woofer, the tweeter must be able to handle 62.5rms.

 

[mylows10 5,000+ posts]

why not get the xovers with a upstage capability

 

[trumpet 5,000+ posts]

Well I plan to wire a supertweeter into the input of the crossover, dropping the ohm load to 2.66 ohms. My amp pushes about 250 watts at 2.66 ohms.
When below the crossover point of the tweeters, the woofer must be able to handle 150rms.

When playing above the xover point of the woofer, the tweeter must be able to handle 62.5rms.

This isn't quite how power is distributed from an amplifier through a passive crossover. The tweeters will get less power because there's less energy content in music, not so much because of the impedance. As you seem to know, one job of a passive crossover is to make the amplifier see a certain impedance at rest that's different than the drivers in parallel or in series.

Another effect to consider is that adding tweeters in parallel with a 2-way component set doesn't actually make the amplifier see that low of an impedance while music is playing. The effect is smaller because the voice coil in the tweeter is much less massive than in a woofer, and it also doesn't move as much.

 

[Bwap]

Hmm is there a component set you would recomend that I could wire in parallel with an ft1 supertweeter(crescendo 8ohms 80rms)?

Im hoping to use as much power as I can, amp pushes 150@4x4 or 300@2x4

I plan on wiring the supertweeter on a switch, so i guess take that into consideration.

 

[mlstrass 5,000+ posts]

you will also change the xover point/slope for the tweeters by wiring in a 2nd one and changing imp.

Why not just get some Crescendo PWX's?

 

[Bwap]

you will also change the xover point/slope for the tweeters by wiring in a 2nd one and changing imp.
Why not just get some Crescendo PWX's?

Not if you wire in parallel before the crossovers, as far as I know.

I planned on getting pwx's and morel tweets.. then wiring the supertweet on a switch.. the problem i ran into with this was finding the right crossovers.

I would build my own, but i dont have the equipment to test it so I have been leaning more towards a comp set and ST with factory xovers

 

[mlstrass 5,000+ posts]

Let's say the xover for the tweeters is set up for a 4ohm tweeter. Presenting an 8ohm or 2.66ohm load will change the xover point/slope. Pretty sure 12v has a calc if you want to figure out what they will be.

I would get 2 diff amps, run your comp set up off one amp, then the PA stuff off the other amp. Toggle switch on the REM and you're golden. Use a cap to HPF the FT1, and HPF on HU or amp and FMOD's for LPF to bandpass the mids.

 

[okiedokie 10+ year member]

Why not just go active ?

I think Morel tweeters are 6 ohm thru 8 ohm.

 

[Bwap]

Well I cant go active because these speakers all have to be wired in parallel, my amp pushes a lot of power that I would like to utilize. (300@2x4)

Only 2 of the channels are available, as my rear doors are using the other two channels.

I cant add another amp as I already have 3 amps and two batteries in my trunk so no more space.

 

[trumpet 5,000+ posts]

You can use an amp small enough to hide behind a panel or under a seat. A small 20W-50W x 2 amp is plenty for tweeters.

300W x 2 is quite a lot of power for any passive crossovers to handle. You'll probably have your tweeter protection kicking in, assuming that's present in the crossovers. There are some systems I sell that could take it, but not with a pair of supertweeters. They use a 6.7" or 8" midbass, 3" or 4" midrange, and 2" or 1" tweeters. They need to be high passed at 100 Hz to handle 300W per side. These will get loud and sound good doing so.

 

[Bwap]

Well I already have two midbass 8s running on a separate amp, so im just looking for midrange/tweeters.

I know its a lot of power but im sure that there is some setup I can conjure up/find.

 

[Why So Cereal? 5,000+ posts]

Just ditch the extra tweeter and run a solid comp set.

But, to answer your question, I know the Boston PRO60 set has an 8 ohm tweeter, 4 ohm mid, and 4 ohm final impedance. But, you WILL change the crossover point by adding that extra tweeter and changing the impedance.