I have a technical question regarding crossovers and speakers. I have selected a mid range speaker and tweeter that has the following specs:

6.5

 

Not that I'm an expert, but are either of these crossovers made for this driver combination? Or are they generic crossovers? Are the drivers matched for efficiency? (db output/watt). If they are within 1 db, extra adjustments are nice but not a necessity. If the efficiencies are 3 db or more different, you will almost for sure be better off with the adjustable x-over.

I noticed your tweeter is 6 ohm. If the crossover is made for 4 ohm, your crossover point for the tweeter only will change. I believe the crossover point will go down with the higher impedance tweeter, I'm guessing about 30% lower. Get other opinions on this, I don't remember the math.

I am sure of this - As a general rule -

Lower crossover points give better dispersion, that is, the sound output at an angle to the speaker will higher compared to the output directly in front of the speaker. This is a desired feature in cars where the tweeters are not mounted line-of-site with the listener. If the tweeters are mounted high and pointed towards the listener, dispersion is less important.

Lower crossover points make power handling more of an issue though. If your power output is close to the tweeter limits, a higher crossover point will be less likely to damage the tweeter. That's probably why the 2500 x-over has 24 db/octave slopes - saves your tweeter.

 

Polk makes some good cheap X-overs... BUT Honestly, what I would do:

Don't cross over the woofers at ALL... try and get as much treble out of them as you can, and what they can't produce you simply won't hear anyway...

Get some Caps. for the tweeters.. (put it in series) and poof..your done. You can also get "bass blockers" and/or any other number of cheap passive tweeter crossovers for a few dollars.

Ohh-- reason I say this: We tried the mid X-over on Kirks S2000, and then without...it was MUCH better sounding without the mid x-over.
-- Aaron

 

I would do exactly what amartin suggested if you don't want to dick around with it.

Your tweeter should have come with a graph showing it's freq. response vs it's impedance (as it will change with freq.).

I think I would cross this tweeter off at around 3.5K as a start point.

If you have the graph, find where 3.5K is on the graph and look at what it's impedance is at that point.

Then use this formula to calculate the size of the capacitor you need:

Fc= 1/2PiRC

Fc = Cutoff freq = 3.5K
Pi = 3.14
R = The impedance the tweeter will have at 3.5K Hz
C = The size of the cap need to give you that cutoff freq.

I would try a couple of different Fc to see where it will sound the best, the caps should be pretty cheap.

If you don't have the graph just use R=6.

Hope this helps.

PS get an unpolarized capacitor for this so it does blow up.

 

Thanks for all the input ... if you would like me to post the specs, as well as the graphs for the drives I can. These are not matched sets per say; however, they are a recommend set from the manufacture. I have also learned that I can purchase a x-over for this combo of drivers for about $27 each ... from what I was told, the x-overs were made based on some computer program utilizing the drivers specs ?? I have also heard of using caps like you mentioned, but really don't know much about how to do that. Any other thoughts ... from what I'm understanding for other posts, it is hard to get great sound from an S2k, but I would like to try my best.

 

[QUOTE]Originally posted by Jaysom
[B]Thanks for all the input ... if you would like me to post the specs, as well as the graphs for the drives I can.

 

I would do exactly what amartin is saying. If you post the specs and graph, I will do a quick calculation for you, but you can do it yourself using the formula I posted above. A couple of caps are really cheap and really easy to install.

 

Thanks again ... I think I will take your advice. I will let you know what I end up with and also post some pic's once completed. As if I don't have anything else to do, I'm taking measurements to fit a 8" sub in the passenger footwell ... looks like it (the enclosure) will only be about 5" deep, so not much leg room lost.