Need Help with a 2 way design.

[dawg1161]

First I would like to thank all who reply.

Wednesday morning i get all the supplies i need for the sonosub minus the subwoofer(other active thread).

I know that in every post that i read one is not to use a stock crossover, I did not know this until i began reading all the information that is availible on this forum as well as htforum. Well i have a parts express 4500hz 2 way crossover that i would like to use and need idea's for a woofer to go with this tweeter from mcm electronics titanium 30 mm High End Dome Tweeter

Specs: Power Handling: 50 W RMS/80 W Peak,
Voice Coil Diameter: 30 mm,
Impedance: 8 ohm,
Frequency Response: 1000~22 KHz,
Magnet Weight: 10 oz,
SPL: 90 dB 1W/1M,
Fs: 880 Hz
Dimensions: 4-1/4" dia. x 1-1/8"
Cutout: 3-3/16"

Any Idea's will be helpful. Prefer to keep it a 6 1/2" or smaller. I do have 4 Dayton 6 1/2" dc 160-8 but i read somewhere that they need to be crossed at 2000hz ?

Thank You All.

[dawg1161]

It must be the pre-made crossover that keeps the guru's from replying....lol.
I know, I have read all the previous posts about using premade crossovers but like i said that was after i had purchased it. I'm not expecting a miracle but i sure don't want to waste the money i spent. I am open to any ideas as to me it would be more experiance in the building the cabinet phase and who knows it just might have a nice sound to it for a childs room or even the garage ?

[joecarrow]

You're going to get limited results since the "standard" crossover doesn't take into account the baffle step, and it doesn't take into account the actual impedance or phase of the drivers in the crossover region.

You could whip up a quick test box to see how this sounds, but what you could do is make a bipole speaker with the woofers you have. Make the cabinet (cheap and dirty to start out, scrap wood if you have it, or heavy cardboard to fake it), with one woofer on the front of the cabinet, and one woofer on the back of the cabinet. Wire the positive terminals of the woofers together, and the negatives together so that the woofers work together in parallel. This will raise the sensitivity of the woofers to get closer to the sensitivity of the tweeter, and it will eliminate the baffle step issue.

This arrangement would probably be listen-able, but it won't win any awards. Definitely has potential for a garage speaker, but I wouldn't put any more money into it.

Your woofers should ideally be crossed lower due to cone breakup. This means that the crossover region will have a bit of a gap in the frequency response (the falling response of the woofer adds to the cutoff of the crossover, cutting the woofers out prematurely), but since it's a paper cone woofer the cone breakup isn't nearly as objectionable as it would be for kevlar or aluminum.

I'd expect this to go a lot louder and sound a little better than a cheap boombox, but again- try not to build up your expectations too much.

Good luck!

[dawg1161]

Thanks for the suggestion.

[ThomasW]

PE let's people return unused merchandise up to 45 days after purchase..

Don't have a clue about the tweeter....

[dawg1161]

thomas it wasn't purchased by me from parts express. before i found this forum and found massive amount of information i would look at a drivers freq. responce something like 5 1/4 driver 45-7000hz and then the tweeter 2000-20,000 and i just assumed(bad word) that it could be crossed at 4500 and it would work out fine.
so if you have any idea's what might work around store bought 4500hz crossover in a mid-tweeter or mid-tweeter-mid ? thanks again

[morbo]

Well I suspect for a start, find out what impedance the crossover expects to see. Then find drivers that have a nominal impedance close to that, and with similar efficiencies. Because the XO frequency is so high, you will need to keep the center to center distance between the drivers as low as possible. So, I would suggest no larger than a 5.5" midwoofer, probably 4.5", and if possible a small flange tweeter like the morels, vifa h26, or the dayton neo. If you want to use the tweeter you have, consider trimming the bottom of the flange for closer mounting. Since you have no control over the slopes of the XO or any breakup nodes, I would go with wide bandwidth drivers that don't have big breakups in the passband, probably paper or poly cone, something like the CSS wr125 (though its efficiency is likely too low without lots of tweeter padding) that is well behaved out to 9-10khz would be best.

This will of course not be optimal in any way, but if you are dead set on attempting the "silk purse out of a sow's ear" approach, its how I would proceed. I do suggest you think about it long and hard though, because using the premade XO will force you to make a lot of compromises in driver selection and ultimate quality, and you may end up not saving any money at all if it forces you to use more expensive drivers or leaves you unsatisfied in the end.

[ThomasW]

4500Hz is a crossover point for dome or small cone midrange going to a tweeter. It's a terrible crossover point to try and force a standard midwoofer run up that high. The high frequencies coming out of the midwoofers will be beaming like mad.

The 30mm dome tweeter is designed to use a low crossover point hence it's 880Hz Fs.

So fundamentally you have a collection of parts that have no performance characteristics in common.

If ditch the crossover you could make the dome work with your 6.5" midwoofer. Use a 2khz-2.5kHz crossover point.

[dawg1161]

Thank You, I will ditch the crossover then. I will try the tweeters with my 6 1/2's and see how that turns out. Consider this thread closed.