Crossover help please?

Electricblue · #1 03-29-2011, 07:49 AM

What capacitor would I use to high-pass a 4 x Eminence Alpha 6 OR 2 x Eminence Alpha 6 cab?

It will be used with 2 x 115's at 8 ohm each.

I heard that if I put a highpass capacitor into the DIY cab, it would have no effect on the amp's impedance when connected. Is this true?

Electricblue · #2 03-29-2011, 07:59 AM

Bump?

Electricblue · #3 03-29-2011, 08:20 AM

Anyone?

washburn_it · #4 03-29-2011, 08:24 AM

Do you want it with 6 dB/oct or 12 dB/oct slope?
For the first type you need only a capacitor, for the 2nd you need also an inductor.

Regards,

Roberto

will33 · #5 03-29-2011, 08:25 AM

I entirely depends on what frequency you're passing them at, the impedance at that particular frequency and how steep. You should be lowpassing the 15's at the same spot as well.

BTW, a single capacitor would only give you 6db/octave.

Electricblue · #6 03-29-2011, 08:43 AM

Im not entirely sure about my figures yet, thats what im here to learn

I was hoping to pass the eminence's at as low as they can handle really. I dont know if thats the best idea.

I will probably go for 2 Alpha's. 8 or 4 ohm each, not sure.

Whats the difference between the 6db/oct and 12db/oct? I take its the steepness of the slope after the crossover point.

Electricblue · #7 03-29-2011, 09:01 AM

BurningSkies · #8 03-29-2011, 09:17 AM

Loudspeaker Design Software

To start...

Arjank · #9 03-29-2011, 09:42 AM

Quote:

What capacitor would I use to high-pass a 4 x Eminence Alpha 6 OR 2 x Eminence Alpha 6 cab?

It will be used with 2 x 115's at 8 ohm each.

What is the plan?
1 cab with each 2 alpha6 drivers to complement a 115?
First, why do you want to use two alpha6 drivers?

Quote:

I heard that if I put a highpass capacitor into the DIY cab, it would have no effect on the amp's impedance when connected. Is this true?[/

You mean connected together with the 115?
It will not have any effect on the amp's impedance

But, it sure has effect on the total loudspeaker impedance curve (diycab+115) and in turn has effect on the load the amp "sees".

Electricblue · #10 03-29-2011, 10:02 AM

Quote:

Originally Posted by Arjank

What is the plan?
1 cab with each 2 alpha6 drivers to complement a 115?
First, why do you want to use two alpha6 drivers?

You mean connected together with the 115?
It will not have any effect on the amp's impedance

But, it sure has effect on the total loudspeaker impedance curve (diycab+115) and in turn has effect on the load the amp "sees".

Plan is, 2 x (8ohm 115) and 1 x (2x6)

I would want the above setup but not fry my amp

Im ordering the drivers soon. Should I order 2 x 4ohm drivers or 2 x 8ohm?

The 2 x 6 will be wired in series, then all 3 cabs in parrallel into the amp.

MuzikMan · #11 03-29-2011, 10:32 AM

Won't 2 x 6s wired in series give you the same output as 1 x 6?

Electricblue · #12 03-29-2011, 10:42 AM

Quote:

Originally Posted by MuzikMan

Won't 2 x 6s wired in series give you the same output as 1 x 6?

More surface area, and less stress on each driver.

When lifting something heavy, do you use one hand or both hands? Youre lifting the same object, but using both hands is easier.

mcapote · #13 03-29-2011, 10:43 AM

Quote:

Originally Posted by MuzikMan

Won't 2 x 6s wired in series give you the same output as 1 x 6?

not really because its still double the cone area, though not worth the money on that design imho for a 3dB pump

MuzikMan · #14 03-29-2011, 10:47 AM

Quote:

Originally Posted by Electricblue

More surface area, and less stress on each driver.

When lifting something heavy, do you use one hand or both hands? Youre lifting the same object, but using both hands is easier.

That's true but there are also high frequency dispersion issues. If those were accounted for in the design then all is good.

MuzikMan · #15 03-29-2011, 10:48 AM

Quote:

Originally Posted by mcapote

not really because its still double the cone area, though not worth the money on that design imho for a 3dB pump

That 3db gain is offset by doubling the impedance, thereby halving the wattage.

tocs100 · #16 03-29-2011, 10:50 AM

Everything you need is here (and a couple posts back in the thread I link a site) if like me, you don't mind running your woofer full-range. I used at one time a full-range PA speaker and an actively-lo-passed sub together and the overlap actually helped. mcapote might build one for ya to save you some time & trouble.

Quote:

Originally Posted by tocs100

Great info from Greenboy here, but I just want to clarify some minor spec-stuff, as after 3 "no's" via pm's here I found a guy who will at least experiment with a protoype of my dual-6"-cube. Yes, there will be anomalies, like Avatar's tb153, but plenty are liking that cab. I just wanna come-up with something inexpensive that fills a niche and doesn't depend on others' designs, as I need some small income from music-tech stuff (esp. after 2 builders ran-off with my c/o-eq-pedal design). Others too, like me, have physical disabilities meaning they must buy premade products rather than being able to diy stuff--even from kits.

^Gotcha. I've done the full-range to the drummer and have a list of pros and cons. Some cons include bass-bleed into the drum-mics, and just overkill in basements (wives will love the efficient, bell-like mids and lack of woofing, lol) and on small-stages. Taking gb's advice, I decided on a rolloff slope at 125Hz when load is 16ohms (barely noticeable when using the cube alone) but about 350Hz at 5ohms (that is, when combined with an 8ohm cab. Again, no crossover involved, just a 1-cap passive rolloff on the 2 mid-drivers.) And the slope is only -6dB per octave, so there'll still be lots of chunk around the still-"embodied" 175Hz. The 4-octaves between 250Hz-4kHz will be perfect though--unlike 10"s which scoop there so when you bi-amp them you don't get much more than a hissy tweeter. :=( :=( (I despise 10"s! lol.)

^This stuff is just beyond me. Unless someone wants to volunteer any advice, I'll just have the 2 Eminence Alpha 6a"s mounted in an 8" square cube. (I think my builder has driver-data-software too.) The single-cap rolloff defeats the low-bass, so I don't see the need for porting--it's basically just 2 mid-boxes combined, but angled 90-degrees away for versatile dispersion. I want to use this with my guitar amp too.

Last quote below here links to others besides here curious about a simple (under $300), mid-satellite better suited than a tweet or a (scooped) 10":

Electricblue · #17 03-29-2011, 10:52 AM

Anyway, should the 2x6 be 8ohm or 16ohm total? I want to run all 3 cabs, but not fry my amp. Still not sure if its possible.

MuzikMan · #18 03-29-2011, 10:55 AM

It can be either. Your amp will not care, but you cannot select your crossover components until you decide which one it will be because filters are impedance dependent.

tocs100 · #19 03-29-2011, 10:56 AM

Wow, you're welcome....

Electricblue · #20 03-29-2011, 10:57 AM

Quote:

Originally Posted by tocs100

Everything you need is here (and a couple posts back in the thread I link a site) if like me, you don't mind running your woofer full-range. I used at one time a full-range PA speaker and an actively-lo-passed sub together and the overlap actually helped. mcapote might build one for ya to save you some time & trouble.

And cheers dude, I think the problem is just impedance now. I would run the 2x6 high-passed and leave the 115's how they are for now.

Whats the lowest you can go on a 4ohm amp, safely? I know its 4ohm or above, but what about 3.5ohm or something?