# Crossover help. I'm so lost and confused.



## Hogger (Nov 25, 2009)

I've got this idea to build these speakers for my theater.
1. The drivers are affordable.
2. I've heard good things about the drivers.
3. I like the look of my design.
4. I like to say, "ya, I made those."

So here is my idea. I don't know all the MTM, MMT acronyms, so. It's a tower with a 6 1/2" woofer(8 ohm), 2 4" mids(4 ohm that I will wire to 8 ohm), and a 1 1/2" tweeter(8ohm).
The woofer will have it's own enclosure, as will the tweeter, and the 4"s will share an enclosure.

I've tried a bunch of the different calculators to get a rough idea about where to cross the speakers at, but I have no idea. WinISD doesn't seem to show this info on the graphs, or in the calculators, or maybe I'm just not getting it. Somehow I need to find the FqL and FqH?

The speakers are from Parts Express:
6 1/2" = Jamo 21330
4" = Jamo 20305
1 1/2" = Jamo 20301

Can anyone give me some idea about what type of crossover, and or what frequencies to cross at. I'm thinking at my stage a pre-made crossover would be good.
I can provide TS parameters if needed.


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## Warmon (Aug 25, 2007)

As someone who is about to build a 3-way center channel of my own design, I can tell you that you are in for a mind numbing conundrum. As confused as you are now, this is just the tip of the iceberg. There are only two ways to do this properly and have it come out right - you have to learn all the ins and outs of intensive computer modeling / simulation or you have to get all the gear to do measured responses yourself. This is why everybody says to build something already designed / built by somebody that knows what they are doing. Building a speaker makes building a sub look like a cakewalk..:heehee:

My advice is if you haven't bought the Jamo's yet, don't.


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## lsiberian (Mar 24, 2009)

Hogger said:


> I've got this idea to build these speakers for my theater.
> 1. The drivers are affordable.
> 2. I've heard good things about the drivers.
> 3. I like the look of my design.
> ...


Pre-made crossovers usually don't work very well. I suggest you get a premade design instead.

Look up a kit in your price range at Madisound and build it.


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## lsiberian (Mar 24, 2009)

Warmon said:


> As someone who is about to build a 3-way center channel of my own design, I can tell you that you are in for a mind numbing conundrum. There are only two ways to do this properly and have it come out right - you have to learn all the ins and outs of intensive computer modeling / simulation or you have to get all the gear to do measured responses yourself. This is why everybody says to build something already designed / built by somebody that knows what they are doing. Building a speaker makes building a sub look like a cakewalk..:heehee:
> 
> My advice is if you haven't bought the Jamo's yet, don't.


The best center driver I'd suggest is the Loki coaxial. It provides a wave guide to prevent inteference with the L-R channel and will have zero lobing issues. Don't worry about timbre matching well built speakers don't have this issue.

http://www.madisound.com/catalog/product_info.php?cPath=35_40_402_275&products_id=1696

At least take a look at it. It's a very good driver, but may be out of your price range. (it's out of mine)


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## Hogger (Nov 25, 2009)

Thats not the answer I was looking for, but probably the answer I needed. It's a project I would love to do, but without the proper equipment, and the know-how; it's probably best I don't waste my money and create a headache until I have a better understanding. 
I will look into the Madisound stuff.
_Posted via Mobile Device_


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## JCD (Apr 20, 2006)

I'd skip either the 4" drivers or the 6.5" -- they're reproducing 6 of the same octave ranges. The 4" extends one higher and the 6.5 extends one lower, but mostly they're hitting the same octaves. Note, I'm just looking at their published operating range. The real 

If I were to choose, I'd drop the 4" drivers and get two of the 6.5" drivers. With those two drivers, I'd probably cross them 2000 to 2500hz. That gives you about the same octaves on both sides of the crossover point.

If you really wanted to go with a three way, I'd go back to the 4" driver then look for a driver that was more like 10" or 12".


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## Warmon (Aug 25, 2007)

Hogger, go here to Zaph Audio and check out the fully documented DIY speaker systems section. There are a few designs that are very affordable. Also good is RJB's website.

This is also a great site with lots of really cool projects.. Read what he says about designing crossovers.

http://www.troelsgravesen.dk/Diy_Loudspeaker_Projects.htm

This is probably my favorite and my inspiration:

http://www.troelsgravesen.dk/VifaPL14WJ+XT25TG.htm


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## jackfish (Dec 27, 2006)

I agree two four inch drivers seems excessive. An MTM with a couple of good 6.5" and a good tweeter would do just fine.

Why not just buy these? An incredible value and should be pretty easy to finish.

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=300-702

http://www.parts-express.com/projectshowcase/tritrix/index.cfm


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## 1Michael (Nov 2, 2006)

I agree. Do not attempt to design a crossover for your first project. Even a child can design a subwoofer but a fullrange speaker is a Whole Other Deal! Pick a design that has already been created. http://www.htguide.com/forum/forumdisplay.php4?f=39 :T


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## Hogger (Nov 25, 2009)

Thanks for all the links. Now I have some research to do.


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## Ricci (May 23, 2007)

The crossover is the most difficult part of a speaker to get right. Good luck...


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## fbov (Aug 28, 2008)

More research... this is the master list of proven DIY speaker designs. 
http://techtalk.parts-express.com/showthread.php?t=211558

I'm also impressed how well you took the bad news. When I read post #1, the back of my mind was saying "uh oh, here's another noob with a Goldwood project, in for a disappointment." Your transition to the more-desirable "noob looking for the right project."

HAve fun,
Frank


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## lsiberian (Mar 24, 2009)

Just to enhance the discussion and learning. When selecting a midrange driver. you are looking for a range from 5khz to 500hz generally. 

This allows you to use a wide dispersion tweeter and a deep extending woofer. Discovering an appropriate driver takes experience. There are currently few drivers I've seen suitable for this. 

The Dayton RS 2" dome 
The Infinity MRS driver
The CSS WR125ST

There may be others out there, but these 3 are certain to lead to a good speakers.

For the bottom I suggest an Exodus Anarchy.


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## Rubensnvs (Jan 26, 2010)

You really should not try to design your own speakers :no:, unless you have lots of experience. 

It demands many tests, and the xover is the point where people usually get lost, specially in a 3 way project.

I will make a pair of 2 way EROS MKII. I can´t post links, but you can see it at the speakerbuilder site.
I have bought parts in Madisound (around US$1,000 - Clarity caps), and will make the cabinets myself.

2 Woofers: Vifa PL 18-08 (in paralel= 4 ohm)
1 Tweeter: Scan Speak D2905/9500 - very good tweeter

If you can spend a little more (US$ 1,500), take a look in THOR project, also.

Excuse my poor english :T.

Rubens.


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