Help needed - understanding crossovers

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Okay so here is what I want to accomplish:
3 way - 4 driver all 8ohm (2 x woofer, 1 mid, 1 tweeter)

So with this calculator I have the values for a normal 2nd order butterwoth design.
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But now when I add a 2nd woofer in parallel obviously the ohms would become less, Rtotal = R1×R2/(R1+R2) = 4ohm

So by using this online calculator, i change tha value of woofers to 4ohm.
attachment.php


The inductor and capacitor values did change at the woofer level, but what about the rest of the circuit? Will the rest of the circuit still run at the desired 800/4500hz ?

Thank you.
 

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Forget about online calculators. They work on the assumptions of constant impedance, flat frequency response and infinite baffle, and all those assumptions are wrong. If it were so easy to build a crossover we would have only speakers with perfect performance. The truth is that the crossover is the core component of a speaker, and must be designed to suit the drivers chosen, and also the box shape and driver placement.
The best option for starting in this hobby is to build a proven design, but if you want to start designing a speaker read at least the sticky post in this forum about designing a crossover without measurement. Keep in mind that for a complete novice designing from scratch a 2 way is difficult, but a 3 way is probably impossible.

Ralf

The answer of you question is that on a parallel crossover what you do on the woofer part doesn't modify the behavior of the other parts.
 
Thanks for the reply!
I want to figure out how driver placement, cabinet design etc influences the XO design.
There is no fun or learning in a DIY speaker since everything is pre calculated and designed. I want to broaden my knowledge of speakers and crossovers and how it works together.
Obviously I will chop and change values on the XO depending on the sound I get once everything is assembled, but was unsure of the effect the 2 x woofers in parallel will have on the rest of the XO.
 
Have you thought about finding a speaker that fits what you want, but that's already been designed?
The Parts Express Tech Talk forum is all about DIY'ing speakers. You might find some specific help over there.
I had one that fit that configuration that used 2 Dayton Dayton DC-160's, a Tang Band W4-1337, and a Vifa tweeter. If you'd like, I can try to find the crossover and build specifics.

Forums - Techtalk Speaker Building, Audio, Video Discussion Forum

Mike
 
Yes, I have these drivers with me:

HIVI M8N x 4
HIVI M6N x 4
HIVI M5N x 2
HIVI M4N x 2
Dayton Audio DC28F-8 1-1/8" Silk Dome Tweeter x 2
Peerless D27TG-35-06 1" Silk Dome Tweeter x 2
Visaton DT94-4 0.8" Polycarbonate Tweeter 4 Ohm x 2

So with a combination of these I want to build a decent speaker.
 
For a speaker DIYer there are 2 different skill sets. One is designing and the other is building, and the latter is fairly easy to understand. If you are building a proven design, you still have a lot of things to do correctly and to learn. OTOH what is under the design skill can be a little obscure for a novice. If you want to undergo this route I suggest you to buy two books: Loudspeaker Design Cookbook by V. Dickason and Testing Loudspeakers by J. D'Appolito. And then also buy some measurement equipment, at least a calibrated mic is needed, if you have a windows computer with excel then the sw is free. And don't forget to buy lots of crossover components for testing purposes.
As a first design, try a 2 way, the M5N coupled to either the Vifa or the Dayton crossed at around 2.5KHz should work.

Obviously I will chop and change values on the XO depending on the sound I get once everything is assembled, but was unsure of the effect the 2 x woofers in parallel will have on the rest of the XO.
If you build a crossover based on an online calculator you could be so far off that you can't remedy. And is surprisingly difficult for an untrained ear to understand what is wrong without a measurement.

Ralf
 
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Joined 2013
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Yes, I have these drivers with me:

HIVI M8N x 4
HIVI M6N x 4
HIVI M5N x 2
HIVI M4N x 2
Dayton Audio DC28F-8 1-1/8" Silk Dome Tweeter x 2
Peerless D27TG-35-06 1" Silk Dome Tweeter x 2
Visaton DT94-4 0.8" Polycarbonate Tweeter 4 Ohm x 2

So with a combination of these I want to build a decent speaker.

http://www.htguide.com/forum/showthread.php?39369-Swope-3-way-(TMWW-or-WTMW)

Go here and READ all of it..."Swope Tower" is a fantastic speaker and you are only missing the tweeters (which aren't expensive). Easy box to build, or spice it up to your taste (keeping internal volumes the same) and the speaker spacing the same distance from the top/sides and each other. You will have an extremely nice speaker that will play very loud and have bass with authority.
 
Thank you guys for your help. Can I use my yamaha rxa3060 mic? Then I'll download the software and test the driver response once inside the cabinet and then use the response measurement to better design the XO. What is this sound easy v21 software like?
Is this the room EQ mic supplied with your receiver? If it is, then yes, its probably a unidirectional mic. Your PC probably has an internal sound card with sufficient resolution to do "relative" measures for checking/tuning.

BTW you are correct in trying to calc/sim your crossover network before building it. You may have to "tweak" a little after building but you'll at least be in the ballpark. Even better you'll have a baseline as to what to expect and hence know where to initial look for problems.
 
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Joined 2013
Paid Member
I'm not sure about the Yamaha mic, not personally tried that.
Look at a UMM-6 from Parts-Express and use REW software (free), but you also need to get the phase (zma) of the drivers to use with the FR graphs (frd) you get with the mic.
DATS (again Parts express) is a very easy to set-up and use product, but you can google and make your own jig with a few parts and a computer sound card, but not as easy as DATS. You would be hard to beat the Swope using those drivers, IMHO even taking months of study and XO design. Paul C. has been designing XO's for 10+ years and is highly regarded in the DIY world.
Google "Paul Carmody undefinition" and read every link on the right-hand margin of his site, you will immediately increase your knowledge 300%.
 
Okay so here is what I want to accomplish:
3 way - 4 driver all 8ohm (2 x woofer, 1 mid, 1 tweeter)

So with this calculator I have the values for a normal 2nd order butterwoth design.

But now when I add a 2nd woofer in parallel obviously the ohms would become less, Rtotal = R1×R2/(R1+R2) = 4ohm

So by using this online calculator, i change tha value of woofers to 4ohm.

The inductor and capacitor values did change at the woofer level, but what about the rest of the circuit? Will the rest of the circuit still run at the desired 800/4500hz ?

Thank you.
I don't recognize the calculator you're using, can you post a link. Does it at least require you to enter both the speaker DC resistance and inductance for each speaker? I say at least because usually a 5 element model for the speaker is preferred.
 
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Is this the room EQ mic supplied with your receiver? If it is, then yes, its probably a unidirectional mic. Your PC probably has an internal sound card with sufficient resolution to do "relative" measures for checking/tuning.

BTW you are correct in trying to calc/sim your crossover network before building it. You may have to "tweak" a little after building but you'll at least be in the ballpark. Even better you'll have a baseline as to what to expect and hence know where to initial look for problems.

Yes thanks that was my idea, to get a basic idea of components ill need.
 
ERSE - Crossover Calculators

dont know if its any good, but was just to get the basic values.
Not a useful calculator.

There are many combinations of L&C that will create a filter curve and their impedance depend (interact) with the speaker model. I don't know what this calculator assumes for the speaker electrical characteristics. Would be a huge leap of faith to use it.
 
I think bullittstang has given you a terrific set of ideas with the Paul Carmody "Swope" designs.

https://sites.google.com/site/undefinition/swope-ht

Last time I looked, the old Hivi M...A series were almost identical to current M...N series. And swapping tweeters is plain simple, IMO. Just adjust for level.

There is a way of impedance correcting well-behaved drivers so they work with off-the-shelf calculated designs with a capacitor and resistor, and adding the bass box correction known as bafflestep with a coil and resistor in parallel. And it can make for an easy to drive speaker.

But, really, Paul Carmody has done all the heavy lifting for you here.
 
I think bullittstang has given you a terrific set of ideas with the Paul Carmody "Swope" designs.

https://sites.google.com/site/undefinition/swope-ht

Last time I looked, the old Hivi M...A series were almost identical to current M...N series. And swapping tweeters is plain simple, IMO. Just adjust for level.

There is a way of impedance correcting well-behaved drivers so they work with off-the-shelf calculated designs with a capacitor and resistor, and adding the bass box correction known as bafflestep with a coil and resistor in parallel. And it can make for an easy to drive speaker.

But, really, Paul Carmody has done all the heavy lifting for you here.

Thank you appreciate the advice!
 
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