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Crossover calculator for DIY folks


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Awesome...I finally don't have to do all the calculations by hand anymore [:D]

I just guess, or go with the cap color that matches the room they'll be in.[:D]

lol! my profs will get a kick out of that one...too funny

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  • 2 weeks later...

Does not work as in.... the spread sheet did not function for you? The

values are incorrect? Granted you can't integrate an autoformer

into the equation, but other than that I 've missed the drawback.

I ran this 3 way on there, and it's calc's look correct to me, but hey I could be wrong.

Third Order Butterworth

Spread (FH/FL)

10

(8 or 10)

® Woofer :

4

Ohm

® Midrange :

16

Ohm

® Tweeter :

8

Ohm

F low :

400

Hz

F high :

4000

Hz

F high :

1264.91

Hz

Tweeter- High Pass

Section

C1 =

3.56

uF

L1 =

0.24

mH

C2 =

9.30

uF

Woofer - Low Pass Section

L2 =

2.23

mH

C3 =

132.94

uF

L3 =

0.85

mH

Midrange - Band Pass

Section

C4 =

17.17

uF

L4 =

4.79

mH

C5 =

52.77

uF

L5 =

0.76

mH

C6 =

3.78

uF

L6 =

0.32

mH

Bandpass gain =

0.85

dB

Midrange Polarity=

Normal

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They don't work right in that that they don't spit out the right values for the crossover points you want. None of those calculators factor in the reactive component. In a three-way filter, the crossover points shift without the addtional calculation. The only online calculator for three ways that has any value can be found here: www.kbapps.com

Anyone doing anything higher than first order should invest in some decent software.

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They don't work right in that that they don't spit out the right values for the crossover points you want. None of those calculators factor in the reactive component. In a three-way filter, the crossover points shift without the addtional calculation. The only online calculator for three ways that has any value can be found here: www.kbapps.com

Anyone doing anything higher than first order should invest in some decent software.

I gave this some thought after reflecting back on some past projects. Cross over design is a science only if you have a complete life cycle development process for it. Driver analysis, cabinet considerations, crossover calculation, assembly, performance measurements, adjustments based on measurements, production version. You will need Design software, measurement tools, appropriate environment to test, etc.<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

Ironically, you still wind up making some trade offs, since the available parts, do not exactly match the often required values. Capacitor values needed rarely match what is available from capacitor vendors. Inductors have the same issue, but they often come with charts that estimate the amount of turns to take off to get to a lower value. During one project I sought absolute values and wound up with a crossover board that was 18" by 18" in size due to the needed space of all the combinations of parts needed.

For most, crossover construction is an art, and the available crossover calculators work just fine. Most cross overs use parts that have been approximated to the nearest available value. Some considerations for the artist, do you round up, or do you round down. Some artist round up for capacitors and round down for inductors. There are pros and con's for rounding up or rounding down.

As another point on the emphasis of the artist side of this process, the klipsch LaScala just happen to be able to be constructed with one and a half sheets of plywood each...3 sheets for the pair. There is less than 8 square feet of scrap from the avaialbe 96 sq feet. Running the woofer requirements through design software and calculators using the woofers expected performance range would result in a considerablly larger cabinet, and would use considerablly more wood than just the 96 SQ feet on three sheets of plywood per pair. While some bandwith improvements may result in a larger cabinet, the construction, warehousing, and transporting cost of going down 20 more hertz was probally not cost effective. My view is that the goal was to produce a pair of cabinets using less than 96 sq feet of plywood reguardless of the design software or calculator.

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