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Multi-Way Conventional loudspeakers with crossovers

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Old 25th October 2013, 04:34 PM   #1
Fradbut is offline Fradbut  United Kingdom
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Default diyaudioandvideo.com misinformation ?

Hi Team. I'm new to this but please tell me the info from diyaudioandvideo.com is incorrect ?? re- 3 Way Crossover

thanks :-)
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Old 25th October 2013, 05:07 PM   #2
DougL is offline DougL  United States
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Nothing obvious jumps out at me.
What's your issue with the information?
I personally wouldn't use a crossover calculator, preferring a program that takes actual measured driver response.
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Old 26th October 2013, 12:20 AM   #3
tvrgeek is offline tvrgeek  United States
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Being new at this, what background do you have in electronics? Do you understand impedance and phase? Crossovers have as much to do with phase as amplitude
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Old 26th October 2013, 03:17 AM   #4
badman is offline badman  United States
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Someone who can't be bothered to ask complete questions, will not find assistance from me, and I bet plenty of others feel that way.
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Old 26th October 2013, 03:32 AM   #5
nezbleu is offline nezbleu  Canada
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OK: It's incorrect. You're welcome. Feel better?
Now tell us what you are actually asking, and why. Did you have a question?
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Old 26th October 2013, 04:23 AM   #6
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Quote:
Originally Posted by nezbleu View Post
OK: It's incorrect. You're welcome. Feel better?
Now tell us what you are actually asking, and why. Did you have a question?

I understand, OP's frequencies don't match the calculators...
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Old 26th October 2013, 05:09 AM   #7
Fradbut is offline Fradbut  United Kingdom
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whoa... easy fellers.... only asking a simple question. Firstly the article suggests a 3rd order at 3000 Hz and a 1st order at 800 Hz but then follows with a description of a 3rd order at 800 Hz and 1st order at 3000 Hz ? I'm struggling to decipher the complete circuit diagram. I read it that the 1st order has been applied to the Mid/Tweet and the 3rd order to the Woof/Mid drivers when it should be the other way round ?? Please correct me if I'm wrong.

Many thanks for your help.

p.s. may I suggest stay off the coffee ?

Last edited by Fradbut; 26th October 2013 at 05:11 AM.
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Old 26th October 2013, 05:41 AM   #8
Fradbut is offline Fradbut  United Kingdom
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also has he got his speaker sensitivities and L-pad circuit compensations confused ?
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Old 26th October 2013, 06:44 AM   #9
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That's the problem of using and reading, and abusing things when you are trying to grasp basics...
The article mentions using a 3. order for the tweeter and a basic first order for the woofer.
Then when you see 800Hz crosover should be between Mid and Woofer and probably a first order, and between Mid and Tweeter a 3. order, but who cares... 3K, 800Hz 1. order and 3. order; it could be also a 1. order for the woofer and a 3. order for the Compression driver horn tweeter, or 2. order for the midwoofer..., or...
It's just a test to your knowledge. The most important is that you understand after all.
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Old 26th October 2013, 04:39 PM   #10
jReave is offline jReave  Canada
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As a teaching tool, this is rather poorly done.

The 1st diagram shows a 3rd order High Pass(HP) on the tweeter and 3rd order Low Pass(LP) on the mid, supposedly at 3000Hz. The 2nd diagram is labelled as the tweeter and woofer again but is actually meant to show a 1st order HP on the mid (the tweeter in the diagram) and a 1st order LP on the woofer, supposedly at 800Hz. I say "supposedly" because I assume that the calculators use an 8ohm impedance value for each driver to derive the component values which is completely incorrect (8ohm are these drivers' nominal values whereas in reality, their impedances vary with frequency anywhere from perhaps 6ohm to about 32ohm) and will therefore not result in the desired xo slopes.

Note also that the labels (C1 and L1) are used twice for different components. Not very helpful. And then in the final diagram there are no parts labelled at all so that just compounds the confusion when every single xo group is incorrectly located. That's right, the final diagram hasn't got a single xo in the right place!! No wonder you were getting confused.

The 1st order HP on the tweeter should be on the mid. The 3rd order HP on the mid should be on the tweeter. The 1st order LP on the mid should be on the woofer and the 3rd order LP on the woofer should be on the mid.

The L-pads and the notch filter on the tweeter and woofer are in the right places, except for the fact that you should probably never use an L-pad (or more specifically, a series resistor) on a woofer. That is a horrible teaching example. That design approach is completely wrong. The correct method is to start by taking Baffle Step Loss into account for the woofer (usually from 4 to 6dB) so in fact its sensitivity will in reality be about 83 to 85dB (89dB - 4 to 6dB) and in consequence the tweeter and mid both need to be padded down more than shown and the woofer requires no padding at all. That means all the R values in the example will be incorrect as well.

I could go on but suffice it to say that the success of using these types of xo calculators is analogous to hitting a bull's eye while throwing blindfolded. For a higher probability of getting it right, start reading all you can from this - The Speaker Building Bible. You want to get to the stage where you can use a piece of freeware like PCD, Passive Crossover Designer.
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