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Multi-Way Conventional loudspeakers with crossovers

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Old 20th January 2013, 09:16 PM   #61
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Thank you, inductor!
Yeah, I know, my english 'vocabulary' is not adequate, I'm sorry
I Have to search a lot of words to translate them in Dutch to understand what is meant That doesn't make it easy

Wayne was also helpfull and mentioned that the de250 + H290C needs a 8dB attenuation with my active X-over.
But that I can't just use the components + values of the compensation part of the 4pi crossover: the compensation part is not an individual part, it interacts with the splitter filter. It's more complicated then I thought.

New challenge: finding a filter that simply compensates the de250 (without the complete crossover).

Dumptruck talked about CD compensation on more sofisticated active crossovers. It doesn't sound THAT bad.

However, it's more challenging to make a passive compensation filter that I can put between my amp and de250.
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Old 21st January 2013, 02:03 AM   #62
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Quote:
the compensation part is not an individual part, it interacts with the splitter filter. It's more complicated then I thought.
I know. What you said (besides the vocabulary being difficult for you) you already know. (And) That's why a lot of people don't understand, I can assure you. You go to basics with Wayne and that's why. Very down to earth...
You have the high impedance (and compensation) that's going to give you the lift of the high frequency but you add the L-pad (hybrid with compensation) to bring the output down at pass band. It interacts with the 3. order crossover.
If the "de250 + H290C needs a 8dB attenuation" active, do you make the rest 4dB L-pad in a passive configuration? With compensation/cap or without? Does it need to be modeled in SPICE or is it straight forward?
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Old 21st January 2013, 10:54 AM   #63
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I read a lot on his forum and I understand the basics of crossovers (the top octave compensation, matching the sensitivities of the tweeter and the horn, the highpass and lowpassfilter and avoiding 'nulls').

This link + video, that Wayne sent me, helped me a lot:
AudioRoundTable.com: Measurement => Crossover optimization for DI-matched two-way speakers

However, there is a difference between understanding the basics and making crossovers on your own
I just don't have the time to read read read and try with all sorts of components to get a configuration that sums the drivers perfectly through the crossover region and to make a configuration that compensates the CD on his own.

Would it sound 'disastrous' if I just connect the drivers with the amps (both in phase of course), filtered at 1.6khz with the active crossover, compensating the CD manually by matching the sensitivity of the tweeter before mass-rolloff with the sensitivity of the woofer and compensate the higher frequencies with the treble knob on my preamp?

Last edited by vandevoordekoen; 21st January 2013 at 10:56 AM.
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Old 21st January 2013, 12:02 PM   #64
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Quote:
Originally Posted by vandevoordekoen View Post
... and compensate the higher frequencies with the treble knob on my preamp?
Clever, that's probably why you have 4dB headroom...
(8+4=12)
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Old 21st January 2013, 03:58 PM   #65
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I don't think Wayne wants his crossovers posted publicly, guys, but is anyone else confused about the resistors? 25Ω in series with the DE250 doesn't work... I must be reading it wrong?

Anyway, you can use 2.2uF and 10Ω (resistor and capacitor connected in parallel with each other, and then in series with the DE250). It's not very elegant, because of the impedance (compare the brown filter curve with my hybrid one posted earlier), but it will work. You can put 16Ω across the DE250 terminals to damp it a little better at 2kHz... that might be just fine after the active LR4 is applied.
Attached Images
File Type: gif 2.2uF_10ohm.gif (20.3 KB, 55 views)

Last edited by dumptruck; 21st January 2013 at 04:00 PM.
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Old 21st January 2013, 04:35 PM   #66
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Quote:
I don't think Wayne wants his crossovers posted publicly
Not at all! The link I posted refers to his forum. However, he explains a lot in his forum, if you want to, you can find everything there.

Does the configuration that you propose (2.2uF and 10 ohm resistor + 16 ohm parallel with the de250) give me the compensation (about 8db atenuation) that is needed for the compression driver on a CD horn?

It's that I don't know how to transfer the theory in values and components I understand the goals of crossovers and compensation circuits, but I can't make them myself.


For a good result, do I need to do other things then CD compensation using an active crossover?

Last edited by vandevoordekoen; 21st January 2013 at 04:40 PM.
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Old 21st January 2013, 04:52 PM   #67
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Yes, it is -8dB compensation. You would still attenuate the HF level down a bit to your taste with the active level control, as the DE250 sensitivity would end up at about 100dB (with the 16Ω included).
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Old 21st January 2013, 04:54 PM   #68
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Quote:
Originally Posted by dumptruck View Post
I don't think Wayne wants his crossovers posted publicly, guys, but is anyone else confused about the resistors? 25Ω in series with the DE250 doesn't work... I must be reading it wrong?
I have no idea of what you are talking about. In relation to Wayne's work in the passive crossover attenuation it's evident that 12dB attenuation comes from a 25/16 L-pad like it was posted before by vandevoordekoen on post #58.
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Old 21st January 2013, 05:02 PM   #69
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vandevoordekoen,
From previous posts I would not regard dumptruck comments as very enlightening, and I would take them with a grain of salt. That's all I have to say. Please follow Wayne's P. suggestions if you want to achieve a successful speaker project. He has all the keys because he has been there.
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Old 21st January 2013, 05:12 PM   #70
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Quote:
Originally Posted by Inductor View Post
vandevoordekoen,
From previous posts I would not regard dumptruck comments as very enlightening, and I would take them with a grain of salt. That's all I have to say. Please follow Wayne's P. suggestions if you want to achieve a successful speaker project. He has all the keys because he has been there.
For goodness sake, I was simply saying I was having a problem simulating the pi4 high pass, using Wayne's measurements. I didn't mean to imply Wayne made a mistake in his crossover. I've been designing, simulating, building, and measuring exactly this type of crossover for the past year, and I mostly learned from Wayne's writing on CD speakers. If I have made a mistake about something in this thread, please explain what it is.

I don't suppose you are at all interested, but here is the problem I'm getting in simulating the pi4 crossover as it was posted.
Attached Images
File Type: png pi4 crossover.png (20.3 KB, 46 views)
File Type: gif pi4.gif (20.8 KB, 44 views)

Last edited by dumptruck; 21st January 2013 at 05:16 PM.
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