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Multi-Way Conventional loudspeakers with crossovers

Combining cross overs
Combining cross overs
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Old 24th June 2020, 10:37 AM   #1
hasselbaink is offline hasselbaink  Denmark
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Default Combining cross overs

Hi friends,

I was wondering if it is possible to combine a passive high pass filter with a passive shelving filter? for flattening a compression driver with a rising response that drops around 10kHz.

Please post diagram of solutions.

Much obliged, Kris
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Old 24th June 2020, 02:30 PM   #2
Lojzek is offline Lojzek  Croatia
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You are the one to post the needed data so people can offer solutions. Frequency response (.frd) and impedance(.zma), at least.
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Old 29th June 2020, 11:46 AM   #3
hasselbaink is offline hasselbaink  Denmark
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Quote:
Originally Posted by Lojzek View Post
You are the one to post the needed data so people can offer solutions. Frequency response (.frd) and impedance(.zma), at least.
Thanks Lojzek,

I do have all the tools I need, but I am missing a method for combining a high pass (say a large cap) with a shelving section. I am asking what the concept would look like and NOT a specific implementation that would fit my setup.

Truly yours.
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Old 29th June 2020, 01:20 PM   #4
AllenB is offline AllenB  Australia
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Combining cross overs
Are you trying to shelve down with frequency, away from the cross (which frequency range), is there any overall attenuation required?
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Old 29th June 2020, 01:29 PM   #5
Lojzek is offline Lojzek  Croatia
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Alright, can you share what is the compression driver and horn that you are interested in? I think you will get more appropriate answers to your question that way. Normally, you can start with parallel/series notch filters before/after the HP section or in any conceivable way that works in your favor. There is a schematic in Passive Crossover Designer that you may find helpful.
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Old 29th June 2020, 01:33 PM   #6
EarlK is offline EarlK  Canada
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The OP should "draw out" ( via Napkin-CAD in "MS Paint" or equal ) the exact shape of the HF response he desires.

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Old 29th June 2020, 02:12 PM   #7
Lojzek is offline Lojzek  Croatia
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Kris was clear that much, he wants it flattened out, as far I understood anyway. So, we want to see the crooked graph.
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Old 29th June 2020, 04:09 PM   #8
EarlK is offline EarlK  Canada
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Yes, lets see the "crooked graph"!

The short answer to the original question is;

Yes, the functions of the High Pass filter may be combined with that of the shelving/flattening filter ( this is best employed under limited circumstances ). It can reduce component count ( usually eliminating a resistor and maybe a cap ).
- The application is most effective when the HF roll-off of the horn/driver combo approximates a straight line that slopes downwards ( with increasing frequency ).
- This approach ( of course ) also has some built-in mid-range attenuation ( choose a smaller 1st cap for more attenuation ).

Methodology ( for a 2-3 Pole filter ) ;

1st cap; choose a very small value, say 2uF - 5uF where the turnover value could be around 8 - 12K.

Coil & 2nd Cap; values are chosen to combine/interact at the waveguide/drivers natural LF rolloff ( loss of loading ) .
- As indicated by a loss of level ( going down in frequency ) and found below the peak value of the overall ( raw ) response of the Horn/Driver combo.

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Old 29th June 2020, 04:37 PM   #9
Robh3606 is online now Robh3606  United States
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Yes it is but how much sensitivity difference is there between the woofer and the CD/Horn. The more the better as you can selectively attenuate the 1-3K with a notch and by pass the attenuation with a small series cap or a series notch filter to lift the upper octaves response.

The easiest would be a simple sereis cap but Earl is correct you need to have a typical 6db per octave rool off after the mass break point of the driver. Take a look in the referenced PDF's it will give you are idea of how it can be done.

Rob

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Old 29th June 2020, 09:13 PM   #10
EarlK is offline EarlK  Canada
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As one example;

Here's one compression driver/horn combo that's pretty straight-line ( in it's downward slope from 2.5K on up ) for a driver.

These traces done by Zvu ( are from the Peerless DFM-253508 on the 152i Clone from B52 .

Click the image to open in full size.

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