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Multi-Way Conventional loudspeakers with crossovers

Crossover advice
Crossover advice
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Old 6th August 2018, 07:25 PM   #11
kimmosto is offline kimmosto  Finland
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Where or how did you get measurement data?
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Old 6th August 2018, 09:59 PM   #12
system7 is offline system7  United Kingdom
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Something odd has gone on here. You got entirely different results with a bass section of 0.82mH/15uF and 1mH/12uF.

How can that be? They should be similar.
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Last edited by system7; 6th August 2018 at 10:02 PM.
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Old 6th August 2018, 11:43 PM   #13
hubi is offline hubi  Poland
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With the tool inside -> VirtuixCAD - SPL Trace
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Old 7th August 2018, 12:49 AM   #14
hubi is offline hubi  Poland
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sorry guys... I traced the SPL of ETON again and now its looks like -> something more normal
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Old 7th August 2018, 01:27 AM   #15
system7 is offline system7  United Kingdom
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When you do an SPL trace, you need to know what conditions the bass measurement was done. And inform the simulator.

Most hobbyists measure in the actual used enclosure. Manufacturers don't. SEAS use some standard boxes close to typical use.

What I am getting at is that bass response you are getting looks close to +6dB wall-mounted or infinite baffle measurement. Shouldn't be that high in the bass once it's in a box.

Below is yet another way to do the bass filter. This one ends up quite butterworth and 90 degrees at 4kHz crossover, which may suit an MTM. The LCR notch is a moveable feast that suits some drivers. Here it works at 1.3kHz. You take out the resistance to see where it acts on FR.

The Zobel and 22R resistor in the tweeter section is just one of those "sounds good" ideas. It damps the tweeter voicecoil, so might sound smoother.
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File Type: png Notched 5 inch MTM.PNG (9.5 KB, 146 views)
File Type: png Notched 5 inch MTM electrical.PNG (18.8 KB, 96 views)
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Old 7th August 2018, 04:32 AM   #16
LineSource is offline LineSource  United States
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Quote:
Originally Posted by hubi View Post
Sorry it's too much for me - I did not get it ...
This paper has math + illustrations which explain how multiple driver T+M and M+T+M topologies interact to generate the polar dispersion. Think of the speaker cone as a collection of points generating air pressure waves. Around the crossover frequency when all cones vibrate at the same frequency, several different points separated by several inches can generate air pressure waves which reach the listen's ear at different angles which might combine in phase and raise the SPL, or null out-of-phase to reduce the SPL.

Biro Technology

Vertically Symmetric Two-Way Loudspeaker Arrays Reconsidered
MITHAT F. KONAR, AES Member
Biro Technology
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Old 7th August 2018, 06:58 AM   #17
kimmosto is offline kimmosto  Finland
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Quote:
Originally Posted by hubi View Post
With the tool inside -> VirtuixCAD - SPL Trace
That alone is usually wrong method, but it may work if manufacturer has measured driver in a cabinet which is close (size and shape) of your box. For example Seas measures in a box, but most of the manufacturers measure to half space i.e. driver is flush mounted in the wall or very large baffle.

Proper method and gear to produce measurement data at home (without large anechoic lab) is here, but very shortly:
Preparation of response measurements for crossover simulation with VituixCAD

And againg, name of the program is VituixCAD (without R)
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Old 7th August 2018, 08:10 AM   #18
kimmosto is offline kimmosto  Finland
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Small addition. You can load traced half space response to VituixCAD Diffraction tool and generate axial response to full space. That is usually minimum effort with traced responses to get decent estimation about baffle step. Diffraction tool is also able to generate directivity; off-axis response in two planes to +/-180 deg, but that is quite reliable only with woofer of 3-way because cone is simulated as ideal piston.
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Old 7th August 2018, 06:07 PM   #19
hubi is offline hubi  Poland
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Thanks to everyone
I'm getting crazy, I tried some new xovers but the original one that i don't love - sounds best of all of my tries.

I decided to make modifications to the original one.

The problem with him is that I hear to much mid when there is a bass tone.

Any suggestions how I can fix that?
I draw in the original one in VituixCAD 2 (sorry for R from before)
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File Type: png crossover6.png (186.5 KB, 117 views)
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File Type: zip test_orginal_xover.vxp.zip (2.4 KB, 2 views)

Last edited by hubi; 7th August 2018 at 06:19 PM.
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Old 7th August 2018, 07:47 PM   #20
system7 is offline system7  United Kingdom
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I'm struggling to read this but it looks like L2 in the tweeter filter is 0.82mH.

Click the image to open in full size.

Lots wrong with it. If a diyaudio member had designed it, I'd say it was complete rubbish and he/she would go off in a huff. But it is rubbish. Shame it isn't a diyaudio member.

* Tweeter phase is wrong. This is positive polarity.
* The way the tweeter filter is wired after the RL bafflestep adjust is just stupid. It should be wired on its own circuit with a 2.4R attenuator.
* Using a purely reactive fourth order bass with no impedance correction or resistors makes for that huge midrange bump at 1.3kHz.
* Crossover is unnecessarily low.

I knocked something better up using a lot of your components, but it looks like that bump at 1.3kHz needs attention. I think I suggested a notch circuit:

Click the image to open in full size.

That looks most promising to me. You could try 4.7uF/0.3mH/6.8uF in the tweeter circuit too. 0.6mH and 15uF in the bass LC would probably be OK too..
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