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Multi-Way Conventional loudspeakers with crossovers

2-way floorstander beginner build log
2-way floorstander beginner build log
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Old 23rd January 2019, 05:10 PM   #11
dublin78 is offline dublin78  United Kingdom
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Join Date: Mar 2006
Location: Cheshire
I was just reading Jeff Bagby's write-up on his Kairos build from Meniscus Audio. I found his thought process simply amazing.
There are a few good write ups on the Meniscus website. Check out the Mandolin one. It is a bit humbling for us mere mortals.
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Old 23rd January 2019, 05:30 PM   #12
montana1 is offline montana1  United States
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Thanks dublin78,
I will check that one out for sure.

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Old 28th January 2019, 10:43 PM   #13
joostie12345 is offline joostie12345
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Pff those write ups were quite something and send me in another reading frenzy... especially off-axis response and especially interactions between the drivers is something i can't get my head around... oh well

In the meanwhile I have been tinkering in all kinds of different simulation tools. Vituixcad is quite amazing I must say. I started out using Unibox to simulate the Satori MW19P-8, and I think I found a nice sweet spot with a volume of about 30 liters, however this was as far as that could take me.

So I turned to VituixCad... After some less than fruitfull experimentation I had a look at the guide and everything started to make some more sense. The pictures below show the results!

What I did was the following. First I imported the FRD and ZMA data from the manufacturer (drivers used were: Satori MW19P-8 and the SB26ADC-C00-4) using the SPL trace tool. Then I recreated the enclosure from Unibox which did give slightly different results but it happens, the final volume was 30L tuned to about 36Hz.

Then I made a quick mock-up of how I envision the enclosure and let the program calculate the baffle step response. I set the listening distance at 30 cm because then the response was approx. -3dB which I thought I had read on Troels Graven his site was a more appropriate figure for actual response in a room than the theoretical -6dB.

Then I used the merge tool to combine the low end which was modelled using just the T/S parameters with the high end which was just the original frequency response graph from the manufacturer. This frequency response and impedance file I used in the crossover design. For the tweeter I simply used the impedance, and frequency response curve from the manufacturer.

To design the crossover I started with a theoretical 4th order Linkwitz-Riley crossed over at 2kHz. Then I added an L-pad to the tweeter and a Zobel network to the woofer. And then I started tinkering around (both manually and using the optimatization tool from the program). Anf in the picture you can see the final response.

I know I need to do measurements on the actual speakers to do all this properly but I must say that the results do look promising. Maybe even promising enough to actually start buying the components.

I'm quite sure I have missed quite a lot of stuff, so please do feel free to enlighten me if you feel like it. One thing I am already aware I have not addressed is the acoustical off set between tweeter and woofer, but I'm thinking about physically off setting them to solve that, but I'm not sure yet.

Let me know what you think!

Attached Images
File Type: png 2-way MW19P8 SB26ADC 0004 overview.png (195.4 KB, 129 views)
File Type: png bafflecorrection.png (79.5 KB, 125 views)
File Type: png box.png (241.8 KB, 128 views)
File Type: png merge.png (119.8 KB, 129 views)
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Old 29th January 2019, 06:51 PM   #14
Dave Bullet is offline Dave Bullet  New Zealand
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I don't think you have enough BSC. I can see an upward slope from 100Hz to 500Hz in your finished full system response. The first woofer inductor looks to small (1mH ). I usually go for the 100Hz point as my system sensitivity, therefore think you should target ~ 86dB
"Usual diyaudio train wreck of dubious drivers and just the crossover to sort out. Well, how are you on crossovers and modelling? Pretty green, I reckon" - system7 (Steve)
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Old 30th January 2019, 04:39 AM   #15
LineSource is offline LineSource  United States
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The Satori MW19P-4 with a 1650Hz LR4 circuit works well with the 1.1" SB29RDC-4 dimple-dome tweeter with either BW3 or LR4 circuits at 1650Hz. The extra area and durability of the 1.1" dimple dome tweeter is necessary for 1650Hz. There are several low cost Bi-amplifiers with active crossovers capable of 1650/1650Hz which will also perform well with these two drivers.

A tall'ish cabinet designed with a MLTL Mass Loaded Transmission Line alignment(shape) will both extend the deep bass, and smooth any internal resonances.

Last edited by LineSource; 30th January 2019 at 05:02 AM.
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Old 1st February 2019, 02:02 PM   #16
joostie12345 is offline joostie12345
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Good point about the BSC, I added a correction for this in the next iteration. You can see this in the picture below that the aside from a small peak at 3.7kHz, and a slight dimple at 1.2kHz the response is pretty flat. Also phase coherency seems to be excellent.

This time around I did include offsets, I based these on a sketchup model I made (156mm vertical offset, and 12mm in the "z" direction), and made the assumption of a 20mm acoustical offset if they were mounted on a vertical baffle. The 20mm I took because of a article I read at some point on measuring acoustical offset, where they recommended 20mm as a first guess for the input.

As far as the 4-ohm version and the other tweeter that does sound good, because it would solve the issue of the peak at 3.7kHz. I will give that a try!

As always, let me know what you think!

Attached Images
File Type: png crossover 01-02-19.png (195.5 KB, 72 views)
File Type: png cabinet.png (120.1 KB, 35 views)
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Old 4th February 2019, 03:52 PM   #17
joostie12345 is offline joostie12345
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So I just found out that the measurement equipment my brother said he had access to is no longer available...

I just found this Amazon.com: Dayton Audio iMM-6 Calibrated Measurement Microphone for iPhone, iPad Tablet and Android: Musical Instruments I realize that it probably won't be of the same quality as for example the UMIK-1. But does anyone have any experience using this little thing?

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Old 4th February 2019, 05:40 PM   #18
6thplanet is offline 6thplanet  United States
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Honestly if you want a nice measurement devise, the Omnimic and DATS combo from Parts Express is hard to beat. Especially if you plan on playing around with more projects down the road.
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