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Multi-Way Conventional loudspeakers with crossovers

Yet another cost effective main speakers build
Yet another cost effective main speakers build
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Old 20th September 2019, 12:38 AM   #11
Mazza is offline Mazza  Australia
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Try the Celestion CDX1-1745 it is superb!
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Old 20th September 2019, 01:10 AM   #12
JRiv is offline JRiv
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Quote:
Originally Posted by Mazza View Post
Try the Celestion CDX1-1745 it is superb!



Hi, ironically I did saw an eBay deal for two of this CDX1-1745 before pulling the trigger on the MB clones, so indeed it is one of the candidates I'm targeting right now, unfortunately PE does not provide Flat-Rate USPS services at the chekout so the shipping is mostly a dealt breaker on heavy items to Puerto Rico.

Luckily I've sold the MB DE250 clones to a friend starting in the car audio, but I have lying around a pair of the PRV D280Ti-S (from a previous build), and the Eminence S2B-A adapters I could use until I find a deal.

I will take some measurements on this particular combo, D280Ti-S >> S2B-A >> LTH102 to see if it can be usable at least to 1.8Khz or lower.

Regards
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Old 20th September 2019, 03:55 AM   #13
AllenB is offline AllenB  Australia
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With regards to the PRV woofer. According to Sd, I would expect to cross near 1k3Hz to get 90 degree dispersion.

According to the breakup modes, I would want to cross firm near 1k3Hz to get all the usable bandwidth.

According to FaitalPro, LTH102 horizontal matches 90 at 1k3. Vertical doesn't reach 90 until 1k4, and pattern flip happens at 1k6.

This may be ok, and it is only 0.25 octave, so 1k3 is where it appears you should initially cross. The mouth is large enough to support the directivity in theory, but it remains for measurement to see whether the mouth wants an extension for smoothness.

BTW, nice Sankens
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Old 20th September 2019, 06:11 AM   #14
JRiv is offline JRiv
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Quote:
Originally Posted by AllenB View Post
With regards to the PRV woofer. According to Sd, I would expect to cross near 1k3Hz to get 90 degree dispersion.

According to the breakup modes, I would want to cross firm near 1k3Hz to get all the usable bandwidth.

According to FaitalPro, LTH102 horizontal matches 90 at 1k3. Vertical doesn't reach 90 until 1k4, and pattern flip happens at 1k6.

This may be ok, and it is only 0.25 octave, so 1k3 is where it appears you should initially cross. The mouth is large enough to support the directivity in theory, but it remains for measurement to see whether the mouth wants an extension for smoothness.

BTW, nice Sankens

Hi AllenB, thanks for the great information about this 10" woofer ideal crossing frequency with the LTH102, looks like I still have much to learn in this regards definitely, Oh and yes, I really like much MT200 Sankens, they're like tanks.

So I did some quick on-axis measurements off the PRV D280Ti-S on the FaitalPRO LTH102 using the Eminence S2B-A aluminum adapters at about 1 feet from the compression driver throat to the mic, also the horn and mic placement was far from ideal, and the window air conditioner unit was on, the results will be tainted with reflections noise etc., but just to get an idea until I can make proper measurements, I hope someone with more technical background with this measurements can tell me if they look ok or bad to tame.

All the measurements was done with 24db/oct LR crossovers and without the 33uF bypass capacitor:
D280Ti-S_&_LTH102_FR_Edit.png

What I noticed on that measurements is that when I applied a quick PEQ(the PA2 has 8-band/ch) the response flatten a bit and lifted the top end, so maybe with more effort they may be tamed, OTOH they don't like to go lower enough to reach 1.3KHz even crossed at 1KHz unfortunately.

Note that I've used a paper as gasket and some clamps for this quick test but the horn and CD throat was well aligned, I will use 1/16" thick neoprene pad with adhesive back to make proper gaskets if I go this route though.

Regards
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Old 20th September 2019, 12:17 PM   #15
AllenB is offline AllenB  Australia
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They don't naturally want to go there. If you had a crossover simulator you could set them against a target response and push them into shape. At the least you could do it by sight working off a plot. It isn't yet sure what the smallest effective rolloff would be.
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Old 20th September 2019, 02:37 PM   #16
JRiv is offline JRiv
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Originally Posted by AllenB View Post
They don't naturally want to go there. If you had a crossover simulator you could set them against a target response and push them into shape. At the least you could do it by sight working off a plot. It isn't yet sure what the smallest effective rolloff would be.

Thanks AllenB, that's indeed a great idea, I could simulate some in XSim if I could manage to get/generate the FRD/ZMA files for the PRV drivers, but I guess I will continue with the speaker project(can't wait ), then perform several measurements on REW with the combined drivers in the enclosure.

Regards
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Old 20th September 2019, 03:38 PM   #17
AllenB is offline AllenB  Australia
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You mean like this?
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Old 20th September 2019, 03:41 PM   #18
AllenB is offline AllenB  Australia
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I needed to rename this to *.txt so it would upload. I can do others if you have a screenshot.
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Old 20th September 2019, 03:55 PM   #19
AllenB is offline AllenB  Australia
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Originally Posted by JRiv View Post
ZMA files
In case you want to start passive, I prefer to begin there too. Shaping the CD may take a few dB. ZMA should only be necessary for active if your amp has a non-zero output impedance, or you do something creative
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Old 20th September 2019, 04:05 PM   #20
JRiv is offline JRiv
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Originally Posted by AllenB View Post
In case you want to start passive, I prefer to begin there too. Shaping the CD may take a few dB. ZMA should only be necessary for active if your amp has a non-zero output impedance, or you do something creative

That's absolutely awesome AllanB, thanks a lot for the data file on this PRV woofer, I've been looking for it for quite some time, I did duplicated and renamed the files as FRD/ZMA extensions and XSim is happy with them.

I will try to take a better measurement of the D280Ti-S on the LTH102, with some pillows at the back and bottom of the measurement area to minimize the reflections, so I can upload a screenshot from REW, hopefully you can CAD it so I can have a better idea if they will integrate well with the 10" woofer at xover point.


EDIT: I've used your latest PRV10_Z.txt as .zma, and now I can see the impedance curve.

Regards
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Last edited by JRiv; 20th September 2019 at 04:12 PM.
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