My first attempt at a passive 2-way - any input?

Defo

Member
2008-11-06 9:15 pm
Here goes my first attempt at a passive speaker :)

I've aimed for drivers with smooth rolloffs and/or allowing for a simple/minimal crossover. Other goals was decent sensitivity and power response.

So I've settled on 3 alternatives:

Seas W22NY001 + Wavecor TW030WA12
Seas W22NY001 + Morel CAT378
Seas A26RE4 + Morel CAT378

I've attached simulations and relevant files for the first two.
The latter combo has numerous battle tested crossovers out there.
Note the listening height in the simulations (phase only matches up at that height)

I really like waveguide tweeters that can be flattened out with a simple cap like the CAT378. And since Seas does their measurements on typical baffle sizes for each respective woofer size, their measurements include baffle step. Which makes things a lot easier to simulate. And their measurements are proven to be trusted.

Any input?
 

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Defo

Member
2008-11-06 9:15 pm
Defo, Hei!

I think the E0045-08S W22NY001 is the best 8" woofer in the SEAS catalogue. :)

Joachim Gerhard, who knows what he is talking about, quite likes this one too: H1659-08 U22REX/P-SL.

I can't think of any reason to venture beyond Moss for a waveguide tweeter: H1499-06 27TBCD/GB-DXT.

Hey, I've got a design for you:

W22NY-001 + H1499 2way Passive Crossover Design - Madisound Speaker PDF Library

Ha Det! :D

"Hei" to you too :D

I've actually been looking a bit at the DXT tweeter, but been put off by it from reading that it's a bit difficult to work with and is extremely sensitive to baffle size.

Sure a finished design would simplify things, but where's the fun in that? ;)
Although I like the idea of having some proven design to fall back on if all goes to s**t.
 
s**t is quite a polite word in Norwegian. Dritt, if I remember correctly. :D

Sort of thing you could use with your Norwegian Grandmother. Just means Dirt.

But I'd never use it with an English Grandmother.

I got in terrible trouble swearing in German. What I thought was a fairly polite word turned out to upset everybody in Germany. And who needs WW3, though TBH we'd doubtless beat them again! It's football we always lose at.... :eek:

For all that, I do know how to swear in Svensk!

My German friend, Joachim Gerhard, thinks the H1499-06 27TBCD/GB-DXT is what we English call "The Dog's Bollocks !".

I'd give the DXT a go. I really can't believe a highly directional waveguide tweeter is terribly baffle dependent. :cool:
 

Defo

Member
2008-11-06 9:15 pm
s**t is quite a polite word in Norwegian. Dritt, if I remember correctly. :D

Sort of thing you could use with your Norwegian Grandmother. Just means Dirt.

But I'd never use it with an English Grandmother.

I got in terrible trouble swearing in German. What I thought was a fairly polite word turned out to upset everybody in Germany. And who needs WW3, though TBH we'd doubtless beat them again! It's football we always lose at.... :eek:

For all that, I do know how to swear in Svensk!

10/10 Scandinavian language skills :D

My German friend, Joachim Gerhard, thinks the H1499-06 27TBCD/GB-DXT is what we English call "The Dog's Bollocks !".

I'd give the DXT a go. I really can't believe a highly directional waveguide tweeter is terribly baffle dependent. :cool:

Did some simulations with the DXT, but it didn't lend itself to a simple filter.
Looking at the nicely declining response, I would think you could simply flatten it out with a small cap and end up with a natural roll off at 1-2 KHz. Proved itself not to be the case.

So far I've found the Morel CAT378 is the easiest tweeter to cross (only needing a single small cap). However, judging from tests it seems the Wavecor one outperforms it.

Maybe there are some small compression driver/horn combination out there that works with a single cap?
 
I still have a friend in OSLO, on the edge of Kampen Park:

Kampen park - Parker og friomrader - Oslo kommune

Nice swimming pool and sauna too. The Sauna was 99 degrees C! Why didn't I cook? Unbelievable. :)

I've done more 8" + 1" speakers than most folks:

This sort of thing uses negative polarity at 3kHz on a regular tweeter to solve time-alignment issues. Very BBC actually.

714064d1541548033-restoring-monitor-audio-r300-bookshelf-speakers-ma-r300-md-4th-xo-png


I thought this bass circuit is very good:
https://www.madisound.com/library/stacks/LEAP-W22NY001-D29059900.pdf

8" woofers benefit from a little notch around 4.5 kHz, where you get some storage on the CSD waterfall plot, also known as BREAKUP!

Joachim Gerhard assured me he'd got the DXT working with the U22 on a simple cap and resistor, and bass coil network.

And Michael Chua is quite a fan of the Morel CAT 378 on a simple 5uF.

MOREL CAT 378 Soft Dome Horn Tweeter – AmpsLab

No baffle diffraction:

Finch (Morel CAT378 + Vifa PL18W0-09-08) – AmpsLab

All easy drivers. :cool:
 
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Defo

Member
2008-11-06 9:15 pm
8" woofers benefit from a little notch around 4.5 kHz, where you get some storage on the CSD waterfall plot, also known as BREAKUP!

Isn't a notch filter at such a smooth driver as the W22 a little overkill? :scratch2:

Joachim Gerhard assured me he'd got the DXT working with the U22 on a simple cap and resistor, and bass coil network.

Here's what I got with a cap and resistor, but I doubt it protects the tweeter enough?

vdNddsI.png


Both the W22, U22 and CA22RNY all seem like excellent and easy to work with drivers. Guess I'll just simulate them all to find the most fitting one for whatever tweeter I settle on.

And Michael Chua is quite a fan of the Morel CAT 378 on a simple 5uF.

MOREL CAT 378 Soft Dome Horn Tweeter – AmpsLab

No baffle diffraction:

Finch (Morel CAT378 + Vifa PL18W0-09-08) – AmpsLab

All easy drivers. :cool:

Love the simplicity!

Would be cool if one could do the same trick with a small compression driver and a horn. A response like this should be easily equalised with a single cap as well I think (although you would probably need to flatten the impedance):

WZakTML.png
 
Simplicity is alright for first attempts, but you then move on to refinement:

714062d1541548033-restoring-monitor-audio-r300-bookshelf-speakers-monitor-audio-r300-md-original-schematic-png


377922d1382302599-restoring-monitor-audio-r300-bookshelf-speakers-monitoraudio_r300-md_final-png


TQWT-

That speaker confirmed everything I had been fiddling about with on 8" bass. And Troels uses a little breakup notch on the goodish woofer, around 6kHz I think. Believe me, all paper cones have a bit of breakup. It's why people tried polypropylene.

Troels has done a huge amount of experimenting with simple stuff. Looking for the detailed sound:

Supravox DTQWTSupravox 215RFT-

Vifa C20WH

For more refinement, I was amazed how well this circuit works:

679880d1525986018-wharfedale-shelton-xp2-minor-classic-imo-wharfedale-shelton-xp2-crossover-circuit-jpg


645295d1510487763-wharfedale-shelton-xp2-minor-classic-imo-wharfedale-shelton-xp2-grille-jpg


Poor impedance, but sounds good. Very classic BBC/KEF in style.