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Multi-Way Conventional loudspeakers with crossovers

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Old 21st July 2016, 09:04 AM   #1
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Default Summary of "Cecropia" Build...

Cecropia design, colors based on moth, width akin to large wingspan. Time frame from thought inception to finished, about 3 years.

Drivers: Morel CAW634 and TLabs N26MGR-G

Enclosure: 30 ltrs tuned to 35Hz, F3/10 of 28/24Hz. Wide and shallow with diamond x-section to allow driver depth. High difficulty . 2x 2"D x 12" long ports out the bottom.

Xover: LR4 @ 2.2k, plus BSC and response notches, as well as input notch to smooth impedance rise in top-octave. Facilitation of test-bed for varying xover coils at minute tolerance and close DCR. Anti-waveguide baffle reduces response of tweeter low-end, so notch was required to flatten it out. Felt dot for flat 10-20k, and felt for diffraction reduction.

Finished:
Click the image to open in full size.
Inside (66 biscuits per cab):
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Final stripped down schematic:
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Full switching circuit before adding notch tweaks:
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Xover out of case:
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Xover in case with switches:
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No smoothing, 400Hz+ valid:
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Thanks for looking!
Wolf
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Old 21st July 2016, 07:42 PM   #2
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like the colour scheme, even if I wouldn't choose it myself...
you've got enough copper in there for a small mine...
so tell us, what is the difference in sound with the woofer notch in/out?
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Old 21st July 2016, 08:16 PM   #3
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The notch is active from, well- it's better if you just look here:
Click the image to open in full size.

The vocals get very forward in the range you don't normally hear them shout. Not only that, but it can sound like (and not actually be) a cabinet resonance issue that kinda grates on your ears after awhile, sorta hollow and resonant. This isn't the first build I've had to comp the BSC bump on. It really makes a difference some times.

Oh- and the xovers weigh about 16 pounds.

Later,
Wolf
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Old 21st July 2016, 09:58 PM   #4
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Have you decided on a favourite switch setting yet?
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Old 22nd July 2016, 08:12 AM   #5
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To be honest, yes. I find the I-cores add some emphasis in the bass range, the P-cores lack detail, and the foils are also not quite as realistic, IMO. I find the Air 14 gauge on the woofer to sound better than the others listed above, and the Litzes being just above there.

The tweeter circuit also has Litz, and others, and I find the Air14 to be current top rank, and I have a possible coupling issue or some other reason with the Litz somehow in the tweeter circuit so I cannot really evaluate why it sounds different other than a dip of -3dB from 3-6k when using it. The Foils on the tweeter don't really sound different from one another, except for maybe the 12AWG. Since the DCR is resistor matched, it's hard to say other than constructions/reactances being the reason for sound differences.

In a crowd-challenge as I have this currently, they steered toward the I-core in the woofers with some slam in the bass and Litz in the tweeter with the inherent BBC dip as it were, whether it's having issues or not.

I've personally settled on the Litz for the woofers and the Air on the tweeters if that was not easy to get from all of that.

More or less- I guess the cheaper actually sound better to most people.

Later,
Wolf
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Old 20th September 2016, 06:38 AM   #6
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Update!

I opted to swap out for the TSCW636 Morel Supreme woofers. The dip in the FR that the CAW had at 1.1k is now gone, and I only had to adjust the padding on the TLabs due to a more sensitive midbass.

I'm VERY happy with the change, and they sound like they should in the midrange now.

Click the image to open in full size.
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Later,
Wolf
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Old 26th September 2016, 06:34 AM   #7
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New measurements, new modeling, and likely better results....

Click the image to open in full size.

I used what I refer to as a 'Crosspad' which involves different attenuations to either side of a 6dB xover point node for a driver that has a shelved difference in nominal level. The 15uF is to limit the response range that is affected by the crosspad contour filter on the LP side and tweak the magnitude better, but it's not required.

What prompted this is some upper brass and higher range female vocals sounded a bit thin on some familiar source material. I'm hoping this makes them the best they can be.

I have the crosspads assembled, and will patch them into the circuit at some point this week to see what I think.

Later,
Wolf
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Old 9th November 2016, 06:04 AM   #8
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And the final!

1/6th octave FR:
Click the image to open in full size.

HD comparison of CAW634 vs. TSCW636 in this system:
Click the image to open in full size.

Final Circuit:
Click the image to open in full size.

And the final "Xpad" component arrangement:
Click the image to open in full size.

The Auricap is more 'open' than the Eton caps, so that was a good change.

I'm finally happy with these. Project done, and completed!
Later,
Wolf
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Old 9th November 2016, 08:01 AM   #9
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Nice work indeed. Is that a Clarity MR you've got in there?
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Old 9th November 2016, 08:11 AM   #10
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Yes- it's a 6.2uF/600V ClarityCap MR. I was able to score those for half price about a year and a half ago or so. List was about $100 each, and I got the pair for just over that number. Mad had a clearance sale on the last 2 in stock for that value, and it just so happened that it was what I needed.

These resolve complex midrange passages better than most anything else I've built. Bass is extended and deep reaching, as well as being impactful. I can crank on them and seem to not reach a level where they get fatiguing, save for mechanical overshoot- and that is LOUD. Both bright and muted recordings sound as they should- they are honest to the source.

Thanks for the compliment!
Wolf
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