From measurements alone, I would not think 2k would be an issue at -35dB. It drops above there, to roughly -40dB by 2.2kHz. In theory, most ribbon style drivers like higher xovers. This is a large membrane AMT, so it's more sensitive than some others. I would think the current 2.4k with 3rd order xover in theory should be okay. If using 2nd order, 3k would be likely.
We shall see in the relatively near future. I have one xover almost done. Needs leads, some negative jumpers and solder and the 1st is done.
They are long gone, but All Electronics had them some years ago for like a buck fifty. 6 terminal single row, and come with 0.25" male disconnects attached. There are 3 dual-ended males per mount, and I just use what I need.
There is more space on the 5x7 boards remaining in the case I need to go further on either driver.
Yeah, they are X2 caps I think. They just happened to be the only 0.22uF caps I could find on hand. I need to restock my under 1uF sector. I have plenty of 0.47uF though.
Thanks for that notice on the Bevenbi. They are supposed to be silver foil, so I thought maybe I'd give them a shot. That's not the only ebay listing, so they may vary a bit in price.
The red-ended Bevenbi are conventional metalized poly, and cheaper! The S being silver will cost more.
Don't know if they are good or not, but I can find out.
I just found this on AliExpress:
$44.97 | 10pcs/lot Bevenbi 250V MKPA-S Gold and silver foil high-end polypropylene custom polypropylene film capacitor free shipping https://a.aliexpress.com/_mteQPk7
Here are the same 4.7uF for $11 and change. Have to buy ten to get that price.
@a4eaudio said:
Bevenbi says they are a long run supplier to B&W on their web page. I'll start a Group Buy Interest thread when I get home tonight.
They might very well be at the moment and still yet for a while. Not saying they aren't the B&W supplier currently. What I will also say is that the Bevenbi name seems to be a legit company. There are all kinds of 'pretty expensive badged' caps on the market claiming to be awesome for some serious dough, and Bevenbi looks to actually be reputable.
Okay, did some off axis modeling with both lowpass coil values, using the woofer notch:
There is a bit of bunching from 2.9k-3.9k, in either configuration according to the sim, but looks less offset with the smaller woofer coil value. Sometimes a BBC dip is warranted to smooth out the shoutiness, and the larger coil pushes the breakup down further.
I also did some listening with tones as well with individual drivers and xovers in place with the 1.2mH lowpass coil in the woofer trial, with and without the notch. The woofers seem to have a little beam around 2k, but the peaking is reduced in magnitude by comparison when the notch is used. The 3k breakup peak seems better attenuated in the xover with the notch as it was intended. Story short- the notch stays.
I also listened to the AMT with tones and xover, and I may have to notch the 3.5k area to keep the directivity in check and make it more pleasing and listenable. The bunching appears to be audible with tones, we'll see how music does, especially as a whole system.
At this time, I'm just needing to figure out when assembled if the spectral shape is more pleasing with the smaller or larger woofer coil, and whether or not to fix the 3.5k region.
I'm going to wind a pair of 1.0mH to compare and see what I think when the second speaker baffle is assembled for testing.
Comments
It's looking like based on THD, the crossover point would like to be above 2500 Hz, do you agree Ben or do you have a different feeling yet?
From measurements alone, I would not think 2k would be an issue at -35dB. It drops above there, to roughly -40dB by 2.2kHz. In theory, most ribbon style drivers like higher xovers. This is a large membrane AMT, so it's more sensitive than some others. I would think the current 2.4k with 3rd order xover in theory should be okay. If using 2nd order, 3k would be likely.
We shall see in the relatively near future. I have one xover almost done. Needs leads, some negative jumpers and solder and the 1st is done.
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Sans solder and leads;
I will likely flip the position of the woofer output terminals. Their crossing just irks me a bit.
More to come...
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Nice and tidy!
What terminal strips are those?
They are long gone, but All Electronics had them some years ago for like a buck fifty. 6 terminal single row, and come with 0.25" male disconnects attached. There are 3 dual-ended males per mount, and I just use what I need.
There is more space on the 5x7 boards remaining in the case I need to go further on either driver.
InDIYana Event Website
Those look solid Ben. What are those yellow caps? They look like some X2 caps I've used in my tube amp projects.
Yeah, they are X2 caps I think. They just happened to be the only 0.22uF caps I could find on hand. I need to restock my under 1uF sector. I have plenty of 0.47uF though.
InDIYana Event Website
Very sanitary with all that white. Not sure if the color scheme was a conscious choice or coincidence but I dig it.
Maybe a little bit conscious. If I wanted to do all blue and white, I'd have used these....
https://www.ebay.com/itm/386878830176?_skw=bevenbi+silver+capacitors&var=654140601818&itmmeta=01JJN7YH2DV6HS1A2NHGFWJNXB&hash=item5a13c67660:g:rWUAAOSwF8FlcDim&itmprp=enc:AQAJAAAA0HoV3kP08IDx+KZ9MfhVJKmzeMIOpvwV1NSPgFSrLWkpVCr6aURxbkh/Mz6v4mBjMiaYdud9cP1URDK0cVOREv72T1mZWg8uKCuy8ob9J60EKpVsq8P50fTqM10PlfZyHs3Z8A+yRWumxpfH+7gHBpvvp7dCbbSFeKFxYxGGAIjbZRTQvNc3EGEQbNg8AEH8kza50juNfwbpZL6f14Q9KtJ5S0bWyU6F8QpoO9D+3NCzF2H1dMj0ZpI8TD1d8bS5V4udmWt95md85nmIiptvgGY=|tkp:Bk9SR6yR-qeVZQ
Or maybe the Jantzen Standard Zcaps or Clarity PX.
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Those Bevenbi are a bit cheaper on AliExpress.
Thanks for that notice on the Bevenbi. They are supposed to be silver foil, so I thought maybe I'd give them a shot. That's not the only ebay listing, so they may vary a bit in price.
InDIYana Event Website
I've never heard of Bevenbi, are they supposed to be good?
They better be good quality . . .
Yes, for 5 pieces, $23.20 a piece. A few $ more than a ClarityCap, less than Audyn Plus.
The red-ended Bevenbi are conventional metalized poly, and cheaper! The S being silver will cost more.
Don't know if they are good or not, but I can find out.
InDIYana Event Website
I just found this on AliExpress:
$44.97 | 10pcs/lot Bevenbi 250V MKPA-S Gold and silver foil high-end polypropylene custom polypropylene film capacitor free shipping
https://a.aliexpress.com/_mteQPk7
Here are the same 4.7uF for $11 and change. Have to buy ten to get that price.
I heard they are the supplier for B&W.
ICW is the manufacturer of ClarityCap components, which I've seen B&W have xovers made from a good many times.
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Bevenbi says they are a long run supplier to B&W on their web page. I'll start a Group Buy Interest thread when I get home tonight.
Are you home yet?
They might very well be at the moment and still yet for a while. Not saying they aren't the B&W supplier currently. What I will also say is that the Bevenbi name seems to be a legit company. There are all kinds of 'pretty expensive badged' caps on the market claiming to be awesome for some serious dough, and Bevenbi looks to actually be reputable.
I look forward to your group buy thread....
InDIYana Event Website
Yes, sorry, I posted that message from my phone about B&W, but I didn't mean to imply that they didn't ever use ClarityCap.
I have not listened yet, but chose to revisit the sim for better woofer breakup suppression.
Tweeter network did not change.
This looks a lot better:
More to come, and I'll listen first before I shift to the later simmed components.
InDIYana Event Website
Okay, did some off axis modeling with both lowpass coil values, using the woofer notch:
There is a bit of bunching from 2.9k-3.9k, in either configuration according to the sim, but looks less offset with the smaller woofer coil value. Sometimes a BBC dip is warranted to smooth out the shoutiness, and the larger coil pushes the breakup down further.
I also did some listening with tones as well with individual drivers and xovers in place with the 1.2mH lowpass coil in the woofer trial, with and without the notch. The woofers seem to have a little beam around 2k, but the peaking is reduced in magnitude by comparison when the notch is used. The 3k breakup peak seems better attenuated in the xover with the notch as it was intended. Story short- the notch stays.
I also listened to the AMT with tones and xover, and I may have to notch the 3.5k area to keep the directivity in check and make it more pleasing and listenable. The bunching appears to be audible with tones, we'll see how music does, especially as a whole system.
Individual impedance sweeps:
woofer+XO-without-notch/woofer+XO-with-notch/AMT+XO:
At this time, I'm just needing to figure out when assembled if the spectral shape is more pleasing with the smaller or larger woofer coil, and whether or not to fix the 3.5k region.
I'm going to wind a pair of 1.0mH to compare and see what I think when the second speaker baffle is assembled for testing.
InDIYana Event Website