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Multi-Way Conventional loudspeakers with crossovers

SB Acoustics Textreme.
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Old 6th January 2021, 09:14 PM   #721
454Casull is offline 454Casull  Canada
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Quote:
Originally Posted by lbstyling View Post
If the crossover is steep enough to mean a driver is not playing anything at the point of break up, I thought that was job done, and the breakup would have no effect on the driver sound?

Was I wrong?
Depends on the harmonic distortion of the driver. If there's a decent amount of let's say H4, H5, or H7, that happens to land on the breakup frequency (range), the actual level will be magnified by the extra sensitivity of the breakup peak. Look at H2, H3, and especially H5 here as a pretty classic example:

SEAS W22EX001 | HiFiCompass

I suspect that H4 magnification doesn't present just because the driver practically has no H4 distortion to magnify. You can see the slightest hint of the H4 peak around 1.3 kHz.

Some report that this distortion magnification can be largely eliminated by use of a notch, but there is not a huge body of data on this as yet.

Last edited by 454Casull; 6th January 2021 at 09:18 PM.
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Old 6th January 2021, 09:48 PM   #722
Oneminde is online now Oneminde  Sweden
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You can always do measurements
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Old 16th January 2021, 03:31 PM   #723
hifijim is offline hifijim  United States
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I have dismantled the foam-box prototypes of post 606 / 620. I am starting the construction of the real cabinets.

As work progresses, I think I will start a dedicated thread on the build progress instead of tacking it onto this thread (720 posts and climbing...)
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Old 16th January 2021, 04:15 PM   #724
LineSource is offline LineSource  United States
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hifijim,
A diyAudio forum thanks for sharing your textreme build. Do you plan to build a double-thick beveled-edge front baffle identical to your SB-Acoustics ceramic cone speakers?
.... plans to compare ceramic vs. textreme in identical cabinets?
.... experiments with different crossovers for optimal textreme performance?
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Old 16th January 2021, 08:00 PM   #725
hifijim is offline hifijim  United States
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Quote:
plans to compare ceramic vs. textreme in identical cabinets?
Similar cabinets, but not quite identical. I do plan to build a double thick front baffle, 1.5 inch thick. The sides will be profiled with a 1.5 inch radius round-over bit, exactly like the SB ceramic boxes. This new build will use a 2 layer plywood baffle instead of a composite solid wood / plywood baffle. Before I did not have enough experience with veneer to confidently apply it over a curve, so I used solid wood. Now I know I can do it with veneer. The top edge will be chamfered at 45 degrees to a depth of 1.5 inch.

The SB ceramic box is 13" H x 10" W x 9" D. The new box will be 13.5" H x 10" W x 9.75" D. So slightly taller, slightly deeper. The arrangement of the internal braces will be different. I learned a lot while making the first cabinets ("learning" is code word for screw-ups).

I do not have any digital representations of the cabinet design (CAD or Sketchup). I did that kind of thing for 30 years and it feels too much like work... I like pencil and paper.

As I optimize the filters, I will share my measurements, subjective opinions, and my thought process...
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Old 16th January 2021, 10:01 PM   #726
rhale64 is offline rhale64  United States
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I can't wait to here your thoughts. I am seriously thinking about building some speakers using these textreme drivers.
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Old 17th January 2021, 02:24 PM   #727
42476 is offline 42476
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Rhale64, are you thinking 2-way or 3-way??? I plan on getting the MW13TX in the next few months. I will use these as mids but will first test as full range then as a small 2-way just to get a feel for what suitable bandwidth I can use. Ultimately, I would like a 3-way but since I have so much already invested in my current system, that is not likely to happen anytime soon. I'm curious to see the upcoming projects and designs for an all TexTreme 3-way...
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Old 18th January 2021, 12:10 AM   #728
rhale64 is offline rhale64  United States
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Yes 3 way with all Textreme drivers.
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Old 18th January 2021, 05:05 AM   #729
42476 is offline 42476
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OK, me too eventually! Would you do WO or MW19 as bass drivers??? I would do WMTMW with MW19, MW13 and TX tweet. I would also try a WO dual as subs.
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Old 18th January 2021, 05:44 PM   #730
animal farm is offline animal farm
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When designing a midwoofer-cone, the manufactorers look for three key characteristics: lightness, rigidity/stiffness/velocity and internal damping. They stir/heat/dry-, vacuum-, compression-, injection-mold/press multidirectionally oriented (ply-layers) of light and strong carbon/kevlar/glass/mineral/polystyrene/cellulose-fibers, mixed with some epoxy binder for shaping and stiffness, added some polymer/foam/pulp for damping, this is is how 99% of non-metal/ceramic midwoofer membranes are made, and every manufactorer has their own secret receips. Don't want to sound more grumpy than I am, but the Satori Textreme is no revolution or holy grail, it's just another thin-fiber, black-art, fancy looking membrane, one among many.

A measurement of a membrane's breakup modes, on-axis and off-axis, can tell how well damped the breakup is. The breakup behaviour does not tell how rigid the membrane is, (or what the breakup sounds like) but it can give an indication of the membrane's stiffness as well. When you look at the FR-plots of the SB Acoustics' different 6½" midwoofers below, between 2-20kHz, you see that the off-axis breakup of the new MW16tx is just as bad as aluminium and ceramic, very low internal damping indeed, don't be fooled by the nicer looking on-axis response, this driver rings! The new stiff cone of the MW16tx will add some low level resolution compared to the soft papercone of the brilliant MW16P, but at a cost.

My experience with kevlar/epoxy-midwoofers, which may have lots in common with the new Satori textrene, is that for one; they need to be crossed low and steep, and two; they need really large cabinets (give them a small cabinet and some high SPL bass/lower-midrange, and they ring like hell). I never crossed a ScanSpeak 8546 or 8554 above 1400Hz, and I'm afraid that it will be the same with the MW16tx (some prefer the added "details" that echoes down from an uncontrolled breakup, but that’s another story). This might explain why SB Acoustics hasn't implemented Textrene in their Satori midrange drivers?

SB17 rohacell/carbon-fiber costs $34 more than SB17 aluminium/paper/polypropylen. MW16tx costs $114 more than MW16P, and I don't for a second belive that a textrene cone costs 3 times more to produce than a rohacell/carbonfiber-sandwich cone. In 2011 the new MW16P was $290 and the 15WU was $340. Today the MW16P is $148 and the 15WU is still $340. Danes are known for being clever in business, and this is a good example, SB Acoustics teased the marked a year ahead with this textrene-secret, building expectations, rumours, excitements, forum-discussions, etc etc, … and whoops, they can get away with $270 for a driver that is only "worth" around $170.

For midrange duties I don't like the unnatural upper-midrange sound from carbon/kevlar/glass-fiber + epoxy, I prefer Audio Technology's PP, Seas' tpx-PP, Dynaudio's PP, and Eton's Hexacone-sandwich, they all can be crossed rather high, with clean, high level detail and nice sounding breakup modes.
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