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Multi-Way Conventional loudspeakers with crossovers

Yet another 6+1 construction: SB17MFC35-8 + SB26ADC-C000-4
Yet another 6+1 construction: SB17MFC35-8 + SB26ADC-C000-4
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Old 29th August 2016, 01:31 PM   #11
DIYBras is offline DIYBras  Brazil
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Talking about cone break-up, even with this original strange woofer response, the MFC break-up don't sounds very harsh and seems to be fair hidden even with shallow LR2 filter. I have experienced some woofers with more "beautiful" response with more hash sounding break-up. Go figure...
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Old 29th August 2016, 02:33 PM   #12
DIYBras is offline DIYBras  Brazil
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Originally Posted by DIYBras View Post
Talking about cone break-up, even with this original strange woofer response, the MFC break-up don't sounds very harsh and seems to be fair hidden even with shallow LR2 filter. I have experienced some woofers with more "beautiful" response with more hash sounding break-up. Go figure...
**LR2 plus some filtering LRC trap**
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Old 30th August 2016, 04:28 PM   #13
DIYBras is offline DIYBras  Brazil
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Now the results for 8.9Vrms (aka. "10W re. 8R") for this project. For most audio band, the higher order harmonics are low to really low, including the aluminium tweeter area. I've included a test with the ER18+DXT (MarkK project) to compare the results. The SBA components seems to be less high order HD than the SEAS components, but in bass department the SEAS has a little advantage.
Please note my homemade DIY "brute" measurements technics, but at least the 2 projects are measured from same methods.
Attached Images
File Type: png MFC+AL 20.png (60.3 KB, 449 views)
File Type: png SEAS ER18+DXT testes 12.png (58.4 KB, 444 views)
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Old 30th August 2016, 04:34 PM   #14
DIYBras is offline DIYBras  Brazil
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Now showing the reverse-polarity test for catch the null point. Maybe a point to be perfected.
And the resulting impedance after stuffing the box internals (before have absorbing material only in the walls).
A FFT showing the HD content at some frequency (and shows the low frequency rumble from my living room)
Attached Images
File Type: png MFC+AL 19.png (47.3 KB, 441 views)
File Type: png MFC+AL 22.png (46.2 KB, 433 views)
File Type: png MFC+AL 21.png (51.8 KB, 429 views)
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Old 31st August 2016, 01:44 AM   #15
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Phase alignment is overrated, IMO. I say this as a person who does 90 degree phase BW3 as preference which has no significant reverse null at all. The most natural sounding of filters according to some pink-noise listening tests which I might be able to dig up with some effort.

But you battle on. I have built a dozen filters for my own favourite speakers. Strengths and weaknesses, but I mainly like a flat power response and a flat impedance. Michael Chua did an interesting SEAS ER18RNX 6" here, called the Starling: "STARLING" (Seas 27TDFC + Seas ER18RNX) Bookshelf by AmpsLab

I like the way he separated out the bafflestep with the LR.

BTW, how do you get your drivers and crossover components? Krafty seems to find this difficult in Brazil. Huge import taxes.
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Old 31st August 2016, 03:19 PM   #16
DIYBras is offline DIYBras  Brazil
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In practice, in Brazil, imports of consumer goods purchased by individuals should always be taxed at 60% (which I think is too high). A while ago, some products passed without charges, either because of the value, either by misjudgment from the Customs. But the most common is the Customs overtaxing the products because they will apply the highest price they can find on the Internet, or guessing that it is another product category.
And the worst is that the goods sometimes can be up to about 3 or 4 months retained in Customs, waiting taxation. A long delay!
This encourages people living in border with other countries trying to order the products in neighboring countries, with friends or store owners of these places.
And also people can "stuck" with the purchased drivers since is a PITA do send back...
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Old 31st August 2016, 03:31 PM   #17
DIYBras is offline DIYBras  Brazil
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Quote:
Originally Posted by system7 View Post
Phase alignment is overrated, IMO. I say this as a person who does 90 degree phase BW3 as preference which has no significant reverse null at all. The most natural sounding of filters according to some pink-noise listening tests which I might be able to dig up with some effort.

<snip>.
Interesting to know, since the buzzword now is "second order Linkwitz-Riley" crossover for naturality... so in somes cases is another audio myth. And since is easier to make a box without stepped baffle...
Other thing, is Bessel better or worse than BW for third order (or again, is case-dependent)? A friend of mine have a active 5-way (with a huge horn in the bass, the one in my avatar, but deactivated now ), all vias with Bessel-3. He likes Bessel filters very much.
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Old 31st August 2016, 04:21 PM   #18
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Quote:
Originally Posted by system7 View Post
Phase alignment is overrated, IMO. I say this as a person who does 90 degree phase BW3 as preference which has no significant reverse null at all. The most natural sounding of filters according to some pink-noise listening tests which I might be able to dig up with some effort.
As someone who also prefers BW3, I say this is poor advice. For BW3, phase should be single continuous line falling from top left to bottom right. For LR4(and I believe LR2), the reverse null is very important, or the speaker will not sound right at all.
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Old 31st August 2016, 06:19 PM   #19
system7 is offline system7  United Kingdom
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I found the reference to crossover order:
http://www.ctc-dr-weber.de/speaker/A...er%20types.pdf

Quote:
This might come as a shock, but we think that the overall winner was the 3rd order Butterworth filter, which was terribly popular in the 70's and 80's. I think we have heard why that is this case. Another conclusion is that during listening you rapidly gets used to the character of a certain filter. After switching back to the REF, the results can be rather overwhelming, knocking you straight off your feet at times. Even to a point where the REF start sounding... colored!
It's hard to quote from a PDF, the formatting goes crazy, but they could hear the hole in power response with LR2 and LR4 off axis, particularly around 2-3kHz crossover where the midbass beams badly. Bessel did OK too, mainly due to the slight 1.25dB peak at crossover.

Quote:
Odd order filters came nearer to the REF... except Bess2. We found the following explanation for this: textbook Bess2 (which is what we're talking about) has a hump of nearly 1.25 dB at the xo point. This on-axis excess energy compensates for the loss of power off-axis with this even order filter.
That is sort of what Lynn Olson did in the famous 5" MTM Ariel, but easier with flat 5" drivers IMO. I've done LR4 (4th order tweeter filter) with my own 8" bass flat baffle two ways, and it's a very clean sound. LR2 is more musically involving, but harsher on breakup and distortion. BW3 seems to sound great off-axis in ANY direction and quite clean. You don't have to toe them in to your ears. And it sounds most natural all around the room.

BW3 is terribly hard to model, but the basic idea might be to time align it, get a +3dB power flat hump at crossover, then muck up the time alignment so phase is near 90 degrees so it has flat FR but retains the good power flatness and response off-axis. It works well with flat baffle and 8" and negative polarity. 5" is doable too. 6" is problematic IMO. 6" is my least favourite speaker. For instance, the SEAS Idunn and Thor kits attract endless moans about tonal balance, so I'm not alone.
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Old 15th December 2016, 12:56 PM   #20
DIYBras is offline DIYBras  Brazil
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Default A update...

For brave folks following
Since I've listened for various months, here is the "sober" evaluation. Starting with pros and cons, with comnparisions:
PROS:
**midrange+treble to die for... very neutral, very natural, detailed and not fatiging. In fact, is difficult do end the listening session.
**Low HD in midrange and treble area. Good response and fair-to-good dispersion (poor in one axis)
**Good in the "DDR" area, ie, in live recordings, is possible to liste the public even with musics playing, like a good headphone (but Stax eat it for breakfast)
**I liked very much this tweeter. I prefer it to various models costing much more.

Comparisions: is more detailed than JA-8008, but JA-8808 is a different animal with much more bass capability (make sure to read the CONS )
Seems to be more musical, less fatiging and more "neutral" than MarkK project, but it can be my tastes

CONS:
**"strange" bass. What?! Well, the perceived bass response is good, but the HD is very high. Muddy sound if recording is bass heavy (intermodulation). Better to use it like a midbass... I've read in some site a Klippel result with a mere 1.9mm for a linear Xmax from suspension, so I can imagine this suspension optimized for midrange only...
In this regards, the SEAS ER18 is very better, rivalling some 8" in bass linearity!
**Need to use a notch filter is not very funny, but is easy in this driver.
**Low tweeter efficiency.
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