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Multi-Way Conventional loudspeakers with crossovers

100Hz two-way synergy project
100Hz two-way synergy project
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Old Yesterday, 05:37 PM   #51
mark100 is offline mark100  United States
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Originally Posted by Sabbelbacke View Post
@mark100
Nice project
What delay are your FIR Filters introducing at the moment?
Thx Sabblelbackle, about 43ms. (4096taps at 48kHz, impulse centered)
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Old Yesterday, 06:13 PM   #52
wesayso is offline wesayso  Netherlands
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Quote:
Originally Posted by nc535 View Post
I don't think that is so much a tuning dilemma as a horn issue. I think you made a good choice in that 10 degrees off axis should work well as the center of a listening window. There would be little to complain about in the primary seat even if you didn't keep your head still.

Try a shroud slipping over the front of the horn to implement a secondary flare, as Art Welter did on SynTripP, and things should get better, at least at 1 khz and below. Or try other kinds of mouth treatments. A naked single flare horn mouth, not even baffled, is worst case as I found out to my chagrin.

How did you do the round to rectangular conversion and subsequently smooth the throat? There might be some HF improvements available there.
I'd think that this will help. A secondary flare like the Synergies from Danley (and most others, like Art Welter) have. Easy to test, but yes, it will make the whole setup larger.
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Old Yesterday, 06:38 PM   #53
mark100 is offline mark100  United States
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Originally Posted by weltersys View Post
Mark,

It appears to me that your change of vertical resolution and from log to octave has done more to reduce "pattern flip flop" than the transition plates ;^).
The transition plate measurements still show as much as +3 dB at 10 degree off between 2.5 to 5kHz compared to on axis, if anything, a bit worse. It's possible adding a secondary horn break will help the 1.25kHz "waist banding" seen in both the before and after throat plate transitions. Speaking of which, the XT1464 horn profile on their spec sheet looks to reduce the throat to only about 1/2 of the driver entrance, while yours seems nearly 1.4" wide throughout- what do you measure each restriction to be?

It is much easier to look for polar response problems if the on axis response is equalised flat- then one simply looks for deviations in off-axis reduction at each interval, ideally being uniformly -6dB at the initial conical wall angle.
Also, 5 degree increments are helpful, a lot of junk can hide at -5 and -15, and measuring to at least 5 degrees outside the nominal pattern yields important information.

Cheers,
Art
Hey Art, decade, octave, 1/3rd octave.... they're all log, eh?
Just a bit different log scaling, one of the hazards with going back and forth between REW and Smaart I guess...

I'm still in the proto-exploratory stage, will get to 5 deg work (and verticals) when I move back to the larger horn and do careful transition matching.

Maybe the bit of measurement I showed doesn't look like much of an improvement to you, but it was a nice step forward to both my eyes and ears.
The measurements were just a quick on-axis optimization to see how some polars look.... something i couldn't even attempt to do before using OA as the optimazation base...

Lot's of work left to do with better transition matching and processing tradeoffs.

Below is a set of raw HF traces before the transition plate, and second after.
Red = OA Aqua = 10 deg

With the plate, measurements between +/- 10 degs are essentially the same as OA. And the dip above 2kHz definitely reduced. To me,it was a nice improvement.

Not sure which xt1464 spec sheet you're looking at, but any throat reduction is an illusion. It expands throughout.
I made a stack of 1/4 discs that I could set in the horn when facing up, and measure diameter with calipers, as i went towards the mouth stacking 1/4" at a time.
It expanded fairly evenly at +1/8" diameter per 1/4" throat distance for the first inch of throat, ending at 2 3/16" dia at 1.5". So a 2 3/16" round to square match job into the horn...
Attached Images
File Type: jpg HF raw OA and 10 deg no plate.JPG (122.7 KB, 48 views)
File Type: jpg HF raw OA and 10 deg with plate.JPG (131.2 KB, 48 views)

Last edited by mark100; Yesterday at 06:46 PM.
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Old Yesterday, 06:45 PM   #54
mark100 is offline mark100  United States
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Quote:
Originally Posted by wesayso View Post
I'd think that this will help. A secondary flare like the Synergies from Danley (and most others, like Art Welter) have. Easy to test, but yes, it will make the whole setup larger.
Very much agree.

In my methodical step by step, build and measure way, I've wanted to get the primary flare working as well as possible before adding the secondary.

I did try adding some flares to the smaller 60x60 when spitballing anything and everything, looking for change/impact. Convinced me to stick with the primary until it got more livable. Too many variables for my meager mellon to juggle !
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Old Yesterday, 08:53 PM   #55
bwaslo is offline bwaslo  United States
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100Hz two-way synergy project
Quote:
I'd love to play with a 3D printer. Gonna search BWaslo's posts for what he did...
Drop me a PM, I can send you the STL if you want to print it (needs a 12"x12" print bed). I never made the horn in question completely (put boards on one, but never even added drivers). I was going for a gigantic 5' tall speaker but after working out the stub design realized that I don't have, and will never have, space to put a pair of those into nor even a good place to store them. Same basic arrangement as with the larger "3D printed" waveguide speakers I made, so I expect the results would be similar at least before the LF cutoff frequencies.

An early assembly test -- I got the edge-meeting angles wrong on the wood panels (dumb math error), but the idea still works.
100Hz two-way synergy project-stub-assy-pics-png

This is the final version (two printed, never tested, still sitting on a shelf in the basement)
100Hz two-way synergy project-photo-jpg
Attached Images
File Type: jpg photo.jpg (120.4 KB, 79 views)
File Type: png stub assy pics.PNG (653.3 KB, 46 views)
Attached Files
File Type: pdf Stub Assy Pics.pdf (384.5 KB, 2 views)
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Last edited by bwaslo; Yesterday at 09:01 PM.
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Old Yesterday, 08:59 PM   #56
bwaslo is offline bwaslo  United States
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100Hz two-way synergy project
A secondary expansion actually makes the horn smaller. The outer dimensions of the secondary part (assuming the angles are about the right amounts) are what determine the low frequency directivity limit. They reduce waistbanding (by the simple expedient of wider angle for the part that affects low frequencies), but you get to the horiz and vert dimensions faster (with less depth). But it does make the wood cutting and assembly trickier
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Old Yesterday, 09:48 PM   #57
cowanaudio is offline cowanaudio  Australia
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100Hz two-way synergy project
Quote:
Originally Posted by freddi View Post
what did those little foam triangles do to the response of Tom's early Unity horns?
They significantly reduced to the depth of the on axis dip at 4KHz. They were a trapezium, not a triangle. You can see some pictures of them on my webpage.
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Last edited by cowanaudio; Yesterday at 09:51 PM.
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