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Multi-Way Conventional loudspeakers with crossovers

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Old 25th August 2017, 06:31 AM   #351
fluid is online now fluid  Australia
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The tractrix profile beams much more than the SEOS does. You will be trading constant directivity through most of the range by using a tractrix. If you are happy with the narrow HF directivity then give it try.

There has to be a compromise somewhere pick whichever one you prefer
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Old 25th August 2017, 05:54 PM   #352
bwaslo is offline bwaslo  United States
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The Small Syns design is targeted at directivity, loading wasn't much of a concern at all. The efficiency is high enough, SPL capability is more than needed and power is cheap these days anyway. A Synergy horn will load better at low frequencies when driven further up from the throat where the expansion rate is good for lower frequencies (that was one of the main original aims of Danley's Unity design, for high SPL PA use).

Tractrix would work in the same structure, and as you say, the flat sides would make it easier to mount your midranges. But if you're wanting to make your own horn, you can make a conical waveguide even easier than a tractrix, and all walls are flat -- see the SynergyCalc spreadsheet, you can calculate any rectangular flat sided conical waveguide you want.
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Old 7th September 2017, 10:35 AM   #353
Brett is offline Brett
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Hi Bill,

I don't think I'd seen this thread before yesterday, but have read it all now and think I'll build a pair for the bedroom next year. I have a couple of other builds to complete first though.

They'll be active using JRiver on my bedroom PC to do the xovers. The one mod, apart from enclosure shape*, will be to add a LAB12 below the sealed Small Syns to do from 80Hz down to 30Hz or so. Each flare will have 2 mids.

Thanks, you've saved me doing my own design. I love the concept as I have Unitys in the lounge/theatre. If I really like them, I'll build 4 more to replace the surrounds.

* Triangular xsection with a chamfered baffle to fit onto the corners.

Last edited by Brett; 7th September 2017 at 10:38 AM.
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Old 27th December 2017, 01:16 PM   #354
jpak is offline jpak  United States
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How much higher up would they roll off (ported version) if moved into the room by 1.5 meters from front and side walls?

IMHO for my preferences all speakers, constant directivity or not have more depth to the soundstage when they're moved off the front walls, I am guessing because of increased front wall reflections.
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Old 27th December 2017, 02:30 PM   #355
ellisr63 is offline ellisr63  Mexico
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I really would like to build 3 of these for our living room home theater, but I am not confident about making the mounts for the woofers. Is there a template for the woofer mounts that I could use?
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Old 27th December 2017, 10:31 PM   #356
bwaslo is offline bwaslo  United States
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Quote:
Originally Posted by jpak View Post
How much higher up would they roll off (ported version) if moved into the room by 1.5 meters from front and side walls?
I dunno, you could probably just model it based on Baffle Step formulae and not be too far off. There's little to no directivity to speak of down there at those frequencies, so treat it like just a box.

Quote:
IMHO for my preferences all speakers, constant directivity or not have more depth to the soundstage when they're moved off the front walls, I am guessing because of increased front wall reflections.
Probably so. But much of that can be also obtained by some toe in of the horns -- front wall reflection helps to give ambience (only if delayed, hence the need for space behind), but IMO nowhere near as well as if they come from behind or from the sides of you (also delayed of course). Directivity in a speaker can direct energy over paths that take longer to get to you and have similar effect. It's hard to get as strong a delayed reflection from the sides and back without directivity since it is reflected from such a wide range of distances. I think that's why speakers without directivity really need to be out in the room (or else used like headphones!) to get an illusion of depth. More directivity, or ways to better collect the off-axis energy and focus it back delayed can do a pretty good job. In my basement, I use curved diffusors, which create a focused (but diffused!) late reflection, gives gobs of depth. But too large for our little living room.

If you put the small syns out in the room, you'll want to add some BSC. If you aren't religiously averse to EQ ( (: ) , doing that would be a better approach than throwing away all the available power by doing BSC in the crossover.
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Old 27th December 2017, 10:32 PM   #357
bwaslo is offline bwaslo  United States
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Quote:
Originally Posted by ellisr63 View Post
I really would like to build 3 of these for our living room home theater, but I am not confident about making the mounts for the woofers. Is there a template for the woofer mounts that I could use?
No template, but the directions and drawings in the PDF are pretty specific and (I think) clear. You can use a woofer itself as the template to draw borders and mark for holes, too.
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Old 29th December 2017, 03:25 PM   #358
Cask05 is offline Cask05  United States
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Quote:
Originally Posted by jpak Click the image to open in full size.
How much higher up would they roll off (ported version) if moved into the room by 1.5 meters from front and side walls?

IMHO for my preferences all speakers, constant directivity or not have more depth to the soundstage when they're moved off the front walls, I am guessing because of increased front wall reflections.
I've found this type of thinking to be poorly applied to multiple-entry horns (MEHs) with any kind of low frequency extension. Loss of bass doing this using straight-sided horns with mouth sizes of the size of Danley-style MEHs results in a disproportionate loss of bass extension if moved away from a wall or corner position (quarter or eighth space)

See the Olson article on "A Horn Consisting of Manifold Exponential Sections" to give yourself a clue to what's happening...and see the differences between figures 4,5 and 6 in the Edgar article on tractrix horn profiles, attached.

I've done measurements...and it's a significant loss of bass extension--well over an octave when comparing half space vs. eighth space (on floor vs. in a room corner).

If you're building an MEH that loses mouth polar control at 500 Hz or higher frequencies, then you'll have to rely on something else to provide bass. I see a lot of ported bass bin designs used, but the added effects of port group delay growth and modulation distortion doesn't sound very good to my ears, ref: http://assets.klipsch.com/files/Dope_760600_v15n6.pdf

I rather would recommend something like a closed box/acoustic suspension or perhaps a slot-loaded design for a bass bin--when coupled to the clean sound of a Danley-style MEH.

YMMV.

Chris
Attached Files
File Type: pdf The Tractrix Horn Contour-Bruce Edgar.pdf (766.0 KB, 52 views)

Last edited by Cask05; 29th December 2017 at 03:42 PM.
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Old 29th December 2017, 03:55 PM   #359
Cask05 is offline Cask05  United States
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One source for the Olson article on manifold exponential sections mentioned above: Article: A Horn Consisting of Manifold Exponential Sections - Technical/Modifications - The Klipsch Audio Community
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Old 29th December 2017, 05:03 PM   #360
NEO Dan is offline NEO Dan  United States
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Can you attach a copy for those of us who do not have an account over there?
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