Hi all.
Im looking for plans to build from. Synergy tops for small to medium outside use. 130+db@1m(more is more), 90 degree horisontal would be nice and usable to 100ish Hz. For subs im planning a pair of Skhorn double 21”s. If somebody has the plans for these, id be gratefull for those also.
I know there are lots of builds around, but has anybody drawn any plans to build from?
Thanks
Im looking for plans to build from. Synergy tops for small to medium outside use. 130+db@1m(more is more), 90 degree horisontal would be nice and usable to 100ish Hz. For subs im planning a pair of Skhorn double 21”s. If somebody has the plans for these, id be gratefull for those also.
I know there are lots of builds around, but has anybody drawn any plans to build from?
Thanks
So that's a no. Ok. Ill take a stab at designing one then.
From what I understand, finding a suitable midrange cone is critical?
I went through the midrange cone monstrosity thread, but sadly it mostly concentrates on home use. The Misco would be perfect, but availability in the EU is nonexistent. With shipping and taxes the price goes up quickly. Only driver that is small enough, available and me thinks suitable is 4NDF34.
FS 110Hz x 2 / QES 0.28 =785. Thats a bit highish, but could work? How can one guesstimate the f3 frequencies from this center freq? Does this mean that, in theory at least, one could cross to the CD over 1KHz? And would that mean a cheaper CD could be used vs coax CD.s? Im guessing 4 4NDF34 would get me to desired spl? Has anyone played around with these in a MEH?
What about woofers? could I get away by using 2 12"? TS-12W350/8A would have availability, and would not break the bank. I have no clue what to look for in the woofer section.
About the horn itself. Does the flare from S1 to S2 determine the horn geometry, or what ever its called? So lets say I'm going for 90°x50°, is that the rate of the first conical section and the second flare is then wider?
Found the plans for the Skhorn. Does anyone have an idea what kind of spl these are capable with some nice 21"s?
From what I understand, finding a suitable midrange cone is critical?
I went through the midrange cone monstrosity thread, but sadly it mostly concentrates on home use. The Misco would be perfect, but availability in the EU is nonexistent. With shipping and taxes the price goes up quickly. Only driver that is small enough, available and me thinks suitable is 4NDF34.
FS 110Hz x 2 / QES 0.28 =785. Thats a bit highish, but could work? How can one guesstimate the f3 frequencies from this center freq? Does this mean that, in theory at least, one could cross to the CD over 1KHz? And would that mean a cheaper CD could be used vs coax CD.s? Im guessing 4 4NDF34 would get me to desired spl? Has anyone played around with these in a MEH?
What about woofers? could I get away by using 2 12"? TS-12W350/8A would have availability, and would not break the bank. I have no clue what to look for in the woofer section.
About the horn itself. Does the flare from S1 to S2 determine the horn geometry, or what ever its called? So lets say I'm going for 90°x50°, is that the rate of the first conical section and the second flare is then wider?
Found the plans for the Skhorn. Does anyone have an idea what kind of spl these are capable with some nice 21"s?
A Peavey SP4 will get you to 130 db. 2 ea 1508-8 HE woofers, one RX22 CD with horn. 1800 hz crossover because CD is only 70 watts AES, case is trapezoidal bass reflex (vented) to prevent beaming of the woofers 1200-1800 hz. 49"x21" front 29"x13" rear, 23" deep. 3/4 plywood. 113 lb
If you want to avoid building a trapezoid you could use an Eminence N314x-8 CD which allows 150 w AES and can handle down to 800 hz. You could cross there or at 1000.
1508-8 woofer is only 350 w AES with aluminum voice coil. You could instead use one Eminence LA15850 which is 800 w aes with 4" copper voice coil. One pro PA guy posting here said copper voice coils shed heat better in long gigs. It has an 8 db peak from 800 to 1000 hz, you'd have to tame that with crossover or DSP & biamp for accurate sound. One woofer instead of two should save weight & volume.
If you want to avoid building a trapezoid you could use an Eminence N314x-8 CD which allows 150 w AES and can handle down to 800 hz. You could cross there or at 1000.
1508-8 woofer is only 350 w AES with aluminum voice coil. You could instead use one Eminence LA15850 which is 800 w aes with 4" copper voice coil. One pro PA guy posting here said copper voice coils shed heat better in long gigs. It has an 8 db peak from 800 to 1000 hz, you'd have to tame that with crossover or DSP & biamp for accurate sound. One woofer instead of two should save weight & volume.
I wouldn’t try a Synergy with 15’s…. But the N314 would be my first choice of CD, being the kind of guy that doesn’t spend $500 each on HF drivers. I think Art Welter tried it in his SynTripP, which is buried somewhere in this sub-forum. I don’t know how “complete” the plans are, but there is some documentation.
I've played around with the 4NDF34 in a MEH using it as low as 125Hz.
The 4NDF34 works great. Located at the throat apex not a lot of gain from a conical 90x50, but an easy 130dB from four drivers at 400 Hz. At 1kHz four 4NDF34 could exceed 145dB.
Crossover at 1000 Hz is good, so a decent 3" diaphragm driver could be used, though 130 dB may be optimistic. If you don't want the HF to be the weak link, 4" diaphragm or coax will still be required.
Mark100 has lots of good info:
https://www.diyaudio.com/community/threads/syn-10.383607/
High Bl and Xmax in the 6mm+ range would be required for 130dB from a pair, relatively small VAS so cabinet volume does not need to be huge.
The TS-12W350/8A would work, but a pair won't reach much over 120-125 dB in the 100Hz-125Hz range even using bass reflex due to the limited excursion it's Xmax is only 3.8mm.
A conical horn's flare rate depends on the driver entry position down it's axis.
Bwaslo's spreadsheet helps:
http://www.libinst.com/SynergyCalc/
The first portion of the conical horn determines it's flare rate.
Standard practice is doubling the angle for the second flare.
In practice, the horn break makes the two conical sections behave somewhat like an exponential horn approximating the curve between the two parts at lower frequencies.
The square root of the HxV angle of a conical horn is the equivalent of a symmetrical flare.
A 90x50 conical is the equivalent of a 67x67, a 90x40 a 60x60.
Going narrower increases output, the second flare holds pattern control to a lower frequency.
130dB cabinets should be elevated way above head height, usually requiring front fill for clarity- 80x35 would probably be enough coverage, output like a 53 x 53.
Skhorn should be around 140dB at 1m with under 10% THD, depending on drivers used.
Josh says:
"The second harmonic accounts for nearly all the THD 100-120Hz but it doesn't break 10% until it is producing 134-135dB at 2m outdoor ground-plane which is extremely loud."
https://data-bass.ipbhost.com/topic/613-riccis-skhorn-subwoofer-files/page/17/
If you want a good proven 130dB+ top design, Peter Morris PM90 or PM60 would be good choices:
https://soundforums.net/community/threads/new-diy-mid-high-90deg-aka-pm90.11601/
https://soundforums.net/community/threads/60-degree-diy-mid-hi-aka-pm60.12390/
That's what I suggest for those that want more than the 125dB the SynTripP will do.
Art
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