Forgive me if this question has been asked already.. but I couldn't find it: What would the effect be of reducing the width from 26.5 to a bit smaller, 20 to 22 inches? I've got a stack height problem.. my tops (KF650) need to be at around 60 inches so two keystones are too short. Three stacked at 21 inches each would work....
Thanks!
Thanks!
Light-o-matic,
I forgive you
.The reduction in width will reduce output slightly. The Keystone exit should probably be reduced by a similar % as the reduction in volume planned.
Personally, I'd want the KF650 cabinets at least 79.5" off the deck.
Have fun,
good luck,
Art
I have looked over the horn extension pages and have a few questions. Hopefully the rough sketch attached makes it easier to answer.
1- what is a good length to extend the cabs?
2- does it matter if they extend 90 degrees or should they flare out like a wave guide?
2A- if waveguide - what angle?
3- do they need to extend from from the top? or if it's equidistant from the top of the keystone exit to the bottom of the keystone would a mid-height work like in figure 1C
4- I have not decided how I am going to arrange the subwoofers. They will either be 2 per side with the mains sitting on top of them - or 4 lined up in a center cluster and figure out something to set the mains on. If all 4 were lined up in a center - would one large mouth extension work? or should they include subdividers between every driver?
Last year 2 went to the burn - this year it will be 4
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I'm not Art, nor an expert, but I think I can answer that question a bit. The flare angle isn't so much important as the fact that the extension must be flared (or a 90 degree barn-door boundary) for the frontal area to be effectively increased. That frontal area increases forward radiating efficiency by more effectively confining the output so the sub operates more like it's in quarter space than half space. Now much flare or how deep I don't think really affects the frequency response a ton so much as the increased boundary keeps the output directed forward. For four subs, I'd go with a design similar to what Art had in his other thread. It is fairly simple to make them stackable for transport. Then I'd line them up by the edges of the flare. So the frontal area is one continuous boundary but the enclosures are slightly separated.
Bjones,View attachment 565355
I have looked over the horn extension pages and have a few questions. Hopefully the rough sketch attached makes it easier to answer.
1- what is a good length to extend the cabs?
2- does it matter if they extend 90 degrees or should they flare out like a wave guide?
2A- if waveguide - what angle?
3- do they need to extend from from the top? or if it's equidistant from the top of the keystone exit to the bottom of the keystone would a mid-height work like in figure 1C
4- I have not decided how I am going to arrange the subwoofers. They will either be 2 per side with the mains sitting on top of them - or 4 lined up in a center cluster and figure out something to set the mains on. If all 4 were lined up in a center - would one large mouth extension work? or should they include subdividers between every driver?
Last year 2 went to the burn - this year it will be 4
1) I have neither built nor modeled any "horn extenders" as depicted in your sketches.
If you are looking to extend the horn, it would be best to match the Keystone exit shape. Extending the horn will lower the low corner frequency (Fb or Fc), but also will lower the upper null frequency, which may be a problem if your tops can't handle a lower crossover frequency.
2) The "flare" should be equal or greater to the cross sectional expansion of the latter portion of the tapped horn.
2A) The wave-guides I used with the Keystones were designed to match the 90 degree dispersion angle of the Paraline top cabinets. Just using the lower 56.25" portion of the wave-guide increased low frequency forward output by an average of 3 dB. I never did measure the gain using both portions, but I'd say it was better than 4 dB- the 28 eight inch horn loaded drivers clipped (ran out of headroom) at the same SPL as the pair of Keystones. The ten 3" diaphragm HF (high frequency) drivers were also near their headroom limit, but much of that was due to the unusually severe HF air absorption typical in the hot, dry environment of New Mexico.
Now that I'm living in humid (and hot..) DeLand, Florida, it's like getting younger- the highs have their "sparkle" again.
3) No.
4) Mains at 45" above the deck? Guess you don't care about projecting very far, or about deafening those near the stack. Of course, with enough drugs, nobody notices hearing loss...
Unless you model whatever you plan, and like the results, I'd suggest doing wave-guides as pictured below.
Double stacked, the Keystone/wave-guide combination would be a good platform for top cabinets.
The box directly above the Keystone in the picture below is a 4x8", the lowest HF driver is 76" (over 6') above the ground.
Normally, the cord box the center fill cabinet is sitting on to the right of the stack would go below the 4x8" cabinet, raising the lowest HF horn another 11.25", but that extra height made putting tarps over the stack at night (or during monsoons) difficult. That said, I now use PVC "goal posts" to lift the tarp over my SynTripP tops (over 10' high), much easier than climbing a 10' stack with a 25' tarp in a hand with only 2 fingers ;^).
Cheers,
Art
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Sorry Art,
I guess I am using the wrong vocabulary.
the tops are JBL 722's - which don't really have output below 77hz. The horn HF driver would be around 8' with the 2 12's below. I have no mid box. I currently run the xover at 100hz. It sounds to me like I might be talking about dragging a lot more plywood to playa that won't yield much of an spl increase if I do it wrong - and it seems that's the track I am on.
I guess I am using the wrong vocabulary.
the tops are JBL 722's - which don't really have output below 77hz. The horn HF driver would be around 8' with the 2 12's below. I have no mid box. I currently run the xover at 100hz. It sounds to me like I might be talking about dragging a lot more plywood to playa that won't yield much of an spl increase if I do it wrong - and it seems that's the track I am on.
Then change tracks
.Wave-guides like the ones I built yield 3+ dB increase in output.
That is like doubling your amplifier power with no power compression.
Another way to look at it is you will draw half the power compared to without, half the generator size required, or about half the fuel consumed.
Between the wave-guides and doubling your speaker and amplifier count, you will hear about a 10 dB gain from last year, more than twice as loud.
Will be building six "stretch" Keystones, the new model will be 50" tall for a bit more LF extension.
Just got another NU4-6000, so will finally have the amp channels and cabinet count to start playing with cardioid or end fire sub arrays, potentially dropping rear output by 10dB or more. An end-fire "V" arrangement of 6 cabinets should be impressive, and not rattle stages or turntables behind the array.
Art
I had a nice spot to listen to the cardiod setup "thunder stage" from Ian's cockpit at LiB this year - it was one of the best "to my personal ear preference" sounding stages I've heard
Alright - I will draw up another sketch and see if I have it right.
It seems that there is no vertical dispersion angle on horizontal and you selected the angle to match the H angle of the HF - I will have 1 JBL 722 over 2 keystones. They have a 75x50 pattern. I am not sure of a way to align that unless I were to do it solely over 1 keystone vs centered over the 2.
Alright - I will draw up another sketch and see if I have it right.
It seems that there is no vertical dispersion angle on horizontal and you selected the angle to match the H angle of the HF - I will have 1 JBL 722 over 2 keystones. They have a 75x50 pattern. I am not sure of a way to align that unless I were to do it solely over 1 keystone vs centered over the 2.
UPDATE!!!
I got my 2 MDF Keystones (RCF LF18X451) sprayed with some texturized speaker kind of paint.
(Does that paint actually have a specific name?)
And i bought the iNuke 12000 DSP...
And i gotta say: WWWWWOOOOOOOOOOOOOWWWWWW!!!
Sounds absolutely AMAZING!!!
Sounds better, deeper and more powerful than i could ever imagine getting out of 2 subs...
Really impressed.
Still only tried it in a semi small room and i wonder how big a space you could actually cover with 2 keystones?
Maybe because of the room... But i didnt sense much difference between 1 and 2 playing at the same time. They where standing 1 in each corner.
Dont know if i would gain anything (not really that i can say i need it) by putting them next to each other or next to each other but in a 90º angel... Or i seen on some design you can also gain something if they face the wall/corner?
And how would it be with 4 Keystones?
Is it worth it or would you gain much more (low freqs and higher DB) by fx building 4 Super Bass Horns?
Thx a lot Weltersys for a brilliant intelligent design.
Cant wait to use them in a party...
Unfortunately the club where i use to make stuff is closed at the moment for some license issues... Hope they open soon so people here can start enjoying physical music.
I got my 2 MDF Keystones (RCF LF18X451) sprayed with some texturized speaker kind of paint.
(Does that paint actually have a specific name?)
And i bought the iNuke 12000 DSP...
And i gotta say: WWWWWOOOOOOOOOOOOOWWWWWW!!!
Sounds absolutely AMAZING!!!
Sounds better, deeper and more powerful than i could ever imagine getting out of 2 subs...
Really impressed.
Still only tried it in a semi small room and i wonder how big a space you could actually cover with 2 keystones?
Maybe because of the room... But i didnt sense much difference between 1 and 2 playing at the same time. They where standing 1 in each corner.
Dont know if i would gain anything (not really that i can say i need it) by putting them next to each other or next to each other but in a 90º angel... Or i seen on some design you can also gain something if they face the wall/corner?
And how would it be with 4 Keystones?
Is it worth it or would you gain much more (low freqs and higher DB) by fx building 4 Super Bass Horns?
Thx a lot Weltersys for a brilliant intelligent design.
Cant wait to use them in a party...
Unfortunately the club where i use to make stuff is closed at the moment for some license issues... Hope they open soon so people here can start enjoying physical music.
Nice, the spl from these are nothing short of amazing, but what surprised me was the warm soft musical sound that I didn't expect from a TH alignment.
Jesperino,
So many questions for a Sunday morning...
1) Yes, there are several different brands of commercially available truck "bed-liner" paints that are (hopefully) professionally applied.
I have been using an easy to apply (with a little texture roller) textured paint called "Duratex" for the last several years. It cleans up with water before it dries, but is quite impervious to the elements once it dries.
2) I have covered outdoor areas the size of a football field (and larger) with a pair of Keystones with considerably less power than available from the iNuke 12000 DSP.
3) As you have found, room modes can play havoc with speaker response.
4) Placing them together, side by side, gains 7 dB over a single, 3 dB from doubling drivers and cabinets, 3 dB from doubling power, and 1 dB due to the forward directivity from the doubling of frontal area.
I have not measured the increase in level with a pair at 90 degrees to each other, but suspect that since the frontal boundary area would be slightly less than a pair side by side, the forward gain would also be slightly less, but doubt there would be more than a 1/2 dB difference on average in either configuration. However, the 90 degree angled version would look 3 dB more "hinky" than the side by side configuration ;^).
5) Four Keystones would be about another 7 dB louder than two.
In the 35-40 Hz range, a 7 dB difference in level on average is perceived as twice as loud.
6) I have no experience with "fx building 4 Super Bass Horns", but my experience with the Keystone subs was pretty superb, really looking forward to soon having six to play with.
Art
Dan,
I'll be playing until they pry my stiff, dead fingers from the faders, whether they be virtual or real
.Thanks for caring!
The rental house came complete with a vintage Jimmy Carter era metric/imperial "yardstick" (complete with conversion equations on the back), I promise to give accurate dimensions of the "stretch" Keystones in both, assuming the yardstick is marked correctly...
Art
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With the high-BL, strong coned drivers available, I find you need a fairly high compression ratio to get a good response out of a TH. Isobaric (clamshell) mounting makes it very difficult to get the compression ratio up, since you've just put a minimum limit on S2 from the inside driver's mounting depth.
Its cool to sim 2x isobaric pairs of drivers into a design for one driver and see how much noise you can make, though. IIRC I sim'd 130dB down to 40Hz from a 100L box, but there was no way of ever fitting the 4x15" drivers in there.
Chris
LOL I think we are going to have to send you a new yard sick...
Stretch was exactly what came to mind when I was working on the cut sheets, get in touch and I'll knock those out too.
Wow, Dan, that yard stick is too "sick". Unfortunately, it would require a sharper pencil than I use....
I think we are going to have to send you a new yard sick...
Stretch was exactly what came to mind when I was working on the cut sheets, get in touch and I'll knock those out too.
I plan to build a shop sub, a pair of small PA/home theater subs, and two 19" racks, then sharpen my pencil for the new "Keystone B Low Sub™" plans.
Very little will change in the Keystone B Low Sub™ other than the height. The Keystone B Low Sub™ will have back handles that will accommodate the steadying ratchet straps attached to the SynTripP™ top cabinets, and a pole mount socket. Those internal additions will slightly reduce the horn cross sectional area, so minor dimension changes will be required to preserve the "special sauce". The "B" portion of the name may change to a "C" or "C#" if it the extra length does not result in a low corner of 31 Hz. That said, with a step down plate, it should be able to hit a low "A", 27.5 Hz- the lowest note on a grand piano, but "Keystone A Low Sub ™" sounds dumb ;^).
Art
