If you NEED the most output per cubic foot of cabinet volume, 2x18's or 2x21's with loads of power behind them. (In a simple ported configuration)
TH's will take up more space but use a lot less amp power.
Again if $$ and amp power (and in turn power available to run those amps) is no issue then don't use a TH.
TH's will take up more space but use a lot less amp power.
Again if $$ and amp power (and in turn power available to run those amps) is no issue then don't use a TH.
My error with the multiplication. We normally put 4 subs at the bottom and then another row of 4 subs on top. That is how I got the 90 inches H. But the width would be 26.5 x 4 = 106, not 212 as I said. So the sub stack would be 106 W x 90 H. Too big. But I like your suggestion of putting the exit at the bottom of the keystone. That would be perfect for me as long as it would work properly. Thanks for the suggestion. So all I need to know now is if there will be any significant negative effect on the frequency response and SPL compared to the original design. Can this be simed?
Hi Scientific,
Just for the record: how high, how wide and how deep do you want the complete stack of eight enclosures to be?
Regards,
Just for the record: how high, how wide and how deep do you want the complete stack of eight enclosures to be?
Regards,
Actually I was considering this. A guy in Trinidad used 6 cabs, 18sound design double 21 BR cabinets and said the bass was deafening.
http://www.eighteensound.it/Portals/0/EnclosuresKits/18sound_double 21 kit.pdf
I think they were powered by Lab Gruppen clones. I may have to do the same.
That means buying 12 x 21 inch drivers. Hmmm!! $$$. compared with 8 x 18" (18Sw115) woofers. Actually I have not completely thrown out the idea. The investment against the returns has me scratching my head.
In short:
10 x TH115s do a great job. A DSL TH118 is louder and deeper than the TH115 so hopefully 8 TH118s should do the same job (or better). The TH18 is close to the DSL TH118 so 8 x TH18s should do. The Keystone was found to be 2 db louder than the TH18 in actual measurements so the 8 Keystones should be more than adequate. That's what has me sold onto the Keystone.
But I haven not given up totally on the dual driver ported cabs. Anyways the advise so far on this forum has been good. I have to make up mind soon before I loose my opportunity for a deal on the drivers.
No "significant negative effect", the reduced frontal area would loose a dB or so of output compared to the stock Keystone, the upper response would be a little rougher.
The extra path length would extend the LF by perhaps 1 or 2 Hz. Using a grill with a 3/4" frame, the exit size on the 22.5" x 26.5" end is about the same as the normal Keystone exit, reducing exit size would extend the LF a bit lower at the expense of output.
It could be simulated with Hornresp just as any other TH, while the keystone shaped exit can't be.
Art
Width - nominal 96 inches. Ideal.
Absolute maximum width = 112 inches. (that means overlap on both sides of the truck. I would prefer not have it that wide but other sound systems get away with it. e.g. the guy who puts 2 rows of 5 TH115s.)
Height - absolute maximum = 84 inches
Depth - not an issue as there is space on the trailer. However I would not want it excessively deep for the sake of the weight that might result so I think 48 inches would be a reasonable maximum to stay within. I could go deeper if absolutely necessary.
My plan is to use 18 or 21 inch Neo drivers and give each driver around 2500 watts. Even if they can take 3,000 or 3600 watts, I have to take into consideration, hot sun and long hours.
225 lbs, maximum weight per cab.
Hi Scientific,
Thanks for the dimensions, that gives me more of an idea what you are looking for. As usual, I was getting confused, just trying to follow along. 🙂
Regards,
Thanks for the dimensions, that gives me more of an idea what you are looking for. As usual, I was getting confused, just trying to follow along. 🙂
Regards,
Thread hijack? On a different note, has anyone built some Pal 12's? They still intrigue me. I wanna build some but still need a little convincing before I take the plunge.
Sounds good. We usually crossover at 100 hz so if the upper roughness is higher than this, then that's not a problem.
And I was just thinking, we could probably build the keystone in such a way that the front and bottom panels can be unscrewed. For normal gigs, we use the KS as you designed it, with the keystone exit at the front. But when required on a truck which is like twice a year, we just unscrew the front panel with the keystone exit and screw on a sheet of ply with no exit. makes sure it is airtight and well braced. Then we unscrew the section of the bottom to create a new exit. That would be a dual purpose cab. If that could work, that would be super.
A quick question. If a KS is supplied with 2,500 watts, what would be the difference if any (SPL and Frequency) between the one using:
a B&c 21Sw152-4 or
a 18Sw115-4
Also, as I am planning to feed power at maximum 2,5000 watts, should I use a more sensitive B&C 18 to get more SPL, e.g. the 18sw100, 18TBW100 (assuming a HPF at 35 Hz )?
Using Hornresp simulations at rated Xmax values, (and impedance minima) average level from 35-100 Hz, the Keystone has these output levels:
BC21SW152-4 131.6 dB, 92 volts, 3.4 ohms, 2489 watts
BC18SW115-4 130.1 dB, 76v, 3.43 ohms, 1683 watts
BC18TBW100-4 127.8 dB, 59v, 3.32 ohms, 1048 watts
The 18SW100 would probably be similar to the 18TBW100, perhaps a tad more sensitive.
hipass filter at 35hz is high scientific. IIRC a 28hz 18db/oct slope bw hipass will do the trick, though 30hz might be more prudent (art?)
Hi Scientific,
Post #387: "...do you have any suggestions on the cabs?"
I'm trying to redraw the Keystone fold to fit a H42" x W24" x D47(or less)" fold. That should have enough internal width for up to 21" drivers. Would modern plywood material thickness 23/32" (.719"[18.3mm]) suit you?
Also, should this be posted in the Keystone thread?
Regards,
Post #387: "...do you have any suggestions on the cabs?"
I'm trying to redraw the Keystone fold to fit a H42" x W24" x D47(or less)" fold. That should have enough internal width for up to 21" drivers. Would modern plywood material thickness 23/32" (.719"[18.3mm]) suit you?
Also, should this be posted in the Keystone thread?
Regards,
Oliver,
The Keystone sub was named for the exit shape, a cabinet without that exit shape would be a "normal" TH, as such really does not belong in the Keystone thread.
That said, using the same basic fold, size and driver as the Keystone has more in common with it than the cabinet this thread was made for ;^).
Art
The ply available to me is 3/4 inch, that's around 18 mm so that should be OK.
With the Height at 42" you are talking about a cab with the normal keystone exit so I think this can be in the keystone thread.
I was only thinking of Hipass at 35 hz so that I could give the 18s the full 2,500 without having to worry about reaching XMAX. That's the frequency I used in the past on FLHs but they didn't go so low so that was not a problem. But if 28 Hz is what the Keystone needs, then that's what I'll use.
Good. Unless the frequency goes lower with the 21, there does not appear to be a big benefit with using a 21 that cost quite a bit more. If someone said to me that from listening to them the 21 just sounds bigger and gives out more energy, then maybe I would favour it. The BC18SW115-4 looks like the best bet.
Hi guys, sorry for just jumping in and changing subject, but I have a quick question.
I thought that tapped horn is supposed to enable you to go lower with your sub while putting more power in it without it exceeding it's xmax. But I can't make that possible. Every horn I make in hornresp goes as low as my "normal" ported box (20 Hz), but with way more driver excursion. Am I doing something wrong, like beginner mistake, or am I misinformed about tapped hornes?
I thought that tapped horn is supposed to enable you to go lower with your sub while putting more power in it without it exceeding it's xmax. But I can't make that possible. Every horn I make in hornresp goes as low as my "normal" ported box (20 Hz), but with way more driver excursion. Am I doing something wrong, like beginner mistake, or am I misinformed about tapped hornes?