Still need to model up some templates, but one thing at a time.
I think I'll also model the barn doors up, as 3db is certainly worth the extra sheet of ply.
I think I'll also model the barn doors up, as 3db is certainly worth the extra sheet of ply.
It seems like several people used NU or NX amps for powering Keystones. I'm building a rig thus going through several options. Has anyone powered a pair of Keystones with a single NX4-6000?
Ishom,
The NX4-6000 is an updated version of the NU4-6000.
I have powered a pair of Keystones with a single NU4-6000, channel pairs bridged mono to each 4 ohm sub.
That said, with a three way system, normally I used one channel pair of the NU4-6000 bridged into the sub, and the other two channels for mid/high, the two amplifiers on either side of the stage to reduce cable length.
If one amplifier failed, the system could still be run mono, with one sub per channel, ~3dB less power than in bridged mono mode.
Art
The NX4-6000 is an updated version of the NU4-6000.
I have powered a pair of Keystones with a single NU4-6000, channel pairs bridged mono to each 4 ohm sub.
That said, with a three way system, normally I used one channel pair of the NU4-6000 bridged into the sub, and the other two channels for mid/high, the two amplifiers on either side of the stage to reduce cable length.
If one amplifier failed, the system could still be run mono, with one sub per channel, ~3dB less power than in bridged mono mode.
Art
Would someone mind double checking my math? I'm considering a CVR DSP-654 to run one Keystone (two bridged channels) and one Syntripp.
The DSP-654 can put out 3740W @ 4Ω bridged and 72.1V RMS. The 18SW115-4 in the Keystone takes 3400W max and 1700W RMS, and I see Art recommends limiting RMS to 1/2 of the nominal RMS rating, so 850W.
850W at the speaker's DCR of 5.3Ω gives me 67V which is within the amp's RMS output of 72.1V. Is this sufficient, or should I oversize to something like the DSP-1004 with 2 x 5780W or the DSP-1504 with 2 x 7140W? I'm playing low-crest-factor EDM.
The DSP-654 can put out 3740W @ 4Ω bridged and 72.1V RMS. The 18SW115-4 in the Keystone takes 3400W max and 1700W RMS, and I see Art recommends limiting RMS to 1/2 of the nominal RMS rating, so 850W.
850W at the speaker's DCR of 5.3Ω gives me 67V which is within the amp's RMS output of 72.1V. Is this sufficient, or should I oversize to something like the DSP-1004 with 2 x 5780W or the DSP-1504 with 2 x 7140W? I'm playing low-crest-factor EDM.
The nominal 4Ω 18SW115-4 has a DCR of 3.3Ω, near the minimum impedance of it loaded in the Keystone Sub ~ Fb.
In post #1, I recommended peak limiting of ~3400watts, and long term "RMS" limiting with a time constant of longer than 500 ms (milliseconds) no more than half the 18SW115-4 AES rating of 1700 watts (850 watts), but if you tend to get "heavy handed" on the volume fader playing compressed music over long time periods, just 425 watts.
You are asking about a 18SW115-8, a nominal 8Ω speaker with a DCR of 5.3Ω.
72.1V into the impedance minima is around 981 watts.
~47.5 volts should be safe for low-crest-factor (similar to sine waves..) EDM.
If you want to get the peak performance ~3400 watts, ~134volts peak would be required, compared to ~106v for the 4Ω driver.
Whoops, looking at the wrong specs. I'm using the 18SW115-4. Ok, so for maximum peak performance (most of my music has strong bass hits but not sub-bass sine waves) I should aim for something that puts out at least ~106V, but limit the long-term RMS rating to 425-850W. Does that sound correct?
My local plywood supplier only has sheets of birch in 5x5, and their also quite expensive. Would something like ACX ply work? We're just picky on equal plys correct? The cabs will of course be bondo'd, sanded and coated with duratex.
ACX could work OK, without working with a particular plywood brand hard to say.
"A" and "C" refer only to the front and back plys, "X" denotes the use of an exterior grade adhesive to join the panel’s veneers together.
The knots and other imperfections in "C" grade could be a problem on some pieces like the baffle.
The amount (more is better) and what is in the inner plys is important, avoid plywood where gaps, loose knots and "waves" are visible on the sides.
"A" and "C" refer only to the front and back plys, "X" denotes the use of an exterior grade adhesive to join the panel’s veneers together.
The knots and other imperfections in "C" grade could be a problem on some pieces like the baffle.
The amount (more is better) and what is in the inner plys is important, avoid plywood where gaps, loose knots and "waves" are visible on the sides.
Ended up with four sheets of marine grade, though I'll likely use acx for future builds (my wallet is on fire)
It's void free, but lacks as many plys as birch. The birch was just a little more pricy and only comes in 5x5; which makes the layout more inefficient with more waste.
It's void free, but lacks as many plys as birch. The birch was just a little more pricy and only comes in 5x5; which makes the layout more inefficient with more waste.
For reference, I was originally using a behringer nx6000, 1 sub per channel into b&c thw100 8ohm drivers for a fair while. The sound in general was excellent but I ended up upgrading to an admark ad42 for 2 of our cabinets while the other 2 run on a matrix xt7000. The difference in warmth and depth of the bass is quite frankly obscene. These cabinets can move some serious air when driven properly!
Going from the NX6000's 1600watts to 4200 watts with the AD42 is definitely an upgrade, using 8 ohm drivers requires a lot of voltage.
During the last few months I've been building a pair of Keystones to match the SynTripPs I built last year. Have been running them at three parties so far and maaaaan do they kick! I've lost count of the numbers of compliments the subs have recieved. Like others has stated, the output and overall "tightness" is out of this world.
Some build photos: https://photos.app.goo.gl/ZFY16m1YwE1VHc7u5
The only downside is that I've come to the realization that sub-bass gets a lot of neglect in music production haha. After playing around with the subharmonic synth on the PA2 and adding a tiny bit of SX3040-processing I could really feel the sub-bass come alive on most tracks! I like it when the air feels like liquid 🙂 Highly recommend!
Built horns as well! 35cm deep with 45 deg sides. Now in retrospect I'm not really sure why since I was already more than happy with the power output... Anyways, got to try them out today and took some quick measurements with and without the horn extension:
Taken at 2m distance ~5cm from the ground, 1/12 smoothing. If you look close you'll see some minor fluctuation, but it's most likely due to my dying computer having some grounding issues. The measurement with the horn attached had the microphone moved back 35cm to account for the added depth. Here's the separate measurements with phase:
Overall a 2-4dB increase in the whole frequency range! While I could have hoped for an additional dB or two in the 30-50hz region I'm still extremely happy with the results! Art, as I said last year in the SynTripP thread, thank you!
- 18TBW100-4 powered by a NX6000
- 30hz BW24 and crossed to the SynTripP at 100hz with a BW24
- Limiter at 50v
Some build photos: https://photos.app.goo.gl/ZFY16m1YwE1VHc7u5
The only downside is that I've come to the realization that sub-bass gets a lot of neglect in music production haha. After playing around with the subharmonic synth on the PA2 and adding a tiny bit of SX3040-processing I could really feel the sub-bass come alive on most tracks! I like it when the air feels like liquid 🙂 Highly recommend!
Built horns as well! 35cm deep with 45 deg sides. Now in retrospect I'm not really sure why since I was already more than happy with the power output... Anyways, got to try them out today and took some quick measurements with and without the horn extension:
Taken at 2m distance ~5cm from the ground, 1/12 smoothing. If you look close you'll see some minor fluctuation, but it's most likely due to my dying computer having some grounding issues. The measurement with the horn attached had the microphone moved back 35cm to account for the added depth. Here's the separate measurements with phase:
Overall a 2-4dB increase in the whole frequency range! While I could have hoped for an additional dB or two in the 30-50hz region I'm still extremely happy with the results! Art, as I said last year in the SynTripP thread, thank you!
That's wicked! What you have inside the syntrips.
It's complicated to make one?
Can you splay em?
It's complicated to make one?
Can you splay em?
Leo,
Nice looking extensions!
2-4dB increase is like doubling power with no thermal compression, hard to beat.
Your BC18TBW100-4 response looks like it's dropping off below 50Hz, using the BC18SW115-4 it's flat from 40-60Hz, and rises ~+6dB above.
Was there any processing other than the 30Hz/100Hz BW 24?
What was the distance to the van behind, and any other structures?
Art
Quick question - I'm looking at the Front Brace (M). Does anyone think there would be a problem with flipping this brace and connecting to the Back panel (B) instead? I'm toying with some ideas for customizing the Top Front Panel (D) and this would simplify things.
Attachments
The back panel is already braced with K & J, it does not need additional bracing.
Brace M braces the front panel above P, that area needs to be stiff.
If your ideas for customizing the Top Front Panel (D) include some alternate bracing above P, no problem with deleting M.