I noticed that too. I went hunting more than once and came up empty. I did get some verification from others in other threads at some point but agree yours matches Art's best. I kinda wish each thread would offer a verified HR in OP so we don't have to hunt... Gotta scoot but file posted, maybe we'll figure it out.
Putting the wall at the back of the dance floor will cause increases at certain frequencies and cancellations at others dependent on the distance from the speaker, not what you want.
Having tested the effects of walls around speakers (AKA "barn doors"), you can be assured of an increase in SPL on the order of 3-6 dB depending on size. The "waveguides" I used with the Keystone increased output by a full 3 dB at the low corner.
Art,
I am just going to go for it I think with your Keystone design.
Above, it was mentioned that the TW100 may only have an increase in output with substantial power.
I have a bad habit of looking at numbers, but not enough "tell the whole story" numbers. All things being equal the TW should still be a able to go a little lower/louder with the same power correct? It's efficiency is higher.
One crazy thing I am trying to wrap my head around is the versatility of the Keystone size. With so many other enclosures, if not all, you change the driver you change the box. I have only made it through about 12 pages so far of the thread, but is this really working for optimal for 2x12 and 1x18 in the same enclosure design? If so thats fine, I just feel like I have to have missed something here.
Also, do you know if the 4 ohm version is that much different than the 8ohm. I have found in the past, I think with the 3015LF 4 vs 8, the drivers don't seem to behave the same.
I hope you know all the energy, time, broken parts, well they really matter to someone like me. So thanks for doing it. Learning rocks.
I am just going to go for it I think with your Keystone design.
Above, it was mentioned that the TW100 may only have an increase in output with substantial power.
I have a bad habit of looking at numbers, but not enough "tell the whole story" numbers. All things being equal the TW should still be a able to go a little lower/louder with the same power correct? It's efficiency is higher.
One crazy thing I am trying to wrap my head around is the versatility of the Keystone size. With so many other enclosures, if not all, you change the driver you change the box. I have only made it through about 12 pages so far of the thread, but is this really working for optimal for 2x12 and 1x18 in the same enclosure design? If so thats fine, I just feel like I have to have missed something here.
Also, do you know if the 4 ohm version is that much different than the 8ohm. I have found in the past, I think with the 3015LF 4 vs 8, the drivers don't seem to behave the same.
I hope you know all the energy, time, broken parts, well they really matter to someone like me. So thanks for doing it. Learning rocks.
This is still true for the Keystone, there are a great many 18s, 15s, and 12s that have abysmal performance in the KS TH. What's nice is that the expensive pro-sound subwoofer drivers tend to somewhat converge in terms of parameters and behavior. You end up with drivers with very stiff cones, high amounts of excursion, very strong motors, low qts, high power handling, and hopefully very linear BL.
As I understand it, the ~6db gain you can produce in an appropriately sized and designed TH is directly related to the way it acoustically loads the cone with higher air pressures. You need these strong drivers with lots of motor to be capable of controlling that load.
There are plenty of more 'typical' 18s like the Peavey Lowrider that don't have quite the motor grunt you need to pump that air load really well in a TH. It still makes lots of noise, but you start to get a much more peaky and resonant response. Some people call it the "saddle" response. http://www.diyaudio.com/forums/atta...b-using-18-15-12-inch-speakers-kslowrider.png
The high end B&C 18s, the lab 12, and to a certain extent the 4015lf qualify as these high strength drivers.
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1) The B&C 18TBW100-4 should be slightly more efficient than the 18SW115-4, but the 18SW115-4 has more Xmax/Xvar, so given more power will go slightly louder. Given the price difference, I'd now go with the 18TBW100-4, which was not available at the time of the build.
2) The Lab 12 work well in the Keystone, but are not "optimal". Since I had them, I tried them. I would not consider the 4015LF at all for your application.
3) I have not tried the 8 ohm version, but they sim about the same. I don't have any amplifiers that can deliver the power the B&C can take into 8 ohms.
Art
FWIW, I just did some sims with the 18TBX100 and the 18TBW100, and basically the simmed FR results are almost identical when they're used in the same TH at the same voltage level, up to Xmax. The 18TBW100 will have more SPL of course, as its Xmax is 12mm compared to the 18TBX100's 9mm. Given that the sim for the KS is correct, the 18TBX100 will give ~127.5dB in its passband at just over 600W, and the 18TBW100 will up that to ~130dB in the passband with just under 1,200W.
Note that the Keystone's large frontal area is likely to increase efficiency around the midbass area as well, compared to what the sim is showing.
I also compared the KS to my POC4, which are around the same net volume. My POC4 gives up just under 2dB in the passband for a slightly lower Fb (32.8 Hz to 34.9 Hz). The actual difference is likely to be greater at midbass frequencies due the larger frontal area of the KS.
Even the the impedance is the same, is it much easier on an amplifier to be bridged on a single 4 ohm driver than it is bridged on 2 8 ohm drivers in parallel?
I am trying to determine how to make the ohm versions work while I am waiting on an email from a company on their stock of 4 ohms.
The concern I have is that if I get 2 8 ohm cabs for this year, no I am stuck with always having to use them together.
If I get the 4 ohm cabs, for next year I can have a bridged amp on each one, and be able to ad more KS one by one, or use just a single cab in the future, but will be stuck with less power this year due to available amps.
I am trying to determine how to make the ohm versions work while I am waiting on an email from a company on their stock of 4 ohms.
The concern I have is that if I get 2 8 ohm cabs for this year, no I am stuck with always having to use them together.
If I get the 4 ohm cabs, for next year I can have a bridged amp on each one, and be able to ad more KS one by one, or use just a single cab in the future, but will be stuck with less power this year due to available amps.
You want to bridge a CE2000 into 4 ohms, for a subwoofer? You're braver than I thought. It will generate stupid amounts of heat. One 8 ohm cab for that amp is an appropriate load.
Figure out what amplifiers you're ultimately going to use, and let that determine which impedance speaker you need.
Zett, kinda sorted it out. I grabbed the HR inputs for the LAB15 in post 254 KS thread. Looks like yours came from a bit earlier when there was some attempt to better the sim to correct for the KS exit. Not entirely sure if there was a consensus that this new sim was better... You may not recall that Art reminded folks is mic was not flat so the measurements are off slightly. Post 129. In the end, a sim is a sim...
Am I? Or am I uncertain and asking for advice from those I trust have more experience?
Thank you. That was something I did pickup, and informed them we need one. They are going to be going through a list of equipment this week and sorting out what we have available. If one doesn't surface, I will look for something basic that will work.
I guess it will just be smarter to go with the 4 ohm drivers, so I am going to place the order and just hope they get here. In the meantime I will start the enclosures. Hopefully I can get through the rest of the other thread today, figure out how much wood I need and at least get materials gathered.
Nevermind, located 2 18TBW100-4 and they have been ordered!
Are there any amp recommendations since the amp situation is not yet finalized? Cost is forever the factor. I saw an older crown xti 2002 on amazon for around $700 900x2 @ 4 ohms.
Also, Art on the KS would it be beneficial to use all 1" instead of 3/4"? I am going to see if I can pick up some sheets today.
Are there any amp recommendations since the amp situation is not yet finalized? Cost is forever the factor. I saw an older crown xti 2002 on amazon for around $700 900x2 @ 4 ohms.
Also, Art on the KS would it be beneficial to use all 1" instead of 3/4"? I am going to see if I can pick up some sheets today.
I would not bother going to 1", though it certainly would work. Baltic Birch 3/4" would be an upgrade from the Arruco (sp?) plywood I used.
900 watts is not much power for a 18TBW100. I have been happy with the Behringer NU4 6000 which has four channels at 1500 watts each for a lot less money than the Crown. I have been bridging a pair of channels for 3000 watts at 4 ohms, amp runs cool in 100 degree temperature.
As well as the 24 dB per octave Butterworth HP mentioned, you will need about 8 millisecond delay on the top cabinets to phase align at the crossover point.
Holy cow! Should $400 not scare me for that much rated power?
Amazon.com: BEHRINGER iNUKE NU6000DSP: Musical Instruments
That just seems...too good to be true.
Amazon.com: BEHRINGER iNUKE NU6000DSP: Musical Instruments
That just seems...too good to be true.
Just before last Christmas I conducted a battery of tests on some old amplifiers and a new Behringer NU4-6000 four channel amplifier. To my surprise, the NU4-6000 performed as well on low frequencies as on mid/high frequencies, and is capable of full power sine wave output with all four channels driven to rated output at two ohms, or two bridged mono pairs driving four ohm loads each. The $350 NU4-6000 is within 3 dB of the $5500 Powersoft K10 on sustained (more than 1 second) output.
The NU4-6000 with two bridged mono pairs each driving four ohm loads just below the illumination of the clip/limit light each put out 85.5 volts at 60 Hz (1828 watts), 84.6 volts at 30 Hz (1789 watts), dropping the mains voltage on a 100' 10AWG 120v line from 118.1 volts down to 107.2 volts, drawing 31 amperes.
Using just one bridged mono pair, the amp ran for 40+ seconds before I terminated the test, as the amp was drawing 19.8 amperes, and the "tired" 20 amp mains breaker had popped several times in various tests already. The amp would have put out more power given a full 120 volts, but the test represents "real world" situation, we don't generally plug our amplifiers in to an outlet two feet from the mains transformer.
I also tested my old "heavy iron" bass favorite, a Crest CA9, bridged into a 4 ohm load it dropped the mains to 99.6 volts, drew 37.8 amps but only put out 80 volts (1600 watts). The NU4-6000 put out more power, and drew only 50% of the power from the mains compared to the CA9.
My back (and bank account) are very pleased with the NU4-6000.
Art
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Glad Art hooked you up with the amp info. iNuke 6000dsp was going to be my suggestion too. RE: materials; although Art managed to eek out 2 cabs from 3 sheets, I would say play it safe and plan on 2 sheets per cab to allow for an oops. In addition, if you do not have one already, take the time now to build an accurate panel cutting jig/sled.
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