Well here was the weekends trial of the keystone. It was a rush to throw it together in time, but it was just for 20 close friends in our alfalfa bottom haha.
Review:
18sw115 driven by nu3000 dsp bridged.
Having a flatish response does wonders for edm music (havent had time to eq the amp yet). The lower extenstion over our qsc kw181's really made a difference. The bass was incredibly tight and accurate compared to the vented qsc's. I ran the sub for 6 hrs on low volume to break in, then ran the gain and front attenuator around 3/4. Which drove the sub hard. Never got beyond slightly warm with over 8hrs of playing. This design really creates some good forced convection on the sub. People were blown away by the quality of bass and weve been to some pretty impressive venues. Turn downs made everyone smile. I did have to run the sub on its side as it blocked my projection screen. Real world output equalled about two of our qsc's while vastly exceeding their freq range. I a/b'd them and dont seem to notice two much issue with running the tapped horn with vented subs. Im very intrigued to see what a sub that could run down to 20 hz could do.
Great job Art. It exceeded my expectations. The folded horns at Edc Las vegas being boomy and muddy (but loud as hell*) had turned me off anything but vented. I suggest wrapping all the edges in angle iron to protect this puppy as slidding it is very hard on the box. The "sound system for my garage" is quickly becoming something that could damage small children haha. It will only run 3 or 4 times a year so i will report if my ignorant lack of limiting damages the sub.
Review:
18sw115 driven by nu3000 dsp bridged.
Having a flatish response does wonders for edm music (havent had time to eq the amp yet). The lower extenstion over our qsc kw181's really made a difference. The bass was incredibly tight and accurate compared to the vented qsc's. I ran the sub for 6 hrs on low volume to break in, then ran the gain and front attenuator around 3/4. Which drove the sub hard. Never got beyond slightly warm with over 8hrs of playing. This design really creates some good forced convection on the sub. People were blown away by the quality of bass and weve been to some pretty impressive venues. Turn downs made everyone smile. I did have to run the sub on its side as it blocked my projection screen. Real world output equalled about two of our qsc's while vastly exceeding their freq range. I a/b'd them and dont seem to notice two much issue with running the tapped horn with vented subs. Im very intrigued to see what a sub that could run down to 20 hz could do.
Great job Art. It exceeded my expectations. The folded horns at Edc Las vegas being boomy and muddy (but loud as hell*) had turned me off anything but vented. I suggest wrapping all the edges in angle iron to protect this puppy as slidding it is very hard on the box. The "sound system for my garage" is quickly becoming something that could damage small children haha. It will only run 3 or 4 times a year so i will report if my ignorant lack of limiting damages the sub.
Attachments
Treukauf,
Wrapping the box in angle iron would protect it, but in my experience will destroy everything it comes in contact with, and can potentially dice off fingers like Vienna sausages.
If you plan to slide the box rather than wheel it around, EPDM plastic strips work well, and can be made as interlocks between cabinets.
With the corners rounded with a 3/4" router bit, and painted with a primer coat, and a coat of Duratex, I only needed to do minor touch up on my pair of Keystones annually. I keep some touch up paint in a can with a built in brush so I can paint little scratches on the gig.
Thanks for the review!
Art
This Saturday I was running my two cabs 18sw115-8 loaded at a friends techno party.
The first 3 hours I ran the cabs with limiter at 78 volts, the magnets did not get very warm so the last two hours I increased the limiter threshold to around 95 volts. The system was running really hard a few dB's into limiter and I've examined the techno we play and the crestfactor is mostly around 3-4.5 with very heavy 40 hz sub.
The magnets were heating up considerably(I had a ir thermometer that showed around 35°C before the limiter change and around 40°C after so I don't trust it, I would say around 70-80°C). The SPL and SQ was out of this world!
No magic smoke came out. The driver would have seen around 1400 watts if the Zmin is 6.5 ohms
I wonder if the settings are safe for around 12H parties? If run like that for two hours(after 3 hours with more conservative settings) my guess is they reached their max temp at that time for the setting, making 12h+ safe aswell.
Hope it can help someone choosing limiter settings for their cabs!
The first 3 hours I ran the cabs with limiter at 78 volts, the magnets did not get very warm so the last two hours I increased the limiter threshold to around 95 volts. The system was running really hard a few dB's into limiter and I've examined the techno we play and the crestfactor is mostly around 3-4.5 with very heavy 40 hz sub.
The magnets were heating up considerably(I had a ir thermometer that showed around 35°C before the limiter change and around 40°C after so I don't trust it, I would say around 70-80°C). The SPL and SQ was out of this world!
No magic smoke came out. The driver would have seen around 1400 watts if the Zmin is 6.5 ohms
I wonder if the settings are safe for around 12H parties? If run like that for two hours(after 3 hours with more conservative settings) my guess is they reached their max temp at that time for the setting, making 12h+ safe aswell.
Hope it can help someone choosing limiter settings for their cabs!
The system did not sound distressed at all on these levels.
I'm however considering two more cabs if I can find the use for them, as my amp can push two 18sw 115 each channel the only cost would be two more cabinets. It's a good thing finding the limits and reach max potential of the system aswell as utilizing a good number of cabs
USRFobiwan,
Building more subs is always a good idea if one wants more SPL than can be safely achieved with whatever quantity you presently own..
The amplifiers I am presently using (Behringer NU4-6000) "breathe" well enough that they barely get warm running all four channels with two ohm loads driven with sine wave tones at 60 or 30 Hz. Others amps I have tested, such as the QSC PLX3602, had fan output that felt like a blow drier while putting out less power, and drawing far more AC mains power.
Lowering gain on amps does nothing other than increase signal to noise ratio slightly, and allow one to potentially clip drive units upstream of the amplifier gain control without achieving the amplifier's peak output potential.
Art
This is a thing I keep seeing, driving the amp into clipping or driving the processor into protection. So, I wanted to tell you my opinion and the way I use the limitters.
First, I have my own business here where I go in clubs and set the processors and position of equipment. From lots and lots of testing, I found out that those limitters are meant to keep things in check IF they need to. In reality, you have to avoid engaging them because they distort the sound.
The settings I use with Powersoft amps in my Xoc with BC18SW115 8 ohm are
Peak Voltage Limitter, hard brick wall limit at 145 V. Here I felt the driver was still in check on strong transients.
Long term power limitter 110 V Attack 400 ms, hold 2 s ,release 100 ms,
True power limit 900 Watt attack 2 sec, release 4 sec .
This way the sound is immensely powerful and dynamic, the drivers never got hotter than 65° C after 5 hours of dance music and the excursion is kept in check.
But, those limitter are rarely engaged. I keep the gain in the amp or processor as low as it is needed and I keep my eyes on the DJs and only when the go in Over on their mixers, the limitter engages on peaks. I've tested this in many systems with lots of types of music and it never ceases to amaze
Would be interesting to hear your system with these settings.
What is the difference between long term power limit and True power limiter? I don't have that sophisticated limiters in my drpa+.
With my settings I could not notice any considerable nasty distortion, I had maybe 2-3 dBs of limit which I think is okay. my guess is I extract a few more dbs from my drivers than you. I like to dial the settings so that no matter what the DJ does it will not break and sound good and when I have good power on tap I mostly succeed with that.
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As you probably know, Powersoft amps are NOT cheap. I wouldn't be surprised if they have enough smarts to measure the actual power being dissipated by the voice coil despite the complex impedance and hold a long-term average for the true power. I'm imagining long term power limit would then be a rolling average of voltage output with no concern for load impedance. Could be entirely wrong though, I haven't looked into it.
Limiting by peak voltage alone is a relatively ham-handed approach to driver protection because you're pretty much guaranteed to either sacrifice peak power headroom on transients or leave your drivers vulnerable to being cooked by low crest factor material.
I'm pretty envious of the ability to set 3 separate limiters in Powersoft amps. That definitely lets you have your cake and eat it too. Maximum performance with near-guaranteed protection.
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First, yes, Powersoft amps measures in real time the active power dissipated by the voice coil and cables. It can compensate for cable impedance and increase damping up to -2Ohms .
It has a voltage limitter brick wall type and an attack release voltage. There is a white paper with their true power setting and that setting measures the real power that is consumed by the driver and can adapt the output based on that, disregarding the effects of voice coil heating .
It makes graphs with power input power output, temperature, amps,volts,you name it. They are expensive, I can't afford them but I had my subs installed in a club for half a year on a K8 and also worked with K20, K10,X8 and X4. What I can tell you is that no other amps in this world is getting even close to be as well suited for pro audio market as them. Tried Linea research ( which are wonderful) Lab grupped, Crown Itech,Crest, a clone now,none of them comes close regarding usefulness.
Regarding those Xoc with that setting, I really like the kick I get with those settings and I can stay relaxed in the long run. If I forced it a bit to squeeze 2 dB more, I would probably get them but also I would get 10% more THD and less efficiency because of power compression . And probably no one would even care. I tried with no peak limitter but the driver flapped and on transients it gave a muddy bass.so this remained. Anyway, with those true power limiters, one can see in real time an 1,5seconds average power consumption from the driver on Armonia and even playing Outerdub - Sephiroth song or Wiz Khalifa-On my level and it never got higher than 800 Watts, so it probably never engaged in half a year.
It has a voltage limitter brick wall type and an attack release voltage. There is a white paper with their true power setting and that setting measures the real power that is consumed by the driver and can adapt the output based on that, disregarding the effects of voice coil heating .
It makes graphs with power input power output, temperature, amps,volts,you name it. They are expensive, I can't afford them but I had my subs installed in a club for half a year on a K8 and also worked with K20, K10,X8 and X4. What I can tell you is that no other amps in this world is getting even close to be as well suited for pro audio market as them. Tried Linea research ( which are wonderful) Lab grupped, Crown Itech,Crest, a clone now,none of them comes close regarding usefulness.
Regarding those Xoc with that setting, I really like the kick I get with those settings and I can stay relaxed in the long run. If I forced it a bit to squeeze 2 dB more, I would probably get them but also I would get 10% more THD and less efficiency because of power compression . And probably no one would even care. I tried with no peak limitter but the driver flapped and on transients it gave a muddy bass.so this remained. Anyway, with those true power limiters, one can see in real time an 1,5seconds average power consumption from the driver on Armonia and even playing Outerdub - Sephiroth song or Wiz Khalifa-On my level and it never got higher than 800 Watts, so it probably never engaged in half a year.
I'd agree that 2 should be plenty for near all practical uses, but could it perhaps make sense at least in theory to have a more generous peak limiter with a very fast attack time for the upper bandwidth of the box and a more restrictive limiter with a fractionally slower attack time for the lower bandwidth where excursion is increased? Both of them would still be quick limiters to prevent excursion mechanical damage.
radulescu wrote exactly the words i wanted to point out:
Some seems to think that having a limiter is the same as 'allowing' to be as loud as possible because having a limiter. However, engaging the limiter, results in over compression of sound > squashed wave-forms > more work for driver > death driver.
Limiter is to save your driver as last resort. Continuously hammering the limiter and/or allowing DJ's to push their master into the red is asking for trouble. Personally I would tell the DJ that red lights are for prostitutes and if he needs to continue playing in the red zone I would be happy to arrange a pimp for him.
Some seems to think that having a limiter is the same as 'allowing' to be as loud as possible because having a limiter. However, engaging the limiter, results in over compression of sound > squashed wave-forms > more work for driver > death driver.
Limiter is to save your driver as last resort. Continuously hammering the limiter and/or allowing DJ's to push their master into the red is asking for trouble. Personally I would tell the DJ that red lights are for prostitutes and if he needs to continue playing in the red zone I would be happy to arrange a pimp for him.
Yeah, but that's somewhat missing the point. YOU are functioning as the limiter now. And while obviously having some knowledgeable person overseeing the equipment at all times and doing the job of a limiter manually is preferable, it's not practical.
Some people are interested in idiot-proofing the subs so they are protected from any kind of possible input signal, from 40hz sinewaves to pink noise to massively clipped program material. And while it's easy to set a peak limiter so low that the amp simply can't pass enough power to cook the driver, you've just eliminated tons of headroom.
Hence why having 2 (or more) different limiters is appealing for people who have equipment being used in potentially abusive environments without wanted to constantly supervise it.
Some people are interested in idiot-proofing the subs so they are protected from any kind of possible input signal, from 40hz sinewaves to pink noise to massively clipped program material. And while it's easy to set a peak limiter so low that the amp simply can't pass enough power to cook the driver, you've just eliminated tons of headroom.
Hence why having 2 (or more) different limiters is appealing for people who have equipment being used in potentially abusive environments without wanted to constantly supervise it.
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Hilarious, i'll remember to use that one in future
Unfortunately, Most DJ's don't have a clue about sound or electronics etc etc. Some think they do, but if pressed they only show themselves up about how little they Actually know. Of course they don't like being shown up & embarrassed, especially in front of other people, but that's their fault for being ignorant !
I was doing an event several weeks ago, & was behind & off to the side of the DJ off & on throughout the night to on check things. Every now & then the red peak leds kept lighting up on the mixer channels. The first few times i waited to see what he did, which was nothing. The next time it happened i moved over & pointed to the flashing red led, & advised him to reduce the channel gain. And in future when doing pre fade monitoring on the headphones etc, to make sure the level stays under the red. As not not doing so makes me & him look bad, as it negatively affects the sound. He said, "yeah i know, i just forget " Not a professional attitude is it, & sadly very typical too ! You might think they would want everything to be as good as it could be, but most don't seem to care !
As an aside, nearly all the tunes he played were mp3 from a usb stick ! I asked him after the event had finished, if he ever played higher quality wav's or cd's ? He said " sometimes, but most of what he has is mp3" ..... This is also typical these days. More proof that most are clueless, and/or don't much care !
What's really interesting, is that when we do vinyl events with old school DJ's playing, for eg club classics from the late 70's & into the 80's, we get tons of compliments from the DJ's/customers/eventers about the sound quality. At events like the mp3 one, all we get is comments about how loud it was, meaning good to them !
djk,
Following your above "advice" leads to frustrated DJs cranking their desks until the clipping makes it seem louder, due to the ragged additional high frequency harmonic content. The additional HF content can in turn burn out HF drivers, unless they are protected by separate long-term limiter circuits, which is often not the case with top cabinets using passive crossovers.
I hear of this happening over and over, surprised individuals having to replace expensive diaphragms they thought were "protected" by compression.
Art
@Zero-D. Put in your contract that DJ's should provide at least 320kb mp3 format or preferable FLAC. No youtube downloaded mp3 content. Also put in that if Low quality sound source is used, you may/can shutdown,lower volume etc to protect your equipment.
Also let the stage-manager know you want to talk to DJ's before they going on stage or (if it is a good stage-manager) let the stage-manager point out the operation of the equipment.
IMHO you really want to help the DJ / act to let the crowd enjoy the best possible sound experience.
Also let the stage-manager know you want to talk to DJ's before they going on stage or (if it is a good stage-manager) let the stage-manager point out the operation of the equipment.
IMHO you really want to help the DJ / act to let the crowd enjoy the best possible sound experience.