DL1608 with QSC K12 and KSUB

[RoadRanger]

The ART312A's are significantly less powerful than the K12 at 400Watts RMS (against 1000) and the max SPL is 4dB's down, not huge but definitely significant. They are, as you say, a lot cheaper though. OTOH the Alto Truesonic TS112A is half the price again and, on paper at least, a match for the RCF's.

QSC rate their stuff in bullshit watts - no way can their HF driver ever survive 500w. And their LF driver can take maybe 200 continuous - about the same as the more efficient LF driver in the RCF's. The RCF 312s are as loud or louder and sound better when "pushed". The Alto's you mentioned aren't anywhere near the same in output.

[Jerrylee]

RR all the major companies are rating their class d amps the same way, qsc, ev, jbl all list a thousand watts.  And your precious Mackie list that same amp as 2000 watts. Whose more full of shit? I agree with the rating being total bs. But class d amps are rated differently. So are class a and class h.

[RoadRanger]

Those speakers don't just have amps in them - they also have processing that includes limiting for each driver. Those 500w amps in the K's are probably limited to no more than 100w peak into the HF driver which is about what the RCF peaks at. The drivers in the K's NEVER see all 1000w and probably never see more than what the drivers in the RCF see. It's all bullshit marketing - kinda like the new Mackie speakers with their 2000 w . Do you really think the Mackies are twice as loud as the K's ?

[sam.spoons]

I wasn't able to do a side by side comparison of the K12's and RCF's but was very impressed by the sound of the K12's. The Alto's have 400 watts RMS similar to the Art's. Again in isolation they sound very good for the money but not a patch on the K12's. You are right RR (of course) we always used to rate the HF drivers in passives at 10% of the nominal speaker handling (I.e. the LF driver and crossover) obviously a HF driver in a 1000 watt speaker is not going to handle (or need) 500 watts RMS, I have no idea why QSC and others use such a wildly overrated amp for the HF's. In my experience you usually get what you pay for, the 500 watt (ish) 12+horn cabs which seem to get the best comments on the forums all cost around £750-800 (QSC K12, Yamaha DXR and JBL PRX, there are a couple of threads on the Sound On Sound forums about this).

[RoadRanger]

The main reason these new class "D" speakers have equal amps on the LF and HF drivers is that it is cheaper to make a stereo class "D" amp than two differently rated mono ones. The amp itself is just as cheap to make at 500w/ch as at 250w/ch since the limiters keep the power supply size the same anyways. It's all bragging rights and marketing BS. For those who think they haven't heard an RCF speaker before the original Mackie SRM450 speakers that were WAY better than the Chinese copies they started shipping after Greg sold the company were private labeled RCF's. As I said I've done 1000 people outdoors with my pair of $400 310A's - try that with them K12's LOL.

[Harpman]

There are many "aux driven sub" fanatics out there but generally using a properly matched set of crossovers is easier and sounds better unless you really know what you're doing. I only desire aux driven subs outdoors where you want to keep wind rumble out of the subs. Indoors I prefer using crossover(s) but as I said have been using aux driven lately to avoid carrying any outboard rack gear. OTOH if you are into the "hot subs" sound (running the subs significantly hotter than the tops) aux driven works better for that. But I prefer to not sound like a bad DJ .

There are many "aux driven sub" fanatics out there but generally using a properly matched set of crossovers is easier and sounds better unless you really know what you're doing. I only desire aux driven subs outdoors where you want to keep wind rumble out of the subs. Indoors I prefer using crossover(s) but as I said have been using aux driven lately to avoid carrying any outboard rack gear. OTOH if you are into the "hot subs" sound (running the subs significantly hotter than the tops) aux driven works better for that. But I prefer to not sound like a bad DJ .

RR, interesting enough the gig yesterday was an outdoor gig at a local winery.  We had a lots of wind forcing us to use mic wind screens on the vocal mics as well as the Djembe mic. I didn't experience any wind rumble in the KSub but did in the K12's. Many DJ's are very sub oriented and like lots of sub.I'm still on the fence on which method I want to adopt. In one of your earlier posts you mentioned setting AUX 6 at unitiy gain for Bass, Kick, Tom.  I'm assuming your running post fader on AUX 6 as well, so when I adjust lets say the Bass in the house, it's also adjusting the sub proportionally.  Correct?  Also, when I'm using the AUX 6 method, I boost the frequencies between 60 and 800Hz and cut frequencies between 1K and 20K (pseudo crossover - See attached screen shot). So based on that scenerio, how would you handle the PEQ channel for the Bass? The presets for a Bass are based on a the premise that you are using "Full Range" or a crossover (attached photo).  So would you cut low frequencies on the bass PEQ to eliminate the low frequencies in the mains and forcing them to the sub?

Just seems to be a lot more work using the AUX 6 method. I totally understand not having to lug external crossovers to a gig and using the AUX 6 method in lieu of a crossover (pseudo). But since I have the matched KSub, K12's with built in crossovers, its nothing extra I need to lug with me.  Also, if I don't bring a sub and decide to run "Full Range" thru the K12's, I can just set the K12's to NORMAL and leave the PEQ on the bass channel alone.  Your thoughts?  Sorry, couldn't attach photos

[RoadRanger]

Yah. aux6 is set post fader. If you cut the lows on the bass in the PEQ it will also cut the lows in aux6 as all auxes are post-EQ. If I was you I'd not bother with an aux driven sub as the "K" speakers have decent crossovers built-in.

[Harpman]

Yah. aux6 is set post fader. If you cut the lows on the bass in the PEQ it will also cut the lows in aux6 as all auxes are post-EQ. If I was you I'd not bother with an aux driven sub as the "K" speakers have decent crossovers built-in.

Thanks for the feedback

[LeeSteel]

There are many "aux driven sub" fanatics out there but generally using a properly matched set of crossovers is easier and sounds better unless you really know what you're doing. I only desire aux driven subs outdoors where you want to keep wind rumble out of the subs. Indoors I prefer using crossover(s) but as I said have been using aux driven lately to avoid carrying any outboard rack gear. OTOH if you are into the "hot subs" sound (running the subs significantly hotter than the tops) aux driven works better for that. But I prefer to not sound like a bad DJ .

The main benefit I find from running Aux driven subs is that you have separate volume control for the subs right at the board instead of having to turn up power amps or tweaking crossovers.

[Greg C.]

I have no idea why QSC and others use such a wildly overrated amp for the HF's.

Though the actual amp connected to the horn may actually be capable of producing that power, chances are it's being throttled back with limiters. The other thing is that many compression drivers can actually handle a lot more peak power for short transients than their rms or program rating would suggest. But in days before DSP for loudspeaker control, there was no way to use an amp that big without the high risk of blowing things. Today you can do it if the DSP based limiters are setup to tightly control rms and peak amp output. This has the benefit of getting maximum dynamics out of the horn while still keeping things from blowing up. I can't say one way or the other if QSC is doing this with their K boxes, I have no idea. But I know with high end PA systems this is the case. It's one reason why modern higher end systems sound so explosive compared to days gone by - they reproduce the transients with a lot more power than before though the driver components don't handle much more power than they used to.

[CyberHippy]

I have no idea why QSC and others use such a wildly overrated amp for the HF's.

Though the actual amp connected to the horn may actually be capable of producing that power, chances are it's being throttled back with limiters. ...

No, it's being "throttled back" with a controller that keeps the highs in line with the overall volume. The limiters in the controller only kick in when the overall volume level hits the threshold set in the controller.

If they were "throttling back" the highs using limiters the sound would be horrible, very bright at lower levels. The K-series sounds good at just about all levels because of the controllers.

I set up a club with a pair of K12's and a KSUB just over three years ago, they've been running constantly with background music during open hours and live bands at shows 6-7 days a week. One amp had a fault in the first year, QSC replaced it and they've been working perfectly since.

However they go about stating their wattage vs. reality is kind of unimportant to me - they sound great, are work-horses, are affordable for the quality, and they have a 6-year factory warranty.

Wattage is much more important when I'm dealing with passive speakers & crossovers - for powered digital speakers I'm happy to ignore ratings & go with what is appropriate for the situation.

[Greg C.]

If they were "throttling back" the highs using limiters the sound would be horrible, very bright at lower levels. The K-series sounds good at just about all levels because of the controllers.

This is only true of peak or voltage limiters that actually clip the waveform. I'm specifically referring to 2-stage limiting which incorporates both rms and peak limiting. rms limiting is a slow attack/slow release limiter that works to limit average power to the driver and they do not have the artifacts you're talking about. If you're using an oversized amp for a driver that can easily exceed the rms power handling of a driver, you must incorporate rms limiting as part of the protection scheme or you will surely fry the driver as soon as the system is pushed. If QSC is using an amp with that high of an output rating on a 1" compression driver, they are surely incorporating that 2-stage limiting or the driver would be toast in short order.

[jlb]

Two stage limiting was the main reason we went with Crown ITechs. It's nice to be able to control the amount of voltage going to your drivers. We biamp our tops with these powerful beasts. The HF drivers would surely melt down without proper RMS limiting. We have them set at 16v(35watts) with a 2 second attack and 4 second release. The amps are capable of 1500w RMS @ 8ohms.

[musicman7722]

Low end seems lost.
I use K12's for my tops and 1 Ksub for the bottom.  I feel like my low end is not really there.  Is this becasue my tops have technically twice the wattage aofmy bottom.  If so of course I could buy another sub (hmm where is that $1300 I set down a minute ago?) or do I turn the gain down on my tops?  Or neither.

Thanks

Chris

[LeeSteel]

I opt to cut the power on the tops and run the subs wide open.