Help with limiter setting for Imp 1012 over QW218

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chileman
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Posts: 23
Joined: Thu Nov 25, 2010 9:29 am
Location: Little Rock, AR

Help with limiter setting for Imp 1012 over QW218

Post by chileman » Thu Oct 27, 2011 1:25 pm

Hey guys, I'm starting to understand a lot about tri-amping and setting everything correctly set in the VSX25, but the math involved in setting limiters to keep the amp to a certain wattage is a little over my head.

When I purchased my amps I was shooting for my QW2 over QW218 rig. Now I have a gig where I'd like to run my 1012's triamped with the QW218's, but I'm a little worried since some of my amps are just a little too big for the 1012's. Now I am OK with running this rig @ program power, I"m very careful and usually have a brick wall limiter set right before clipping. So let me lay out the specs and maybe you guys can help me through the math of limiting my amps so I don't blow up my rig this weekend.

Impulse 1012
1000w Program 12"
100w Program Horn

How are how I'm running the amps
Low Amp - Peavey CS4080 - 2040 @ 4ohm - 1 218 per side (I know I'm good on this amp)
Mid Amp - Crest CC5500 - 1150 @ 8ohm - Set at 40x - 2.18v input sensitivity
High Amp - Crest CC1800 - 400 @ 8ohm - Set at 40x - 1.32v input sensitivity

So it looks like I need to limit the CC5500 to 1000w.

Now on the horn, I know when I run my QW2's I need to shoot for peak power due to the CD Horn EQ, does that still ring true on the RX22's in the Impulse cabs? Can I shoot for the 200w peak rating? So can I limit the CC1800 at 200w and be ok? And can someone (Steve, Marty, anyone) help me with the math to figure where to limit the amps? I know the best way would be to get slightly smaller amps that more closely match these cabs, but I'm hoping that with some tweaking the same amp rack can power either set of tops.

Btw, The reason I'm using the Impulse cabs is because it's a DJ halloween party and everyone will be right up on the speakers and I just don't think the QW2's sound good til about 20' out where the mids and highs have proper time to mix, plus it's not a huge party, but they want a lot of BOOM BOOM POW.....

As for X-over and EQ settings, I opened the QW2+QW218 preset and copied all the settings for the QW 218, and then opened the SP2 over SP218 preset and copied the SP2 setting and have created a preset that combines these two. I think it will give me a good starting point and I can use my ears and EQ from there.

Thanks for the help guys! I've learned a lot from this forum and over time hope I can contribute my new knowledge to new users on here and in the retail shop where I work.

Rock on
Chris
Chris Hileman
EventProDJ.com - DJ, Live Sound & Lighting Service - Duluth, MN / Superior, WI

Big Rig- Presonus 16.4.2, 2x QW2F, 2x QW218, VSX26
Small Rig- A&H ZED14, 2x Impulse 1012, 2x HPR181i, VSX26
Amps-Crest CC5500, CC4000, CC1800, CS4080hz

tmbrandis
Member
Posts: 394
Joined: Sat Jan 09, 2010 8:09 pm

Re: Help with limiter setting for Imp 1012 over QW218

Post by tmbrandis » Thu Oct 27, 2011 1:37 pm

Need to know what version of the 1012 you have. They made both an 8 ohm and a 4 ohm version. This makes a difference when calculating the limiters.
Tom in Baltimore

8 VR218's, 6 QW218's, 6 QW2F's, 2 QW3's, 4 QW1's, 4 QW215's, 18 VR112's, 16 QWmonitors.
14 GPS3500's, 6 CS4080Hz's, 12 CS4000's, 6 CS3000's, 4 GPS2600's, 4 GPS1500's.

tmbrandis
Member
Posts: 394
Joined: Sat Jan 09, 2010 8:09 pm

Re: Help with limiter setting for Imp 1012 over QW218

Post by tmbrandis » Thu Oct 27, 2011 1:56 pm

If they're the 8 ohm version, I would set the limiter for the 12's at 6.193366 (round down to 6) and for the highs I would set the limiter at 0. Now, that speaker has a CD horn and you need to give it almost what it can handle peak power, which is 240w. If you're someone in the know and trust that you will not let the smoke out of it, set the limiter to 3. This is what the limiter setting would be for 240w from your amp, 0 would be for 120 watts, which will give you some added extra protection if you're a novice.
Tom in Baltimore

8 VR218's, 6 QW218's, 6 QW2F's, 2 QW3's, 4 QW1's, 4 QW215's, 18 VR112's, 16 QWmonitors.
14 GPS3500's, 6 CS4080Hz's, 12 CS4000's, 6 CS3000's, 4 GPS2600's, 4 GPS1500's.

chileman
Member
Posts: 23
Joined: Thu Nov 25, 2010 9:29 am
Location: Little Rock, AR

Re: Help with limiter setting for Imp 1012 over QW218

Post by chileman » Thu Oct 27, 2011 4:23 pm

They are the current model 1000w program 8ohm cabs. Thanks for the help guys. I'll add that to my program tonight and load it in the VSX, I'm pretty confident with not clipping out anything so I am OK living dangerously, I've been pumping 1150w into those cabs full range for 2 years with no issues so I think I'll be ok when going with this setup. I won't be able to test out the rig until right before the gig so that's why I wanted to be as prepared as possible in the DSP. I'll crank it up Saturday and shoot some pictures and report back! Thanks for the help! You guys are the best!

Rock on!
Chris
Chris Hileman
EventProDJ.com - DJ, Live Sound & Lighting Service - Duluth, MN / Superior, WI

Big Rig- Presonus 16.4.2, 2x QW2F, 2x QW218, VSX26
Small Rig- A&H ZED14, 2x Impulse 1012, 2x HPR181i, VSX26
Amps-Crest CC5500, CC4000, CC1800, CS4080hz

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SemperFiSound
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Joined: Sun Oct 12, 2008 8:39 pm
Location: NW Florida - Pensacola area

Re: Help with limiter setting for Imp 1012 over QW218

Post by SemperFiSound » Thu Oct 27, 2011 7:31 pm

Looks like our esteemed colleague (and expert Excel spreadsheet programmer) in Baltimore has you covered.

Best of luck!
Steve
SemperFi Sound; the website
SemperFi Sound On FaceBook
"The Art of War teaches us to rely, not upon the calculated likelihood of
the enemy's coming or not, but on our own readiness to receive him... no
matter what he does." Sun Tzu

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