Mega Flash strobe and power useage

A 15amp circuit's limit is 1800watts. I have two powered subs with a combined continuous power rating of 1400watts. An additional 750watts would be more than the circuit can handle but it's not a continuos 750watts since it's a stobe. Does it make a difference since it's a strobe or should I find a fourth circuit to make room for the additional 750watts?

I haven't measured the power draw on my strobe but I will comment on amplifiers because you mentioned your 1800 watt continuosu rated sub. When amplifiers are rated it is based on a steady state sine wave. Music is very differnt with peaks much higher than the average. I have done gigs with a 2,000 watt amp and a 1,000 watt amp running flat out with the peak/clip lights flashing like crazay and the actual measured average power draw was 750 watts. The peaks cause the clipping and limit the output, the average for the music is much lower. I would be surprised if your subs ever drew more than about 500 watts average. I have a gig tomorrow where I will be using my strobe and I will try to remeber to measure the actual draw while it is running.

I use a pair of these strobes at some of my gigs and have measured their power consumption. According to my 'Kill-a-watt P3' meter, a single mega strobe at full intensity/speed will draw a continuous current of about 6A at 120v Interestingly, a pair on the same circuit in sync will draw just under 7A, out of sync about 9A. This surprised me so if you dig around this forum you will find a thread I started regarding this situation.

As mentioned, sound gear behaves differently from light gear when it comes to power rating. Lighting tends to be far easier to predict. Please keep in mind that you shouldn't put your light and sound gear on the same circuit.

Thanks for the replies. Sounds like I may have to pay more attention to the strobe's power usage than the speakers.

I used a Kilowatt meter to measure my strobe and it drew 99 watts. 6 amps at 120 volts is 720 watts, that sounds really high to me. I will have to measure mine again and see what the amps I see are. My flash was falshing at a high repition rate when I measured it.

You need to keep your lights and sound on sepparate circuits as much as possible. Especially since LED's will induct noise into the system, you don't want that.

And to Scotten:
If you're running flat out(balls to the wall, or even WFO) and you're showing peak/clip lights, dude, you're underpowered and you're gonna damage something soon. You need to figure out if it's more speakers(and amps), signal processing and/or bigger amps to get the job done. Then again, mabye you need to turn your amps UP and your desk output DOWN. Red lights in the meters and clipping are BAD!!

But yes, sound has different draws than lighting. My amps for my active driven gear want a 20-amp circuit each. I can safely run 2 of them off a 15-amp circuit and cover 1000 people and I have no worries and more than ample SPL and covery with plenty of left-over headroom.

As far as strobe usage, it's more important what continuous draw is. But chances are if they are sayinf 750 watts, they are saying "dude, you need to have 750 watts available on that circuit if you want to run this strobe". Also, I find strobes put a lot of noise on the audio circuits, so don't share circuits.

When I plugged my keyboards and lights into the same circut, one of my keyboards went crazy.

I then got a FURMAN M-8x2 Merit X Series M-8x2 Power Conditioner into which I plug all my lights. I plug the conditioner into any of the circuits available and have had no problems since.

In other words, in my experience isolating the light's power from the other equipment's power is the key.

BTW: Since all the circuits from any one circuit breaker box connect all of the circuits to the others (on the other side of the breakers, which I don't think are conditioners), I've never understood how using different circuits made any difference anyway.

quote:

Originally posted by Chris Pickett:
You need to keep your lights and sound on sepparate circuits as much as possible. Especially since LED's will induct noise into the system, you don't want that.

I was going to ask about this but kind of forgot. Now I know. Thanks

quote:

And to Scotten:
If you're running flat out(balls to the wall, or even WFO) and you're showing peak/clip lights, dude, you're underpowered and you're gonna damage something soon. You need to figure out if it's more speakers(and amps), signal processing and/or bigger amps to get the job done. Then again, mabye you need to turn your amps UP and your desk output DOWN. Red lights in the meters and clipping are BAD!!

Just as you're saying, I was thinking his gain structure wasn't set up properly.

quote:

As far as strobe usage, it's more important what continuous draw is. But chances are if they are sayinf 750 watts, they are saying "dude, you need to have 750 watts available on that circuit if you want to run this strobe". Also, I find strobes put a lot of noise on the audio circuits, so don't share circuits.

I may not need the strobe after all because I'm happy with the strobe capability of my Flat Par Tri7's. It's not the same but they get the job done.

I find that DJ's fail to understand things like gain structure. Just smack the red all night and you're fine.... At lesat that's what most seem to do. And they wonder why they go through amps and speakers, and wonder why they only use the cheap stuff. Granted, most mastering processes are becoming highly compressed and slamming as near to digital zero as possible, and hence sucking out any dynamic range out of the recordings, but then a DJ pushing things to the max all night long isn't going to help either.

I've grown tired of educating DJ's that don't want to learn. I say "find, you wanna blow your stuff up? Have fun..."

With only a couple of exceptions, I insert a compressor into all channels that I run a DJ to into my sound console. I've got more than sufficient power in my mains to more than handle the event in question. This way if they feel they want to get abusive, there's a brick wall limiter in place at +3, and they ain't gonna get no louder!


As far as saying stuff like "I may not need the strobe because I'm happy wiht the strobe capabilities of...", I think that's going to be a very true statement for a good many people. I was debating getting a strobe but I I found I was very happy with the strobe capability in my LED cans and wash fixtures, so "why bother". For the shows I'm doing, it's more critical to strobe on the stage. Now, if I wanted to send a strobe out to the audience(which I'm never inclined to do), then a dedicated strobe fixture would be ideal. Of course, this is because of how I have my lights aimed.

SO many LED lights support strobing. It's definately saved me from having to buy a dedicated strobe. Plus, get this(I bet you already have): you can strobe in any color you want! You won't get that with those other strobes. Not only that, but the color mixing/blending, low draw and other features crammed in, it really makes up for the prices you pay for the good LED cans. Multiple functions from 1 fixture.

I setup a scene where all my led par cans, megabars, uplighting strobe together at the same rate and cycle through the same colors. It's a great way to end a fast rock tune.

Sure would be.

What I like about my LED lights that strobe is if I go into a strobe scene in MyDMX and set them all to the same value, they all strobe together. It's nice to have that sort of consistency in a product line, even though some were made more than 3 years apart from others!

I set my strobe scenes to only strobe for a few seconds at most and then go into a solid color wash. So, if I strobe in red, it will strobe for like 2 seconds and then go in a red wash scene.

In reply to the gain sturture comment. My gain structure is set up correctly, my amps at that time were undersized so I was pushing them hard. The warning clipping lights actually mean the amps are limiting gain to prevent clipping so they weren't going to clip and blow out my tweeters. Since then I have upsized my amps. The point I was making is that under real world conditions an 1,800 watt sub will likely draw a lot less than 1,800 watts on actual music.

Another follow on comment. I sometimes have lights and sound on the same generator (working out in a field). I run a furman power conditioner for the aduio equipment and haven't had any problems. So with the proper filter you can combine.

Your amp isn't limiting gain, the input circuit is being over-loaded and is hence limiting INPUT to try to prevent catastrophic failure to your speaker(which may have been too late).

This means you're going into the red on your desk, and hence sending peaking signal to your amp, which is clipping on that, which is sending lovely transients to your speakers.

It's always better to OVER DRIVE than UNDER DRIVE a speaker. Having power in reserve means that you theoretically shouldn't have those issues.

If an amp wants 1800 watts, unless you know what conditions it will require that(bridged WFO), chances are draw will be closer to around 20% average.

As far as generators:
I don't like working off generators, at least not your typical Home Depot/Sears/Lowes/Briggs&Stratton/Hondas. These aren't junk generators, but they more intended as stop-gaps or for work site power tools.

Even front ending the generator with a Furman helps, but it won't clean up the big swing in the frequency. I recommend using a UPS first, just to smooth it out, then a unit like the Furman AC-20 to rectify the power and provide much better protection and clean-up.

You're still wrong though about combining. You need to be on different circuits. Just because you don't hear it doesn't mean it isn't happening. I put audio on one Furman and lights on another Furman, but both pulled from the same circuit. There was still noise on the audio side of the line when the LED's were on.

I was using PL-Plus units.

Hi Chris

I wasn't overloading my deck and the speakers were not damaged at all. Yes the amp was turning down the input on peaks but I was trying to maximize the average output with the amps I had at the time. I agree "too much power" is better than too little and soon after the gig I significantly upsized the amps but sometimes you have to work with what you have. In 30 years of doing sound for bands and DJing I have never blown up a speaker and the only amp failures i have had were two that came from a bad batch.

I also agree that seperateing is good but you don't always have the option. I have combined when I had too and not had a problem using the Furman. I have a very well trained ear. I have studio engineers tell me all the time when I am doing live sound that they can't believe how good it sounds and I haven't heard anything come through. Once agian, it is better not to combine but it can work if necessary.

In terms of generators, I bought one at Home Depot and measured 180 volts coming out of it so I would never run my audio gear off of one of those. I got rid of the Home Depot generator and bought a couple of Honda EU series generators. They are so quiet you can hold a quiet conversation right next to them and they make very clean quality power. i have run computers, audio gear, lighting gear, vidoe gear off of them and never had a problem. I do some gigs where there is no power so generators are a must and the EUs are great.