How Much Power Do I Need?

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Albatross

DJ Extraordinaire
Sep 7, 2016
1,404
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#1
I wrote a proposal for a homecoming set up this fall, and they are booking me for it. But since I'm used to doing smaller wedding oriented set ups, I'm not sure exactly what will be needed for this. The set up will end up being as follows:

- 4 QSC 181 Subs
- 2 Pioneer XPRS-12 tops
- K12 (run as a monitor)
- 2 Chauvet Intimidator 355 IRCs
- 4 Chauvet H6 SlimPar LED Fixtures
- My controller and laptop, etc.

The lights are all LED and should be pretty efficient. But I'm worried the subs would be too much for a single circuit. If I split the subs 2 x 2 on different circuits, do you think they'll blow?

I don't really know how to do the math, but would like to be a little more scientific than "just bring a crapload of extension cords"
 

Cap Capello

Always @ Ur Service
Dec 14, 2006
3,498
2,874
115
74
Saratoga, NY
www.imadj.com
#2
A simple way to calculate:

Add the amps of all the gear (should be in the gear's specs) or add all the watts (should be in the gear's specs).

If amps, take the total and divide by 15. Consider each duplex outlet is capable of 15 amps.

If watts, take the total and divide by 110. There is your amperage. Consider each duplex outlet is capable of 15 amps.
 

rickryan.com

DJ Extraordinaire
Dec 9, 2009
14,711
10,728
115
54
Hendersonville, TN
www.RickRyan.com
#3
I'm no expert but those subs will likely spike 5-8 amps each. The tops/lights/controllers will likely (together) take 4 amps. Personally, I'd plan on distributing that load between 3-4 circuits. BTW, you didn't ask but is it possible to do 4 of those 355 movers? I currently run 2, 255s and anytime I can put 4 beams, it's a huge difference.
 
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Albatross

DJ Extraordinaire
Sep 7, 2016
1,404
3,186
115
#4
A simple way to calculate:

Add the amps of all the gear (should be in the gear's specs) or add all the watts (should be in the gear's specs).

If amps, take the total and divide by 15. Consider each duplex outlet is capable of 15 amps.

If watts, take the total and divide by 110. There is your amperage. Consider each duplex outlet is capable of 15 amps.
They advertise 1000 watts continuous per sub, which on that math would indicate a 9 amp draw, or 2000 peak at 18 amps? I'm not questioning whether the math works, but I think their advertised power is going to cause some confusion using that method.
 
Likes: ittigger

steve149

Urbane Legend
Sep 26, 2011
20,221
28,531
115
Prospect, CT
#6
It will be close .. my old system of Yorkville Unity tops over subs, with a small amount of additional gear used to pull around 8-9 amps running a decent (not pushed) output. 4 KW subs and a pair of tops will probably come in in the 15A+ range and that would be iffy for a 15A circuit (probably OK with 20A) .. but a lot depends on how hard you push them.

Biggest issue with splitting circuits is the possibility of ground loops and hum. You probably would be ideal with 2 or 3 circuits and splitting the subs, but you'd have to use either hum-x AC ground loop eliminators, or some ground lifts on the signal cables.
 

prodjay

DJ Extraordinaire
Dec 13, 2009
887
414
65
Bossier, Louisiana
#7
They advertise 1000 watts continuous per sub, which on that math would indicate a 9 amp draw, or 2000 peak at 18 amps? I'm not questioning whether the math works, but I think their advertised power is going to cause some confusion using that method.

Don't use the output watts to calculate the amount of electric you need.

Use the draw current on the manufacturer web site.

A 1000 watt output speaker does not use a 1000 watts of electric.
 

tunes4046

DJ Extraordinaire
Jul 24, 2008
3,903
5,582
115
48
Fennimore Wi
#9
I wrote a proposal for a homecoming set up this fall, and they are booking me for it. But since I'm used to doing smaller wedding oriented set ups, I'm not sure exactly what will be needed for this. The set up will end up being as follows:
I’ve run 6QSC 181and 2 153 tips on two circuits many times with no issues
- 4 QSC 181 Subs
- 2 Pioneer XPRS-12 tops
- K12 (run as a monitor)
- 2 Chauvet Intimidator 355 IRCs
- 4 Chauvet H6 SlimPar LED Fixtures
- My controller and laptop, etc.

The lights are all LED and should be pretty efficient. But I'm worried the subs would be too much for a single circuit. If I split the subs 2 x 2 on different circuits, do you think they'll blow?

I don't really know how to do the math, but would like to be a little more scientific than "just bring a crapload of extension cords"
 

djtaso

DJ Extraordinaire
Apr 4, 2017
1,496
3,274
115
31
NJ
www.djtaso.com
#10
I do shows of this magnitude all the time... not with 4 subs... but 4 or 6 moving heads that draw 300w each, plust all my sound. Mind you one of my subs draws 2500w compared to the 1000w of the 181. If this was my setup I'd use 3 circuits assuming they're 15 amps. 20 amps is never a guarantee, so I work as if I have 15 amps.

1 for the tops and the monitor.
1 circuit for 2 subs and one head, and another for the other 2 subs and the other head. The slimpars are no big deal and can be plugged in anywhere.
 

Albatross

DJ Extraordinaire
Sep 7, 2016
1,404
3,186
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#11
I do shows of this magnitude all the time... not with 4 subs... but 4 or 6 moving heads that draw 300w each, plust all my sound. Mind you one of my subs draws 2500w compared to the 1000w of the 181. If this was my setup I'd use 3 circuits assuming they're 15 amps. 20 amps is never a guarantee, so I work as if I have 15 amps.

1 for the tops and the monitor.
1 circuit for 2 subs and one head, and another for the other 2 subs and the other head. The slimpars are no big deal and can be plugged in anywhere.
That's kind of what I was thinking to be safe. And I'll, of course, sound check and push them through their paces to make sure it all works together. But 3 different circuits seems like it should be plenty. It's not a crazy rig.

(it will be my first set of movers though, which I finally bought :))
 

Handinon

DJ Extraordinaire
Oct 1, 2014
1,051
1,604
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#12
I think you'll be OK, but when you start drawing serious power, you have to make sure you are really using different circuits, not just different outlets.
Using three outlets that are all wired to the same 15A or 20A circuit breaker (in the circuit breaker box) buys you nothing.

Some commercial installations have stickers on the outlets indicating it's amperage, and what breaker it's connected to - look for different numbers/letters.
 
Last edited:
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steve149

Urbane Legend
Sep 26, 2011
20,221
28,531
115
Prospect, CT
#13
Using three outlets that are all wired to the same 15A or 20A circuit breaker (in the circuit breaker box) buys you nothing.
It does buy you less ground loop issues .. :)
 

djtaso

DJ Extraordinaire
Apr 4, 2017
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NJ
www.djtaso.com
#16
I find that as long as all your tops are on the same circuit... including monitors, you're never gonna really have a noticeable/audible issue. In the past when I put my monitor on a separate circuit, it would often get a hum... but since putting it on the same circuit as my mains, never had an issue. I never ever heard a hum coming out of my subs regardless of how they're wired.

Often people ask me why I never put my subs with my tops on the same circuit...simply because if my sub goes (which has a higher likelihood due to power draw), my mains still work along with my controller and laptop (assuming they were on separate circuits).
 

steve149

Urbane Legend
Sep 26, 2011
20,221
28,531
115
Prospect, CT
#17
I find that as long as all your tops are on the same circuit... including monitors, you're never gonna really have a noticeable/audible issue. In the past when I put my monitor on a separate circuit, it would often get a hum... but since putting it on the same circuit as my mains, never had an issue. I never ever heard a hum coming out of my subs regardless of how they're wired.

Often people ask me why I never put my subs with my tops on the same circuit...simply because if my sub goes (which has a higher likelihood due to power draw), my mains still work along with my controller and laptop (assuming they were on separate circuits).
The hum fundamental is 60Hz, so it can easily come out of a sub if a ground loop exists. If you can't keep all the speakers and sound playback gear on the same circuit (or breaker leg), best to use the prevention techniques.
 

djtaso

DJ Extraordinaire
Apr 4, 2017
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www.djtaso.com
#19
Subs on a separate circuit so long as it is 20 amps, everything else on another. You will be fine.
In theory... yes... but in reality, you just don't always have a 20a circuit... let alone one that is actually operating a full 120v. At 110v you're now at about 18amps, and if its a 15amp circuit now you're at 13amps... and with 4 subs at their max, that's an iffy issue, especially if other things happen to be tied to that circuit that you're not aware of. I may over do it, but spreading them over more circuits is a much safer approach... its just one extra wire run.
 

djcrazychris

DJ Extraordinaire
Jun 12, 2018
309
484
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#20
Biggest issue with splitting circuits is the possibility of ground loops and hum. You probably would be ideal with 2 or 3 circuits and splitting the subs, but you'd have to use either hum-x AC ground loop eliminators, or some ground lifts on the signal cables.
My Hum X has saved me on several occasions with its voodoo ...lol... i sing its praises!!

Not unless they somehow find more money... :)

I think good programming will get the most of out them, but it's unlikely that I go to 4 totems on this one.
the gobos are so huge on the 355s ...2 of them truly do fill up a room ...even big gymnasiums....like u said...creative programming...and keeping them working the dancefloor instead of getting lost in the rafters is key

cc