Power generators - will 49db Kill me?

[Robert Bridgens]

Hi guys - im doing an outdoor shoot that requires additional lighting. It is taking place in a field which unfortunately means no mains power.

All of my lights are 240v mains powered so i was going to hire a generator to run them. The quietest generator i can find is rated at 49db @7m with the cheaper ones being 70db @7m. Now i can probably more than double that distance with a few extension leads daisy chained together but will it be possible to remove that motor "throb" from my final recordings?

How would i go about doing that?

My only audio software is Adobe Soundbooth.

(i know the smart thing would be to hire LED panels but the generator only costs me £80 for teh week whereas i can only hire one light for that.)

Many thanks for your help. Im sorry for posting so many noob questions but i really have no clue.

[Chris Soucy]

First, a question or two.

What's the total power draw of all the mains equipment you intend to use on the shoot?

Do you have the ubiquitous white van & man to hand for the shoot?

Can you lay hands on an old mattress or five for the event?

Just as a pointer, assuming your generator can produce 13 amps (3120 watts @ 240 volts) and your kit uses same, using 4 mm cross section conductor extension cords will allow a total cable run of 67 metres whilst keeping inside IEEE regs (max. 4% voltage drop).

Park the generator in the van on a mattress with the (open) doors facing away from the shoot, another mattress behind it, one on either side, one over it if it can be done, and it's highly unlikely you'll hear anything of it whatsoever.

Drop your power requirements in half and you can double the cable run distance.


CS

[Giroud Francois]

25db is the limit to hear noise. meaning a video projector that runs at that level, you will hardly hear it.
on the other side, in exterior, you can expect that background noise is way higher than 25db.
in military situation, generator are set in a hole in the ground, with camouflage cover, so you can also hardly hear it.
if you do not want to dig a hole, you can build a box with some heavy compact wood and a layer of foam inside. the box will be opened on a side and have no floor, so vibration are not transmitted to the wall..

[Robert Bridgens]

Great ideas guys - i can do either the van or the hole and hopefully put them on the other side of a little bit of woodland.

Chris - The generator i was going to hire is Show Hire The Power To Communicate - Our Services - Event Equipment Hire - Generator & Power Services Hire - Honda EU26i

This is rated at 2400 w at 16amps - i take it I should be able to run 2x mains powered bulbs from this ? (the bulbs say 105w 240/50hz)

What distance can i run a generatror like this through extension cabling?

thanks again for your help!

[Chris Soucy]

Assuming those bulb figures are correct @ 2 X 105 Watts = 210 Watts maximum power draw, probably a couple of miles using 4 mm cross section cable.

Using standard 2.5 mm cross section (from memory) extenders, still a couple of hundred metres.

As the generator is using even less than 1/10 th of it's maximum power O/P (it can be either 2400 watts = 10 amps or 16 amps X 240 volts = 3840 watts, but not both) it will most probably hardly be audible from 20 metres, as it's doing so little work, especially if it's a Honda.

Very neat looking unit BTW, seems like an exceptopnally good deal.

Can't find anything on the site about extension cable hire, tho' I would have thought that an obvious item to have available.

Might be worth giving them a ring, the "real deal" will be far less hassle than you having to jury rig enough el cheapo cables.

Don't forget you'll also need at least one 4 way to get to both lights and anything else you're powering from the gen set.


CS

[Sara Thompson]

I am also planning a shooting and therefore I need a generator. Unfortunately my old one broke and due to this I think I will use a generator rental. I cannot afford to buy one and I think renting one is the best option. Has anyone of you already did this? I am also not quite sure which specs the generator should have but when I figured it out I will contact the company.

[Greg Miller]

Sara,

Your first step is to make a comprehensive list of everything you might possibly want to run from the generator. List the power requirements of each piece of equipment.

If they're all lights, just add up the wattage. Your generator needs to produce at least that amount of wattage on a continuous basis. To be reasonably safe, the generator should produce at least 25% more than that as a continuous rating.

Now, if any of the equipment will be electronics (cameras, audio gear, computers) then you also need to be aware of the generator's output waveform and regulation, to avoid any potential malfunction or even damage to that sort of gear.

And finally, you want the lowest possible noise output, to save yourself headaches with your sound track later on.

[Greg Bellotte]

I am using a Honda 2000i this week at the Tour Championship. it's rated for 53db noise. We moved it 100 feet away anyway, it sits on the ground without any soundproofing. You cannot hear it at our interview position next to the 18th green. NBC and Golf Channel also use the Honda 3000is to power their equipment at every green on the golf course, it is part of their setup every week. You don't hear the generators in any of their golf EFX mics (well most of the time you don't) and they are quiet enough for the golfers and the PGA not to complain.