Subject:OT: keeping mics working at -40 degrees

Posted by: pb

Date:1/21/2004 3:19:02 AM

Hi,

This message is for those who have done a lot of arctic shooting.

I have a Sony C74 with the stock windscreen enclosure and a Sennheiser shotgun, K3U cartridge. Yesterday the Sony C74 (not in its enclosure) froze up in about ten minutes and the Sony cheapo stock mic that comes with the DXC D50/D30 and DSR 370/570 froze up so bad it is no longer usuable and is scrap. What do you guys do to get audio in extreme cold? Would stuffing heatpacks in the C74 enclosure help? Also, does anyone still manufacture that brown mic cable that retains its flexibility in these temperatures? We need this job desperately and have to go back Thursday so I sure would appreciate some advice from those with the requisite experience. This never happens with the Sony shotgun I have on my BetaSX camcorder but there is no time to get one in from the Sony WIllowdale warehouse.

thanks in advance!

Peter Burn

Subject:RE: OT: keeping mics working at -40 degrees

Reply by: Rednroll

Date:1/21/2004 9:21:44 AM

Peter,
Sorry I can't make any suggestions for you, but if it makes you feel any better I know what you're going through and feel your pain. Lexus has a cold test center hidden away in Timmins Ontario. I had to go there last winter to make sure the Mark Levinson audio system in the RX330 vehicle was functioning properly at those -40C temperatures. We had to be up and working at 5am, anytime past 9am they considered too warm to evaluate. I think it got up to -25C at around 9am. Our audio system was just fine, but damn if my oscilliscope wasn't acting crazy. The screen was flickering with a dim look. The power chord was frozen straight. The engineers told me to make sure all my wires where run straight, because they would freeze that way. They where right, I never new wires could freeze like that. Hopefully, that was a once in a lifetime experience for me, that's never a trip I will volunteer for. I can't recall, hearing anything worth recording at those cold temperatures, except the bitter cold wind blowing. I think my ears weren't functioning at those temperatures either.

I can talk to some of the engineers at AKG and see if they have anything that's been tested to work at those temperatures.

Subject:RE: OT: keeping mics working at -40 degrees

Reply by: pb

Date:1/21/2004 9:45:47 PM

Thanks, that is great. AN engineer at Sony told me today the problem is due to the elecret(?0 ecm 672 hainv a more modern (hello?) design than the C74, that latter being a consenser with diaphragm and transistors that were never meant to wok in sub zero weather. Looking forward to your response.

Peter

Subject:RE: OT: keeping mics working at -40 degrees

Reply by: Rednroll

Date:1/22/2004 8:47:17 AM

yeah, That reminds me. The mic you're looking for, does it have to be a condenser type? I'm thinking dynamic mics will be more forgiving at those temperatures, just due to the lack of electrical components. I haven't had a chance to ask yet, I've been more out of the office than in for the past 3 weeks. I know we have AKG mics that have been tested at those temperatures that we use for automotive OEM applications in Mercedes and BMW. That doesn't help you out much because they can't be purchased at a local retail store. I should be able to let you know early next week, getting on a plane in the next 2 hours headed for Indianapolis.

Subject:RE: OT: keeping mics working at -40 degrees

Reply by: Chienworks

Date:1/22/2004 9:01:18 AM

Just a curious thought here, but i'm thinking back to some of the low temperature testing we've done here at work. Those elements that had been through high humidity testing generally fail the low temperature testing much more often than those that haven't. This kind of makes sense since any moisture inside the mic will freeze. I wonder if packing your mics in sealed boxes with silica gel before heading into a cold environment would help? Of course, it's too late for this to help you in this case, but it might be a good thought for future reference.

Subject:RE: cold mics and new field mixer...

Reply by: pb

Date:1/23/2004 9:36:52 PM

Thanks for all the input, guys. Chienworks, the day of the disaster the humidity was about 85%, which coupled with the very low temperature sure does validate your observation. I went digging in the garage and found some 1985 vintage brown cable and made it into one short cord to come out of the Portabrace arctic camera coat and the rest for the boom operator. We put an old Sony F-115 (gee I am the King Packrat, eh?) on the boom and made it through the shoot. Sound from the ancient omni is not the best but good enough. I have ordered a Sony ECM 672 and a pelican case to hold all the audio gear and silica packs.

Can you suggest an affordable alternative to the Shure FP 42? I need a battery powered mixer for the boom operator that has at least two mic in/phantom power, pan pots, LED or VU and two mic outs. I am using a Shure M67 powerd by the M68(?) but it is a quarter century old and shows its age. The new version of the M67 has 6mic in and one mic out, runs on batteries and is a decent price in Canadian dollars BUT I want the sound guy to ride both channels, not just the one.

thanks,

Peter

Subject:RE: cold mics and new field mixer...

Reply by: rraud

Date:1/24/2004 6:30:55 PM

The above from Chien and Red is good advise.
Mixer-wise, I suggest a used FP-32, there's got to be alot of them out there... old but good... e-bay maybe. 3-Ch in / 2 out good mic-pres.
I do much field production work, and have had problems with humitity.. usually warm however. (lucky me) ..
I have worked in extream cold conditions, and to keep my mics warm, have gaffer taped hand warmer packets to the shock mount base, inside the zepplin, (and inside my gloves)... this produced enough heat to keep the mics from frezzing, at least there were no problems with my 416,... but this was low humitiy NY Catskills ice climbing.
Do not gaffer tape directly to the zeppilin. Bring extra batteries for the wireless!!!!!!
The 672 is a great reliable mic, . My cam mic was a 672. No problemo-. 05 degrees w/ wind chill of -30.
Rick