Shooting outside with the internal mic in temps ranging from 18-30F, the camcorder intermittently flashed a warning that the external mic needed to be reconnected--but seemed to recording sound. Of course, there was no external mic. I deliberately left that at home because of the shooting environment. When I got home, I discovered all tracks had no sound at all, just some hiss. All of this, of course, was on tracks that are not replaceable.

Presumably some kind of switch/relay malfunctioned in the cold (cam works normally back here at home). Can't verify right now but it seems reasonable to fear that even with an external mic connected, the camera might not 'find' the mic... Can't be sure if this is specific to my unit, or yet another design/parts flaw. Given what I know about the NX70U's history thus far, I wouldn't bet that I have a uniquely defective unit.

Strictly speaking the temperature was below the spec. operating range, but shooters who buy a documentary-oriented weatherproof camera are probably expecting sound when they shoot outdoors in winter. At this point, I'm feeling really, really demoralized by this camera and it's many, many issues.

At least it's sharp in the center of the frame... :)

As a long term audio tech I'm going to venture that there was a problem with the mechanical external mic input (strictly a guess, without knowing the specific design of this camera). There are usually some small metal contacts in the input jacks that open when a plug is inserted - when there is no plug, those contacts close, connecting the internal circuitry/mics - it may be more complex than this, and there are also other audio I/O points on a typical Sony Cam - the AiShoe, the A/V jack at least that I know of... although I believe that those are electonically activated.

BUT since metal tends to contract when cold, I'd bet there's a couple metal contacts that "shrunk" just enough to open the circuit... an external mic MIGHT have worked fine, depending on WHERE in the circuit the break occurred. First suspect is the external mic 1/8" input... BUT, that's no guarantee without some experimentation - perhaps a bit of "fridge/freezer time" and experimentation with small hair dryer on low to troubleshoot?

You didn't have the audio block/handle on did you? If it's plugged in and nothing is plugged into the 1/8 jack the camera defaults to the XLRs for input, even if nothing is plugged in.

No handle attached. The 1/8 jack contracting is an interesting theory.

This is going to be a big issue for me if I can't get it fixed. I have to say, I'm very happy with the (silent) picture I got. So call me 50% delighted and 50% outraged, which seems to be the way this camera goes...

Well, if you're operating outside the specified temperature range... you're on our own - electronics have to be specially "hardened" if you want them to be "guaranteed" to operate in severe conditions, and then tested under those conditions... even so, they may fail when cycled through extremes.

Not too long ago, I had a Sony P&S camera that came to me non working - sent it in as it was still under Warranty - was one of those supposed to be ruggedized/shock/waterproof ones - no signs it had been damaged or mishandled, OR flooded - Sony said it had "water damage" and wouldn't repair it... hmmm. I don't know if the seals failed or what, but I was left unimpressed.

I guess what I'm getting at is that if you exceed the design parameters, or expect the equipment to, it won't happen...

If you're going to be using the camera much in very cold conditions, you'll have to figure out where the problem is, and probably figure out a way to insulate the camera just a bit in the appropriate area. Anytime one operates outside the engineering specs, one must be prepared to be creative!

I'll need to do some testing to see how extensive this problem actually is. As for operating beyond spec, I don't think many users will be pleased if the camera can't record sound below 32 degrees (if that proves to be the case)...

Well...I finally got the NX70U, all the right parts, and some cold weather together. The outcome was a big surprise -- maybe even some good news here.

First of all, in 28 degree F temps, I still get no sound using the internal mic. But, here's the weird part: pop the 1/8" mic jack cover open, and sound returns! I'm at a loss to explain that. Maybe I've got a defective camera. Could there possibly be something going on with the cover that impacts the switch (which is obviously getting confused in cold weather) between internal and 1/8" mic input?

Bad news: switching to an 1/8" mic gives sound, but terribly erratic, with channels clicking in and out. My odds of getting usable sound with an 1/8" mic in cold weather seem close to zero, unless you're monitoring the sound and jiggling the jack as needed to keep things working. Yuck!

Good news: XLR input seems completely unaffected by all of this. Sound with a good stereo mic and XLR inputs was pristine. No cold effects.

I'm tired of starting new threads, so here's an unrelated issue I discovered: when shooting in Active Image Stabilizer Mode, the white balance wanders. Go figure on why OIS should affect white balance. You can 'cure' this by choosing a manual or fixed white balance setting. Resisting urge to make snarky comment about Sony...