Last Saturday a huge thunderstorm moved in over Copenhagen causing flooded streets, blackouts and demolished cell towers as 150mm of rain fell within a few hours. That amount of rainfall is extreme here as it usually takes a period of three months to get up to 150mm. On this side of the strait we could hear some of the thunder rolling in, so after getting home from work I placed my mics on the balcony and recorded for about half an hour. Here are some extracts.
Geek note: 2 x Røde NT1-A’s (ORTF, 17 cms spacing, 110 degrees) -> Sound Devices 702
As you can hear there are some rattling sounds to be heard during the loudest thunderclaps, I’m not sure if this is the product of the NT1-A’s being overloaded or if it’s something rattling on the balcony. Do any of you with experience of recording with large-diaphragm microphones know if it might be an issue using these mics while recording loud noises containing low frequencys? Would I be better off using for example a pair of AT-4041?
I thought so, you have record this crazy weather when I hear the news from Copenhagen. Malmö is not far away 🙂
Thunder storms are not usual in Iceland so I think I will be just lucky if I can record one thunder in my life in Iceland.
About the rattling sound. I think it is preamp overload, not NT1a. They can withstand 137dB. But even I think SD702 have nice preamp, thunders can be too much if the rec-volume is adjusted a bit to high.
Yes, overloading the 702’s preamps was about the first thing I did, thereby missing one of the louder claps. So I turned down the gain to about 10 o’clock and after that the levels never went above -10 dBFS (I amplified the signal somewhat in post). Hopefully it was just something rattling at or close to the balcony.
I actually tried to record a fan down in my laundry room with one of my NT1’s some months ago and no matter how low I turned the gain-knob on the D50 it still distorted. I can’t help but wonder if the result would have been better in that case with a small-diaphragm mic?
The NT1a can handle thunderstorm recordings ok., I use one of these with the equally large diaphragm NT2a http://audiofieldrecordings.wordpress.com/2010/07/27/field-recording-thunderstorms/
For some reason the recording sounds a bit strange as if it’s only picking up high sound levels, perhaps there’s too little gain, however it could just be due to the recording location, hence the rattles.
As you may know these large diaphragm microphones will pick up a lot of the low frequency signals and it all adds to overloading the preamps, so the trick is to use low frequency cut on the SD702 (as the NT1a doesn’t have a selector switch, but NT2a does) to reduce the input level, this will then enable the use of more gain on the 702. Don’t overdo the low frequency cut as you will lose the rumbling sounds, but use just enough to reduce the input signal. Also make use of the 702 limiter to prevent clipping on the unexpected loud lightning strikes. Recording thunderstorms is quite difficult to achieve – you have to strike a fine line between capturing the subtle ambience present during the quiet periods and having everything set just right for those unexpected and sometimes ear-shattering close lightning strikes.
Try experimenting with the low frequency cut on your laundry room fan – you will see how big a difference it makes to your 702 gain level settings.
Best of luck!
Thank you for your valuable comment!
I will experiment with the low-cut filter and our laundry fan.
The location of the recording was probably the main reason to the somewhat “tinny” sound. Our balcony, where the recording took place, was actually facing away from the thunderstorm. This made the house into a huge sound barrier placed between the microphones and the thunderstorm.
I was hoping for some thunder while being away on vacation, but the sun was shining most of the time, which wasn’t all that bad neither. Hopefully we’ll get some storms moving in during the upcoming weeks.