Capturing Environments with a Zoom H4
December 04, 2006

Throughout my years of being a sound designer, I have accumulated an extensive commercial sound effects library, which has served as an essential tool for creating new sounds. Having access to a large library of professional samples has broadened my capabilities, increased my productivity and served as an educational tool as well. I have done a good deal of recording for post production, but generally these recordings have been saved within project archives and I have never bothered to take the time to organize them into one database, which would be a monumental task at this point. After assembling my commercial library, I decided to focus on creating a personal one. But rather than using sounds that I have already included in past projects, I am starting a new library from scratch, carrying a portable stereo recorder with me on the road. I am also bringing a still camera around so that I can photograph the things I record. Keeping the images with the sounds is a good way to organize my recordings according to subject matter, geography and mood.

The sounds below are are encoded in Apple's Advanced Audio Compression format (AAC), which can be played on iTunes, or with Quicktime.

To launch this effort, I purchased the Zoom H4, which includes a pair of electret condenser microphones, and records at up to 24 bit 96 KHz resolution onto a 2 Gig SmartCard. My initial intention was to use this in tandem with a shotgun microphone, but before I purchased the shotgun, I wanted to experiment with the internal mics to see if they would be at all suitable for recording stereo environments and sound effects. If these microphones were incapable of professional results, I would have to purchase a stereo condenser in addition to the shotgun mic. Since this was a new product, there were no reviews extensive enough to tell me what the mics are capable of.

I took a long drive into the outskirts of Amherst MA in order to record a woodland stream. I had taken some video of this location many years earlier, a peaceful place with lots of water cascading down rocks, splitting off into small streams, and merging back into pools of still water. I figured that this location would offer me an endless assortment of gushes and trickles.

I had seen a lot of hunting trucks parked along the dirt roads on my way there, and since I was wearing black clothing I was a bit nervous about walking around in the woods. At very least I would get a good recording of being nailed by a man with a rifle! Here is a photo I took at the recording position described below (right).

The rain of the previous night had fueled up the stream so that it was in full force. I surveyed the area and found a good spot to record at the bottom of a ledge where the water was very active. I put my headphones on so that I could monitor the input. The water was thundering around a bend and I could hear a lot of high end detail as it splashed and sprayed onto the rocks. The sound changed as I aimed the recorder this way and that, targeting different movements within the stream. Bringing the microphones closer to the water, the stereo field often spread into exaggeration. Pulling it back out of the stream, and further into the woods gave the sound a more smooth airy character. Some parts of the stream were no more than faint trickles moving through the leaves and when I recorded these areas I could hear an occasional bird chirp. I found lots of sweet spots and hit record for sometimes twenty seconds or a few minutes, recording, searching, and recording again. There was literally an endless variety of steam sounds there and the H4 was a perfect tool for capturing them in stereo. Here is an example of some of the sounds I recorded:

Audio:

stream 1 | stream 2 | stream 3 | stream 4 | stream 5 | stream 6

It was growing dark, so I headed back up the long path to my car. Mid-way I could hear a eerie sound as the pine trees above me swayed and clacked in the wind. It was a quiet sound but I could hear it clearly on my headphones when the mic preamp was set to high gain. My microphone was beginning to rumble in the wind so I covered it up as best I could, sometimes shielding it with my body. During moments when the wind died down, I could hear a motorcycle roaring in the distance. Because of the motorcycle and wind problems, I was having trouble getting a recording of decent length. I thought I would have to piece it together in an audio editor but after about 45 minutes of sitting in the frigid darkness the motorcycle vanished. Unfortunately, in order to remove some of the rumbling, I had to cut the bottom end in. I am looking forward to getting a better wind cover for the H4 and when I do so I will return to this location on a windy day. Check out the "Wind in Pines" sample below.

An unsettling view from the microphone tip

Audio:

wind in pines

Eastworks

There is a very large Mill in Easthampton MA called Eastworks that is being renovated and turned into art studios, shops and studio apartments. It is absolutely enormous and much of it is still uninhabited but wide open for exploring. Many areas of the mill have deep droning sounds, presumably from pumps that are used to circulate the hot water heat. There are also some large stairwells with creaky boards and heavy antique doorways. The sounds at Eastworks could provide some good sci-fi/industrial SFX ingredients. There is quite a lot to record at this location and I have only just begun to explore the possibilities. The pump drones sounded best from one of the rear stairwells and this happened to be the one that provided the largest reverberation in the entire building, being 5 floors tall. My wife was with me so I asked her to go down a few floors and make some racket. She scratched a door with her nails, kicked some pipes, tapped a bottle against a rail, and slammed a metal door. The echos were very long, trailing off for almost 8 seconds. By making recordings on various floors, I was able to capture variations in the way the drone and echoing sounds resonated in the stairwell. At one point I was in the basement next to the pumps and heard two people talking a few floors up (stair drone 3). The voices were completely unintelligible and distant but the echo of conversation was very present. Some of these sounds are very subtle and unless you have decent speakers you may not hear everything that's going on.

Audio:

stair drone 1 | stair drone 2 | stair drone 3

The old iron latched doors in the stairways are slowly being replaced by modern ones. There are still a couple left in one quiet corner of the mill so I was able to get some decent recordings of them. The doors have a weight and chain mechanism attached in order to keep them shut. The sound of the chain moving gives the doors a mechanical effect, making them sound almost medevil, especially with the dungeon-like reverberation of the space. On "door 3", I dropped the sample rate from 96KHz to 44.1KHz, which makes the door sound enormous.

Audio:

door 1 | door 2 | door 3

I discovered a rusty old water fountain that oscillated when the handle was turned just enough to let the water trickle out. Hours of fun:

Audio:

fountain

Some of the older stairways are wooden, creaking and moaning as you make your way up and down. One thing I have been very unhappy with in commercial SFX cd's are footsteps. I believe that many of these sounds are made using a foley pit and therefore they often do not have much character. While the recordings below have a highly specialized character (they include ambient reflection and obstruction of a specific enviroment), they are immensely useful, especially for film sound design. Here are some examples:

Audio:

steps 1 | steps 2

Long, wide acoustic chambers for reverberations

City

I managed to find a decent spot in Northampton MA with a blend of moving cars, footsteps, voices, and horns. I got in as close as possible to the sidewalk so that I would get a wide stereo image of pedestrians walking from speaker to speaker. I wanted to get acceleration and deceleration of cars so I set up near an intersection. I was so close to the people on the sidewalk that their movement was causing air to hit my microphone and rumble. I put on the H4's supplied foam wind cover but it deadened the high end too much. I decided to record without it and edit out the bad parts later. The end result is a perfect small city ambiance which you can hear below.

Audio:

city

Night Trains

There is a railyard about 1.5 miles away from the field, on the opposite side of a large river and from my vantage point engines could be heard moving train cars around. The droning of the engines, combined with the wind, gave the recordings a slight industrial wasteland quality. Occasionaly a whisle would blow and echo about the river valley, a nice touch. There were a lot of leaves around my feet which rustled very lightly in response to the weather, and these sounds helped give the recording front detail and more firmly placed the environment into a natural setting. As time elapsed, the wind shifted directions, and new things were going on in the railyard. I was able to get a bit of variety over a couple of hours even without repositioning the microphones. Here is a small sampling of the recordings I made:

Audio:

wind and distant railyard 1
wind and distant railyard 2
wind and distant railyard 3
wind and distant railyard 4

On the following nights, I attempted to get some more recordings of trains, both from a distance and up close. The first night, which was almost completely windless, I could hear a train roaring out of the yard at full throttle. I was still a full 1.5 miles away from the train so it was pretty muffled. I boosted up the H4's preamps to high and the input level to full. The wind was so still that I was able to capture this sound clearly from another town, pretty amazing for an inexpensive handheld recorder! The recordings sound ominous and deep, unlike a train, maybe like a spaceship. Throughout the night I got several variations on these long distance engine drones.

railyard drone 1 | railyard drone 2

I noticed that the trains were most active at around 12:30PM, so the next night I headed out at midnight for a closer recording. I did notnactually have any spot in mind so I got in the car and impusively drove towards the droning. This lead me down a street with a large orange sign that said "bridge out, use detour". I followed this road about 200 feet until a concrete barrier blocked my path. When I opened up my door I heard a metalic screaching - creaking - popping sound coming from the other side of the barrier. One of the engines was pushing a long line of cars into the railyard. It was far enough away and moving so slowly that mostly all that could be heard was the stressing of the metal structures. Eventually it pushed the cars past me and disappeared into the night. Recordings of this can be heard below:

train push 1 | train push 2 | train push 3 | train push 4

I did not want to leave because I figured that I might as well wait for another train to come by, preferably at full throttle. I had to turn off the recorder to preserve the batteries. I sat in the darkness for a couple of hours, waiting...freezing. This was probably similar to what railfans experienced when they wanted to catch a photograph. Railfans have an established comradery and wave to each other and smile when trainspotting on a sunny afternoon. I thought of how creepy it would be if I saw another man on the other side of the tracks, smiling in the dark, waiting to record the train.

Without much warning I heard an engine coming down the tracks. One very unfortunate characteristic of the H4 is that it takes a long time to initialize before allowing one to record. By the time I got the H4 recording, the train was almost in view. I set the input level where I had it for the previous recording, a modest 64 to prevent saturation (127 is full). I watched the meters and the levels stayed about 6 decibels below unity. The train accelerated past me and as it did so the cars got louder and louder, thundering past in a quickening rhythm. It must have been a full mile long. To my dismay, when I played the recording back the engine had clipped. I discovered the preamps were set to high gain and they had saturated. Therefore, what you will hear in this recording is the train cars but not the engine. I have tried several times to catch the train at this location again but I've been unsuccessful. Freight trains do not seem to follow any predictable schedule.

train cars passing

A few days later I took a trip down to the woods behind the railyard. I studied the layout on googlemaps, and found a dirt road running right behind the yard, alongside the river. It runs under a bridge, so I was hoping to get a recording there and sneak about to hear what else was going on. There was a mist coming off of the river, completely enshrouding the area in a thick fog. The road down into the woods was long and bumpy, spooky looking trees were reaching up at the road in odd twisted angles, all around was a the deep thundering moan of the yard. I drove under the bridge and continued about a mile down, shut off the car and listened. It seemed like a great location to get a recording but there did not seem to be anything going on in the yard except for the continuous engine sound. Suddenly the sound deepened and began to move across the horizon. I thought it might be the train moving towards the bridge. I dived into the car and went to turn around but the road was so narrow that I nearly got stuck. I had to spin it back in the other direction and drive down few hundred feet to a spot where the road widened, giving me enough room to do a three point turn. I turned around and raced towards the bridge. I could see a 3000 horsepower GP-40 leaving the railyard but it was ahead of me. When I got to the bridge it had already passed over but there was a long line of cars behind it. I stopped the car about 50 feet away, shut it off and jumped out. The H4 was still recording so I just held it toward the train (train over bridge 1). The sound was incredible. I then moved almost underneath the bridge but kept the microphones horizontal to catch some of the resonance from underneath (train over bridge 2). Listen to that one and tell me you don't hear big huge monsters screaming. After about 30 seconds I decided to get right underneath the train (train over bridge 3). The sound was deafening so I turned the preamp down to minimum gain. The levels looked perfect.

train over bridge 1 | train over bridge 2 | train over bridge 3

I am now starting to record inside the railyard(see the photo above), which is more impressive than I even hoped. Hopefully I will not get caught or even worse...squashed!

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