Recording Natural Sounds

Inexpensive Natural Recording Alternatives

Sony ICD P520 Digital Recorder

Although we use a digital audio tape recorder and Sennheiser microphones for most of our natural sound recording, we've found some nice and fairly inexpensive alternatives. These inexpensive digital recorders allow you to record a bird or frog call, download it to your computer, and then display the sonogram with free software from Cornell.

The small Sony voice recorder at right does a great job of capturing natural sounds. While the sound quality is not as high quality as very expensive systems, it is still good. The latest model number is the Sony ICD-PX312, and it is available from http://www.amazon.com/. The price is around $50.00. I have experience using its predecessor, the Sony ICD-PX820, which had the following advantages:

Extremely compact

Has a USB port to allow you to transfer all recordings to your computer.

Has a time stamp to digitally imprint the date and time on all your recordings

Software CD included

Will run 28 hours on a single set of two AAA batteries - allows inexpensive remote recording for "froglogging."

Has a voice-activated recording feature

Has both low and high sensitivity microphone settings for the (very nice) built in microphone.

Can be used with or without a low-cost home-made parabolic microphone

Can be carried in a coat pocket - allows "quick draw" recording

The ICD-PX820 has a "high quality" mode with an extended frequency range, up to 20,000 hz. This makes it useful for insect recordings as well, something the earlier models did not do well.

The newer ICD-PX312 also has the high quality mode, and includes features that the former model does not. I have no experience with the newer model, but you can download the operating manual and specs for the ICD-PX312 here.

Software:

Cornell's Laboratory of Ornithology has a great free software program called Raven Lite. You can download it at: www.birds.cornell.edu/brp/raven/Raven.html. This program will allow you to see and analyze your recordings and create sonograms of natural sounds (see the image below). At the Raven page, select Raven Lite, then select Raven Lite 1.0 full download for your operating system. Click on "Get a Free License" to have your license number e-mailed to you. You must also download the latest version of Quicktime using the link provided. When you start up the program, if you have a problem loading mp3 files, feel free to contact us for the solution to the problem.

The recorder shown above and the home made parabolic microphone described below were used to make the recording shown in the sonogram below. The recording was made by pointing the parabola at a group of crows flying overhead. Click the sonogram to hear the calls of a Carolina Wren and the American Crows.

An Inexpensive Parabolic Microphone:

1. Parabolic Microphone Front View

2. Parabolic Microphone Back View

3. PVC Parts and Pipe Clamp

4. Handle Assembly View

5. Assembled Handle

6. Elbow and Male Adapter Showing Hole Location

7. PVC Parts and Handle Assembly View

8, PVC Parts and Handle Loosely Assembled

9. Microphone Parts Assembly View

10. Bar Stock Bending Templet

11. Bar Stock Bent and Painted

12. Microphone Holder

13. Assembled Microphone Holder on Parabola

This parabolic microphone plugs directly into the microphone jack of the Sony recorder shown above. It greatly enhances the performance of the recorder, particularly for bird sounds. The total cost of all materials is less than $100.00.

Note: The following project should not be attempted without adult supervision; it involves the use of an electric drill, a hacksaw, and a couple of types of glue. We cannot assume any liability for the misuse of these materials and tools or for accidents resulting from this project. So be careful! Be aware that the camouflage paint that covers the parabola is not just to make it blend in, but to dull the shiny reflective surface. Without the paint, it makes a pretty good solar oven, and your microphone, exactly at the focal point, could come out extra crispy if you point it towards the sun.

Materials:

18" Aluminum parabolic dish - Edmund Scientific Company:

Edmund Scientific Company 18" Parabolic Reflector

Price: $49.95

Olympus ME15 Electret Condenser Microphone - Amazon.com:

Amazon Olympus ME15 Microphone

Price: $22.99

Hardware:

From Home Depot, the following PVC pipe fittings (plumbing dept)

One each: (For detailed views of these parts, along with the part numbers, click here)

3/4" PVC Plug #449-007     $0.79
1"x3/4" Bushing #437-131     $0.64
1"x3/4" Reducing Male Adapter #436-102      $0.93
3/4" Coupling #429-007      $0.24
3/4" 90 Degree Elbow (One side inside threaded) #407-00      $0.67
1 piece 3/4" pipe (you may have to buy a whole 10' length)     $1.99

1 Can PVC pipe cement - About $4.94

Stainless steel pipe clamp 3/4" - 1-3/4" $1.15

From Home Depot, hardware dept:

3/16"x3/16" x36" long square steel bar (enough for 5 microphones) $2.65

From Home Depot, paint dept:

Loctite Epoxy Gel Glue - $3.99 (enough for several microphones)

Medium Sandpaper - (Varies 1 sheet will do) (enough for several microphones)

Rustoleum Camouflage paint - Green - $3.67 (enough for several microphones)

From Home Depot, Lumber dept:

3/4" round wooden dowel x 3' long - $2,59 (enough for several microphones)

From Walmart:

Schwinn Bicycle Handgrips, Item no SW501, about $5.00. (makes two handles)

From Lowes Plumbing dept:

Rubber "O" rings, Danko #47, 10 "O" rings per pack (enough for two parabolic microphones). $2.54

Total cost not including shipping cost: About $96.00 (As noted above, you can save money by building more than one parabolic microphone - this cost assumes that you don't use the extra parts (like the extra bicycle handle) for other microphones.

Tools Required: Drill, 3/8" bit, Hacksaw, Flat end screwdriver, vise, file

General Notes: These assembly instructions are suggestions only. We’ve made three of these parabolic microphones so far, and they all work well. However, there’s plenty of room for improvement. All that is really important in the design is that you mount the end of the microphone 4-1/2 inches above the center of the parabolic dish. If you have a better way of doing that, please feel free to experiment, and let us know how it turns out. This design emphasizes cheap materials, simple tools and is relatively easy to assemble.

Preparation:

Handle – See photos 4 & 5

3/4” Wooden Dowel – cut to a length where about 3/4" of the dowel projects from the inside of the handle when the dowel is fully inserted into the handle.

¾’ PVC Pipe – Cut to ¾” length

90 Degree Elbow – See photo 6

Center punch 90 El at spot shown (roughly the center of the outside curve – the position is not critical.

Drill with 1/8” drill bit

Enlarge hole with 11/32” or 3/8” drill bit (best done while clamped in vise – go slowly – the 3/8” bit will want to “grab” the soft PVC material)

Male adapter – See photo 6

Center punch at spot shown, approximately 5/16" from the edge of the flange.

Drill with 1/8” drill bit

Enlarge hole with 3/8” drill bit (best done while clamped in vise – go slowly – the 3/8” bit will want to “grab” the soft PVC material)

3/16 x 3/16 steel bar – See photos 9, 10 and 11

Cut to 6-1/2” length

Bend to match template (use vise for best results)

Olympus microphone holder – See photo 12 (shows holder after final bend has been made)

Hacksaw off at end of flat piece, file smooth

Coupling – You will use the coupling to make a small 1/4" long spacer that goes between the 90 Degree Elbow and the Parabolic Dish. It allows you to tighten the assembly. See the PVC parts page for an image of the coupling.

Hacksaw off a ¼” inch long ring – this will be a spacer.

Sand smooth and flat

Paint the small parts:

Mask the inside of the 90 degree elbow and male adapter, and the outside of the ¾ plug and reducer, and paint these plus the spacer.

Paint microphone holder and 3/16x3/16 bar stock

Assembly:

To get an idea of how the various parts go together look at photos 7,8,9 and 13

Apply epoxy gel thinly to outside of wooden dowel below the tape. Slowly twist and push it into the Schwinn bicycle handle grip. Use a paper towel to wipe of extra glue. Apply epoxy gel to the part of the dowel projecting from the handle, and then twist and push the ¾” long piece of PVC pipe over the end of the dowel. Wipe off extra epoxy with paper towel. Set aside to dry for 8 hours. See photos 4 & 5.
After the above assembly has dried for 8 hours, dab a little pipe cement on the outside of the PVC pipe and insert the ¾ “ pipe end into the 90 degree elbow. Wipe off any excess cement with a paper towel. See Photo 8.
Dab a bit of pipe cement on the outside of the ¾” plug and then push it into the reducing bushing as far as it will go. Wipe off any extra pipe cement with a paper towel. Set aside.
Remove the microphone from the microphone holder and insert the microphone plug through the 3/8” hole in the male adaptor.
Run the microphone plug and cord through the small end of the male adaptor, through the hole in the parabola, through the ¼ “ long PVC spacer, into the threaded end of the 90 degree elbow and out of the hole in the 90 degree elbow. The excess cord will store in the handle assembly.
Now thread the 90 degree elbow onto the threads of the male adaptor – carefully tighten to make sure you are not crimping the microphone cord. Tighten the elbow by grasping it and not the handle. Tighten in this way as much as you can. Do not use the handle to apply leverage.
Dab a bit of pipe cement onto the outside end of the reducing bushing and push it into the male adaptor, making sure you don’t push it in far enough to block the 3/8” hole. Refer to photos 7 & 8.
The next step is to use the pipe clamp to attach the 3/16” bar stock to the male adapter. Before you do, hold the 3/16” bar stock up against the male adapter and “eyeball” the position of the end of the bar. The end should be just a little short of being over the center of the parabola, so that when the microphone holder is in place the microphone is over the center of the parabola exactly 4-1/2" above the parabola, and pointing straight down at the center of the parabola. You may need to change the bends in the bar stock slightly. See photos 12 & 13
Now you are ready to mount the microphone. The front of the microphone should be positioned so that it is 4-1/2” above the center of the parabola. See where you will need to place a 90+ degree bend in the microphone holder to get the correct placement – see photo. Mark the underside of the microphone holder with a pencil mark where the bend will need to be. Bend and adjust the microphone holder to get the correct position. See photos 12 & 13
With the microphone out of the microphone holder, slip the 4 O rings over the end of the microphone and cord, then over the end of the bar stock. Position two of the O rings to hold the microphone cord to the bar stock. Use the other two O rings to hold the microphone holder to the bar stock. See photo 13.
Check to see if the microphone head is 4-1/2 inches above the center of the parabola. If not, loosen the pipe clamp and slide the bar stock towards or away from the parabola until you get 4-1/2 inches. Check again to make sure the microphone is vertically positioned over the parabola. If necessary, adjust the bend in the microphone holder.
Place masking tape over the microphone head and the handle and then paint the inside and outside of the parabola with camouflage green paint.
The microphone cord may be stored in the handle when you’re not using the microphone. To use, simply plug the 1/8” microphone plug into the microphone jack on the recorder. You'll probably find that the hardest part of recording is finding places to record that don't have a lot of background noise.
When using the parabola with the Sony recorder keep in mind that louder sounds may exceed the recorders ability to reproduce them accurately (they may clip). It's always a good idea after you get a recording with the parabola to unplug the parabola and record just with the high-sensitivity built-in microphone. You can also try using the low microphone sensitivity setting with and without the parabola.

Using the ICD P620 Sony Recorder:

Refer to the instruction manual that comes with your recorder for the correct buttons to push while recording. It's quite simple to use. If you make a parabola, it will plug into the red microphone jack on the top of the recorder. The recorder will come with a CD that will install the Digital Voice Editor software required to transfer sound files to your computer. Just insert the CD and follow the instructions.

The recorder comes with a cable to connect it to your computer. After you finish your field recording, Open up the Digital Voice Editor software on your computer and use the supplied cable to connect the recorder to one of your USB ports. The computer software will automatically detect your recorder and open up your sound files on your computer. In the software, turn on the Autosave option. You can listen to each sound file, and then save the ones you want to keep. To save each file as a WAV file (recommended), right click on the file and choose "save as", then choose "44.1 kHz 16 bit Stereo (*.wav)" or "16.1 kHz 16 bit mono (*.wav) . This will give you the highest quality sound file. Save the file in a folder on your computer. Remember that in the Digital Voice Editor software, all the files shown on the left-hand side of the screen show what files are on your recorder. If you delete them, they're gone forever, unless you've already saved them into a folder on your computer. Once you've saved your files, you can open up Raven Light to view the sonograms.

Minidisc Recorders:

The low cost of the Sony voice recorders make them a very inexpensive way to get into recording, and I always try to carry one of these small recorders in the field. However, they have their limitations, and the frequency response goes to around 16,000 Hz at the high-quality setting. If you find yourself doing much recording that requires sensitivity at higher frequencies (some insect sounds, for instance), or simply want a higher quality recording, you might want to invest in a mini-disc recorder and microphone. Recommended are the Sony MZ-M200 HiMD MiniDisc Recorder ($365.00) and Sony ECMMS907 Microphone ($68.97). You will also need to buy a few of the Hi-MD minidiscs ($6.00). Though not quite as easy to use as the Sony voice recorders, these little recorders to a wonderful job. One of the older models is shown with the Sony ECMMS907 microphone in the image below.

Recording with Cell Phones:

You may already own a high-tech recording device. Some cell phones and Blackberrys have imaging and recording capability built into them. Recently, one of our TAMP (Tennessee Amphibian Monitoring Program) volunteers used a cell phone to photograph an Eastern Spadefoot on a TAMP route. The photographic documentation was approved as a new county record for that species. Recordings were also submitted by cell phone. Cell phones vary widely in how these recording features are accessed, but you can try going to the "media" menu and looking for a recording or voice recording feature.

You can even use the parabola described above with your cell phone. Many of the newer cell phones come with a headset. You can simply use a couple of rubber bands to bind up the earphone pieces and attach the microphone piece at the focus of the parabola. Plug the other end of the headset cord into your phone and you're ready to go!

When you are finished recording, send yourself an e-mail with the recording attached. You can then open the e-mail and save the attached recording into your computer hard drive. Recordings made with my cell phone are saved as a .amr file. Happily, the Raven Lite software described above will open these files. You can do any sound editing in Raven Lite that you like (including sonograms) and then you can resave them as .wav files.

Some Helpful Links:

Overview of Sound Recording Theory:

A good basic review is found in the User Guide for the Raven Lite 1.0 software. Select “Help” and then select “User Guide”.

Cornell Laboratory of Ornithology – A great resource for information about anything concerning birds.

http://www.birds.cornell.edu/

Macaulay Library of Natural Sounds (Cornell) – The Macaulay Library of Natural Sounds is part of the Cornell Laboratory of Ornithology. See also the link below for specialized help on equipment.

http://www.birds.cornell.edu/macaulaylibrary/

Recording Equipment:

http://www.birds.cornell.edu/macaulaylibrary/Contribute/equipmentOverview.html

Field Techniques:

http://www.birds.cornell.edu/macaulaylibrary/Contribute/fieldtechniques.html

Software:

Raven Lite:

http://www.birds.cornell.edu/brp/raven/Raven.html

Sound Forge:

http://www.sonycreativesoftware.com/soundforge

Sound Cards:

M-Audio Delta 66 - http://www.m-audio.com